However, injection molding can also be used to make flexible moldings: parts that are soft, pliable, shock-absorbing, ductile, or elastic. Products like hand grips, gaskets, protective smartphone covers, and certain medical implants all require a rubber-like material in order to perform their function, and injection molding offers two standout material options for making such products.

The first of these materials is liquid silicone rubber (LSR), a thermoset that requires its own special variant of the injection molding process. The other is a group of thermoplastics known as thermoplastic elastomers (TPEs), which can be processed like common rigid thermoplastics but which offer rubber-like properties.

This article examines the LSR vs TPE injection molding discussion, comparing material properties, advantages and disadvantages, and suitable applications.

What is liquid silicone rubber (LSR)?

Liquid silicone rubber is a high-purity form of cured silicone. It is a chemically inert thermoset with material characteristics such as biocompatibility, chemical resistance, water resistance, excellent compression set, flame retardancy, and heat resistance up to 250 °C.

Injection molding LSR requires a special process generally known as liquid silicone rubber molding. Unlike a standard injection molding machine, the equipment comprises a metered pumping device for dispensing the two liquid materials (catalyst and base forming silicone) and a mixer for combining the materials before they enter the mold. The mold cavity is heated, allowing vulcanization of the silicone to take place within the cavity.

What are thermoplastic elastomers (TPEs)?

Thermoplastic elastomers or thermoplastic rubbers are a class of thermoplastics exhibiting both thermoplastic and elastomeric material properties. Because they are thermoplastics, they are easier to manufacture than other rubber-like materials, being highly suited to injection molding and extrusion-style 3D printing.

TPEs have good thermal properties, good stability, and require minimal energy to manufacture. They can also be easily recycled, as TPE parts can be melted down without burning.

Some of the most common types of TPEs are:

• Thermoplastic polyurethanes (TPU): good clarity, good wear resistance, range of hardnesses
• Thermoplastics vulcanizates (TPV): matte finish, high compression set
• Styrenic block copolymers (TPS): highest level of flexibility among TPEs
• Polyolefin blends (TPO): tough, good impact strength
• Thermoplastic copolyesters (TPC): good tear strength, impact strength
• Thermoplastic polyamides (TPA): high temperature resistance, low compression set

LSR injection molding vs TPE injection molding

Both liquid silicone rubber and thermoplastic elastomers have their own unique advantages as injection molding materials. In short, LSR offers superior elastomeric performance in addition to chemical advantages, while TPE is easier and more convenient to process.

LSR injection molding applications

Although the liquid silicone molding process requires specialist equipment and requires longer molding cycles than thermoplastic injection molding, the unique benefits of LSR — such as its exceptional compression set — give it a number of important applications, from healthcare to industry.

Some injection molded silicone part examples include:

• Silicone medical implants such as orthopedics, cardiovascular stents, pacemakers, lenses, and soft tissue implants
• Medical devices such as surgical instruments and drug delivery devices
• Headphone and hearing aid tips
• Baby bottle tips
• Shower heads
• Electronic device components such as keyboard interfaces
• Electronic device protective covers and skins
• Watertight gaskets
• Heat-resistant and UV-resistant automotive components such as O-rings, bellows, and stoppers

TPE injection molding applications

Injection molding thermoplastic elastomers requires the same equipment and process as standard thermoplastics, making fabrication of TPE moldings fast, affordable, and simple. The material also offers important material properties, which can vary greatly depending on the type of TPE chosen.

Some injection molded thermoplastic elastomer part examples include:

• Soft-touch grips for handheld tools and devices (sometimes via overmolding)
• Certain food products such as bottle cap liners
• Electronic device components such as enclosures
• Electronic device protective covers and skins
• Shoe soles
• SCUBA flippers
• Wheels for skates and skateboards
• Sealing rings
• Automotive components such as suspension bushings

Design considerations

Although both LSR and TPEs can be injection molded, different design rules apply to the two materials.

Overall, LSR offers greater design freedom than thermoplastics like TPEs, mostly due to its extreme flexibility. Because silicone moldings are highly pliable, part ejection is simple: the soft part can usually be removed manually from the cavity without the use of ejector pins. Protruding undercuts are generally no problem either, as these sections can be squashed or bent around the corner of the mold.

Furthermore, because liquid silicone flows easily, product designers can be more liberal with uneven wall thicknesses — features that would potentially cause filling or warping issues with thermoplastics like TPEs. However, one advantage of TPEs over silicone is that the higher viscosity of the thermoplastic makes it less likely to leak out at the parting line and cause flash. Silicone molds require effective sealing and clamping to prevent flash.

3ERP offers a range of injection molding services, including plastic injection molding, silicone injection molding, and metal injection molding. Request a free quote for your next batch of flexible molded parts.

The post Flexible injection moldings: LSR vs TPE appeared first on Rapid Prototyping & Low Volume Production.

This comprehensive guide will explore the nuances of machining centers, their functions, types, components, and much more, providing you with in-depth knowledge about this essential tool in the manufacturing process.

What is a Machining Center?

A machining center (MC) is an advanced computer-controlled machine tool that can be used for performing a variety of machining operations and processes. Unlike traditional machines that feature turrets or other mechanisms of manual tool change, an MC consists of an automatic tool-changing mechanism (ATC), allowing for multiple cutting tools to be utilized during the machining process.

This enables quick changes of the cutting tool, thus improving production efficiency and reducing cycle time. The core of an MC lies in its versatility, accuracy, and ability to handle complex operations like milling, boring, drilling, and more.

Who Invented the First Machining Center?

The emergence of the machining center dates back to the early 1950s when John T. Parsons and Frank L. Stulen collaborated to develop the first numerically controlled milling machine. The idea was further refined by the MIT Servomechanisms Laboratory, laying the foundation for the CNC machining centers that we know today. The invention revolutionized the manufacturing industry, paving the way for automation, precision, and flexibility in metalworking processes.

What are the main components of a machining center?

A machining center comprises numerous intricate components, each serving a specific function in the overall process. We’ll delve into the technical descriptions and functions of these critical components.

Main Spindle Area

The main spindle area is responsible for holding the cutting tools and providing the necessary rotation for machining operations. It houses the motor drives and spindle head, contributing to the accuracy and efficiency of the process. The spindle area plays a pivotal role in achieving desired surface finishes and precision in workpieces.

Taper Feed Mechanism

The taper feed mechanism is an essential part of the machining center that allows for the precise positioning and movement of the cutting tools. It controls the depth and orientation of the tools, ensuring smooth and accurate cuts. This mechanism works in coordination with the servo motor, making it a crucial component in determining the quality of the finished product.

Automatic Tool Changer (ATC) System

The automatic tool changer (ATC) system is a groundbreaking feature in machining centers. It provides quick and efficient tool changes, reducing manual intervention and cycle time. The ATC system includes a tool magazine where different cutting tools are stored, enabling the machine to switch between tools seamlessly. This enhances production efficiency and offers versatility in machining operations.

Tool Magazine

The tool magazine is an integral part of the ATC system. It stores various cutting tools such as end mills, drills, and more, providing a central repository for the tools needed in the machining process. The tool magazine ensures that the correct tool is selected and placed in the spindle, facilitating quick changes and continuous operations.

Automatic Pallet Changer (APC) System

Designed to increase throughput and minimize downtime, the automatic pallet changer (APC) system automates the loading and unloading of workpieces. The APC system consists of multiple pallets that can be preloaded with raw material, allowing for uninterrupted machining. This automation significantly enhances production efficiency, reducing manual handling and errors.

Chip and Coolant Handling System

Machining processes generate chips and require cooling to maintain tool life and part quality. The chip and coolant handling system manages these aspects, collecting chips through chip conveyors and providing the necessary coolant to the cutting area. This system ensures a clean and efficient working environment, contributing to the machine’s longevity and performance.

Overload and Wear Detectors

Machining centers are equipped with overload protection devices and wear detectors to monitor tool wear and machine performance. These sensors detect abnormal conditions, such as tool breakage or excessive load, and provide alerts to prevent potential damage. These features add a layer of safety and reliability, ensuring consistent quality and minimizing unplanned downtime.

Automatic Door Operation Mechanism

Modern machining centers often include an automatic door operation mechanism that provides easy access to the work area. This feature adds convenience and safety, allowing operators to load and unload workpieces effortlessly, without the need to manually open and close heavy doors.

What are the main axes of a machining center?

Machining centers function on various axes to control the movement of the cutting tool and the workpiece. The coordination of these axes ensures precise cuts and intricate designs. Here’s a breakdown of the main axes and their purposes:

• X-Axis: Controls the left and right movement of the tool or worktable.
• Y-Axis: Governs the forward and backward movement of the tool or worktable.
• Z-Axis: Manages the up and down movement of the tool or worktable.
• A-Axis: Controls the rotation around the X-axis.
• B-Axis: Handles the rotation around the Y-axis.
• C-Axis: Responsible for the rotation around the Z-axis.

Together, these axes provide complete control over the position, orientation, and movement of the cutting tool, allowing for complex and precise machining processes.

What are the Different Types of Machining Centers?

The versatility of machining centers lies in their variety of types, each tailored to specific needs and applications. Below, we explore the main types:

Horizontal Machining Center (HMC)

A horizontal machining center (HMC) is defined by its horizontal orientation of the spindle. With powerful rigidity and robust construction, these machines are tailored for handling hefty workpieces.

An HMC typically comprises an automatic pallet changer (APC) system with six to eight pallets, which allows continuous work on different pieces without manual intervention.

Designed for large-scale production, HMCs are known for high material removal rates (MRR). Their horizontal setup allows for efficient machining of up to 4 surfaces without reorienting the workpiece.

The metal chips fall away from the workpiece, preventing accumulation and enhancing the suitability for operations like boring.

Some HMC models even feature a spindle that can rotate to a vertical position, falling under the universal machining center category.

Commonly used in the manufacturing of components like automotive parts and gears, brands like Mazak produce HMCs known for their reliability and performance.

Vertical Machining Center (VMC)

A vertical machining center (VMC) is characterized by a vertically aligned spindle, offering accessibility and adaptability.

These centers typically include ATC and APC systems but with a more compact design, making them suitable for smaller spaces or individual users.

The vertical alignment of the spindle means that metal chips can accumulate on the surface of the workpiece and need to be cleared.

With options ranging from 3-axis to 4-axis models, VMCs can access workpieces from various angles without manual adjustment.

Brands like Haas offer VMCs that are utilized for a wide range of applications, including engraving, mold processing, and milling diverse materials.

Universal Machine Center (UMC)

A universal machining center (UMC) stands out for its capability to orient the spindle both horizontally and vertically.

Often encompassing 5-axis systems or higher, UMCs can access a workpiece from multiple sides in one setup, allowing intricate machining processes.

A 5-axis UMC, for example, moves the cutting tool along X, Y, and Z linear axes while rotating on the A and B axes. This results in exceptional precision when crafting components like aerospace parts or complex molds.

Using shorter cutting tools with extensive speed ranges, UMCs minimize vibration and boost production efficiency, all while reducing cycle times.

A fusion of the features of HMCs and VMCs, UMCs represent an adaptable solution for many industries. Brands like DMG MORI are renowned for their state-of-the-art UMC models.

What are the typical operations performed on a machining center?

Machining centers are designed to perform a range of operations, contributing to their widespread application. Here’s a list of typical operations:

• Milling: Milling involves removing material to shape the workpiece using rotary cutters. It can be used to produce a wide variety of complex shapes and features, such as slots, pockets, and even complex surface contours, making it one of the most versatile machining operations.
• Drilling: Drilling is the process of creating holes in the workpiece. It is performed using a rotating cutting tool, usually a drill bit, that moves along the axis of the hole. Drill bits come in various sizes and types, allowing for a range of hole diameters and depths.
• Boring: Boring is used to enlarge existing holes with high precision. Unlike drilling, which creates a hole, boring fine-tunes the diameter to precise tolerances. Boring can also be used to correct any misalignment in the hole, ensuring that it is perfectly cylindrical.
• Tapping: Tapping involves cutting threads inside a hole, providing a path for screws or other threaded objects. The process uses a specialized tool known as a tap that’s threaded in a manner corresponding to the desired thread pattern. It’s essential for applications requiring the secure fastening of components.
• Grinding: Grinding achieves fine surface finishes through the use of an abrasive wheel. Unlike milling or turning, grinding removes material very slowly in small amounts, allowing for extremely precise control of the surface’s shape and finish. It’s often used to finish parts that require smooth surfaces or tight tolerances.
• Reaming: Reaming fine-tunes the size of drilled holes, offering a higher degree of accuracy than drilling alone. A reamer, which is a specialized tool with cutting edges, is used to slightly enlarge the hole and improve its finish and alignment. Reaming ensures that the holes are of the exact size and perfectly round.

By utilizing a combination of these operations, machining centers can produce intricate parts with high accuracy and efficiency.

What are the applications of machining centers?

Machining centers find applications in various industries and manufacturing processes. Some of the key applications include:

Automotive Industry

In the automotive sector, machining centers are essential for producing a wide array of parts, including engine components, gearboxes, chassis, brake systems, and frames. They enable the efficient fabrication of intricate parts, contributing to advancements in fuel efficiency, performance, and safety.

Aerospace Industry

The aerospace industry relies heavily on machining centers for crafting complex, high-precision parts. These include turbine blades, fuselage components, landing gear, and avionic enclosures. The utilization of advanced machining technologies ensures adherence to stringent quality standards and regulations in this safety-critical field.

Medical Industry

Machining centers in the medical industry are vital for manufacturing various devices and equipment. From surgical instruments to prosthetics and implants, the high precision offered by these centers ensures patient safety and effectiveness in medical treatments.

Oil and Gas Industry

The oil and gas sector employs machining centers for creating diverse components essential for exploration, drilling, and production activities. This includes the fabrication of valve bodies, drilling tools, pump parts, and riser systems, all designed to withstand extreme environmental conditions.

Electronics Industry

Machining centers play a crucial role in the electronics industry for the fabrication of parts used in electronic devices. This involves the precision crafting of connectors, housings, heat sinks, and semiconductor components. These parts are fundamental to various products such as smartphones, computers, and other consumer electronics.

Marine Industry

In the marine industry, machining centers are utilized to produce components for ships, submarines, and offshore platforms. This includes propellers, engine parts, hydraulic systems, and structural elements. The robustness and accuracy of machining centers ensure the durability and performance of marine vessels.

Energy Industry

The energy sector leverages machining centers in the manufacturing of components for renewable energy systems and traditional power plants. Wind turbine blades, solar panel frames, hydroelectric turbine components, and nuclear reactor parts are examples of applications that demand precision machining.

Construction Industry

Machining centers are employed in the construction industry to manufacture heavy equipment components and structural elements. This involves the creation of gears, joints, bearings, and other parts essential for machinery such as cranes, excavators, and bulldozers.

Their ability to handle a multitude of operations and materials makes them indispensable in modern manufacturing.

How much does a Machining Center Cost?

The cost of a machining center varies based on size, rigidity, speed, functionality, brand, and accessories. Here’s a general price range for different types:

• Horizontal Machining Center: $150,000 – $600,000
• Vertical Machining Center: $50,000 – $200,000
• Universal Machine Center: $200,000 – $700,000
• 5-Axis Milling Centers: $200,000 – $1,000,000
• CNC Turning Centers: $60,000 – $350,000
• CNC Router Machines: $4,000 – $50,000
• EDM Machines: $30,000 – $200,000
• Swiss-Type CNC Lathes: $100,000 – $300,000
• Waterjet Cutting Machines: $50,000 – $300,000

These prices can fluctuate based on specific needs and customizations, and it is advisable to consult with manufacturers or suppliers for an accurate quote.

How is a machining center programmed and controlled?

A machine center, or CNC machine center, operates through a combination of software programming and control systems. Here’s an overview:

1. CAD/CAM Integration: Designers use Computer-Aided Design (CAD) to create the part’s geometry. Computer-Aided Manufacturing (CAM) software then translates this design into a CNC program.
2. G-Code Generation: The CNC program consists of G-code, a series of commands that the machine understands. It includes instructions for movement, speed, tool change, and other factors.
3. Control Panel: Operators input the G-code into the machine’s control panel. Modern machining centers often feature user-friendly interfaces for easier control.
4. Servo Motors and Drives: These components translate the G-code into mechanical movements, ensuring precise control over the axes.
5. Feedback Systems: Sensors and feedback mechanisms continuously monitor the machining process, making real-time adjustments to maintain accuracy.

This combination of technology and engineering ensures that machining centers can produce parts with high precision and repeatability.

What are the common problems and defects in machining centers?

Like all complex machinery, machining centers can encounter problems. Some common issues include:

• Tool Wear and Breakage: This can occur due to incorrect tool selection or settings.
• Vibration and Chatter: Often caused by misalignment or imbalance in the machine.
• Coolant Issues: Problems with the coolant handling system can lead to overheating.
• Accuracy Loss: Can be due to worn-out ball screws, bearings, or other components.
• Software and Control Errors: These may stem from incorrect programming or system failures.

Regular maintenance and adherence to operating guidelines can mitigate these problems.

What is the difference between machine and machining center?

The term “machine” generally refers to any equipment that performs work, while a “machining center” is a specific type of CNC machine tool designed to perform multiple machining operations.

While a standard machine tool might only perform one type of operation (e.g., milling), a machining center (CNC machining center) integrates various functions like milling, drilling, and tapping, all in one system. The inclusion of features like automatic tool changers and pallet changers differentiates machining centers from traditional machine tools.

Conclusion

Machining centers represent the convergence of technology, design, and manufacturing. By integrating multiple operations, these advanced CNC machines offer unparalleled efficiency, precision, and flexibility.

From automotive to aerospace, machining centers are transforming industries by facilitating the production of complex parts and assemblies.

Whether it’s the speed of a Vertical Machining Center or the rigidity of a Horizontal Machining Center, the choice depends on the specific requirements of the task.

As technology continues to advance, machining centers will likely play an even more significant role in shaping the future of manufacturing, emphasizing the need for skilled operators and continuous innovation.

The post What is a Machining Center: Definition, Types, Components & Applications appeared first on Rapid Prototyping & Low Volume Production.

What is M-code?

M-code, also known as miscellaneous code, is an essential aspect of CNC machining, working in tandem with G-codes. While G-code directs the geometric movements of the machine, M-code is responsible for instructing the machine’s various non-movement functions.

Specifically, M-code handles instructions related to machine operations such as turning the spindle on or off, coolant control, tool change, and program stops. In essence, M-code serves as the backbone of the manufacturing process, allowing the CNC machine to perform precise actions beyond simple movements.

Who Invented M-code Programming?

M-code programming has roots in the mid-20th century, at a time when the transition from manual to automated manufacturing was gaining momentum.

The invention of M-code is often attributed to John T. Parsons and Frank L. Stulen, pioneering engineers who developed numerical control concepts. With the collaboration of the Massachusetts Institute of Technology (MIT) and funding from the U.S. Air Force, the first CNC machines utilizing M-code and G-code were developed.

This innovation was instrumental in transforming the manufacturing industry, enabling unprecedented precision and efficiency in production.

What is the Importance of M-code?

Understanding the importance of M-code requires a deep dive into its functions and impact on the manufacturing process. Here’s a detailed look at why M-code is vital:

• Optimization of CNC Operations: M-code streamlines the machining process by providing specific instructions for various machine functions. These codes enable the automation of actions like tool change and coolant control, thus reducing human intervention and errors.
• Enhanced Flexibility: With M-code, CNC machines can perform a wide array of tasks. Whether it’s stopping the spindle (M05) or activating coolant (M08), the versatility of M-code allows for a broad spectrum of applications in manufacturing.
• Integration with G-code: M-code doesn’t work in isolation; it complements G-code, the instructions that govern geometric movements. Together, G-code and M-code create a comprehensive programming language that covers all aspects of CNC machining, from positioning to specific actions.

How Does a M-code Work?

To grasp how M-code works, one must understand its integration with CNC programming and the specific tasks it governs. Essentially, M-code is a set of commands that control machine functions not related to movements.

For example, the command M03 activates the spindle to rotate clockwise, while M04 commands it to rotate counterclockwise. These codes are written in CNC programming language and interpreted by the CNC machine through its control system.

• M-code Programming: M-code programming involves using specific codes to instruct the machine’s actions. These codes are written in a specific sequence and format, following the requirements of the particular CNC machine being used.
• Execution and Control: Once the M-code is programmed, the CNC machine reads and implements the instructions. The machine’s controllers interpret the codes and execute the corresponding actions, ensuring accuracy and consistency in operations.

What is the Structure of a M-code?

M-code structure is relatively straightforward, comprising a letter “M” followed by a numerical value. The combination of the letter and number represents a specific command or instruction for the CNC machine.

For example:

• M00: Program stop
• M03: Spindle on clockwise
• M06: Tool change

Each code corresponds to a distinct action, allowing the CNC machine to perform a wide range of functions necessary for the machining process.

What are the Different Types of M-codes?

Understanding the types of M-codes means exploring the specific functions each code governs. Here’s a closer look at some prominent M-codes:

M00 Program stop

The M00 code signifies a program stop, halting all machine operations. It provides an opportunity for the operator to intervene, make adjustments, or inspect the workpiece.

M01 Optional program stop

M01 represents an optional program stop. Similar to M00, it provides a pause in operations but can be bypassed depending on the machine’s settings or operator’s preferences.

M02

M02 denotes the end of the program, signaling the completion of the machining process.

M03 Spindle on clockwise

This code activates the spindle to rotate in a clockwise direction, essential for various cutting and milling operations.

M04 Spindle on counterclockwise

Conversely, M04 commands the spindle to rotate counterclockwise, allowing for different machining tasks.

M05 Spindle off

M05 instructs the spindle to stop, a crucial command for safety and transitioning between operations.

M06 Tool change

The M06 code automates the tool change process, allowing for seamless transitions between different machining functions.

M08 Coolant on

Activating the coolant system is essential for temperature control and material handling, achieved through the M08 command.

M09 Coolant off

The M09 code signals the CNC machine to turn off the coolant system, often used at the end of a specific process or when the coolant is no longer needed.

M30 Program end, return to start

M30 marks the end of the program and returns the machine to its starting point. This sets up the machine for the next job or inspection.

Other M-codes

M-codes encompass various other commands, each catering to specific needs within the CNC machining process. Here’s a bullet list detailing some other significant M-codes:

• M07: Coolant on (mist)
• M10: Clamp on
• M11: Clamp off
• M19: Spindle orientation
• M40: Spindle gear at middle
• M98: Subprogram call
• M99: Subprogram end
• (Note: Exact definitions may vary between different CNC machine models and manufacturers.)

How to Read M-code Commands?

Reading M-code commands requires familiarity with the specific codes and their corresponding functions. Typically, an M-code command consists of the letter “M” followed by a number, each representing a specific machine function. These codes are written within the CNC program and are read by the machine’s controllers, translating into exact actions.

For example, M03 is read as “Spindle on clockwise.” Understanding the meaning behind each code is vital for CNC programmers and operators to ensure smooth and accurate machining operations.

What Machines Use M-code?

M-code is utilized across various CNC machines, each catering to different manufacturing needs. Here’s a bullet list detailing some common types of machines that use M-code:

• Milling Machines
• Lathes
• Plasma Cutters
• Laser Cutters
• Water Jet Cutters
• Grinders
• Electric Discharge Machines (EDMs)

What is an example of M-code in action?

M-code comes into play in almost every CNC machining project. For instance, consider a CNC milling operation where a workpiece needs to be shaped and polished:

1. M03 (Spindle on clockwise): The spindle starts rotating clockwise to begin the cutting process.
2. M08 (Coolant on): Coolant is activated to regulate the temperature.
3. M06 (Tool change): Midway through the operation, a tool change is needed, and M06 facilitates this seamlessly.
4. M09 (Coolant off): After the cutting, the coolant is turned off.
5. M05 (Spindle off): The spindle is turned off after the machining process.
6. M30 (Program end, return to start): The program concludes, and the machine returns to its starting point.

Who Needs to Know M-code?

Understanding M-code is essential for:

• CNC Programmers
• Machinists
• Manufacturing Engineers
• CNC Machine Operators
• Manufacturing Technicians
• CNC Machine Tool Designers
• CNC Machine Sales Professionals

This knowledge ensures efficiency, precision, and safety within CNC machining processes.

What is the Best M-code Simulators?

M-code simulators help in testing and visualizing the CNC program before execution. Some of the most popular M-code simulators include:

• CNC Simulator Pro
• Mach3
• Mastercam Simulator
• CAMotics
• NCSim
• NC Viewer
• G-Wizard Editor

Are there any safety considerations or precautions to keep in mind when programming M-code?

Safety is paramount when programming M-code. Some considerations include:

• Understanding the specific M-code for the CNC machine being used.
• Ensuring proper tooling paths and machine functions to avoid collisions or damage.
• Regularly inspecting and maintaining the CNC machine for optimal performance.
• Following manufacturer guidelines and industry standards for safe operations.

What is the main difference between M-code and G-code?

While M-code deals with controlling machine functions unrelated to movement (such as spindle control, coolant activation, etc.), G-code is focused on the geometric movements of the machine (such as positioning, feed rate, and speed). Together, G-code and M-code create a complete set of instructions for CNC machines, catering to both movement and operational aspects.

Conclusion

M-code plays a pivotal role in CNC machining, offering precise control over various machine functions. From its invention to its current applications, M-code continues to shape the manufacturing process. Whether it’s activating the spindle, controlling the coolant, or facilitating tool changes, M-code ensures that CNC machines operate with accuracy, efficiency, and flexibility.

FAQs

1. How many M-code there are in total?

The number of M-codes can vary between different CNC machines and manufacturers. Typically, there are several dozen standard M-codes, but customized codes might be used depending on specific machine requirements.

2. What does the M-code in a CNC machines activate?

M-code in CNC machines activates various functions such as spindle control, coolant management, program stops, tool changes, and more. Each M-code corresponds to a specific action or command within the CNC machine.

The post What is M-Code: Definition, Function, Types & Uses appeared first on Rapid Prototyping & Low Volume Production.

Therefore, understanding ‘what is g code’ becomes essential for anyone dealing with the area of Computer Numerical Control (CNC), 3D printing, or any computer programming language for designing machining parts.

This article will have an in-depth discussion on what is g code, its usage, working process, various types of G-code commands, and many other helpful information.

What is G-code?

G-code is a type of programming language used in the areas of Computer Numerical Control (CNC) and 3D printing for instructing machine tool movement. It is written in Computer Aided Manufacturing (CAM) software to provide automation instructions to various machine functions and tools.

G-code stands for geometric code. G-codes are also known as preparatory codes for CNC machines.

The instructions provided by G-codes tell the machine tool how to move in the (X, Y, Z) cartesian coordinate system.

In addition to the location instructions, the G-code also provides many other input such as speed and angle in the rotational axis, tool length offset, start point, stop point, feed rate, wait time, etc.

G-codes work in tandem with M-codes. M-codes stand for ‘Machine codes’ or miscellaneous codes. M-codes provide instructions on various functions of the machine that are not relative to the movements.

An example of M-code is M0, which means an end to the program.

Who Invented G-code Programming

The G-code was invented in 1958 by the Massachusetts Institute of Technology (MIT) Servomechanics Laboratory. The popularization and standardization of G-code occurred later in the 1960s by the Electronic Industries Alliance.

What is the Importance of G-code?

G-code is indispensable when it comes to the numerical control programming language. Machines by their very nature are not equipped with computer intelligence. They contain servomotors for the movement of various parts within them.

However, integrating the machines with microprocessor units can help in controlling the degree of movement of the motors. It can also make multiple parts of a machine work in tandem to accomplish the required operation.

However, the operators cannot directly communicate with the machine. A G-code acts as a communication language between the machine and the operator.

The G-codes are written in a way the control system of the CNC machine can understand. Using a G-code, the operator can tell a machine exactly what is required.

How Does a G-code Work?

The working process of the G-code is a synchronized process between the machine functions and the operator code programming. Here is how it works:

G-code Working Process At Machine-End

All CNC machines are built with a microcontroller that can interpret the G-code. The G-code is standardized in most CNC machines.

Some machines have advanced features or multiple axes that are outside the control of standard G-code commands. In this case, additional commands are written in the microcontroller to control the added functions.

When the internal control system software reads the commands, it interprets them according to the microcontroller instructions and provides movement directions to the various machine functions.

G-code Working Process At Operator-End

Generally, a Computer Aided Design (CAD) file is a precursor to the G-code programs. It creates a graphical visual in two or three dimensions of the required part. Modern software can automatically turn CAD designs into optimal G-code programming.

The benefit of this process is that the computers can do automated calculations for the best possible tool path and other settings. The G-code can automatically take into account features such as tool offsets.

If any changes are required in the G-code, a dedicated software called G-code editors are used. This editing stage is usually required for making customizations to the design.

The resulting G-code is not a standard for every machine due to the variance in the format and difference in machine features. Therefore, it goes through another software called post-processing.

It standardizes the G-code exactly as the machine is designed to read. This eliminates any possibility of bugs due to difference in various machine controller software. This finished G-code file is transferred into the CNC machine.

What is the Structure of a G-code?

The G-code is a combination of an alphabet and a number. The number can have multiple digits. The placement of space between the alphabet and the number varies based on the particular CNC machine.

Some examples of common G-code commands are: ‘G00’, ‘F10’, ‘M03’, etc. The commands don’t necessarily start with the letter ‘G’. However, ‘G’ is the most common letter that comes along in a G-code instruction.

Every line of the G-code programming language can contain multiple sets of instructions. This is also known as a G-code block. The CNC machine reads and implements the instructions in a particular sequence from left to right and top to bottom. Here are the representations of common alphabets used in the G-code:

• G: General machine movements
• F: Feed rate
• T: Tool change
• S: Spindle speed
• X, Y, and Z: Three linear axes in the cartesian coordinate system
• A, B, and C: Angular rotation axes around X, Y, and Z

What are the Different Types of G-codes?

A G-code can be divided into several different classes based on what it does. These classes are:

Positioning Commands

CNC machines have many different types of positioning systems that determine the motion control of the machine tool. The various G-codes for controlling motion are:

• G00: Rapid Positioning of Machine Tool
• G01: Linear Interpolation
• G02: Clockwise Arc Interpolation (Circular Interpolation or Helical Interpolation)
• G03: Counter-clockwise Interpolation (Circular Interpolation or Helical Interpolation)
• G90: Use absolute coordinates

Speed Commands

• G08 – G09: Increment or Decrement Speed
• G93 – G95: Choosing the Linear Feed Units
• G96: Constant Surface Speed
• G97: Constant Spindle Speed

Machining Operation Commands

• G81: Simple drilling
• G82: Simple drilling with dwell
• G83: Deep hole drilling
• G84: Tapping

Offset Commands

• G40 – G44: Tool Offset Values
• G53 – G59: Zero Offset Value

Miscellaneous Commands

• G61: Exact Stop Mode
• G04: Wait time
• G80 – G89: Process Description

How to Read G-code Commands?

It is fairly easy to read G-code commands with a little bit of practice. Here are some steps to help you identify what a G-code command will do:

1. Start by focusing on the alphabetical character of the command instruction.

2. Letters like ‘G’ and ‘M’ relate to machine operation. The number next to these letters are not for movement but to indicate what machine process or function will get affected. For example, G00 will provide rapid positioning of the machine tool. G81 will tell the machine to use the simple drilling cycle.

3. Letters like ‘X’, ‘Y’, and ‘Z’ provide the location in the coordinate system. The number next to these letters do not represent any code. Instead, these numbers provide the precise location in each of the axes. For example, X1 will tell the machine tools to move one unit in the X-axis.

4. Letters like ‘A’, ‘B’, and ‘C’ indicate angular position similar to the X, Y, and Z. The numbers next to these letters do not represent any action but the value of the angular rotation in a particular direction.

5. Letters like ‘F’ and ‘S’ relate to feed rate and spindle speed. The numbers next to these letters relate to the speed of the associated values. For example, F200 instructs the machine to use feed rate as 200 units. The particular units used are selected with the proper G93-95 codes.

6. Comments can be added in the g-code by using a semicolon (;) at the end of a line. Anything written in a line after the semicolon will not affect the operation of the CNC machine.

Therefore, a command such as G01 X10 F100 tells the machine tools to move at the coordinate X = 10 with a feed rate of 100 units.

What is an example of G-code Programming?

G-code programming language works for every type of CNC machine. The example below demonstrates a G-code program for a CNC mill. The objective is to machine a simple square with 20mm x 20mm dimensions in the linear XY plane.

• G21 ; Set all dimensions to millimeters
• G90 ; Set the s system to absolute positioning
• G00 Z5 ; Raise the tool at height of 5 mm above the workpiece
• G00 X0 Y0 ; Rapid positioning of tool at the point of origin
• G01 Z-1 F100 ; Lower the tool at a depth of 1 mm (height= -1 mm) with a feed rate of 100 mm/minute
• G01 X20 F200 ; Move the tool to the coordinate X= 20 with a feedrate of 200 mm/minute
• G01 Y20 ; Move the tool to the coordinate Y= 20
• G01 X0 ; Move the tool to the coordinate X= 0
• G01 Y0 ; Move the tool to the coordinate Y= 0
• G00 Z5 ; Raise the tool to its safe height of 5 mm
• M0 ; Program End Point. The machine stops running the program at this point.

This is just an example of a G-code program. The actual program can vary for different machines. For instance, some machines require G0, G1, and G2 instead of G00, G01, and G02.

An important thing to keep in mind is that ‘M30’ is not a G-code in itself. It is an M-code command related to the machine controller function.

What Machines Use G-code?

G-code is used in CNC machining and 3D printing. Among CNC machining, the different types of machines that use G-codes are:

CNC Milling Machine

A CNC milling machine uses a rotary cutting tool against a stationary workpiece. The cutting tool for this CNC machine comes in many different shapes and forms. This leads to a lot of different types of milling processes.

CNC Turning Machine

A CNC turning machine uses a stationary cutting tool against a rotating workpiece. Turning machining is used to create symmetrical features on cylindrical and conical surfaces. A turning CNC machine has a helical tool path around the workpiece. Turning is used for the machining of external surfaces in the process of shaping. CNC lathes are based on the principle of a turning machine.

CNC Grinding Machine

Grinding is a type of machining that is used for fine machining of surfaces. It creates minimal material from the surface to smoothen it. Grinding is generally used as a secondary finishing process after other methods like milling and turning. Grinding can also remove the burrs made after welding and other joining processes.

CNC Drilling Machine

CNC drilling is a common process that creates holes in the workpiece by a drill bit. The purpose of the holes may be to fix screws, secondary assembly, or aesthetical. Drill presses are generally used after other machining methods. The diameter of the hole is limited. CNC boring is used when the required hole diameter is large.

CNC Routing Machine

A CNC router is a machine that is used for cutting of different materials. It generally combines a CNC system with a handheld router. The router can remove a very controlled amount of material from a surface. This provides the ability to carve intricate carvings.

CNC Laser Cutting Machine

A CNC laser cutting machine uses the heat of a highly focused laser beam to melt and cut the workpiece material. The laser has a very high level power focused through a system of optics. The cutting method is limited in terms of materials it can cut. Cutting any sensitive materials like plastics generate toxic gases which can harm the optical system.

CNC Water Jet Cutting Machine

CNC water jet cutting is an innovative technique that uses the force of high pressure water to cut through any material. The thickness of the water stream is less than a human hair. CNC programming can move the cutting head around. Waterjet cutters can pierce through high thickness of materials making them suitable for any application.

Who Needs to Know G-code?

G-code is a beneficial skill for people working with CNC machines such as the operator. CAM software is capable of generating the G-code for most CNC machines. However, understanding the G-code and knowing what it means allows the operator to micromanage the program. They can add any degree of customization to the program by modifying the G-code. Understanding the G-code also helps troubleshoot certain problems that may arise during the machining process.

G-code also turns out to be a useful skill for engineers, architects, and hobbyists. The application of G-code also comes up in 3D printing, further expanding the usefulness of this programming method.

What is the Best G-code Editor?

Some of the best G-code editing software are NC Viewer, Notepad++, Cura, gCode Editor, and G-code QnDirty.

All of these are free and come rich with features. There are also many paid G-code editing applications.

G-code editing software is generally used for making small changes to the program file. It also provides the option of replacing particular instructions with other instructions in the entire program. This find-and-replace feature is relatively quick with a G-code editor.

Are there any safety considerations or precautions to keep in mind when programming G-code?

Yes, there are important safety considerations to keep in mind when programming G-codes. G-code instructions should be written knowing the machine’s working limits.

Any wrong instruction can lead to tool collisions and breakage. Additionally, it is important to include compensations such as axis offsets. G-code program should also take into account factors such as the tool length.

What is the difference between G-code and M-code?

G-code and M-code handle different aspects of the CNC machine’s working process. The G-code handles aspects that relate to the movements of the tools in the X-axis, Y-axis, and Z-axis.

It also handles the tool rotation, feed rates, and other movement and speed controls.

M-code, on the other hand, handles various functions of the machine such as the coolant flow, program start and stop, calling subprograms, tailstock advancing and reversing, gear selection, etc. M-code commands are not related to the geometry of the part.

Both the G-code and M-code work together to create a complete CNC program.

Endnotes

G-code programming is a very useful skill for people working with CNC machines. The good thing is that G-code programming is fairly easy to learn with the right approach.

A good handle on G-code CNC programming provides the ability to craft even the most complex workpieces with a high level of quality and precision.

Frequently Asked Questions (FAQs)

Here are the answers to some common questions that are asked regarding G-codes:

1. Are G-codes universal?

Yes, G-codes are universal when it comes to CNC machines. All CNC machines work on G-code commands. Certain machines seem to have other features for designing parts that do not require programming. However, they still use the G-code for working. In such cases, the G-code layer is hidden from the end user.

2. Is G-code a Programming Language?

Yes, G-code is a type of programming language. The technical specification for this programming language is RS-274. CAM software can automatically generate G-code programs. Therefore, unless designing a complex part with many customizations, it may not require a dedicated programmer.

3. Is G-code hard to learn?

No, G-code is not hard to learn. In fact, any operator can learn simple G-codes easily within a short amount of time. The skills are then built up with practice and experience with the execution of codes

4. Do you have to be good at maths to understand G-code?

No, G-code does not require any special knowledge of mathematics. However, having a familiarity with the basics of mathematics can be helpful at times for the optimization of the program.

5. What are the 3 basic G-codes?

The three basic G-codes are G00. G01, and G02/G03. G00 instructs rapid movement of the machine tool at the required coordinate system. G01 provides instructions for the linear feed move. G02 and G03 relate to the clockwise and counterclockwise movements of the feed.

The post What is G-code: Definition, Function, Types & Uses appeared first on Rapid Prototyping & Low Volume Production.

What is G-code?

G-code is a type of CNC programming language used for controlling the functions of a CNC machine that relate to the movement of the cutting tool.

It stands for ‘Geometric code’. G-code consists of instructions that the microcontroller in the CNC machine can read and interpret. The instructions are then passed to the relevant machine part. A single line of G-code can contain multiple instructions. Each line of the G-code is defined as one block. It is a very simple programming language requiring no complex logic or mathematical skills.

G-code programming works in combination with the M-code. M-code stands for Machine code, and is thought by some to stand for miscellaneous codes. The M-code controls the various functions of the CNC machine that are not directly related to the movement. These functions include instructions like the machine loading the program, pauses in the program, and coolant flow.

Modal vs Non-modal G-codes

Two types of G-codes are used in CNC machining- modal and non-modal. A modal G-code remains in effect through the program until another G-code changes it. In contrast, non-modal G-codes remain in effect only for the block where they are used.

Do All CNC Machines Use G-code?

Yes, all CNC machines use G-code. The implementation of the G-code comes built-in with every type of CNC machine in the microcontroller.

However, manufacturers often change the format of the G-code in minor ways so it works on their particular machines.

For instance, some machines might have an added ‘0’ before the G-code numerical values. For instance, while some machines have rapid movement G-code as G00, others might have it as G0.

What is the Role of G-code in CNC Machining?

G-codes play a crucial role in CNC programming. The automation in CNC machining comes with the interpretation of G-codes. CNC machines cannot understand conversational languages. They work on a dedicated set of machine language commands. The programmers compile these commands in a G-code file to instruct the CNC machines on how to operate.

The CNC programming microcontroller is preprogrammed with the meaning of every G-code command. Therefore, when the microcontroller reads a particular command, it immediately knows what to do. If any G-code command is outside the dictionary of the CNC microcontroller, it will not work.

G-code commands work in combination with their counterpart- the M-codes. G-codes control CNC machine tool movement, while M-codes control CNC machines’ functioning processes, such as the coolant flow or the tool change. The M-code and the G-code commands are used together to make a complete CNC programming file.

How Many G-codes Are There in a CNC Machine?

There are over a hundred G-code commands for CNC programming. Most of the G-codes are common for every CNC programming operation. However, certain G-codes are specific to the type of operation like milling, turning, drilling, etc.

There can be variation in the G-code list between the different CNC manufacturers.

Every machine does not support every G-code. Additionally, machines with unique features or multi-axis machining capabilities might have additional G-codes. The manufacturer may provide instructions on the G-codes for CNC programming in the reference annual provided with the machine.

What are the Common G-code Commands Used in CNC Machines?

There are over a hundred G-codes used in the CNC programming process. Therefore, it can be difficult to memorize all the individual codes and their meanings.

Below is a G-code list for the commonly used commands in the CNC programming process.

You can use this list as a reference point when writing any CNC programming file. It is useful to memorize important commands such as the G00-G03 as they are used throughout every CNC programming project.

CNC Movement and Travel

The codes below are used for controlling the movement and tool path in the CNC programming:

G00: Rapid Move of the Machine Tool

Rapid move command moves the tool from one point to another without cutting the material. The movements are done at highest speed possible. Therefore, no feed rate is required for the rapid move commands. It requires location coordinates in the X axis, Y axis, and Z axis.

G01: Linear Interpolation of the Machine Tool

Linear interpolation moves the tool from one point to another in a straight line. The speed is according to a feed rate specified by ‘F’ in the G01 command block.

G02: Clockwise Arc Circular Interpolation

Instead of a straight line, G02 commands the cutting tool to cut in an arc in the clockwise direction. It requires a feed rate specified by the value ‘F’. It requires the specification of the center point (I, J, K) or the radius (R) of the arc.

G03: Counter Clockwise Arc Circular Interpolation

Same as G02. instead of clockwise direction, it cuts an arc in the counterclockwise direction.

G04: Dwell

Dwell indicates a pause in the program. It ceases the machine movements but the auxiliary functions stay on. For instance, the spindle keeps on moving while the program is in Dwell mode. The duration of the dwell is indicated by pause time ‘P’. The machine reads the P value in seconds.

G09: Exact Stop

The exact stop G-code is used when a sharp corner is required. Conventional machining creates rounded corners due to the inertia of the cutting tool. G09 elimiantes this problem by stopping the cutting tool temporarily at the corner and then moving it again, leading to perfectly sharp corners.

Plane Selection

Plane selection G-code programs specify the two-dimensional plane in the X, Y, Z axis cartesian coordinate system. These commands are:

• G17 – XY Plane Selection
• G18 – XZ Plane Selection
• G19 – YZ Plane Selection

Dimensions

G-code programs for dimensions indicate which measurement units are chosen. These commands are:

• G20: Change unit measurement to inches

• G21: Change unit measurement to millimeters

Compensation Codes

Cutter compensation codes consider parameters such as the tool length and tool radius. Using these commands can increase the precision of the overall CNC operation.

They are also known as tool offsets. These commands are:

• G40 – Turn off tool compensation
• G41 – Cutter compensation left
• G42 – Cutter compensation right
• G43 – Tool length compensation
• G40 – Cancel tool length compensation

Work Offsets

Work offset ensures that the workpiece is at the true zero position. The commands for work offset values are:

• G54 – Work Offset 1
• G55 – Work Offset 2
• G56 – Work Offset 3
• G57 – Work Offset 4
• G58 – Work Offset 5
• G59 – Work Offset 6

Canned Cycles

A canned cycle in CNC is a repetition of a particular machine operation such as drilling, reaming, tapping, boring, etc. Some of the common canned cycle G-code programs are:

• G73 – High-Speed Peck Drilling Canned Cycle. Drill holes while breaking chips
• G74 – Peck drilling canned cycles generally used for face grooving. Use for tapping only.
• G75- Quick grooving cycle for CNC lathes
• G76 – Fine Boring Canned Cycle and threading cycle
• G81 – Standard Drilling Canned Cycles
• G82 – Standard Drill with Dwell at the bottom of the hole
• G83 – Deep Hole Peck Drilling Cycle Retracting All Through the Hole
• G84 – Right-Hand Tapping Cycle For Machining Threads Into Pre-drilled Holes
• G85 – Reaming Cycle or Boring Cycle
• G86 – Bore and Stop Canned Cycle; Spindle Stops When Tool Reaches the Bottom of the Hole
• G87 – Boring cycle with a special tool for expanding diameter of hole
• G88 – Boring Cycle with P instruction; P instructs the number of seconds to dwell
• G89 – Back Boring Cycle with Dwell

Cancel Codes

• G50: Scaling off; in some machines it may be used for programming absolute zero center point or for setting spindle speed limit

• G80: Cancel all active canned cycles

Positioning Modes

The positioning mode refers to how the CNC machine will read the position commands. The G-code program for various positioning modes are:

• G90 – Use absolute mode for positioning
• G91 – Use incremental positioning

Speeds and Feeds

Speed and feed mode refer to how the machine interprets the value units. These commands are:

• G94 – Feed per Minute Mode
• G95 – Feed per Revolution Mode
• G96 – Constant Surface Speed
• G97 – Constant Spindle Speed

Plane Return

Plane return commands contemplate the cutting tool location in various planes. Common plane return commands are:

• G98 – Return to Initial Plane
• G99 – Return to Rapid Plane

Lesser Used G Codes

Some of the G-codes are not as common as the ones listed above. However, you may need them now and then for specific program requirements. Here is a list of some of the lesser used G-code:

• G10 – Programmed Offset Input
• G22 – Stored Stroke Limit
• G23 – Stored Stroke Limit Cancel
• G27 – Zero Return Check
• G28 – Zero Return
• G29 – Return From Reference Position
• G30 – Second Position Zero Return
• G31 – Skip Function
• G44 – Negative Tool Length Compensation
• G45 – Single Offset Increase
• G46 – Single Offset Decrease
• G47 – Double Offset Increase
• G48 – Double Offset Decrease
• G51 – Scaling
• G52 – Temporarily Shift Program Zero
• G53 – Return to Machine Zero Position
• G60 – Single Direction Move
• G61 – Exact Stop Check (Modal)
• G64 – Normal Cutting Mode
• G65 – Custom Macro Call
• G66 – Custom Macro Modal Call
• G67 – Cancel Custom Macro Modal Call
• G68 – Coordinate Rotation Mode
• G69 – Cancel Coordinate Rotation Mode
• G92 – Program a Work Offset

Are There Any Safety Considerations When Programming G-code For CNC Machines?

Yes, some safety considerations exist when programming G-code for a CNC machine. A CNC machine is capable of cutting material of extreme hardness.

Therefore, incorrect G-code can be a safety hazard for the machine, the operator, and the work area. The G-code should consider factors such as the work offsets and tool length offsets to ensure there is no tool breakage.

Tool breakage is a frequent accident that occurs due to tool collisions. Running prior simulations in CAD and CAM software can eliminate any chances of errors and bugs in the G-code.

What are the Other Codes Used in CNC Machining?

M-code is the other important code used in CNC Programming besides the G-code. M-codes control the various CNC machine functions unrelated to the movement.

M-codes are specific to the particular CNC machine controller and its supported features. M-codes and G-codes are used together for complete CNC programming. Some common M-code commands are:

• M00- Mandatory program stop
• M01- Optional program stop
• M02- Program end point
• M30- Program stop and rewind
• M06- Tool change

Conclusion

Understanding G-code is essential for learning CNC programming and making any part through an automated machining process. The good thing is that learning how to read G-code takes a very short while.

There are many different G-codes for various instructions. You can check the reference list above to use the G-codes when working on CNC programming projects.

An important thing to remember is that the G-codes can vary slightly based on the particular manufacturing model you are using. Therefore, refer to the machine’s user manual to check for any differences in your equipment’s CNC programming design.

The post G-code For CNC Machine: Commands & Uses appeared first on Rapid Prototyping & Low Volume Production.

Thermoplastic pellets can be melted down and injected into a mold cavity, where they harden, but thermosets do not behave in this way. For a thermoset to harden, it must be cured via heat, radiation, or mixing with a catalyst. The standard injection molding process does not permit this.

Fortunately, it is possible to mold thermosets using the process of reaction injection molding (RIM), which was developed in the 1960s for the production of more impact-resistant automotive parts. Instead of melting down solid pellets, this form of injection molding using a special mixer to combine the two liquid parts of the thermosetting polymer and cause a chemical reaction that allows the material to cure and harden once injected into the mold cavity.

This article goes over the basics of reaction injection molding, looking at the available materials and the main advantages and disadvantages.

How does reaction injection molding work?

Reaction injection molding works by mixing two parts of thermosetting polymer that react and cure when combined. The mixture is injected into a mold cavity, where the curing takes place, allowing the material to solidify and form a part shaped like the mold cavity.

Although reaction injection molding tooling can closely resemble the molds used for standard injection molding, a special type of injection molding machine is needed for the RIM process. This machine usually comprises the following components:

• Two tanks for storing the two liquid parts of the thermoset
• High-pressure pumps for moving and metering the liquids
• Mixhead for blending and dispensing the two liquids
• Mold for forming the thermoset into the desired shape

High pressures are required to move the liquids from the tanks to the impinging mixer, where they are mixed at a high velocity (1200 psi). However, the mixed material can often be injected into the mold at relatively low pressure. This is because the thermosets are typically less viscous than the molten thermoplastics used in standard injection molding. For similar reasons, the mold often does not have to be made from extremely hard tool steel, allowing low-cost aluminum molds to be used, and the cavity can have sections of varying thickness since there is minimal risk of the parts warping while they cure. The mold is typically heated to a moderate temperature to facilitate the curing process, unlike in other forms of injection molding where coolant helps to speed up solidification.

Curing of the thermoset within the mold usually takes between one and seven minutes, depending on the material used and the geometry of the mold cavity.

Reaction injection molding is similar to liquid silicone injection molding, although the latter does not require high-pressure mixing of the two components of the silicone.

Process variants

Added steps can be added to the RIM process to alter the type of parts produced. Reinforced reaction injection molding (RRIM) involves the use of additives such as glass fibers, which are fed to the impinging mixer via a separate channel. This results in parts with improved strength.

Another way to improve the strength of the molded parts is to use a fiber mesh — pre-arranged within the mold cavity — as a reinforcing agent. This variant is called structural reaction injection molding (SRIM).

Reaction injection molding materials

Several thermosets can be used in reaction injection molding. The most common materials are:

• Polyurethanes
  • Elastomeric polyurethanes
  • Polyurethane foams
    • Structural
    • Rigid
    • Flexible
• Polyureas
• Polyisocyanurates
• Polyesters
• Polyphenols
• Polyepoxides
• Nylon 6

Reaction injection molding benefits

There are many advantages of reaction injection molding. Besides simply offering a way to produce molded parts with thermosetting polymers, the process also has a few benefits over standard injection molding.

Due to the low-viscosity liquid materials, it is possible to create large, thin-walled parts. And because the parts do not thermally contract within the mold, it is also possible to have varied wall thickness throughout the part if needed. Low clamping forces are required due to the low injection pressure, reducing setup time and cost. Additionally, low-cost aluminum molds are sufficient for many parts.

Because of the materials used, reaction injection molded parts are typically lightweight and flexible, which can be beneficial in many applications. RIM foams have a low-density core with a tough, high-density skin.

Limitations

One disadvantage of RIM is the high cost of raw materials compared to thermoplastics. Another is the requirement for a dedicated RIM machine. Additionally, cycle times are slower than standard injection molding, though they are faster than other thermoset forming processes like vacuum casting.

Reaction injection molding applications

Reaction injection molding is a valuable process for creating lightweight parts such as automotive components and high-strength packaging foams.

In the automotive industry, where the very first applications of reaction injection molding were devised in the 1960s, RIM is today widely used to make parts like bumpers, air spoilers, fenders, body panels, trunk covers, and insulated cab flooring. Other uses can be found in areas like sporting equipment (internal helmet foams, for example), furniture, packaging, enclosures for electronic devices, and machinery housings. RIM may also be preferred over injection molding for unique geometries (such as oversize parts with varied wall thickness) or for overmolding and insert molding.

Molding with 3ERP

3ERP offers several injection molding services, including thermoplastic, silicone, and metal injection molding. We also offer a reliable and affordable urethane casting service for rigid or flexible parts. Contact us for a free quote.

The post What is reaction injection molding (RIM)? appeared first on Rapid Prototyping & Low Volume Production.

Outsourcing CNC machining services is an increasingly popular strategy for businesses across various industries. The benefits range from reduced expenses to superior quality control, making it a sought-after solution to many manufacturing needs.

In this article, we will explore the multitude of advantages that come with outsourcing CNC machining services and how it can revolutionize your production process.

Utilization of Specialized Knowledge

One of the most potent benefits of outsourcing your CNC machining is access to a pool of specialized knowledge. When you outsource, you essentially tap into a world of experts who are well-versed in the intricacies of CNC machining.

These professionals possess industry expertise and are equipped with the most advanced technology. As a result, you receive high-quality output without investing in training or equipment.

Lower Capital Requirement

In the business world, cost reduction is always a primary concern. Outsourcing CNC machining services can dramatically decrease capital requirements. Instead of investing in expensive machinery, you pay a service provider to use their equipment.

It alleviates the burden of significant upfront expenses and allows funds to be allocated towards other business operations.

Adaptability

Outsourcing CNC machining offers unrivaled flexibility. As market demands fluctuate, your production process needs to keep pace. With an outsourced CNC machining company, scale adjustments become effortless.

Whether you need to ramp up production during high demand seasons or scale back during slower periods, outsourcing provides the adaptability your business requires to stay competitive.

Precision

Another noteworthy benefit is the precision that CNC machining brings to the table. By leveraging computer programming, CNC machines deliver components with an accuracy level that is hard to achieve with manual operations.

When you outsource your CNC machining needs, you entrust your manufacturing to machines capable of producing parts with the highest precision.

Diverse Range of Materials

Whether it’s metal, plastic, wood, or even exotic materials, CNC machines can handle a diverse range of materials.

This versatility ensures that no matter what your product design requires, an outsourced CNC machining service provider can produce it with the highest quality and precision.

Simplified Adjustments

In a fast-paced business environment, agility is key. With CNC machining, making design adjustments is as easy as tweaking the machine’s programming. It negates the need for manual adjustments and ensures a quicker turnaround for product modifications.

Quickness

In manufacturing, time is money. Outsourcing your CNC machining needs can significantly expedite the production process.

The automated nature of CNC machining allows for around-the-clock production, ensuring that you meet your deadlines and keep your customers satisfied.

Reduction in Expenses

As a business, maintaining a healthy bottom line is vital. The cost savings from outsourcing CNC machining are twofold. Not only do you save on capital expenditures by eliminating the need to purchase equipment, but you also save on operating expenses.

These include energy costs, maintenance costs, and labor costs, all of which can add up quickly.

Enhanced Manufacturing Procedure

CNC machining brings a high level of automation to the manufacturing process, reducing the chance for errors and improving overall efficiency. Outsourcing your CNC machining allows you to reap these benefits without investing in expensive machinery or training your staff.

Lower Risk of Mistakes

Errors in manufacturing can be costly, both in terms of wasted materials and time. CNC machines follow exact programming, significantly reducing the chance of mistakes.

When you outsource, you entrust your production to these high-precision machines, minimizing material wastage and ensuring optimal use of resources.

Minimal Material Wastage

CNC machining is renowned for its precision, which naturally leads to minimal material wastage. Outsourcing to a CNC machining service ensures that your components are produced with maximum efficiency and minimum waste, promoting a more sustainable production process.

Superior Control Over Quality

Quality control is a fundamental aspect of any manufacturing process. With CNC machining, every aspect of the production process is programmable, providing superior control over quality.

Outsourcing your CNC machining needs to a service provider means entrusting your production to machines capable of maintaining consistent quality across all components, enhancing customer confidence in your products.

Efficient Process Flow

CNC machining streamlines the manufacturing process, resulting in a smoother, more efficient process flow. By outsourcing your CNC machining, you can ensure a quicker production phase, improving your ability to meet customer demands and boosting your bottom line.

Shortened Completion Time

The speed and efficiency of CNC machining result in a significantly shortened completion time. This means that you can deliver your products to the market faster, improving your competitive edge.

Quicker Production Phases

The high-speed, high-precision nature of CNC machining leads to quicker production phases. When you outsource, these quicker production phases translate into faster product launches, giving you the upper hand in a competitive market.

Simplified Expansion

Outsourcing your CNC machining services facilitates easier business expansion. Since the service provider handles the production process, you can focus on expanding your business, secure in the knowledge that your manufacturing needs are being met.

Absence of Equipment Purchase

Purchasing CNC machining equipment can be a significant financial investment. When you outsource your CNC machining needs, you eliminate this expense. You gain access to top-of-the-line machinery without the hefty price tag, allowing you to allocate your resources elsewhere.

Superior Design Skills

Outsourcing to a CNC machining service provider also gives you access to superior design skills. Service providers like 3ERP, a trustworthy machining shop and manufacturer, have teams of experienced engineers who can transform your designs into high-quality components.

How to choose the right CNC machining provider?

When looking for a trustworthy CNC machine shop, consider the following factors:

• Range of Services Offered When considering a CNC machining service, it is vital to evaluate the range of services they offer. A full-service provider, such as 3ERP, which provides milling, turning, EDM, wire EDM, and surface grinding, can handle all of your machining needs, ensuring a streamlined production process and superior control over quality.
• Quality of Machinery Used The quality of machinery used by a CNC machining provider is directly linked to the precision and efficiency of the resulting products. Choose a provider that utilizes advanced CNC machining centers with 3-, 4-, and 5-axis capabilities for ultimate precision and versatility.
• Expertise and Experience of the Team A seasoned team with extensive knowledge in CNC machining is crucial for project success. Their industry expertise and experience enable them to handle diverse range of materials and make necessary adjustments promptly and accurately, minimizing the risk of costly mistakes.
• Price and Value for Money While cost is a significant factor in outsourcing CNC machining, it should not overshadow the importance of value. A trustworthy provider will deliver high-quality products that represent excellent value for money, without compromising the precision, quality, and timeliness of delivery.
• Customer Satisfaction and Reviews The credibility of a CNC machining provider is often reflected in their customer satisfaction rate and reviews. Look for a service provider that consistently receives positive feedback for their quality control, turnaround time, and commitment to customer satisfaction, like 3ERP.
• Turnaround Time The ability of a provider to meet deadlines without compromising the quality of the output is a key indicator of their efficiency. Choose a CNC machining provider, such as 3ERP, who can deliver high-quality, precise components in as little as five days, helping you maintain an efficient process flow and shortened completion time.

3ERP provides a variety of online custom CNC machining services including milling, turning, EDM, wire EDM, and surface grinding.

With precision 3-, 4- and 5-axis CNC machining centers, combined with other advanced capabilities and an experienced team, we can handle all types of CNC machining parts in both metal and plastic materials.

Whether you need prototypes or production parts machining, 3ERP’s CNC machining service will be your best choice.

Conclusion

Outsourcing CNC machining services can be a game-changer for businesses looking to enhance their manufacturing process. The multitude of benefits, from cost savings and superior quality control to quicker production phases and simplified business expansion, make it a viable strategy for businesses across the spectrum.

In a dynamic and competitive market, staying ahead of the curve is crucial. By outsourcing your CNC machining needs to a reliable and experienced provider like 3ERP, you can ensure that your manufacturing process remains streamlined, efficient, and of the highest quality. Leverage the benefits of outsourcing CNC machining today and propel your business towards greater success.

The post What are the Advantages of Outsourcing CNC Machining? appeared first on Rapid Prototyping & Low Volume Production.

CNC machining services are primarily delivered in specialized CNC machine shops. A CNC machine shop is usually equipped with technologically advanced equipment and offers precision CNC machining capabilities in a controlled environment.

With so many CNC machining suppliers, choosing the right CNC machining service has become a critical decision that requires careful consideration and evaluation of several key parameters.

Let’s dive right in the 22 factors to consider when choosing CNC machining services.

What type of Equipment and Tools are being used?

A CNC machining service is only as effective as the tools at its disposal. Whether it’s lathes, mills, or routers, the variety and quality of machinery can make or break your project. Different types of CNC machines cater to different kinds of tasks.

Notably, a service with a diverse range of high-tech machinery means they are likely capable of handling an array of projects. If they can employ advanced techniques like surface grinding, it also indicates their commitment to offering extensive machining services.

Does the Company have substantial Experience in CNC Machining?

Experience equates to expertise. CNC machining is a precise process, and with each project, a CNC machining company acquires more knowledge and skills. An experienced service provider would be familiar with handling diverse machining needs, reducing the chances of errors and ensuring a smoother process overall.

However, don’t just look at the years of operation. Also, consider the projects a particular CNC machine shop has worked on and the types of clients it has served. This provides a clearer picture of their breadth and depth of experience.

Is the Material you need readily Available?

Each CNC project requires specific materials, from aluminum to stainless steel and everything in between. Not all CNC machining services will have the exact material you require.

Therefore, it’s critical to ask if they can source the material readily. Delays in sourcing materials can lead to extended lead times and increased production costs.

What Certifications and Qualifications does the Company have?

Quality assurance is a non-negotiable aspect when choosing a CNC machining service. Look for companies with recognized certifications, such as ISO 9001, which is a standard for quality management systems. These qualifications serve as a testament to their commitment to maintaining high quality and consistent results.

What are their typical Lead Times?

Time is money, and in the world of CNC machining, this rings especially true. Extended lead times can stall your projects, cause delays, and even lead to financial losses.

Therefore, understanding the typical lead times of a CNC machining service is crucial. It would also be wise to ask about their policies on expedited orders, should you require quicker turnarounds.

3E Rapid Prototyping (3ERP), an ISO9001-2015 certified manufacturer, provides lead times from 3 business days on all CNC machining services.

How effective is their Communication process?

Communication is the backbone of any successful partnership. An effective communication process means the service provider can promptly address your queries, update you on progress, and quickly rectify any issues that may arise.

Look for services that offer transparent and open communication channels, like regular updates via email or other preferred methods.

Where is the Company Located?

The location of the CNC machining service provider can significantly impact various aspects of your project, including shipping costs, lead times, and even the ease of communication.

Choosing a local CNC machining service can offer quicker lead times and lower shipping costs. However, if the overseas service provider offers better expertise and prices, the additional shipping costs and time could be worth it.

How do their Pricing align with your Budget?

The cost of CNC machining services can vary widely. Ensure that their pricing structure aligns with your budget without compromising on the quality of service.

Be sure to factor in hidden costs, such as shipping and any additional fees. Remember, the cheapest option is not always the best. Quality should never be compromised for cost.

Do they offer Flexibility and Accuracy in their service?

The world of CNC machining is one that requires precision and flexibility. The service provider should be capable of delivering accurate results, adjusting their operations to accommodate changes, and catering to your specific project needs.

What is the Size of the Business?

The size of the CNC machining business can indicate its capacity to handle your project. Larger businesses might have more resources, but smaller ones might offer more personalized service. Understand the implications of their business size on your project before making a decision.

Can they meet your Company’s specific Needs?

Each company has unique machining needs, from design complexities to quantity requirements. The right CNC machining service should be able to meet these specific needs, offering customized solutions instead of one-size-fits-all services.

What is their Online Reputation like?

In today’s digital age, an online reputation can make or break a business. C

heck for customer reviews, case studies, and testimonials to gain insights into their performance, reliability, and customer satisfaction levels. Remember, every company will have a mix of good and bad reviews. The key is to see how they handle the negative ones.

What Quality Assurance processes do they have in place?

Quality assurance is critical in the world of CNC machining. Look for a service provider with robust quality control measures.

These might include regular checks during the production process, final inspection before shipping, and policies to rectify any errors or defects.

What are their Technical Capabilities?

The technical capabilities of a CNC machining service extend beyond just operating machines. It includes their ability to understand complex designs, use CAD/CAM software, and their proficiency in various machining processes.

Do they provide Top-Quality Customer Service?

Customer service goes hand-in-hand with the quality of work. A CNC machining service that provides top-notch customer service is likely to be more responsive, reliable, and committed to meeting your expectations.

What After-Sale Services do they offer?

After-sales service is often overlooked, but it’s an important factor to consider. It could include everything from addressing post-delivery issues to offering assistance in assembly or installation.

Is the Company Scalable to meet future demand?

Scalability is key when considering a long-term partnership. A scalable CNC machining service provider will be able to adapt to increased demand, ensuring your future growth isn’t hampered by their capacity limitations.

How do they ensure Data Security?

Data security is crucial in the digital age. Ensure that the CNC machining service has robust data security protocols to protect your project data and intellectual property.

Can you see examples of their Past Projects/Portfolio?

Past projects provide a sneak-peek into their capabilities, the kinds of clients they’ve worked with, and the complexity of projects they can handle. Ask to see their portfolio or case studies to get a better idea of their expertise.

What is the Skill level of their Workforce?

The skill level of the workforce is a critical factor that influences the quality of work. Look for a CNC machining service that invests in training their staff and keeps them updated with the latest industry advancements.

Do they offer Rapid Prototyping Capability?

Rapid prototyping is an essential factor to consider when choosing a CNC machining service provider. This capability can significantly reduce the product development cycle, allowing your business to get your product to market faster. By creating a prototype quickly, you can evaluate the design, function, and performance of your parts or products before committing to full-scale production.

CNC machining services that offer rapid prototyping typically possess advanced CNC machines and software that allow them to quickly and accurately produce prototype parts. Moreover, their team of engineers should be adept at understanding your design requirements, offering valuable feedback and suggestions for improvements.

Do they follow Continuous Improvement Practices?

Continuous improvement is a business philosophy that emphasizes constant, incremental improvements in processes, products, and services. It’s a crucial factor to consider when choosing a CNC machining service provider.

Machining services that follow continuous improvement practices will regularly analyze and optimize their processes to deliver better results over time. They prioritize quality control and are committed to improving their service by reducing errors, improving efficiency, and enhancing customer satisfaction. This results in cost savings, better quality products, and increased reliability for your business.

Conclusion

Choosing a CNC machining service involves more than just comparing prices. It requires a thorough evaluation of a host of factors, including the service provider’s experience, equipment, material availability, certifications, lead times, communication effectiveness, location, and their commitment to rapid prototyping and continuous improvement.

By carefully assessing these aspects, you can make an informed decision that aligns with your project’s requirements, budget, and timeline, and choose a CNC machining service provider that can deliver high-quality products in a cost-effective and timely manner.

Remember that a good partnership with a CNC machining service provider is not just about meeting your current needs. It’s also about their ability to meet your company’s future demands, scale with your growth, and continually improve their service to provide the best possible results.

Ultimately, the CNC machining supplier you choose should not only be a provider but also a trusted partner that adds value to your business.

ISO9001-2015 certified 3ERP offers superior CNC machining services, excelling in both plastic and metal materials. With capabilities ranging from one-off CNC prototypes to 100K+ mass production, we maintain a tight tolerance of ±0.01 mm and promise rapid delivery.

Equipped with advanced 3-, 4-, and 5-axis CNC machining centers, 3ERP can handle all types of CNC machining tasks. We boast advanced equipment for both manufacturing and testing, ensuring consistently high quality and fast turnaround. With rich experience and commitment to customer satisfaction, 3ERP stands as a strong contender in the competitive landscape of CNC machining services.

Contact us today and get a quote for CNC machining services.

The post Choosing a CNC Machining Service: 22 Key Factors to Consider appeared first on Rapid Prototyping & Low Volume Production.

With a single point cutting tool and a rotating workpiece, it opens up a world of precision cuts and intricately shaped components.

This article will unravel the ins and outs of turning, laying bare the parameters, operations, types, and equipment involved. Get ready to explore the world of turning, where raw materials are shaped into engineered perfection.

What is Turning?

Turning is a type of machining operation that involves a cutting tool removing material from a workpiece while it rotates around an axis. This operation is performed on a turning machine or lathe, a specialized tool that accommodates various geometries and materials.

With turning, operators can achieve a good surface finish and manufacture parts with high tolerances. It’s a process that allows for the creation of internal and external surfaces, even contoured ones, with unparalleled precision.

The Dawn of Turning: A Historical Perspective

Tracing the origins of turning takes us back centuries, to when manual lathes were used to shape wood and metals. The transformation of the process came with the introduction of Computer Numerical Control (CNC) technology in the mid-20th century, revolutionizing the industry.

Turning evolved from a manually controlled process to an automated one, enabling the production of intricate and accurate diameter components, limited only by the specifications of the machine and operator skill.

What is the Working Principle of Turning?

Turning operates on a simple yet effective principle:

1. The workpiece is rotated at high speed while a single point cutting tool traverses along the workpiece’s surface, cutting off a thin layer of material.
2. The cutting action takes place at the point where the tool’s cutting edge meets the workpiece.
3. This cutting speed, coupled with the feed rate (the speed at which the cutting tool moves relative to the workpiece), determines the shape and surface finish of the final product.

What are the Stages of Turning?

The turning process unfolds in a series of carefully calibrated stages, which we will explore below.

Mounting the Workpiece

First, the workpiece is mounted onto the lathe. This is often achieved by fixing the workpiece between two centers or securing it in a chuck, allowing it to rotate around a fixed axis.

Tool Setup

Next, the single point cutting tool is positioned perpendicular to the workpiece surface. The tool’s cutting edge angle, rake angle, and relief angle, which determine the quality of the cut, are adjusted as per the desired outcome.

Cutting Process

Once the setup is complete, the lathe machine is started, and the workpiece begins to rotate. The cutting tool moves in a longitudinal direction along the rotating workpiece, removing material in the form of chips.

Quality Checks and Finishing

The last stage involves checking the workpiece for any imperfections and making necessary corrections. The final part is then measured for dimensional accuracy and surface finish, which may require additional turning operations such as finish turning or sizing.

What are the Different Types of Turning?

Turning is not a monolithic process, but rather a collection of methods, each with its unique characteristics and applications. Here are some of the most common types:

• Straight Turning: Straight turning involves the removal of metal from the external surface of a cylindrical workpiece. The cutting tool moves longitudinally along the workpiece, reducing its diameter. It is often used to ensure cylindrical workpieces have a consistent diameter along their length.
• Taper Turning: In taper turning, the tool is not parallel to the axis of the lathe, but at an angle, allowing for the creation of conical shapes. This technique is commonly used to create machine tool spindles and drive shafts that require a tapered end for fitting components.
• Facing: This operation involves reducing the length of a workpiece or creating a smooth end or face. The cutting tool moves radially across the end of the workpiece, removing material. It’s used frequently to clean up the ends of parts or prepare surfaces for additional machining processes.
• Groove Turning (or Grooving): This type involves cutting a narrow groove on the external or internal surface of the workpiece. Groove turning is commonly used for oil grooves, retaining ring grooves, and for parting off sections of a workpiece.
• Parting: Parting or cutoff is the operation of cutting off a piece from a larger workpiece. It involves the creation of a narrow slot down to the center of the workpiece, ultimately separating a section of material. It is typically the final operation after the part is fully shaped.
• Thread Turning: This type involves cutting a helical groove of a particular pitch along the external or internal surface of a cylindrical workpiece. Thread turning is used to make screw threads for fasteners and other components requiring threaded features.
• Boring: Boring is the process of enlarging a hole that has already been drilled or cored. It can improve hole accuracy and provide a smooth internal surface. It’s used for finishing internal surfaces or preparing them for additional operations like thread turning.
• Knurling: This operation produces a regularly shaped roughness on the workpiece surface, often to provide a better grip for handling. The knurling tool presses a pattern into the surface of the workpiece as it rotates.
• Drilling: In a lathe, drilling is the operation of making a cylindrical hole by removing metal along the circumference of a pointed tool or drill bit. It’s typically the first step in creating an internal feature that will be further refined by operations like boring or thread turning.
• CNC Turning: Computer Numerical Control (CNC) turning employs computer programs to control the cutting tool’s motion. It enables the creation of complex parts at high speeds and with high precision. CNC turning is particularly useful for producing parts with complex radial features or when tight tolerances are required.

Turning Techniques and Methods

Different turning techniques have been developed to suit the needs of various applications. These include:

Parting Off

Parting off, also known as cut off, involves cutting a piece off a part that is being turned.

Grooving

Grooving is a turning operation where grooves are made on the surface of a workpiece.

Facing

Facing is the process of cutting along the end face of a workpiece, generally to make it flat or to cut it to a specific length.

Knurling

Knurling doesn’t involve cutting but rather pressing a pattern onto the surface of a workpiece. It is often used to create a serrated pattern for better grip or aesthetic appeal.

Reaming

Reaming removes a small amount of material from an existing hole to improve its dimensional accuracy and surface finish.

Tools and Equipment in Turning

Turning, as an essential machining operation, employs a range of equipment for different purposes. Here are some of the critical tools involved:

Lathe Machine

A lathe machine, also known as a turning machine, is the central equipment in the turning process. Different types of lathes are used for various turning operations, such as turret lathes, special-purpose lathes, and CNC lathes.

Single Point Cutting Tool

A single point cutting tool, typically made of high-speed steel or carbide, is used in the turning process. The tool’s characteristics, such as the cutting edge angle and tool life, play a significant role in the turning process’s success.

Chuck

A chuck is a device used to hold the workpiece in place while it rotates.

Tailstock

A tailstock supports the end of the workpiece when it is being turned between centers.

Feed Mechanism

The feed mechanism, usually controlled by a lead screw, controls the speed at which the tool moves along the workpiece.

Parameters in Turning

Several parameters influence the turning process. Understanding these can help optimize the process and achieve the desired results. Some of the main parameters include:

Cutting speed

The cutting speed, often expressed in meters per minute or feet per minute, refers to the speed at which the cutting tool or the workpiece moves during the cutting process. It’s a paramount factor that influences the quality of the cut, tool life, and overall productivity of the turning operation.

There are numerous factors to consider when setting the cutting speed, such as:

• The type of material being worked on
• The hardness of the material
• The type of cutting tool being used
• The desired surface finish

Depth of Cut

Another pivotal parameter in turning is the depth of cut, which is the distance the cutting tool penetrates into the workpiece. This factor can have a significant impact on the production rate, surface finish, and tool life.

To highlight a few considerations related to the depth of cut:

• It should not be so shallow that it wastes time or so deep that it overworks the tool and machine.
• The material type, its hardness, and the type of tool being used all come into play while deciding the appropriate depth of cut.

Feed Rate

The feed rate in turning refers to the distance the tool travels along the workpiece in one revolution of the workpiece. Like other parameters, it can significantly influence the quality of the finish, the life of the tool, and the speed of production.

Here are some key factors to consider regarding the feed rate:

• Higher feed rates can lead to higher production rates but might negatively affect the tool life and surface finish.
• Different materials and tool types might require adjustments in the feed rate for optimal results.

Other important turning parameters are:

• Tool geometry: This includes various angles on the cutting tool, such as the rake angle and relief angle. They influence the cutting action and the surface finish.
• Workpiece material: Different materials have different machining properties, affecting the choice of cutting speed, feed rate, and tool material.

Supported Materials for Turning

Turning is a versatile process that can be used on a wide range of materials. Commonly turned materials include metals like steel, brass, aluminum, titanium, and nickel alloy, as well as plastics such as nylon, polycarbonate, ABS, POM, PP, PMMA, PTFE, PEI, and PEEK.

Some turning operations also extend to wood and other materials, though metals and plastics remain the most common.

Turning is chosen based on the material’s machinability, the complexity of the required features, and the desired surface finish.

More robust materials such as steel and titanium may require more power, specialized tools, or specific cutting force, while softer materials like aluminum and plastic are relatively easy to machine.

Certain materials, due to their unique properties, may produce better surface finishes or allow for more intricate shapes and forms to be machined.

Advantages and Disadvantages of Turning

Like any manufacturing process, turning also comes with its share of advantages and disadvantages.

The advantages of turning include:

• Efficiency in mass production due to automation
• High level of precision and accuracy
• Ability to handle complex shapes and geometries
• Provides a good surface finish

On the other hand, the disadvantages are:

• Initial setup can be time-consuming
• Less efficient for non-cylindrical or complex shaped parts
• Operator skill and experience play a critical role
• The process may require frequent tool changes due to tool wear.

Design Tips for Turning

When it comes to designing for turning, there are a few critical points to keep in mind. The following guidelines can help you achieve optimal results:

• Keep the design as simple as possible.
• Avoid sharp internal corners; they can cause stress concentration and are difficult to machine.
• Maintain a uniform wall thickness to prevent distortion during the machining process.
• Opt for standard thread sizes to reduce cost and machining time.
• Design parts that can be machined in a single setup to save time and maintain accuracy.

Softwares used in Turning

With the advent of computer numerical control (CNC) technology, turning operations have become highly automated and precise. CNC lathes are controlled using specialized software that enables complex geometries to be machined accurately and repeatably. Some of the popular software used in turning include AutoCAD, SolidWorks, Mastercam, and Fusion 360. These software tools allow operators to design the part, plan the machining operations, and generate the necessary G-code that controls the movement and operation of the CNC lathe.

Potential Dangers of Turning

Turning, like any other machining operation, presents potential hazards. Accidents can happen due to tool breakage, flying chips, or entanglement with rotating parts. It’s crucial to ensure all safety measures are in place and adhered to, including wearing protective clothing and equipment, regularly maintaining and inspecting the machinery, and providing proper training to operators. It’s also important to maintain a clean and organized workspace to reduce the risk of accidents.

Possible Side Effects in Turning

Turning involves the removal of material from a rotating workpiece using a single point cutting tool. This machining operation can produce several side effects, largely contingent on the operation parameters, the nature of the workpiece material, and the cutting tool characteristics.

A key concern is tool wear, an inevitable occurrence in turning operations, impacted by factors such as cutting speed, feed rate, and the tool’s cutting edge angle. Wear leads to degradation in the tool’s performance, affecting the accuracy and surface finish of the machined component. Moreover, the produced chips, a by-product of removing material, may impose handling and disposal challenges.

Frequently, turning operations require continuous supervision to monitor these side effects. Despite such automation advancements in CNC lathes, an operator’s role in maintaining high tolerances, mitigating tool wear, and ensuring a good surface finish remains essential.

Environmental Impact of Turning

Like other machining processes, turning can have environmental implications. The energy consumption of turning machines, waste generation from the removed material, and the disposal or recycling of spent cutting tools represent significant environmental factors.

Moreover, coolant and lubricants used to mitigate friction, cool the cutting tool, and extend tool life often pose environmental hazards due to their chemical compositions. As the machining industry progresses, eco-friendly alternatives are increasingly being sought, aiming for a more sustainable turning process.

Cost-effectiveness of Turning

The cost-effectiveness of turning is largely dependent on several factors, including machine cost, operator costs, tool life, and maintenance expenses.

How Much Does Turning Cost Per Hour on Average?

The cost of turning services can vary significantly based on factors such as the complexity of the part, material type, tolerances required, and regional labor costs. On average, however, one might expect to pay between $50 and $100 per hour for CNC turning services.

Where to Get Turning Services?

Several organizations offer professional turning services, one notable provider being 3ERP. They specialize in various CNC services, including CNC turning, catering to a broad array of parts. Turning at 3ERP is carried out on a variety of metals like aluminum, magnesium, steel, stainless steel, brass, copper, bronze, titanium and nickel alloy, as well as plastics like nylon, polycarbonate, ABS, POM, PP, PMMA, PTFE, PEI, and PEEK.

Alternative Technologies to Turning

Although turning is a vital operation for creating cylindrical or tubular components, there exist other technologies capable of generating similar results. Milling, for instance, although fundamentally different in operation, can be used to produce components with cylindrical characteristics and even contoured surfaces.

Furthermore, advancements in additive manufacturing or 3D printing offer an alternative approach for creating complex geometries without the need for subtractive processes like turning.

Conclusion

Turning is an integral component of the machining industry, enabling the creation of intricate components through high precision cuts. Its versatility is showcased in its ability to handle a variety of materials and produce a wide array of shapes and geometries.

While turning brings numerous benefits, it also presents challenges such as tool wear and environmental concerns. As technology progresses, continuous efforts are made to optimize this technique, making it safer, more efficient, and more sustainable. The mesmerizing world of turning will continue to evolve, molding the future of mechanical engineering.

The post What is Turning: Definition, Types, Operations, Parameters & Equipment appeared first on Rapid Prototyping & Low Volume Production.

People new to the industry often ask what is milling, its working process, and its various types. This article will have an in-depth discussion on the milling technology. It will provide a lot of beneficial information for beginners and professionals alike. Additionally, it contains many tips for improving the quality of milling operations.

What is Milling?

Milling is a type of machining process that uses a rotating cutter to remove material in a controlled manner from a workpiece. This subtractive manufacturing technique aims to turn the workpiece into the required shape.

A modern milling machine is often paired with Computer Numerical Control (CNC) for automated control over the whole process.

History of Milling

Traditionally, the crafting of complex shapes was done with manual hand filing. Hand filing created the requirement for a highly skilled laborer.

In the early 19th century, milling machines began to replace these processes. A milling machine eliminated the manual filing skill requirement. Instead, operators could use these machines with little expertise. Only short training on the machine was needed.

Initial milling machines found application in making rifle parts for the army. The milling machines were manually operated until the middle of the 20th century.

With the rise of computing technology, milling machines integrated with CNC technology in the 1950s. This gave birth to the modern automated milling machines used industry-wide today.

Who invented Milling Machine?

Eli Whitney invented the first milling machine in 1818. The purpose of this milling machine was to manufacture rifles for the US government. The basic design and features of this machine were so perfect that the same carried on for over 150 years. Incidentally, Eli Whitney is also credited with inventing the first cotton gin.

How Does Milling Work?

The main working part of a milling machine is the rotary cutting tool. This cutting tool is responsible for the material removal process. Milling machines can utilize both single-point and multi-point cutting tools.

The cutting tool in milling moves perpendicular to the rotational axis. For instance, if the cutting is rotating in the X-Y plane around the Z-axis, the movement of the cutter also occurs in the X-Y plane. The workpiece meets the cutter at the rotating tangent, resulting in the material removal process.

What are the Different Stages in the Milling Process?

Here is a step-by-step breakdown of the working process of milling machines:

1. Workpiece Loading: The preliminary setup involves keeping the workpiece on the machine table feed and securing it. Wobbly fixtures will result in machining errors and poor precision.
2. Tool Selection: Many different types of milling machine tools exist. Choose the right tool for the job, which depends on the workpiece materials and the required result.
3. Machine Setup: Machine setup involves adjusting parameters like spindle speed, coolant flow, feed rate, cutting depth, etc.
4. Milling Execution: The operator starts the actual milling operation once the setup is complete.
5. Roughing: Roughing is the process of removing abundant material from the workpiece. This is done to get the workpiece into a vague resemblance of the required shape. This is done at a high cutting speed and feed rate.
6. Semi-finishing: Once roughing completes, the speed of the milling machine is reduced. The workpiece is shaped identically to the final part.
7. Finishing: Finishing occurs at a very slow feed rate and low depth of cut. The aim is to improve the dimensional accuracy of the part and make it as close as the machine possibly can.
8. Unloading: The operator removes the finished part from the milling machine.
9. Inspection and Quality Control: The final part is inspected to ensure there are no flaws. In case of any defects or further machining requirements, the operator loads the part on the machine and goes through a further finishing pass. This stage repeats until the part meets the required standards.
10. Post-processing: The part can undergo any secondary machining requirements after milling. Common post-processing steps are deburring, cleaning, grinding, surface treatment, etc.

Types of Milling Operations

There are many different types of milling operations. Each of these types can create different components of shapes. These different types are:

• End Milling: An end mill is similar in shape to a drill bit. However, end mills are able to cut radially and axially. The drilling machine can only cut in the axial direction. A conventional milling machine can cut only in the radial direction.
• Face Milling: A face mill is used when working on the surface finish of a workpiece. Face mills can turn an uneven surface into a flat surface. It can also create very smooth surface finishes. There are different automatic and manual milling options for face milling.
• Chamfer Milling: Chamfer milling machine is used to make chamfers and bevels. A chamfer mill is also known as a chamfer cutter. Chamfer mills also have other applications like deburring, countersinking, and spotting.
• Slot Milling: Slot milling uses a long rotary cutting tool to create grooves in a workpiece. It is also known as groove milling. The slots made by this machining process are deeper than what end mills can create. The grooves can be closed or open, with many options for shapes.
• Peripheral Milling: In peripheral milling, the cutting tool is placed parallel to the workpiece. Therefore, the sides of the cutting tool grind against the work surface instead of the tool tip. This is the opposite of the face-milling process. Peripheral milling is preferable when a large amount of material removal is required.
• Climb Milling: In climb milling, the cutting tool rotates in the feed direction. This is the opposite of conventional milling operations, where the cutting tool rotates opposite the feed direction. The cutting tool climbs over the workpiece resulting in an accumulation of chips behind it. This eliminates the problem of chips obstructing the cutting tool.
• Profile Milling: The profile milling process is used when machining vertical surfaces or vertically inclined surfaces. It can be used in the roughing as well as the finishing stage. Different types of cutting tools in profile milling are based on roughing or finishing operations.
• Helical Milling: Helical milling makes helical pathways, channels, and holes in a cylindrical workpiece. The workpiece is present on rotary tables. The rotating cutter moves along a helix angle along the workpiece. Helical milling is a common type of process for making lubrication holes and path on a workpiece.
• Plunge Milling: In plunge milling, the feed is in the same direction as the tool axis. This process is also known as z-axis milling. Plunge milling is commonly used in the roughing stage. The cutter plunges into the workpiece and carves out pockets in the material.
• Thread Milling: Thread milling is used to make threads inside a workpiece. Thread mills work on predrilled holes only. The thread mill rotates as well as revolves around the interior surface. Thread turning is more commonly used than thread mills.
• CNC Milling: CNC stands for Computer Numerical Control (CNC). CNC milling utilizes computer programs to control the cutting tool’s motion. It can create parts of high complexity at fast speeds. Depending on the complex shapes required, there are multiple axes options for CNC milling machines.

What is the most common type of milling process?

End milling and face milling are the most common types of milling process. These are used in conjunction with most other machining processes. These milling processes can craft the surface and the interiors of the workpiece.

What is the Equipment Used in Milling?

Milling requires a dedicated set of equipment and an in-depth knowledge of how it works. Here are the different tools used in the milling process:

Milling Machine

The milling machine houses the movement mechanism for the tool and the workpiece. The size of the machine depends on the dimensions of the part that requires milling. A milling machine contains several components like the worktable, monitor, knee, column, base, saddle, quill, spindle, and more. The particular parts in a milling machine highly depend on the type of mill being used.

Milling Cutter

The milling cutter is the tool bit used in a milling machine to remove material from the workpiece. Milling cutters always have a rotational ability due to the nature of the milling operation. The particular design of the milling cutter is highly variable depending on the milling process. Some of the common types of milling cutters are:

Horizontal Milling Machine

• End Mill: The end mill is a long and narrow cutting tool with a sharp end. The cutting teeth are present on the side and the end. The bottom of the end mill can be flat, rounded, or radiused.
• Face Mill: Face mill has multiple cutting points on the side of the cutter. Therefore, face mills cut the workpiece horizontally. The cutting points are made with removable carbide inserts. The inserts can be attached by screwing on the face mill. This leads to a highly efficient mill operation.
• Slab Mill: Slab mill cutter is used for machining planes. It is also known as a plane mill. There are multiple cutting teeth present on the periphery of the cutter. The teeth may be straight or spiral.
• Shell Mill: Shell mill is a modified design of a face mill. It contains a bow that can host an arbor for mounting additional inserts. Sometimes, shell mill is used interchangeably with face mill.
• T-slot Cutter: A T-slot milling cutter is used to machine undercuts. It can widen the bottom part of an existing groove in a part. This results in a ‘T’ shaped groove. It is used for making machine tooling and keyways.
• Fly Cutter: A fly cutter is a single-point cutting tool. It is used for machining a flat surface on a large area. It is similar to lathe cutters. The cutting edge is generally a replaceable carbide insert.
• Ball Nose Cutter: Ball nose cutter is common for machining dies and molds. It is similar to an end mill with a hemispherical rounded end. A ball nose cutter is also called a ball mill or full radius end mill.
• Double Angle Mill: Double angle mill is a highly versatile cutting tool. It can create threads, chamfers, back chamfers, countersinks, bevels, grooves, and slots in a workpiece. It can also help in machining surface finish processes such as deburring.
• Staggered Tooth Mill: Staggered tooth mill is used for making slots of high depth. The staggered tooth design aims to remove the chips from the work surface. This prevents the chips from interfering with the cutting tool operations. It results in a longer tool life and cleaner cutting operations.
• Form Mill: Form milling cutter creates contours on a work surface. The contours can have any shape, such as concave, convex, straight line, and irregular shapes. It can also create rounded corners.
• Slot Mill: A slot mill cutter is also known as a slot drill. It has a flat end and two flutes. The periphery of the flutes cuts slots on the workpiece. There are many different sizes and pitches of slot milling cutters available. The ideal size depends on the slot dimensions.
• Woodruff Mill: Woodruff mill makes keyways in horizontal milling machines. It has a flat end and multiple cutting teeth on the sides.

Vertical Milling Machine

• Flat-end Mill: Flat end mill is also called square end milling cutter. These cutters have multiple functions in vertical milling machines. Typical processes are plunging, face milling, side milling, grooving, and counter-boring.
• Ball-end Mill: Ball-end mills have a hemispherical bottom face. The purpose of ball-end mills in a vertical milling machine is to create rounded grooves. Grooves for metal bearings in machines are commonly made with a ball-end mill.
• Chamfer Mill: Chamfer milling cutter is used for the edge treatment of the workpiece. It creates rounded corners in chamfers and bevels.
• Twist Drill: Twist drill bits have multiple flutes converging at a single point. The number of flutes varies between two, three, or four. The purpose of a twist drill is to cut metals and wood.
• Reamer: Reamer is used for enlarging holes made previously with a boring or drilling machine. Precision reamer provides a small enlargement of all but a high degree of accuracy. Non-precision reamer can give a higher enlargement but with low accuracy. Reamer is also used for improving the surface finishes of a hole.
• Tapping Mill: A tapping mill or tap is used for making threads in a hole. Generally, tapping is preferable for holes that pass entirely through a workpiece. Tapping can provide a high-speed operation compared to thread milling process.

Prolonging Milling Tool Life

Tool life is a crucial parameter when it comes to milling cutters. Understanding tool life and how to prolong it can result in significant savings in milling costs and the generated waste.

What is Tool Life?

Tool life is the time period of useful operation of a cutting tool. It is the lifespan of a tool from its first use to the point it stops providing desirable results. An important thing to note is that tool life is not limited to tool breakage. A tool can be at the end of its life even if it has not broken but has stopped providing required milling results. At the end of tool life, you need to replace the tool.

Tool life is a major factor in the operational costs of a milling machine. Low tool life means a higher tool replacement. This can lead to a significant increase in the running costs of milling machine tools.

What is Tool Wear?

Tool wear is the degradation of the cutting tool due to operation. Tool wear occurs in all machining processes. The rate of wear can vary on the tool material, build quality, and how the operator uses the machine.

All tools come with an estimated tool life. However, the tool usage considerably varies between applications. Therefore, the exact tool wear and tool life cannot be determined beforehand. The operator needs to inspect the tool regularly to analyze wear. The operator can decide if more tool life remains based on examining the tool wear.

What is Cutting Fluid?

Cutting fluid is a type of compound that reduces tool wear and prolongs its life. It is common when milling metal materials. Cutting fluid is known by many other names, such as lubricant, coolant, cutting oil, or cutting compound. Cutting fluid provides multiple benefits:

• Heat Dissipation: Cutting metal with milling generates a lot of heat. This heat results in faster tool wear. The cutting fluid absorbs this heat and lowers the tool’s temperature, reducing tool degradation.
• Lower Friction: Cutting fluid lowers the friction coefficient between the metal and the cutting tool. This results in a faster cutting process and further reduces the tool wear.
• Chip Removal: Chips often stick to the cutting surface due to high heat. This obstructs the movement of the cutting tool and increases tool wear. Cutting fluid prevents chips from hindering the process and avoids welding of chips with the work surface.

Types of Cutting Fluids

There are many different types of cutting fluids for the milling process. These types are:

• Liquids: Liquids are the most common type of cutting fluids. There are three classes of liquid cutting fluids: mineral, semi-synthetic, and synthetic. Mineral oils are petroleum-based cutting fluids. Synthetic oils are water-based compounds.
• Paste: Liquid cutting fluid is not suitable for all applications. Therefore, cutting fluid is also available in paste and gel form.
• Aerosol: Aerosol cutting fluid is sprayed on the work surface. These are not highly preferred due to the dangers to workforce health.
• Air-based: Air-based cutting fluids use gases such as nitrogen. These are new and evolved types of cutting fluids. Generally, these are used when milling tough materials like titanium and Inconel. It can lead to a ten times longer tool life.

What are the Key Parameters in Milling?

The important parameters for milling machining process are:

• Feed Rate: Feed rate is the relative speed of movement between the cutting tool and the workpiece during the CNC milling process. This value is measured in millimeter per minute (mm/min) or inches per minute (IPS or in/min).
• Depth of Cut: Depth of cut is the vertical thickness of material removal in a single pass. It can be measured in inches or milimetres. A higher depth of cut leads to a slower cut and a higher tool wear.
• Spindle Speed: Spindle speed is the speed at which the tool (or spindle) rotates. It is measured in revolutions per minute (RPM). A higher spindle speed leads to a faster cutting and a higher rate of material removal process.
• Axial Depth of Cut: Axial depth of cut is the length of cut measured axially in the direction of the cutting tool. This value is also the width of the cut in a single pass. The axial depth of cut determines the chip thickness.
• Radial Depth of Cut: Radial depth of cut is measured along the radius of the cutting tool. This value is also the diameter of the cut on the workpiece. It determines the deflection of the milling machine tool.
• Tool Diameter: Tool diameter is the diameter of the particular milling cutter. It can be measured in inches or mm. Tool diameter determines the dimensions of the cut, the cutting forces, and chip evacuation.
• Cutting Speed: Cutting speed denotes the rate at which the tool moves along the workpiece. This value is obtained by multiplying the circumference of the tool with the spindle speed. This value is measured in surface feet per minute (SFM) or metres per minute (m/min).
• Tool Overhang: Tool overhang is the distance between the tool holder and the tool edge. This distance can be seen as the functional length of the tool. A larger tool overhang increases the vibrations, reduces stability, and increases the tool wear.
• Coolant Flow Rate: Coolant flow rate is the rate at which cutting fluid flows to the work surface. The coolant flow rate is adjusted according to the cutting speed and the feed rate.
• Tool Coating: Special coatings are applied on milling tools to increase cutting quality and reduce tool wear. Common tool coatings are Diamond Like Carbon (DLC), Titanium Nitride (TiN), and Titanium Aluminum Nitride (TiAlN).
• Stepover: Stepover is the distance between two back to back passes during milling. Too low stepover can result in interfering cuts leading to poor precision and errors.
• Ramp Angle: Ramp angle is the angle of contact between the milling tool and the workpiece during entering. This angle is used during ramping operations.

Acceptable Standards for Milling

Learning about the milling standards can help know what to expect from the milling operation.

Tolerance

Machining tolerance is the deviation of the milled cuts from the intended cuts in the blueprint. A lower tolerance means a higher accuracy of operation. CNC milling machine tools can create parts with tolerance as low as ± 0.005″ (approx. 0.13 mm). This is a very low value which gives high-precision features to the milling process.

For plastics, the tolerance is higher at around ± 0.010″. This is due to the effect of plastic deformation and heat.

Minimum Wall Thickness

Parts made with milling require a minimum wall thickness. Walls thinner than this value can often collapse during milling or later operation. The minimum wall thickness value is 0.5 mm for metals and 1.0 mm for plastics.

However, it is recommended to go over this value to keep some margin of error. The recommended values are 0.8 mm for metals and 1.5 mm for plastics.

What are the Advantages of Milling?

There are many benefits that milling has to offer over alternative manufacturing processes. These benefits are:

• Versatile: Milling is a very versatile process. It can create a wide range of shapes on many different types of materials. Alternative manufacturing processes like 3D printing are limited in terms of materials.
• Precision: CNC milling is one of the most precise manufacturing technology. It is the go-to process in fields such as aerospace, where precision is paramount.
• Efficient: Milling has a very high efficiency. CNC milling can create parts at a rapid pace that is suitable for mass production.
• Quality: Milling is a high-quality process. The parts created by milling usually do not require secondary surface finishes.
• Automation: Milling is often integrated with CNC machine tools. This makes the whole process automated, reducing the labor requirement and increasing the production rate.
• Cost-effective: The high production rate and low labor costs lead to a very cost-effective operation.
• Consistent: The high precision of milling makes very consistent parts. This is important for making commercial parts where repeatability is the key.
• Machining Hard Material: Milling can easily machine hard materials like titanium and Inconel. These materials are tough to machine with alternative technologies.

Common Milling Materials

Milling can work on a wide range of workpiece materials. Some common materials that undergo milling are:

Metals

Metals are the most common class of materials that undergo milling. Milling can create parts from any type of metal. This includes hard metals like titanium and soft metals like copper. Some of the metals and alloys best suited for milling operations are:

• Aluminum
• Stainless Steel (all grades)
• Carbon Steel
• Copper
• Nickel
• Chrome
• Bronze

Plastics

Milling of plastic parts is common for high precision parts or to produce parts at a large scale. When milling plastics, monitoring temperature is important. This is because plastics can undergo deformation in the presence of heat. Common types of milled plastics are:

• ABS
• Nylon
• Peek
• POM
• Polycarbonate

Composites

Composite materials are common in sectors like aerospace due to extreme physical characteristics. These physical characteristics also lead to poor machining by conventional processes. However, milling can work on these materials with ease. Commonly milled composites are:

• FRP
• Carbon
• Metal Matrix Composites
• Polymer Matrix Composites
• Ceramic Matrix Composites

Woods

Milling can work on a wide variety of woods without causing any adverse effects. Milling of wood is a common process in the furniture industry. These woods include:

• Hardwood
• Softwood
• Plywood

Ceramics

Ceramics can be hard to machine due to excessive chipping and brittle nature. To solve this, ceramics are milled before their final sintering. Commonly milled ceramics are:

• Alumina
• Macor
• Aluminum Nitride
• Boron Nitride
• Alumina Silicate
• Glass
• Graphite
• Quartz

Others

Besides the above materials, milling process is also common for materials like:

• Rubber
• Foam
• Stones like marble and graphite

Which Materials are Unsuitable for Milling?

Milling can work on most of the materials. However, certain materials can pose additional challenges during milling. Here are some of these challenging materials:

• Brittle Materials: Brittle materials have the problem of excessive chipping. These chipping often fly around in the workplace causing hazards. Additionally, there is also the risk of material cracking.
• High Hardness Materials: Materials with high hardness have poor machinability. Milling these materials causes tool wear at a rapid pace. This results in frequent tool replacements and a high milling cost.
• Reactive Materials: Milling can increase the temperature of the work surface significantly. Therefore, cutting materials with a reactive nature becomes very challenging.

Is Milling Expensive?

Yes, CNC milling can be expensive due to the high equipment cost. Good quality CNC mills can start at around $50,000 and go astronomically high. The operating expenses of milling are not high. It can start at around $40 per hour.

Therefore, the most cost-effective method to mill parts is to outsource the milling process. Most manufacturers choose 3ERP to handle all the machining operations. The parts can be created on the exact blueprint that you supply. This results in a very affordable operation without investing in the equipment itself.

Is Milling Process Safe?

Milling machines are capable of cutting the toughest materials in existence. These cutters can easily pierce through human body parts, making it very unsafe. Therefore, a milling machine should be operated only with a trained operator. Additionally, it is essential to use safety equipment and machine with all the safeguards.

What are the Hazards in the Milling Process?

Common milling hazards include:

• Sharp Cutter: The milling cutters are very sharp and rotate at extreme speeds. The cutter or any other rotating machine part should never have human contact during operation.
• Chips: Milling removes unwanted material in the form of chips. These chips fly at a high speed and can puncture the skin or sensitive organs like the eyes.
• Noise: Milling, like other industrial equipment, creates high noise levels. It requires proper noise-canceling ear protection.
• Heat: The process generates high temperatures that should not come in human contact. The parts can retain the high temperature for some time after the operation has stopped. Therefore, handling with gloves is essential.
• Electrical Hazard: The machines use extremely high voltage. It is important to cover all electrical parts with guards and label them as electrical hazards.

What is the Duration of the Milling Process?

The milling process lasts for a few seconds to a few minutes. The cutter movement is extremely fast. The main time taken is during the loading and unloading of the part.

Common Problems in Milling

There are certain problems that can be commonly encountered during milling operation. These are:

• Chatter: Chatter is a common issue when the tool is not mounted correctly. Chatter is also typical during the milling of corners. Chatter causes high vibrations, breaking the tool and creating defects in the parts.
• Tool Wear: Certain level of tool wear is unavoidable when it comes to milling. However, not optimizing the milling process can accelerate the wear and require frequent tool changes.
• Workpiece Deformation: The high heat and large cutting force can sometimes cause workpiece deformation.
• Chip Evacuation: Milling requires a proper chip evacuation strategy. Otherwise, the chips keep on re-cutting with the tool.
• Tool Collision: Tool collision occurs when the dimensions are not accurately accounted for.

Conclusion

Milling has been the most common industrial process since its inception over 200 years ago. The wide variety of milling operations can result in parts of any required shape. This makes milling the preferred operation, especially crucial in metalworking. Get in touch with 3ERP to receive an exact quote on how much milling will cost you for your next project.

Frequently Asked Questions (FAQs)

Here are the answers to some common questions regarding milling:

1. What is the golden rule in milling?

The golden rule in milling is- thick in, thin out. The operator should aim for thick chips when the tool enters the workpiece. The operator should aim for thinner chips during the later operation and tool exit from the workpiece. This results in a stable milling operation.

2. How accurate is the milling process?

Milling is one of the most accurate manufacturing processes. It can provide tolerance as low as ± 0.005″.

3. What is the difference between milling and turning?

There is a vast difference between milling and turning. Milling uses a rotary cutting edge against a stationary surface. On the other hand, turning uses a stationary cutting tool against a rotating surface.

4. What is the difference between milling and 3D printing?

There are a lot of differences between milling and 3D printing. Milling is a subtractive manufacturing technique. On the other hand, 3D printing is an additive manufacturing technique. Milling works on all materials, but 3D printing works only on certain plastics.

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