Introduction to CNC Turning(how to remove chrome from metal Burke)

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CNC turning is a machining process that uses computer numerical control (CNC) to automate the turning operations performed on a lathe. Turning is a form of machining that produces cylindrical parts by rotating the workpiece while a cutting tool is moved against it. CNC turning utilizes programmable machine tools, called CNC lathes, that can accurately and repeatedly execute turning operations as defined in the CNC program.
CNC turning has revolutionized the production of rotational parts like shafts, pins, rods, and disks by bringing automation, precision, consistency, and flexibility to the turning process. Compared to manual turning, CNC turning is much faster, more accurate, and enables complex geometries and designs that would be impossible to produce manually.
Some key advantages of CNC turning include:
- High production rates and fast cycle times. CNC turning is highly efficient and suitable for mass production.
- Excellent dimensional accuracy and repeatability. CNC lathes can repeatedly hold tolerances within 0.001 inches.
- Ability to make complex cuts. CNC allows complex turned geometries like contoured shapes and threads.
- Minimal setup and changeover times. CNC programs can be stored and reused.
- Reduced labor costs. CNC automation reduces the need for skilled manual machinists.
- Increased flexibility. Quick design changes can be made by editing the CNC program.
- Safer working environment. CNC eliminates risks associated with manual turning processes.
How CNC Turning Works
The CNC turning process relies on predefined machining instructions that are executed by the CNC lathe. Here is a basic overview of how CNC turning works:
1. Part Design - The dimensions and geometries of the desired part are defined using CAD software. The CAD file provides all the necessary specifications of the part to be machined.
2. CNC Programming - The CAD model is used to generate the CNC program code (e.g. G-code) that will guide the machining. The program is written using specialized CAD/CAM software.
3. Setup - The workpiece material is fixtured and held tightly in the lathe chuck. The necessary cutting tools are mounted onto the tool turret.
4. Simulation - The CNC program can be virtually simulated to detect any errors. Simulation verifies the machining before it is executed on the actual machine.
5. Machining - The verified CNC program is loaded and executed. The CNC lathe will automatically turn the workpiece based on the programmed instructions. The entire process runs unattended.
6. Inspection - Once complete, the machined part is removed and inspected. The part is checked for any defects and ensured that it meets specifications.
7. Iteration - If any revisions to the part design are needed, the CNC program can be easily edited and the part can be machined again. Iterations enable quick design improvements.
CNC Turning Operations
CNC lathes are highly versatile and enable a variety of turning, facing, boring, drilling, threading, grooving, knurling, and other milling operations to be performed. Here are some of the most common operations done on CNC turning centers:
- Facing - Machining and squaring the face of the workpiece. Performed using a standard cutting tool.
- Turning - The fundamental operation of rotating the workpiece while cutting to reduce the diameter and achieve the required dimensions.
- Boring - Enlarging existing holes or internal diameters often using single point boring bars. Used to achieve accurate hole size and finish quality.
- Drilling - Machining holes using rotating drill bits mounted in tool holders. Allows holes to be precisely positioned.
- Tapping - Internal thread cutting using taps. Allows threaded holes to be created.
- Grooving/Parting - Cutting grooves and recesses into the workpiece using specially shaped tool inserts.
- Knurling - Produces a knurled pattern on the workpiece using a knurling tool. Used to create a better grip surfaces.
- Threading - Precisely cutting external and internal threads using thread turning inserts or dies.
- Form turning - Using shaped tool inserts to machine complex rotational contours and profiles.
CNC turning centers use a turret or gang tooling to automatically change between tools during the machining process. The appropriate tools are selected and changed based on the programmed sequence of operations.
CNC Turning Best Practices
Adhering to proven CNC turning practices and methods will help maximize productivity and achieve high quality machined parts. Here are some key CNC turning best practices:
- Optimize cutting feeds/speeds - Selecting the right cutting parameters improves tool life and surface finish. Consider the workpiece material, insert material, depth of cut, and surface speed.
- Use quality tooling - Invest in high quality carbide insert tooling from reputable brands. Use inserts designated for your specific workpiece material.
- Utilize proper chip management - Curled chips and chip buildup can easily damage the machined parts. Use chip breakers and positive chip control.
- Employ proper fixturing - Securely hold the workpiece in a chuck, collet, or between centers. Use extra support for slender parts.
- Use coolant - Coolant helps regulate cutting temperatures, flush away chips, and prolong tool life. Choose flood coolant or high pressure through tool delivery.
- Document best practices - Develop machining guides and keep records of proven feeds/speeds for different tool and material combinations.
- Inspect workpieces - Diligently check machined parts for any errors and defects using inspection tools like calipers, micrometers, and CMMs.
- Schedule regular maintenance - Follow a preventative maintenance program for the CNC lathe to identify and replace worn components before they fail.
By following fundamental best practices, manufacturers can achieve exceptional results and maximize their return from investment in CNC turning equipment. The key is using the technology combined with machining know-how.
CNC turning has revolutionized round part production by bringing automation, precision, consistency, and flexibility to the machining of shafts, rods, pins, and other rotationally-symmetric components. With CNC technology, turned parts can be produced faster, more accurately, and with more complex geometries than is possible manually. By utilizing proven CNC practices and methods, manufacturers can achieve high productivity and top quality turned parts. CNC turning provides an efficient means for producing high precision parts cost-effectively and at scale. CNC Milling CNC Machining