What is CNC Turning?(precision die cast Justin)

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  • source:NEWRGY CNC Machining
CNC turning is a manufacturing process that uses computer numerical control (CNC) machines to shape cylindrical parts out of metal, wood, or plastic. The workpiece is rotated at high speeds while a stationary cutting tool removes material from its surface to create the desired shape.
CNC turning has revolutionized the production of round parts, enabling fast, precise, and repeatable machining for complex geometries that would be difficult or impossible to produce manually. Modern CNC turning centers provide high accuracy, fine surface finishes, and the flexibility to produce small batches or mass production runs.
How CNC Turning Works
CNC turning uses programmable machine tools that are controlled by coded instructions from pre-written G-code. The instructions direct the machine to perform various turning operations including facing, turning, boring, grooving, threading, and drilling.
The basic CNC turning process involves these key steps:
1. A 3D CAD model of the part is created and then converted into a CNC program through CAM (computer-aided manufacturing) software. The program contains the coordinates, speeds, feed rates, and tool paths.
2. The workpiece is loaded into the CNC lathe chuck, which holds and rotates the part during machining. The chuck can be moved horizontally and vertically to allow access to different areas of the workpiece.
3. Tools are loaded into the tool turret or tool post at designated positions. Common tools include turning, grooving, threading, drilling, and boring tools. The turret indexes to change tools automatically based on the CNC program.
4. The machine operator runs the CNC program, which executes the coded instructions. The turning tools approach the rotating workpiece and follow the toolpaths to remove material and create the desired shape.
5. Coolant is applied to the cutting area to reduce heat, flush away chips, and prevent tool wear. Compressed air may also be used to blow chips away during machining.
6. Once complete, the finished part is removed from the chuck and any post-processing steps are completed, such as deburring, polishing, or adding surface treatments.
CNC Turning Capabilities
Modern CNC turning centers offer a wide range of capabilities that enable them to produce precision parts from various materials:
- Facing - Machining and squaring the face of the workpiece.
- Turning - Machining the external diameter of a cylindrical part. Both straight and tapered profiles can be produced.
- Boring - Enlarging and smoothing internal diameters.
- Grooving/parting - Cutting grooves and recesses into the part or cutting it off from the source material.
- Threading - Single-point or multi-start thread cutting.
- Drilling/tapping - Creating thru holes or tapping threaded holes in the axial direction.
- Knurling - Roller impression to create a textured pattern for grip.
- Thread milling - Milling threads instead of single point cutting them.
- Contouring - Complex shapes, profiles, and edges can be machined.
CNC turning centers can also perform secondary operations in the same setup, eliminating the need for multiple machines. This includes:
- Back turning - Accessing the rear of the part to machine the back side.
- Milling/slotting - For flats, keyways, slots, and milling small features.
- Hobbing - Gear cutting for spline shafts or other gear profiles.
The variety of operations allows CNC turning to produce parts with premium accuracy and intricate details not always feasible with manual methods.
CNC Turning Machines
There are several types of CNC lathes designed for specific turning applications:
- Horizontal turning centers - The most common, with a horizontal spindle. Suitable for small to large parts.
- Vertical turning centers - Spindle is vertical, ideal for large diameter parts. The chuck loads on the side.
- Chucking machine - For high production turning. Automatically loads/unloads parts.
- Automatic lathe - Fully automated operation. Makes complex parts unattended.
- Multi-axis turn-mill center - Combines turning and milling capabilities. Allows complex part machining in one setup.
- CNC Swiss-style lathe - For small, precision turned parts. Uses sliding headstock and guide bushings for support.
- CNC cylindrical grinder - Highly accurate grinding of external cylindrical surfaces and diameters.
The choice depends on the size and geometry of parts, production volumes, precision requirements, and features needed. CNC turning machines range from basic 3-axis models to complex multi-axis machines with live tooling, Y-axis, B-axis, or C-axis capabilities.
CNC Turning Advantages
Here are some of the main benefits of CNC turning compared to manual turning:
- Higher accuracy and repeatability. CNC machines offer precision down to 0.001mm or less. Complex geometries are machined correctly every time.
- Faster process. CNC turning is highly efficient, with faster cutting speeds and feed rates possible. Cycle times are reduced.
- Intricate capabilities. CNC allows features like threads, tapers, grooves, and radii that could be infeasible to do manually. No special tooling required.
- Quick changeover. Changing programs on a CNC lathe allows switching between parts without manual setup changes.
- Reduced labor costs. One CNC operator can manage multiple machines. Skilled manual machinists are not required.
- Safer operation. The operator does not need to directly interface with the machine during cutting.
- Reliable automation. CNC lathes can run 24/7 with minimal supervision and make unattended precision parts.
- Flexible production. Small batches can be machined cost-effectively.
For these reasons, CNC turning has become the standard for most production turned parts, enabling more complex components to be machined with better efficiency.
Common CNC Turned Parts
CNC lathes are commonly used to manufacture these and many other precision turned parts:
- Engine components - pistons, camshafts, crankshafts, valves
- Drive shafts and couplings
- Screws, fasteners, and bolts
- Rollers and pulleys
- Bushings and bearings
- Wheels and pulleys
- Axles and spindles
- Collars and cylinders
- Nozzles and fittings
- Plugs, rods, and shafts
- Sleeves, barrels, and housings
- Gears and sprockets
Many products rely on turned parts made on CNC lathes, including automotive, aerospace, medical, plumbing, hydraulics, electronics, robotics, and more. The technology is a fundamental component of modern manufacturing.
Implementing CNC Turning
Here are important factors to consider when implementing CNC turning:
- Machine selection - Choose a turning center suited for your parts, production volumes, precision, future needs, budget, etc. Compare brands based on specs.
- Tooling - Carbide insert tooling allows faster speeds and feeds. Use proper inserts for each material. Quick change tooling is more efficient.
- Fixturing - Chucks, mandrels, faceplates, and other workholding must suit part sizes and features. Consider 4-jaw chucks for irregular parts.
- Programming - Use CAD/CAM software that programs efficiently and has simulation to verify programs. Simplify toolpaths for optimal performance.
- Operator skills - Train machine operators on programming basics, setup, tool offsets, and how to measure parts accurately.
- Maintenance - Schedule routine cleaning, lubrication, inspections, and preventative maintenance to maximize uptime.
- Work flow - Organize raw material, staging workpieces, and offloading finished parts for a smooth process.
With proper implementation, CNC turning can provide a flexible and efficient manufacturing process that produces high quality turned components. Continual improvements in technology and techniques will ensure CNC turning remains an indispensable fabrication method. CNC Milling CNC Machining