CNC turning is a precision subtractive manufacturing process where a cutting tool removes material from a rotating workpiece to produce cylindrical, conical, and spherical shapes. It is the go-to process for shafts, bushings, pins, sleeves, flanges, and any part with rotational symmetry. Modern CNC lathes combine turning, drilling, boring, threading, and grooving in a single setup, dramatically reducing cycle time and improving accuracy compared to manual lathe operations.
How CNC Turning Works
In CNC turning, the workpiece is clamped in a spindle chuck and rotated at high speed while a stationary cutting tool moves along the X and Z axes to remove material. The CNC controller executes programmed tool paths that define cutting operations: roughing passes to remove bulk material, finishing passes for final dimensions and surface quality, threading cycles for screw threads, and drilling/boring operations for internal features. Advanced CNC lathes with live tooling can perform milling operations on the part (Y-axis capability), enabling off-center holes, flats, and cross-drilled features without a second setup.
CNC Turning Capabilities
| Parameter | Стандарт | Precision |
|---|---|---|
| Tolerance (Metals) | ISO 2768-m / ±0.05mm | ±0.005mm achievable |
| Tolerance (Plastics) | ISO 2768-c / ±0.1mm | ±0.02mm achievable |
| Max Diameter | 200mm | 200mm |
| Max Length | 500mm | 500mm |
| Min Diameter | 2mm | 2mm |
| Surface Finish (Ra) | 1.6 microns standard | 0.4 microns with finishing |
| Threading | Metric, UNC, UNF, BSP | Custom thread profiles |
Key Advantages of CNC Turning Services
Superior Cylindrical Precision
CNC turning excels at producing round parts with precise diameters, concentricity, and cylindricity. Roundness tolerances of 0.005mm are achievable, making it ideal for bearing seats, seal surfaces, and shaft interfaces where dimensional conformance is critical for function and assembly.
High-Speed Production
Turning is inherently faster than milling for cylindrical geometries because the cutting tool engages continuously rather than intermittently. Cycle times for simple turned parts can be under 2 minutes, and CNC lathes with bar feeders can produce thousands of small parts per day with minimal operator intervention.
Live Tooling for Complex Parts
Modern CNC lathes with live tooling (Y-axis) can cross-drill, mill flats, cut keyways, and produce off-center features in the same setup as turning operations. This eliminates secondary setups, reduces cumulative error, and lowers per-part cost for parts that combine cylindrical and non-cylindrical features.
Broad Material Compatibility
CNC turning processes aluminum, steel, stainless steel, titanium, brass, copper, and engineering plastics (nylon, POM, PEEK, PTFE, UHMWPE, PC). Plastics turning benefits from the rotational motion, which helps dissipate heat and produce smooth finishes, but requires careful speed and feed control to avoid chatter and thermal deformation.
CNC Turning Materials Guide
| Материал | Turnability | Best Applications |
|---|---|---|
| Aluminum 6061/7075 | Превосходно | Shafts, pins, spacers, pulleys |
| Stainless Steel 303/304 | Good (303 excellent) | Valve stems, fasteners, medical shafts |
| Brass/Copper | Превосходно | Electrical contacts, fittings, decorative parts |
| Nylon PA6/PA66 | Хорошо | Bushings, bearings, rollers, seal rings |
| POM (Delrin) | Превосходно | Precision bushings, spacers, gear blanks |
| PEEK | Moderate | High-temp seals, aerospace bushings, medical components |
Common Applications of CNC Turning
- Shafts and Axles: Motor shafts, transmission shafts, drive axles, pump shafts with keyways and thread features
- Bushings and Bearings: Precision sleeve bushings, flanged bushings, thrust washers in nylon and POM
- Valves and Fittings: Valve bodies, hydraulic fittings, pipe connectors, threaded couplings
- Medical Components: Surgical pins, dental implant abutments, catheter handles, instrument shafts
- Aerospace Hardware: Pivot pins, fastener bodies, spacer rings, linkage components
- Electronics: Connector pins, RF shield sleeves, sensor housings, heatsink cores
Часто задаваемые вопросы
What is the maximum part size for CNC turning?
Our CNC turning capacity handles workpieces up to 200mm diameter and 500mm length. For longer shafts, we can process up to 1000mm with specialized steady rest support. Bar stock feeding allows high-volume production of parts under 50mm diameter from 3-meter bars, reducing material waste and setup time.
Can CNC turning produce threads and internal features?
Yes. CNC lathes can produce external and internal threads (metric, UNC, UNF, BSP, custom profiles), drill cross-holes, bore internal diameters, cut internal grooves and O-ring seats, and even mill flats and keyways with live tooling. Multiple operations are completed in a single setup for maximum accuracy and efficiency.
How does CNC turning differ from CNC milling?
CNC turning rotates the workpiece while the tool remains stationary (except for linear movement), making it ideal for cylindrical and rotational-symmetric parts. CNC milling rotates the cutting tool while the workpiece remains stationary on a table, suited for flat surfaces, pockets, and complex 3D profiles. Many parts benefit from both processes: a shaft might be turned first then milled for cross-holes and flats.
What surface finish can CNC turning achieve on plastics?
Standard turning on engineering plastics achieves Ra 1.6 microns (32 microinches). Precision finishing passes can reach Ra 0.4 microns (16 microinches) on materials like POM and nylon. Plastics generally produce smoother turned surfaces than metals due to their self-lubricating properties, though thermal control is essential to prevent surface defects on heat-sensitive materials like PEEK.
