What is CNC Turning?(cnc laser engraving Les)

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CNC turning is a machining process that uses computer numerical control (CNC) to automate the turning operations of a lathe. A CNC lathe is a machine tool that rotates the workpiece while a single-point cutting tool removes material to create cylindrical parts with high precision and repeatability.
CNC turning has revolutionized the way parts are made compared to manual lathe operation. By utilizing CNC, intricate components can be produced faster, more consistently, and with higher quality than manual machining.
How Does CNC Turning Work?
A CNC turning center has the same basic components as a conventional lathe - a headstock, tailstock, tool post, chuck, etc. The major difference is the addition of CNC capabilities through a computer control unit. This allows the machine to be programmed and operated automatically.
Here are the key steps in CNC turning:
1. CAD Model Creation
The dimensions of the desired part are modeled in CAD software. The CAD file contains the geometry that will be turned on the CNC lathe.
2. Convert to CNC Code
CAM (computer-aided manufacturing) software converts the CAD model into G-code, the numerical control programming language understood by CNC machines. G-code contains coordinates, speeds, feed rates and other instructions for the cutter path.
3. Setup and Fixturing
The workpiece is properly secured in a chuck or fixture on the CNC lathe. Tooling is installed in the tool turret and offsets are set. The machining parameters are input based on the capabilities of the machine.
4. Execute Program
The G-code program is loaded into the CNC control which then executes it by precisely controlling the movement of the cutting tool and workpiece. All the turning operations are automated based on the programmed instructions.
5. Inspection
Once the program cycle is completed, the finished part is unloaded and inspected to ensure accuracy. If needed, the part may go through additional secondary operations before completion.
Key CNC Turning Operations
CNC turning centers can perform a variety of rotational operations with a single setup:
- Facing - Machining the face of the part to length with a square shoulder
- Turning - Reducing the diameter as the tool feeds along the axis of rotation
- Boring - Enlarging interior diameters
- Drilling - Creating holes axially in the center or on the periphery
- Grooving - Cutting narrow channels on the OD or face
- Cutoff - Severing a completed part from the bar stock remnant
- Threading - Creating external or internal screw threads
By integrating multiple operations in one CNC program, complex geometries can be produced through turning that would otherwise require several setups on manual machines.
CNC Turning Methods
There are two main methods used in CNC turning:
1. Turning with Live Tooling
Live tooling refers to a rotating cutting tool driven by a separate motor within the turret. This allows milling, drilling and other rotary machining without unclamping the workpiece. Complex parts like gear shafts can be completed in one setup using live tools.
2. Turning with Backside Milling
Some CNC lathes feature a milling spindle located behind the part, opposite the turning spindle. This makes it possible to mill the backside of a part after turning operations on the front side are completed. Backside milling enhances flexibility for intricate part shapes.
CNC Turning Capabilities
Modern CNC turning centers offer advanced capabilities that maximize productivity and part quality:
- Multiple axis control - Simultaneous control of the X and Z axes enables complex contours. C-axis control facilitates eccentric turning and contouring.
- Live tooling - As described above, this expands the range of operations that can be performed. Some machines have dual independent tool turrets with live tools for decreased cycle times.
- Y-axis for off-center milling - In addition to X and Z-axes, the Y-axis allows front side milling at angles to the spindle centerline.
- Backside machining - Backside milling or drilling through the spindle bore enhances flexibility.
- Automated part handling - Robotic part load/unload automation minimizes non-cut time. Pallet changers keep a part queued for continuous production.
- Powerful CNC control - Advanced controls accommodate multiple-axis Simultaneous machining and real-time adjustments through integrated software.
- In-process measurement - Probing measures the workpiece during production so adjustments can be made automatically to minimize scrap.
- Tool management - An automatic tool changer swaps tools as needed from a carousel or chain magazine. This enables long periods of unattended operation.
CNC Turning Accuracy and Repeatability
The precision and consistency of CNC turning stems from details like:
- Rigid machine construction - Minimizes vibration and deflection during cutting.
- Precision ground ballscrews - The leadscrews that drive axis motion have tight tolerances for positioning accuracy.
- Tight tolerances - Guideways, spindles, turrets and other components are machined and assembled to close tolerances.
- Digital servomotor drives - CNC axes are driven by digital servomotors that precisely control position, speed and acceleration.
- Close-loop feedback - Linear scales and rotary encoders provide real-time position feedback to the CNC control enabling precision monitoring during motion.
- Thermal compensation - Temperature sensors and software compensation help maintain accuracy as heat is generated.
These technologies enable CNC turning centers to hold tolerances within 0.001" or better depending on the machine model and setup. This reduces scrap and ensures consistency across production runs.
CNC Turning Applications
Due to its precision, consistency and efficiency, CNC turning is ideal for high-mix, low-volume parts as well as high-volume production. Example applications include:
- Automotive - Engine components, fuel system parts, steering/suspension parts
- Aerospace - Structural brackets, engine parts, landing gear components
- Medical - Implants, instrumentation, dental components
- Military/Defense - Missile/rocket components, fasteners, casings
- Optics - Mirrors, lens housings, camera components
- Robotics/Automation - Joints, couplers, actuators, sensors
- Fluid Power - Hydraulic cylinders, valves, connectors
- Fasteners - Threaded pins, screw machine parts
- And many more!
Benefits of CNC Turning
Here are some of the primary benefits that CNC turning offers over manual lathe turning:
- Faster cycle times - CNC automation increases production rates compared to manual operation.
- Consistent quality - Programmed tool paths are repeated precisely producing uniform parts.
- Reduced labor costs - Less manual intervention is needed. One operator can run multiple machines.
- Increased uptime - CNC turret tools allow longer runs with less downtime for tool changes.
- Complex geometries - Intricate shapes can be produced through programming that would be infeasible manually.
- Quick changeover - Switching programs for a new job takes little time versus manual setups.
- Improved safety - Removes operator contact with the cutting process reducing risks.
- Digital capabilities - CNC accommodates data exchange, production monitoring, and statistical process control.
With its efficiency, accuracy and flexibility, CNC turning continues to gain popularity for precision machined components. CNC lathes have become indispensable for high-mix and high-volume production environments alike. CNC Milling