The Basics of CNC Turning-Milling Compound Machining

The Basics of CNC Turning-Milling Compound Machining Programming

The programming basics for CNC turning-milling compound machining can vary due to different CNC systems used in milling machines. These systems may differ in their commands’ definitions and functions, but their basic functions and programming methods remain consistent.

Main Functions of CNC Milling Machines

1. Point Control Function
   The point control function of CNC milling machines is primarily used for hole processing in workpieces, such as center drilling, drilling, reaming, countersinking, reaming, and boring various holes.
2. Continuous Control Function
   By utilizing linear interpolation, circular interpolation, or complex curve interpolation movements, the CNC milling machine can mill the planes and surfaces of workpieces.
3. Tool Radius Compensation Function
   If programming directly according to the workpiece contour line, the actual contour line will be larger by one tool radius value when processing the inner contour and smaller by one tool radius value when processing the outer contour. By using the tool radius compensation method, the CNC system automatically calculates the tool center trajectory, making the tool center offset from the workpiece contour by one tool radius value, thus producing a contour that meets the drawing requirements. This function can also compensate for tool wear and machining errors, allowing for both rough and finish machining of workpieces.
4. Tool Length Compensation Function
   Changing the tool length compensation value can compensate for the length deviation after tool change and adjust the cutting plane position, thus controlling the axial positioning accuracy of the tool.
5. Fixed Cycle Processing Function
   Using fixed cycle processing commands can simplify the machining program and reduce the programming workload.
6. Subprogram Function
   If parts of the workpiece have similar or identical shapes, they can be written as subprograms and called by the main program. This simplifies the program structure. By using subprograms, the machining program becomes modular, dividing the machining process into several modules, which are written as subprograms and called by the main program, completing the CNC turning-milling compound machining of the workpiece. This modular program is convenient for debugging and optimizing the machining process.
7. Special Functions
   With profiling software and devices, CNC milling machines can scan and collect data from physical objects using sensors. After data processing, NC programs are automatically generated, achieving profiling machining and reverse engineering. The functionalities of CNC milling machines can be expanded by configuring specific software and hardware.

Machining Range of CNC Turning-Milling Compound Machining on CNC Milling Machines

1. Plane Machining
   CNC machine tools can perform plane milling on workpieces, including horizontal plane (XY) machining, vertical plane (XZ) machining, and side plane (YZ) machining. These plane milling operations can be completed using a CNC milling machine with two and a half-axis control.
2. Surface Machining
   Milling complex surfaces requires a CNC milling machine with three or more axis linkage.

Equipment of CNC Milling Machines

1. Fixtures
   Common fixtures for CNC milling machines include vises, magnetic chucks, and clamp plates. For medium to large batch or complex-shaped workpieces, combination fixtures need to be designed. If pneumatic and hydraulic fixtures are used and controlled through programs, automatic loading and unloading of workpieces can be achieved, further improving efficiency and reducing labor intensity.
2. Cutting Tools
   Common milling cutters include end mills, face mills, form mills, and hole processing tools.