Basic Knowledge of CNC Turning-Milling Compound Machining

Due to the different CNC systems configured on CNC milling machines, the instructions used vary in definition and function, but their basic functions and programming methods remain the same.

1. Main Functions of CNC Milling Machines

1. Point Control Function: The point control of CNC milling machines is mainly used for hole machining, such as center drilling positioning, drilling, reaming, countersinking, reaming, and boring various holes.
2. Continuous Control Function: By using linear interpolation, circular interpolation, or complex curve interpolation movements of the CNC milling machine, the machine can mill planes and curved surfaces of the workpiece.
3. Tool Radius Compensation Function:If the programming is done directly according to the workpiece contour line, when machining the inner contour of the workpiece, the actual contour line will be larger by one tool radius value; when machining the outer contour of the workpiece, the actual contour line will be smaller by one tool radius value. By using tool radius compensation, the CNC system automatically calculates the tool center trajectory, causing the tool center to deviate from the workpiece contour by one tool radius value, thus machining the contour that meets the drawing requirements. Using the tool radius compensation function, changing the tool radius compensation value can also compensate for tool wear and machining errors, achieving rough and finish machining of the workpiece.
4. Tool Length Compensation Function: Changing the tool length compensation value can compensate for the length deviation after a tool change, and can also change the planar position of the cutting process, controlling the axial positioning accuracy of the tool.
5. Fixed Cycle Machining Function: Using fixed cycle machining commands can simplify the machining program and reduce programming workload.
6. Subprogram Function: If the workpiece has identical or similar shapes, it can be written as a subprogram and called by the main program, simplifying the program structure. The subprogram function modularizes the machining program, dividing the machining process into several modules, each written as a subprogram and called by the main program to complete the CNC turning-milling compound machining of the workpiece. This modular program is easy to debug and optimizes the machining process.
7. Special Functions: By configuring profiling software and devices on the CNC milling machine, sensors can scan and collect data from physical objects. After data processing, the NC program is automatically generated, enabling profiling machining and reverse engineering. Configuring certain software and hardware can expand the functional capabilities of the CNC milling machine.

2. CNC Milling Machine Turning-Milling Compound Machining Range

1. Plane Machining: CNC milling machines can mill planes, which include horizontal planes (XY machining), front planes (XZ machining), and side planes (YZ machining) of the workpiece. Such plane milling can be completed using a two-and-a-half-axis control CNC milling machine.
2. Surface Machining: Milling complex surfaces requires a CNC milling machine with three or more axes for simultaneous control.

3. Equipment of CNC Milling Machines

1. Fixtures: General fixtures for CNC milling machines include vices, magnetic chucks, and clamping devices. For machining medium to large batches or complex-shaped workpieces, combination fixtures need to be designed. Using pneumatic and hydraulic fixtures, controlled by programs, can achieve automatic loading and unloading of workpieces, further improving work efficiency and reducing labor intensity.
2. Tools: Common milling tools include end mills, face mills, form mills, and hole machining tools.