There are many parts in the
CNC milling machine, and each part plays a very important role. The tool of
CNC milling machine has a radius compensation function, which can compensate the machining error of the tool, which is a way of finishing. The working principle of CNC milling machine is more complicated, we still need to understand it well.
Tool radius compensation function
If you program directly according to the contour of the workpiece, the actual contour will be larger by one tool radius value when machining the inner contour of the workpiece; and the actual contour will be smaller by one tool radius value when machining the outer contour of the workpiece. Using the method of tool radius compensation, the CNC system automatically calculates the tool center trajectory, so that the tool center deviates from the workpiece contour by a tool radius value, thereby machining a contour that meets the requirements of the drawing. Using the tool radius compensation function, changing the tool radius compensation amount can also compensate the tool wear amount and machining error, and realize the rough machining and finishing machining of the workpiece.
The tool length compensation function changes the compensation amount of the tool length, which can compensate the length deviation value of the tool after the tool is changed, and can also change the plane position of the cutting process to control the axial positioning accuracy of the tool.
The fixed cycle processing function uses the fixed cycle processing command, which can simplify the processing program and reduce the workload of programming.
Subroutine function If the workpiece has the same or similar shape, write it as a subroutine and call it from the main program, which simplifies the program structure. The function of citing subroutines makes the processing program modular, and is divided into several modules according to the process of the processing process, which are respectively written into subroutines and called by the main program to complete the processing of the workpiece. This modular program is convenient for processing and debugging, and optimizes the processing technology.
After 1950, the control system of milling machines developed rapidly, and the application of digital control greatly improved the automation of milling machines. Especially after the 1970s, the digital control system of the microprocessor and the automatic tool change system were applied on the milling machine, which expanded the processing range of the milling machine and improved the processing accuracy and efficiency. With the intensification of the mechanization process, CNC programming has been widely used in machine tool operations, which has greatly released the labor force. CNC programming milling machines will gradually replace the current manual operations. The requirements for employees will be higher and higher, of course, the efficiency will be higher and higher
CNC engraving and milling machine is a kind of CNC machine tool capable of both engraving and milling. Its main feature is the use of small tools and high-speed electric spindles for engraving and milling. Among them, the operating speed of the electric spindle is usually 20,000~60,000r/min, up to 100,000r/min, and it is required that the electric spindle should work stably when it is running without load, and the actual speed error must be within 10.
In the process of no-load operation, the temperature and temperature rise of the electric spindle bearing should be controlled at a low level; in terms of rotation accuracy, it is usually about 2m at low speed, and about 10m at 20000r/min or above. Because the CNC engraving and milling machine is mainly used to process small products, the cutting load of the electric spindle is small in actual processing, and the power of the CNC engraving and milling electromechanical spindle is small, usually only a few kilowatts. It is much easier to achieve high speed than the BT40 spindle . It can better meet the needs of high-speed and high-precision processing.
