CNC machining is a method of controlling machine tool movement and machining process through computer digitization and information digitization. It is an intelligent universal pneumatic numerical control device developed with high speed, reliability, multi-function, intelligent and open structure. CNC machining is also an important indicator to measure the level of technological development and comprehensive national strength of a country, as well as the degree of modernization of information technology. It plays an immeasurable role in high-tech industries such as aviation, biology, and medical care, and it is also a manifestation of a country’s strength. Therefore, improving this technology is an important way to enhance the country’s comprehensive national strength and status.

CNC machining error

So, what errors may occur during CNC machining?

The principal error of CNC machining is caused by the approximate machining motion mode or approximate tool contour. The reason why it is called machining principle error is because there is an error in the machining principle. As long as the principle error is within the allowable range, this processing method is still feasible. Manufacturing errors, installation errors and wear in the use of machine tools directly affect the machining accuracy of the workpiece. Among them are the rotary motion of the machine tool spindle, the linear motion of the machine tool guide rail and the error of the machine tool transmission chain.

The manufacturing errors, installation errors and wear of CNC machining tools will affect the machining accuracy of the workpiece. In the cutting process of the tool, the cutting edge and cutting surface produce strong friction with the workpiece and chips, which leads to tool wear. When the tool wear reaches a certain value, the surface roughness value of the workpiece increases, and the color and shape of the chips change, accompanied by vibration. Tool wear will directly affect cutting productivity, machining quality and cost. Fixture errors in CNC machining include positioning errors, clamping errors, fixture installation errors and tool setting errors. These errors are mainly related to the manufacturing and assembly accuracy of the fixture.

CNC machining error

CNC machining positioning errors mainly include datum misalignment errors and positioning pair manufacturing errors. When machining a workpiece on a machine tool, multiple geometric features on the workpiece must be selected as the positioning reference in the machining process. If the selected positioning reference does not match the design reference, a reference misalignment error will occur. The workpiece positioning surface and the fixture positioning element together form a positioning pair.

The large position change of the workpiece caused by the inaccurate manufacturing of the positioning pair and the fit gap between the positioning pairs is called the inaccurate manufacturing error of the positioning pair. The inaccurate manufacturing error of the positioning pair will only occur when the adjustment method is used, and not when the trial cutting method is used.