What are the reasons for the error of CNC machining parts?

During the operation of the CNC machining center, there is a certain gap between the screw and the nut. As the operating time of the equipment increases, the clearance gradually increases due to wear. Therefore, the corresponding backlash compensation of the reverse movement is the main factor in overcoming the shoulders created on the machined surface. Gap measurement is usually done with a dial indicator, which requires error control.

However, it should be noted that the gage seat and gage rod should not extend too high or too long, as during the measurement, the gage seat is subject to force movement due to the long cantilever, resulting in inaccurate counts and compensation values. error.

Improper tool selection in CNC machining can also lead to dimensional errors. During cutting, the tool removes material through the main cutting edge. However, after the arc passes through the quadrant and the arc is tangent to the second cutting edge of the tool, the second cutting edge can participate in cutting. Therefore, the wedge angle of the tool must be carefully considered when selecting or grinding tools.

In the CNC machining process, if the machining allowance is not uniform, errors will also occur. In the process of realizing the design performance of the part, whether the machining allowance of the surface to be CNC machined is uniform or even is an important reason for whether the forming surface can meet the design requirements. Because the machining allowance is not uniform, it is easy to cause 'remapping' errors. Therefore, for parts with high surface shape requirements, the machining allowance should be as much as possible before forming, or the design requirements should be met by machining multiple contours.

CNC machining has clear regulations on the workshop environment and the need to reduce heat sources: the focus is on spindle bearing speed, clearance adjustment and reasonable preload. For thrust bearings and tapered roller bearings, due to their harsh working conditions and high heat generation, thrust angular contact ball bearings can be used if necessary to minimize friction and heat generation in certain parts.

CNC machining also requires thermal insulation: keep the heat source away from the spindle, such as isolating the motor and drive, using a separate drive, etc. CNC machining also needs heat dissipation: strengthen lubrication and cooling, and use oil cooling, air cooling and other methods to speed up heat dissipation. Reduce the influence of thermal deformation: No matter what method is used, it can only reduce thermal deformation, and it is difficult to completely eliminate thermal deformation. Therefore, measures should also be taken to reduce the influence of thermal deformation.