the machining accuracy of CNC machine tools

Numerical control machine tools will inevitably be affected by various factors in the processing process, which will cause certain deviations in their processing accuracy and bring some inconvenience to production and life.

1 Precision problems in CNC machine tool processing

(1) The influence of position error in CNC machining on machining accuracy

Position error refers to the amount of change or deviation between the actual surface, axis or symmetry plane of the part after processing relative to its ideal position, such as perpendicularity, position, symmetry, etc. The position error in CNC machine tool processing usually refers to the dead zone error. The cause of the position error is mainly due to the gap and elastic deformation generated during the transmission of the machine tool parts during the processing of the machine tool, and the tool head of the machine tool needs to overcome the friction force during processing. Factors such as lead to position error. In the open-loop system, the position accuracy is greatly affected, while in the closed-loop follow-up system, it mainly depends on the accuracy of the displacement detection device and the speed amplification factor of the system, and the effect is generally small.

(2) Machining accuracy errors caused by geometric errors in CNC machine tool processing

In CNC machine tool processing, the geometric accuracy of the machine tool is affected due to the influence of external forces and heat generated by the tool and fixture under the influence of external factors such as the heat generated in the process, and the parts processed on the machine tool are geometrically deformed, which leads to geometric errors. According to research, the main reasons for the geometric errors of CNC machine tools are nothing more than the following two: internal factors and external factors. The internal factors of the machine tool's geometric errors refer to the geometric errors caused by the machine's own factors, such as the levelness of the machine table, the levelness and straightness of the machine tool rails, and the geometric accuracy of the machine tools and fixtures. External factors mainly refer to the geometric errors generated under the influence of factors such as the external environment and thermal deformation during processing. For example, during the cutting process of tools or parts, due to thermal expansion and deformation, geometric errors occur, which affect the processing of machine tools. Precision and machining precision of parts.