How to Improve the Error Compensation of CNC Machining Machine Tool Accuracy?

Numerical control machine tools have the advantages of good machining flexibility, high machining efficiency, and high machining accuracy, and they have been widely promoted and applied in modern numerical control machining manufacturing. Contour error compensation of CNC machine tools is a key technology to improve machining accuracy and machining quality. In order to achieve the goal, it is necessary to model the feed axis of the contour error and the tracking error first, and then determine the appropriate compensation strategy.

Practice has proved that error compensation is an effective way to effectively improve the machining accuracy of CNC machine tools. In order to realize the error compensation, before the CNC machining, the CNC machining program is reconstructed according to the predicted error in the virtual machining process. Two controlled processing experiments were carried out. The results show that by reconstructing the CNC machining program for error compensation, the motion accuracy of the CNC machine tool can be significantly improved.

However, due to non-linear problems such as the clearance and friction of the feed axis, it is a challenging task to establish an accurate tracking error prediction model; in addition, the sensitivity of the optimal compensation parameters to the CNC machining tool path is also difficult to determine.

Summary of CNC machining errors

The main factors affecting the machining accuracy of CNC machine tools are CNC machining system errors and random errors. And because machine tool equipment is a product of mechanical manufacturing, it will inevitably have a certain amount of original error. Moreover, the CNC machine tool is controlled by the CNC system, so the relative error of the control system will also affect the CNC machining accuracy.

CNC machine tools will generate a certain amount of heat during cutting, causing a certain degree of tool deformation, which will also cause errors. Mechanical cutting will have cutting force, which will cause deformation of the workpiece, tool or fixture, and even serious deformation of the machine tool, which will also bring certain errors.

After analyzing and determining the factors that may lead to CNC machining errors, we can improve the design to eliminate the error source as much as possible, improve the machining and assembly level of the machine tool, improve the CCNC machining environment, and improve the ball screw of the machine tool by adopting a high-rigidity machine tool spindle The manufacturing accuracy of the machine tool minimizes the error of the machine tool guide rail and preheats the machine tool, which effectively prevents the occurrence of errors.

Error compensation method to improve the machining accuracy of CNC machine tools

In the process of CNC machining, if the accuracy of CNC machining is found to decrease, it must be an error. In order to realize the error compensation, before the CNC machining, the CNC program is reconstructed according to the predicted error in the virtual machining process. Systematic evaluation and analysis of the possibility of the original error are made, and corresponding improvement methods are formulated according to the cause of the error and the main error type. Through position control and geometric accuracy control, it is necessary to reduce the occurrence of errors and the influence of geometric errors. At the same time, air cooling and water cooling should be used to control the thermal deformation of the whole process for the deformation errors generated in the CNC machining process. Reduce the impact of thermal deformation on accuracy. The positioning accuracy of the machine tool has a great influence on the processing of parts, and affects the positioning accuracy of the core components of the machine tool. Such as the straightness and straightness of the feed system, guide rail and work platform. In the design process of CNC machine tools, CNC machine tools adopt reasonable core components.

Static compensation method: This method is to first set the error compensation value, and then compensate according to the set value, which obviously has a big defect.

Real-time error compensation method: This method is based on the detection and feedback of the hardware system. According to the information fed back to the compensation system, the compensation value is adjusted in real time, which effectively improves the accuracy of mouthwash processing. The disadvantage is that all error elements cannot be compensated.

Comprehensive dynamic compensation method: This method is developed on the basis of the real-time error compensation method. It can dynamically adjust the compensation amount according to the changes of working conditions, environmental conditions and spatial position, so as to achieve comprehensive compensation for various errors.