Research On Thermal Error Measurement System Of NC Machine Tool Based On Eddy Current Sensor

At present,the manufacturing industry is making continuous progress in the direction of precision driven by the continuous development of advanced science and technology,and how to improve the machining accuracy of CNC machine tools and reduce machining errors has become the focus of attention of many people.And the thermal error of CNC machine tools accounts for 40%-70% of the total error,so the measurement and compensation of thermal error has become a very necessary research topic.In the machining of some complex and precision parts,the workpiece error even reaches hundreds of microns due to the thermal deformation of the machine tool,which shows that the thermal error has a great impact on precision machining.After investigating the relevant data at home and abroad,the most economical and available thermal error elimination method is to adjust the position of machine tool in real time through software compensation to reduce the influence of thermal error on the size of machined workpiece.The key link of software compensation is the establishment of thermal error model,which needs to obtain the thermal deformation of machine tool very accurately,which lays the foundation for the establishment of accurate thermal error model.Now,the thermal error measurement of high-grade machine tools in the world is mainly measured by laser interferometer.There is no doubt that the measurement accuracy of laser interferometer is great,but it is expensive,the installation process is complex and the request of measurement environment is hard.Therefore,this paper analyzes and compares the thermal error measurement systems of CNC machine tools at current field.A thermal error measurement system based on eddy current sensor and international commonly used "five-point method" measurement scheme is proposed.Through the combination of software and hardware,the measurement accuracy of the eddy current sensor is ensured and its nonlinear problem is effectively corrected.Finally,the scheme is applied to the Taichung Seiko V-center 55 vertical NC machining center.The experimental results show that the system can collect the thermal error of CNC machine tool efficiently and reliably in real machine,which provides a strong support for the follow-up theoretical research of thermal error compensation.