Thermal error compensation method for machine center

High-speed machining (HSM) technology has become the most important application in metal cutting industries. However, overcome the positioning error is one of a great concern. The position error happens due to poor machine structure design and thermal expansion comes from cutting, especially when HSM is applied. In this paper, a new technique is developed to compensate for these errors. The thermal images are used to confirm dispersion of all the affect positions. PT-100 thermo-measuring sensors are applied to detect the thermal expansion. And a mathematical model is built by multi-variable regression analysis, which is based on the sensed temperature variation and the thermal expansion. Finally, these errors are reduced significantly by sending a feedback to the microprocessor. Meanwhile, the thermal deformation can be compensated by the mathematical model, under the condition when the machine is equipped with linear encoder. Moreover, based on the simulation, it is possible to reduce the number of sensors from ten to six, which save the memory capacity and great benefit for calculating and speeding the process of algorithm. The model improves the accuracy of machining which meets the precision requirement of HSM technology. As the result of various machining tests, the axial positioning error can be reduced from 20 μm to be 3 μm, which is a significantly improvement than existing methods.