An Arm Based Embedded Controller for the Measurement and Compensation of Machine Tool Thermal Error

Abstract

Among the factors affecting machine tool accuracy, thermally induced errors are considered to be significant. Thermal effect on machine tools is a well-recognized problem in an environment of increasing demand for product quality. Machine tool thermal distortion accounts for 75 percent of the total machining error. Thermal error models are derived based on the temperature variations data collected from the specified temperature sensors. As a result there has been a great deal of interest in techniques for reducing thermal errors. Error compensation technique is widely used to reduce the thermal errors. The performance of a thermal error compensation system typically depends on the accuracy and robustness of the thermal error model. The general practice is that temperature sensors are mounted at different locations on important elements of machine tool and temperature rise or fall is monitored at a constant interval of time. Based on the temperature measurements, the correction value to be given for each and every slide is computed. This correction value is used to either modify the tool offset table directly or passed on to the servo controller for further action. In the present work a fast and low cost thermal error measurement and compensation system developed and the simulation results are verified through experiments.