Thermal Deformation Estimation of Triaxial CNC Machine Tool Base on Whole Machine Temperature Model

• Main Authors: TSAI, HUNG-HSIANG, 蔡宏祥
• Other Authors: YU, YUAN-CHEN
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/7aac7a

碩士 === 國立高雄科技大學 === 電機工程系 === 107 === CNC machine tool plays an indispensable role for manufacturing the parts in wide industries. Machining accuracy is one of the most critical performance for CNC machine tool. Among many factors that affect machining accuracy, thermal deformation error is the most serious one which can be as high as 50 μm to 100 μm. As a consequence, accurate thermal deformation estimation and compensation are necessary in CNC machine tool. Most of previous researches estimated the thermal deformation based on some measured temperatures through regression or ANN learning. This study thought that only a few measured temperatures can not make the thermal deformation estimation meet the required accuracy. In facts, the temperature raise of all parts affect the overall thermal deformation, and it is difficult to measure the temperature of all parts. Hence forth, the approach adepted in this research is to establish the heat generation model and temperature raise model of the whole machine, and then estimate the thermal deformation based on the temperature raise of all parts obtained in the temperature raise model. Knowing the motion order from CNC controller, heat generation model can estimate the heat generated by all the motors, bearings, nuts, sliding guides and the cutting process. Using those generated heats, temperature raise model can estimate the temperatures of all parts of the whole machine dynamically. To built the temperature raise model, with better accuracy, the whole machine was divided into part and each part was further divided into blocks to simulate the temperature distribution in the part. Not only the structuring parts, but also the sheet metal, the tool magzine, the air zones inside the machine are considered in the model. Some temperature measurements are still needed for a calibration of the model parameters. For thermal deformation estimation, not only the thermal expansion of each block, but also the distortions due to unbalanced expansion of symmetrical blocks of a part are taken into account.