| High grade CNC machine tools are the cornerstone of industrial modernization and an important symbol to measure the level of manufacturing industry and comprehensive national strength of a country;After years of research by scholars at home and abroad,it is shown that the thermal error of CNC machine tool is the main reason for the machining error of CNC machine tool,which accounts for 30%-70%of the overall error of the machine tool.Therefore,it is of great significance to reduce the thermal error of CNC machine tools for improving the machining acciracy.The most economical and fast way of thermal error compensation is through modeling software,and tihernal error modeling is the core technology of thermal error compensation.In this paper,four key technologies of thermal error compensation for CNC machine tools are systematically introduced,which are data acquisition,temperature sensitive point selection,thermal error model establishment and thermal error compensation technology.The paper mainly includes the following contents:(1)developed a high-precision integrated thermal error measurement system to realize the integration of real-time online automatic collection of temperature and thermal displacement,online data analysis,automatic generation of reports and other functions.(2)a scientific method to determine the temperature sensitive points is put forward.The temperature measuring points are selected by comprehensive fluzzy clustering algorithm and grey correlation analysis method,and a model to predict the thermal error of machine tool is built based on the collected data analysis.(3)the thermal error compensation control system is developed.The thermal error compensation is realized by the on-line communication between the thermal error compensation system and the numerical control system based on the principle of the coordinate origin offset of the numerical control machine tool,and the compensation effect is verified by experiments. |
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