Research On The Thermal Error Distribution And Error Compensation Of NC Grinding Machine

In this dissertation, based on fully understanding and deeply analyzing the current status of the research and application of the NC machine tool error compensation technique, some theories and techniques concerned have been studied, some new methods are used to research the machine thermal errors and error compensation technique, and got better result.In chapter 1, a survey of the important role of NC machine tool error compensation in industry production application is given, and the review of the current status of the research and application of the NC machine tool error compensation technique is provided. Finally, the main contents of the dissertation are presented.In chapter 2, new theories and methods of thermal error modeling are discussed. Because of fully depending on modeling data, the models which are set up by current methods are not very robust, and one model couldn't be used by several machine tools even though the machine tools are the same type and used to machine the same parts. One new modeling method, the synthesis least squares approach, is proposed, which possess the characteristics of combining the statistic theory with machine's structures, engineering judgments and surrounding temperatures, so they can make the thermal error models more robust and accurate.In chapter 3, the thermal Measuring points location optimization is studied. The Temperature field and error compensation are measured and analyzed. By thermal dynamical analysis and study, five strategies are proposed for the thermal Measuring point's location optimization. A peculiar measurement of Temperature Field which is different from the traditional measurement. An infrared camera is used to measure the Temperature Field of NC machine tool. Two different situations are respectively measured--empty and loaded grinding. According to structure of the machine, Temperature Field, thermal error and strategies of the thermal Measuring points location, the key Measuring points which are used in the mathematical model are got. And then, the method of least squares is used to build the mathematical model. At last, by real grinding, it shows the real error and the error forecasted by the thermal error mathematical model have good comparability. The mathematical model can be used save the machine error compensation.In chapter 4, the NC machine tool error compensation technique and method is studied theoretically. Two methods of error compensation are proposed:the method of feedback interruption and the method of origin translation.Finally, in chapter 5, the conclusions deduced from this dissertation and prospects for future research will be suggested.