Rapid Measuring Device Of Position Error For NC Machine Tools

At present, most of the commercial NC machine tools have pitch error compensation function. All machine tools have to be carefully adjusted errors and written pitch error compensation file to NC system before they go out. Deviations existed between the processing position and the command required location after machine tools were used for a period of time by the users, and they need to be corrected again. So it's necessary to find a simple efficient and low-cost error measuring device to measure errors, especially for the middle-grade or low-grade economical machine tools in large production and consumption. The main contents are summarized below.Doing the research on the error source of the position error and analyzing the detection requirement of position error. An error measuring device, which is composed of reference pace gauge and inductance micrometer and corresponding measurement soft, is developed to improve the shortage of common position error measurement methods. This device includes the function of automatic generating measurement program, automatic collecting error data, automatic precision evaluation and automatic error compensation, and is high in automatic and measurement efficiency.The characters of the position error have been discussed. On this basis, using pace gauge relay measuring method to solve the problem in using small high accuracy equipment to measure position error of the large working stroke of NC machine tools is proposed. The accuracy and error accumulation rule of this method have been studied further. The result of the experiment shows that the measurement error increases when relay time increases, but the measurement error in the position error as a percentage of smaller, still meet the requirement of error compensation.At last, this thesis shows the result of measurement curves and precision evaluation of the x, y and z axis by using this device. Using this device and linear grating to measure the same point respectively and the result indicates that the deviation of the same point's position error is less than 4μm. So the high calibration precision can be achieved with this method. The error data can be used for the compensation of position error of the middle-grade or low-grade economical machine tools.