The Research On Error Measurement And Error Compensation Of CNC Machine Tools Based On The Step Gauge

The error measurement of numerically controlled machine tools is fundamental to the error compensation. This paper researches on a new type of CNC machine tool accuracy testing device—the granite step gauge. An error model of CNC machine tools is established, the intelligent error measurement system for CNC is developed and based on VB. Furthermore, the characteristics of granite step gauge about measuring the error of machine tools are under deep discussion. The mainly aspects of this paper are as follows:First, in view of the analysis of error measurement of CNC machine tools at home and abroad, and of the status of error modeling, the main purpose and the methods of error measurement of CNC machine tools are definite. Besides, the analysis of the advantages and disadvantages of various error measuring instruments accounts for the importance of developing the granite step gauge error measuring device.Secondly, the specific structure of the granite step gauge device is analyzed and studied. Meanwhile, this thesis also introduces its error measurement principle and deduces in detail its computational formula of the particularly micro displacement measurement and of the deviation displacement measurement between planes. Analyzing the error measurement accuracy of the device determines various factors affecting the accuracy, especially the manufacturing error and installation error.Thirdly, the calibration and the measurement methods of the granite step gauge device are studied and the error compensation software platform is developed. Besides, the calibra tion means of the granite step gauge is worked over and its experiments are done; the impact of the manufactural error of the measuring base surface on the measurement accuracy during the granite step gauge calibration process is investigated. In the meantime, it elaborates on the principles of realizing each function of the error compensation system of the fool typed CNC machine tools developed on a basis of VB.Finally, on the CNC machine tools error measurement test of the granite step gauge device, the error amount of calculation machine tools relative to the measurement machine tools is calculated after completing the position calibration and the position measurement. Meanwhile, the error is calculated during the development of the accuracy error compensation software platforms. The reasonableness and the authenticity of the obtained measurement results are judged by the software linear analysis and software comparison analysis. The results, if credible, will be put into the deviation of the CNC machine tools to approach error compensation. Backlash on the axis is measured and compensated by a compensation, the multiple measurement error by coordinating the axes X, Y repeatedly to the same point can be controlled within the error range, eliminating backlash errors on surface error field measurement.Granite step gauge device offers the convenience, high accuracy, low cost measurement, and its unique advantages can be shown especially in workshops with harsher working environment. This is because Granite step gauge, which is independent of influence of temperature, noise etc, requires lower working environment compared with other high precision measuring instruments. With these characteristics being very suitable for wide application, it has important significance to improve the precision on manufacturing machine tools.