Research Of Essential Technologies Of On-machine Measurement Based On HNC8 Numerical Control System

With the rapid development of aviation, aerospace, automotive, shipbuilding, the free-form surface part has been widely used in modern industry. The reverse, accuracy test and adaptive machining of such parts are inseparable from accurate measurement. Meanwhile, in terms of high-precision machining center, It is of great significance to integrate high-speed measurement function on the basis of the existing equipment, so as to it can not only complete the measurement of parts, but also can achieve the detect ion of their own error and the health status..In this paper, the CNC milling machine which equipped with HNC8 numerical control(or referred to as HNC8) system was the base of research. We made full use of measurement characteristics of three-dimensional contact scanning probe Renishaw SP2-1 to integrate the high-speed on-machine measurement function for machining center.Based on the in-depth analysis of the characteristics of the measuring probe SP2-1,the overall framework of the system was designed; Then, with the help of the STM32 analog I/O module which is for high-speed data acquisition(HIO-1000PULSE), the data processing software was designed and developed; The key technologies of the HNC-8 CNC system scanning measurement is studied, including data sampling and processing, adaptive tracking control, scanning measurement information interaction, etc;Finally, the scanning on-machine measurement system based on HNC8 was developed, making the scanning measurement of the workpiece whose G code is known or whose surface is the typical type and the adaptive measurement for unknown surface come true.Experiments show that the scanning measurement system developed in this paper can reach the theoretical accuracy 0.001 mm, and the actual repeat accuracy is 0.01 mm. If used in the ultra-precision machining center, it can obtain higher precision of measurement.