Due to the greatly shortening of the transmission chain, the NC gear hobbing machine reduces the influence of manufacturing error, clearance and assembly error of shaft, bearing and gear, and has the function of error compensation, which greatly improves the machining accuracy. Made in China 2025 lists CNC gear hobbing machine and basic manufacturing equipment industry as one of the strategic areas of China’s manufacturing industry. CNC gear hobbing machine will become a key CNC machine tool developed by the country in the next decade. The development of high-speed and high-efficiency CNC gear hobbing machine has become the focus of gear hobbing equipment manufacturing technology in recent years.
1) Development of CNC system for gear hobbing machine
Since the reform and opening up, the domestic NC system has developed rapidly and basically occupied the low-end NC system market, but most of the medium and high-end NC systems are still occupied by foreign brands, especially the special NC system. Domestic CNC gear hobbing machines generally use German Siemens, Japanese FANUC, French num and other systems. Therefore, the independent research and development of CNC system of gear hobbing machine has become the key to improve the manufacturing capacity of gear hobbing equipment in China. Due to the complex structure of gear hobbing machine and few special CNC systems, the domestic research on the CNC system of gear hobbing machine mainly focuses on the open CNC system. For example, Huang Qiang and others put forward the development strategy of open gear hobbing machine CNC system based on PC and PMAC motion control card.
2) Zero programming technology
CNC gear hobbing machine generally adopts manual programming, but the process processing and numerical calculation are complex and easy to make mistakes. In recent years, some domestic colleges and universities have continued to study the automatic programming technology of NC gear hobbing, such as the embedded NC gear hobbing zero programming technology developed by Chongqing University and the gear processing graphic parametric automatic programming system developed by Lanzhou University of technology, which can automatically generate NC programs by inputting gear parameters and processing parameters, It provides a theoretical basis for further developing the zero programming method and system of gear hobbing machine based on Open NC.
3) Thermal error real-time compensation technology
Thermal error is the machining error caused by thermal deformation of machine tool. Among the various factors affecting the machining accuracy of NC gear hobbing machine, thermal error accounts for the largest proportion, accounting for 45% of the total error of NC gear hobbing machine. Therefore, reducing thermal error is the key to improve the machining accuracy of NC gear hobbing machine. Shanghai Jiaotong University, Sichuan University, Chongqing University and other universities have carried out thermal error compensation Modeling Research on the basis of thermal deformation test, and put forward technical schemes such as thermal error on-line compensation and automatic compensation, which will help to improve the quality stability of NC gear hobbing and improve the intelligent level of high-grade NC gear hobbing machines in China.