Development Of Special Software For Worm Gear Based On HNC-8 System

Hobbing belongs to intermittent processing.The cutting force is discontinuous and the impact is large in this processing,and the accuracy is required to be high.The spindle works in the speed mode,that is,the spindle not only cuts the work piece,but also participates in the linkage among other shafts.Therefore,the motion control of gear hobbing is complicated,and the traditional gear changing mechanism is difficult to guarantee the accuracy of gear hobbing.The high-precision hobbing machine manufactured by domestic gear manufacturers almost all adopts imported high-grade CNC system with integrated electronic gearbox function,while that function of domestic system is still in the research stage.This paper takes WG37125 CNC high-precision hobbing machine as the research object and HNC-8 system as the secondary development platform,being devoted to developing a special domestic CNC module which is suitable for the hobbing process and meeting the requirements of gear hobbing motion control.Aiming at the mechanical structure and motion characteristics of WG37125 CNC hobbing machine with six-axis and four-link,the hobbing principle and process were analyzed,the motion control requirements of hobbing machine were defined and the software and hardware schemes of special software were determined.In order to satisfy the linkage of hobbing machine,the structures characteristics of two kinds of electronic gearbox were compared.The master-slave electronic gearbox was selected as the control module to realize the linkage among the work piece rotation shaft,the spindle,the tangential feed shaft,and the column moving shaft.The multiaxial follow-up relationship was controlled in the Robot module of HNC-8 system.By analyzing the hobbing method and extracting process parameters,the input interface of the hobbing processing module was designed.The parameter input and the motion control algorithm were realized by using the information transmission between control module and interpolator.Finally,the parameter-input interface and electronic gearbox function module of high-precision worm gear machine tool were developed.The macro program of hobbing processing was also completed by configuring user-defined macro variables.Based on HNC-8 system platform and servo self-test tool,the master-slave following experiment of the linear shaft,the rotating shaft and the spindle was carried out.The tracking error and the follow-up error of the master and slave shafts was analyzed to determine the control error of the electronic gearbox module,which is to be micron level and meets the accuracy requirement of hobbing.