Design And Implementation Of PCB Tool Grinder CNC System

CNC system has been developed from a closed mode to an open mode adapting formarket demanding, and the secondary development of an open CNC system is a hottopic in today’s digital technology. In order to Integrating the special tool-grinder’sfunctional modules to CNC system, and to realize intellectual property autonomy, thesecondary development of CNC system is very necessary.For this research project, industrial PC (personal computer) has been selected as anexploring basis, Soft open CNC system—TwinCAT NCI which belongs to BECKHOFFcompany in Germany as a control exploring platform, software of Dragonfly that wascreated in Canada as a several platform, embedding these into Visual Basic6.0softwareto explore VBScript, and to develop human-machine operation interface. Puttingfive-axis CNC PCB tool-grinder as a design object, which has three-axis linkage,mainly research problems which should be solved have been listed by analyzing thebackground of system development and state-of-the-art in home and abroad. Usingstructure analysis method (SA) to analyze the requirements of CNC system, andadopting structure design method (SD) to design HMI operation, PLC and NCIfunctional module, and program codes can be realized, finally the CNC system of PCBtool-grinder is coming true. By PLC program and CNC program in TwinCAT NCI, thelogical control of CNC grinding machine, the interpolation of curves, even the motioncontrol of automatic loading and unloading blank for robot can all be realized.Combined with mechanical part, via BECKHOFF open system, the digital servocommunications between Ethernet EtherCAT and I/O modules actually controlmovement of grinding machine and finish tool grinding.This CNC system operating under Windows XP system integrates the specificfunctional modules of PCB grinder into BECKHOFF CNC system, which is very easyto mastery, and this system has been operated in PCB section of Xiamen Golden EgretSpecial Alloy Co. Ltd.(GESAC). Via this CNC system, PCB section of GESAC has thecapability of higher production precision, production efficiency and production stability.The roundness error of PCB tool is less than1μm, the beat error is less than5μm,helix angle error is less than0.5°, and channel length error is less than10μm, reachingthe international advanced level. During designing, controlling the modular structure of system greatly enhance the versatility and transplanting, also conducive to systemextensions.