Geometric Error Compensating Technique For P3G CNC Grinding Machine

As the mechanical development of high-efficiency、high-velocity、high-precisionand multifunction，the requirement of function and quality are increasing higher intransmission machine. Compared to the frequently-used joints of key and spline，P3G（polygon profile with3lobes） shaft and hole have the excellent performance ofhigh-strength in joint、self-centering in loading、keep dynamic balance between shaftand moving parts、high transmission torque、no stress concentration、low noise and lowvibrate in transmission and so on. However，cultural CNC（Computerized NumericalControl） P3G grinding machine existing various unavoidable machining errors. Re-search showed that geometric errors and thermal errors take part in70%in total errors.So，it is necessary to compensate geometric errors for improving working accuracy. Themulti-body system theory is widely used in the geometric error compensation in recentyears. And through the computer software technology, achieved real-time calculationand error correction.This paper is based on increasing the machining precision of CNC P3G grindingmachine，researched on the geometric error compensation technique of grinding ma-chine. Researched on the geometric error compensation technology which based onP3G CNC grinding system, explored the design process by computer software to estab-lish the framework of the geometric error compensation, and proposed geometric errorcompensation system of the high precision CNC grinding machine by the theory of dy-namics multi-body system theory. The main works carried out in this study are as fol-lows:1）Analyzed main machining errors in the system of P3G grinding machine，obtained that geometric error is the main reason of machining P3G shaft and holewith errors. Comprehensive considered the various error factors in grinding sys-tem’s kinematic chain, derived the error transformation matrix.2）Described21errors in P3G grinding machine，and used9nines to identify geo-metric error parameters.3）Developed compensate system of geometric errors in CNC P3G grinding machinewhich based on the geometric error model. Establish math model of geometricerrors through software, and analyzed P3G curvilinear motion of grinding ma-chine in detail, finally presented compensate proposal for CNC P3G grinding machine，and developed error compensate software for the grinding machine.Obtained a revised NC instruction and attained precise CNC machining.4）Through the results of experiment，the error compensate effect is apparently tomachining P3G shaft and hole, comparing the work-pieces machined by com-pensated CNC codes, showed that software geometric error compensation is ef-fective to improve the work piece’s machining precision, and finally provedsoftware geometric error compensation is effective and feasibility.