Indexing error transfer law of a gear grinding machine

To predict the pitch machining accuracy of a gear to be ground, the transfer law of the systematic indexing error of the gear-grinding machine (Y7125) with flat-faced grinding wheel was researched. The normal 36 prism for angle measurement datum was calibrated in high-precision by using the full closure measurement method, then the systematic indexing error curve with 36 equal points was extracted on-machine based on the normal 36 prism and the relative measurement method. Finally, the precision gear-grinding experiment was conducted on the gear-grinding machine. The indexing error transfer law of the machine was studied by comparing the difference between the cumulative pitch deviation of a gear specimen and the original systematic indexing error of the gear grinding machine, and the uncertainty during the error transfer process of the gear-grinding machine was obtained by experiments. Experimental results show that the measurement uncertainty of the full closure measurement method to calibrate the normal 36 prism reaches to 0.05″. The total cumulative pitch deviation varies from 2.1 μm to 2.6 μm and the relative error increases by 24% after the systematic indexing error of the gear grinding machine transfers to the gear to be ground. Moreover, the uncertainty during the error transfer process is ±0.6 μm. The transfer law of systematic indexing error of the gear-grinding machine from the experiments mentioned above can be used to predict the pitch machining accuracy of the gear to be ground and can provide technical supports for the development of the scientific gear-grinding process. © 2016, Science Press. All right reserved.