The performance of large-scale CNC gear profile grinding machines is needed to be improved. One of key technologies is how to accurately control the assembly geometric errors according to the accuracy requirements of the gear tooth surface. The profile grinding tooth surface model including assembly errors was established using the surface envelope method

based on the error transmission chain of the profile grinding system and the conjugate motion relationship between the grinding wheel and the workpiece. The error evaluation method of the profile grinding tooth surface was proposed by calculating the difference between the theoretical tooth surface and the envelope tooth surface. On the basis of the above

the influence of assembly geometric errors on the profile grinding tooth surface errors was quantitatively analyzed. Finally

the assembly geometric errors were optimized according to the analysis results and accuracy requirements of the gear tooth surface. The gear forming grinding test was carried out. The results show that this method provides a reliable theoretical basis for the performance improvement of large-scale CNC gear profile grinding machines.