The principles and processes for grinding face gears with disc grinding wheel were described. The envelope residual mechanism was studied for two machining methods of profile envelope and longitudinal envelope. The envelope residual computing models for two kinds of cutting mode were established

and the generating characters of envelope residual were investigated. The influences of cutting parameters

such as circumferential feeding angle

longitudinal feeding and grinding disk diameter on surface envelope residuals were analyzed. Computing results indicates that longitudinal envelope has much higher efficiency than profile envelope. A grinding experiment of face gear by profile envelope was performed. When the tool circumferential feeding angles were taken as 2 degree

1 degree

0.5 degree and 0.2 degree

respectively

the tooth surface roughness was improved significantly

and the number and direction of the grinding traces were consistent with the envelope simulation results. The appropriate feeding parameters adopted according to the envelope residual computing results can ensure surface roughness level of face gear teeth by grinding.