Crucial errors identification of worm grinding process of face gears based on tooth flank posture error model and their influences on tooth flank errors

Currently, worm grinding is the most effective way to manufacture high-precision face gears, but complicated and difficult. For disclosing the mapping laws between the worm-face gear posture errors and face gear tooth flank errors, the face gear tooth flank posture error model (TFPEM) was firstly deduced by decomposing the worm-face gear posture errors into 18 worm and face gear posture errors. The improved Sobol method (ISM) was applied to calculate the sensibility of each posture error to identify the crucial errors (CEs) in each error direction (ED) of the tooth flank. Then the error correction tests on the CEs were carried out to verify the identification results. Finally, the influences of the CEs in different EDs of the tooth flank were analyzed. The results show that the δy-direction with the smallest error reduction rate (ERR) reaches 73.83%, which indicates the reliability and effectiveness of the identification results. The established TFPEM is effective to reveal the effects of the worm and the face gear posture errors on the face gear tooth flank errors.