A flank correction methodology for a five-axis CNC gear profile grinding machine

Abstract

Form grinding is the most popular finishing process for large-size gear because of its high accuracy, efficiency, and flexibility in tooth flank modification. Theoretically, this tooth flank topographical modification is calculated using loaded tooth contact analysis (LTCA), which takes into account the gear tooth, shaft, and housing deflections. Such topographical modification, however, is difficult in the existing gear form grinding method. To simplify production of the ground tooth flank topography, this paper proposes a tooth flank modification grinding method with high-order correction based on the degrees of freedom in the five-axis computer numerical control (CNC) gear profile grinding machine. Each axis of the grinding machine is formulated as a high-order polynomial, and the sensitivity of the polynomial coefficient is derived based on the topographic normal deviation on the gear tooth flank. The ground tooth flank can be approximated to the theoretical tooth flank by adjusting the coefficients of the polynomials based on their sensitivity. We demonstrate the validity of this flank correction method numerically using a helical gear made by the five-axis CNC gear profile grinding machine.