Identification of Manufacturing Process Causes In the Teeth Distortion of Gearbox Shafts

Gearbox shaft manufacturing is related to severe tolerances and complex shapes in automotive industry. During heat treatment, teeth are subjected to local and global distortions partly caused by previous manufacturing steps and material characteristics. The overall objective of our study is to improve the understanding of distortion. Previously, a methodology has been proposed to identify its potential carriers during gearbox shaft manufacturing and it has been validated on a single process step.

In this paper, a new approach is added to this method. First, workpiece geometry and a multi-step manufacturing process is modeled by FEM. As a consequence, simulation gives a new representation of industrial conditions. Then, an identification method is applied to this model. Thus, influences of each single manufacturing step on final heat treatment distortion are obtained. This method enables to determine main causes of distortions and to anticipate it by focusing on most influent manufacturing steps. Finally, propagation of uncertainties is carried out to evaluate a possible correlation between simulation and experimental data coming from an industrial process.