New surface requirements for electromobility drivetrain: interaction between Isotropic Superfinishing and grinding

The future of mobility is tied to increased efficiency and energy utilization, where downsizing components becomes a key-task. In the perspective of gearboxes, the need for increased load-carrying capacity is highlighted. In this scenario, the isotropic superfinishing appears as a potential candidate of meeting the new requirements of surface integrity. Superfinishing stands as the final finishing process for gears, usually proceeded by a grinding process. However, the interaction of isotropic superfinishing with previous manufacturing steps and their corresponding characteristics is barely explored by the state-of-the-art. The objective is the evaluate the influence of the manufacturing chain and how surface integrity is affected after the Isotropic Superfinishing process . In the grinding process, lubricant flow, feed rate, and wheel grit were varied, resulting in different residual stress states. It was possible to verify the influence of the grinding process; this influence was tied to hardness, microstructural, fatigue life, and residual stress features, which preserved the heterogeneity and residual stress intensity previously defined in the grinding. This work also illustrates a mechanism that links the interaction of residual stress during grinding and isotropic superfinishing, showing that the grinding process, besides altering a deeper layer, caused a change in the lattice structure, which differed from that of superfinishing.