Gear Hobbing Predictive Model

This program will demonstrate the feasibility of innovative physics-based modeling of gear hobbing to predict and improve residual stresses and heat treat distortions while reducing production cycle times and costs of transmission gears. TWS will develop a general, validated, physics-based modeling capability for the gear hobbing process, resulting in detailed chip formation and residual stress prediction. This will be achieved through both a detailed finite element modeling of tool-workpiece interaction, and CNC toolpath-level analysis. The combined outputs of these comprehensive models will provide the ability to predict machining-induced residual stresses and their effects on distortion from subsequent heat treatment, and determine interactions between machining process changes and cost, cycle time and workpiece characteristics. Feasibility will be demonstrated by: 1) advancing physics-based machining modeling for gear hobbing processes, 2) developing physics-based gear hobbing predictive models based on finite element modeling, and 3) validating these physics-based models against machining experiments. Anticipated results results of the program will: (1) predict residual stresses, forces, temperatures, and tooling performance for hobbing; (2) improve fatigue life of gear components through residual stress management while reducing cycle times and cost; and (3) advance knowledge of material removal mechanisms in gear hobbing and their effects on post-machining operations.