Die design optimization for improvement of hot forging die life

In the present investigation, an attempt is made to improve the hot forging die life by reducing load and wear. An approach for optimization of multi-stage hot forging die design by combining Grey-Taguchi analysis and finite elemental analysis (FEA) with tribology study is presented. As a practical example, the forging of a multi-axle differential spider is considered. The die's critical section is defined using five geometric parameters. For each geometric parameter, four levels are considered to vary the die design. Taguchi L16 design of experiments is proposed to reduce the number of experiments. Forging load and wear depth are the considered response parameters in both the blocker & finisher. An estimation of responses is done for each design using finite element simulations. The Grey-Taguchi analysis is incorporated to optimize the parameters, and regression analysis is adopted to establish a relation between input and output parameters. It is observed that the optimal die set resulted in a significant reduction of wear depth (blocker wear depth - 25% and finisher wear depth - 10%) and load (blocker load - 16%). The tribological analysis is done to validate the optimal design. For tribological analysis, the simulation data (contact pressure, sliding velocity (mm/s), and die temperature) is extracted and converted to input data (load, speed (rpm), and temperature) for the tribometer. The wear analysis reveals that the optimal die set reduces wear depth and wear volume, leading to die life improvement.