Numerical and experimental investigation of process parameters optimization in hammer forging for minimizing risk of crack

Hammer forging is a traditional manufacturing technology to produce high stiffness product and is widely used in heavy industries. In the hammer forging, the product is produced through several blows. Unlike forging using mechanical press, the product is produced by the energy in the hammer forging, and consequently the energy distribution in blows plays a crucial role for producing highly accurate product. Conventionally, the energy distribution is determined by the trial-and-error method. This paper proposes a methodology to determine the optimal energy distribution using numerical simulation and design optimization technique. It is important to minimize the total energy for energy saving and the risk of crack for product quality. To produce the highly accurate product, underfill should be avoided, which is handled as the design constraint. Therefore, multi-objective design optimization is performed to minimize the total energy and the risk of crack without underfill. The numerical simulation is so intensive that sequential approximate optimization that response surface is repeatedly constructed and optimized is adopted to identify the pareto-frontier between the total energy and the risk of crack. It is clarified through the numerical result that the proposed approach can determine the energy at each blow effectively. The experiment is also conducted to examine the validity of the proposed approach.