Shape Optimization of Preform Dies in two-stage Near Net Forging

In a forging process، a preform dies shape plays an important role in the improving the quality of forging parts and decreasing the cost of production. Some important defects in the forging process are die filling، folding، nonhomogeneous Metallurgical properties and large amount of flash. A proper preform die can reduce or eliminate these defects. In the present research، shape optimizing of preform dies in the two-stage forging process is investigated. A code is developed in ABAQUS commercial software in order to simulate the forging process. The optimization method is based on Genetic Algorithm (GA) supported by an elitist strategy which is developed by authors. To verify the proposed method، two examples have been studied. In the first example، folding defect will occur in the inner surface of a hollow cylinder if forging is done in a single-stage. In order to eliminate folding defect، forging process is done in two stages and the preform die shape is determined by optimization. In the second example the amount of flash is reduced from 13. 9% to 3. 5% in forging of a sliding cluster gear3rd and 4th of Peugeot 405 vehicles. For validation of optimization results the gear has forged in Ahangari Company by optimum preform die shape.