Optimisation of parameters for upset forging of bolt using Taguchi Method

• Main Authors: LIN, JIAN-HONG, 林建宏
• Other Authors: FANG, LIAN-BIN
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/73azg5

碩士 === 建國科技大學 === 機械工程系暨製造科技研究所 === 105 === In several forging processes for various products, upsetting is used as one of the major process for the formation of bolt head, in which the defects such as buckling, fracture and internal flaw should be under control during these processes, and the rate of defect-free increases here from. In order to fully understand the effect of parameters for upsetting process, the axisymmetric CAD model of dies and billet was built by using the software of computer-aided design, SolidWorks, and the model was imported into the software for metal working industry, simufact 10.0, to simulate the three-stage formation process of bolt head. The Taguchi method was employed to arrange the parameters concerning the geometry of dies during simulation process of each stage. The values of normalized Cockroft-Latham coefficient, a ductile fracture criterion, was calculated in each simulation process of different combination of parameters as a basis of finding out the optimal combination of parameters for each stage of formation. The results show that the three impact factors on formation of bolt head are the side height of lower die, the height of head on lower edge of the upper die and radius of bolt head. Accordingly, we have the conclusion deduced from the results that the dramatic variation of geometry dominates the formation of bolt head. The materials flow to the regions which geometry varies dramatically during simulation process, and the effective stress and effective plastic strain possess the similar higher value nearby the initial contact region of workpiece.