Studies on Tool Wear Analysis and Parameters Design Optimization for Hot Forging

• Main Authors: Jin-Long Jou, 周金龍
• Other Authors: Rong-Shean Lee
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/32153652433981412581

博士 === 國立成功大學 === 機械工程學系碩博士班 === 93 === 　The finite element method (FEM) has been widely used to evaluate forging process design by transferring the trial-and-error design procedures from factory workshop to computer. However, to obtain optimum process parameters, it may take several times of computer simulation, which is very time consuming. This research therefore focused on shortening the process development cycle and a forging design parameter optimization model has been successfully constructed. The forging process simulations were considered as experiments. The orthogonal arrays and Taguchi method were adopted to plan and to minimize the simulation analysis. From the analysis, the optimum process conditions and the process parameters sensitivity were obtained. In the optimization procedure only one objective function was considered to simplify the analysis. Therefore, the quality requirement was considered as restriction and the optimum parameters were assessed based on the design experience. 　The die life has been used as the objective function in this research. Since majority of the forging die failure results from wear, this research therefore tackled the die life optimization based on the Archard wear theory by assuming that the die hardness and the die material wear coefficient is function of temperature. Furthermore, high temperature hardness tests and high temperature wear tests were performed to establish the relationship between the die hardness with the temperature and the wear coefficient with the temperature. A modified Archard wear model that accounts for the temperature in hot forging was proposed. 　By applying the modified Archard wear model and the proposed optimum parameter design method an optimum parameter design for forging titanium artificial hip joint accelebulum cup was obtained by minimizing the die wear objective function. This optimum design not only had a good quality conforming to the demanded microstructure and dimensional tolerance, but also had a die life longer than the estimation based on experiences. The methodology constructed in this research not only can shorten the design process but also can be used to estimate potential die life in the design stage. The proposed method is beneficial to the estimation of die cost, selection of die making method and efficient production scheduling.