| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 96 === In the production of after-market car body panels in the automobile industry, gypseous models are applied to develop the stamping dies, resulting in problems in die tryouts and poor product quality. The advanced scanning equipment and CAE technology are then adopted to help the stamping die design. Due to the high precision of the scanning equipment, the scanning data matches to the product shape to a very small tolerance. The scanned data is usually converted into a CAD format to construct the CAE meshes. In the present study, the CAE simulations using the STL format of the scanned gypseous die were studied. The CAE technology with the scanned part shape for the die cavity and CAD format for the die addendum was also developed. The developed CAE technology can save much time and cost in the reverse stamping die design process.
The design of the die addendum for engine hood and fenders was investigated in the present study as well. The existing addendum designs for the engine hood and fenders were surveyed and studied first. The effects of the addendum shapes on the formability of parts were then examined by the finite element analysis. The forming of either part without die addendum was simulated and the flow pattern of the material under the blank-holders into the die cavity was analyzed. The effects of different features of the addendums were identified and proper addendum designs were suggested. The suggested die addendum designs can be used as guidelines for the stamping die designs for engine hood and fenders.
In order to reduce the cost of die manufacturing, the reduction of die weight is desired by the die engineers. To achieve this goal, the stress distribution of the die structure during the stamping process is required to be calculated first. The current approach needs two operations of the finite element simulations. The first operation is to simulate the stamping process, followed by the die stress calculation in the second simulation using the force distributed in the stamped part as load boundary condition. In the present study, the dynamic/explicit finite element code was employed to simulate the stamping process and calculate the stress in the die structure in one simulation. The die stress distribution at any stage of the stamping process is then obtainable from the finite element simulation and only one simulation is required. The developed approach can then be applied to optimize the die structure with the use of an optimization code.
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