Effect of the pipe connecting tank to an air cushion on sheet metal stamping

• Main Authors: Chung-Lung Hsieh, 謝宗倫
• Other Authors: 范光堯
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/40841585905800698429

碩士 === 國立中興大學 === 機械工程學系所 === 97 === One of the most important factors by stamping a sheet metal is the blank holder force which can offer appropriate clamping forces letting the sheet metal flow or blocking it to flow and therefore a perfect part can be achieved. However when an air cushion is used to build up the blank holder force, the blank holder force might not be appropriate for the forming part due to the limited space underneath the press where the cushion is installed. If a tank out of the press is attached to the cushion, the situation might be improved though, the pipe connecting the tank and the cushion still might affect the blank holder force. Hence a model was generated in this study to describe the pressure drop between two ends of the connecting pipe. The pressure in the air cushion and in the tank at any time during the press operation can therefore be determined. An investigation of the size of the connecting pipe, the press stroke, and the stroke per minute on the pressure in the cushion was performed in this study for forming with a mechanical crank press. To check the feasibility of the model created by this study, a FDM simulation was accomplished with the commercial computational fluid dynamic software FLUENT. Furthermore, an investigation of the blank holder forces above calculated in this study on forming a sheet metal part was carried out with the commercial sheet metal stamping software DYNAFORM. The results show that the model created by this study is suitable to determine the appropriate pipe size for the forming application and the pipe size as well as the application setups should follow the design guideline so that the pressure in the cushion at the bottom dead center does not exceed above 16.67%.