| Summary: | 碩士 === 逢甲大學 === 機械工程學所 === 91 === Abstract
Because of its high productivity, traditional thread cutting die has been widely applied in the manufacturing of products including bolted connections. However, it is difficult to manufacture a thread cutting die with specification of small inner diameter and large thread pitch. Moreover, the cutting performance of an adjustable thread cutting die can often be influenced by the expanding deformation due to loading imposed from fixtures. To overcome the above-mentioned problems, we employ both ANSYS and experiments to improve the design of an adjustable and inserted thread cutting die.
The computed results show that the phenomenon of stress concentration occurs in the thinner, corner, and contact areas obviously. It also indicates that maximum von Mises stress appears initially on top of the above hole in the cutting die and will finally moves to the contact area as a result of the increase of load. The latter implies that the cutting die has been fixed. The average error of cutting radius of the original specification can be reduced from 6μm to 1μm through an optimal design of the thread cutting die. In addition, the relationship between the gap contraction of adjustable bolts (p) and its corresponding variation of inner diameter (q) of the cutting die is found to be approximately linear, and the effect of inner diameter (range from 5mm to 15 mm) on the ratio (q/p) is not significant. The average ratio by computation (about 0.355) is very close to that by experiment (about 0.365), it might thus provide a simple and reasonable reference for the cutting industry and help them in improving the efficiency of tuning the drive for thread cutting die, reducing the waste of specimen, and increasing the productivity.
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