| Summary: | 碩士 === 中原大學 === 機械工程研究所 === 103 === Abstract
Plastic injection products with light weight, high precision and productivity have been widely utilized on consumer electronics. However, the uneven volume shrinkage during the process of injection will cause the product curved or deformed after demolding. It will also result in poor roundness of round products.
To find the best approach, the study focus on the round plastic products with different molding conditions, including mold temperature, melting temperature and injection speed. Comparing PC material in 0% fiber, 10% fibers and 30% fibers by CAE software and physical experiment will know the effect of fiber content in terms of the roundness. It came to a conclusion that the roundness of products in PC material without fibers is better than those with fibers. Moreover, those which contain more fibers got lower flow balance. Due to small shrinkage rate of the fiber, adding fibers can restrain shrinkage rate of the product. The reason of uneven shrinkage and variation of roundness came from the fiber orientation in the direction parallel or perpendicular to the flow, as well as the temperature difference inside the product. Rising temperature in molding condition can improve roundness.
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