| Summary: | 碩士 === 龍華科技大學 === 機械系碩士班 === 92 === This study aims to improve the manufacturing process and warpage of the electronic dictionary battery cover in thin wall injection molding. The major technique is to replace the mainstream electronic dictionary battery cover made in insert molding with the thin wall electronic dictionary battery cover made in high-speed injection molding. The later has merely 0.2 mm in thickness, and its ratio of flowing length and thickness(L/T) can reach 338. The first step is MoldFlow numerical simulation to retrieve the data of best gate position and the sum. The second step is the molding window of applying ABS and PC+ABS respectively in molding the thin wall electronic dictionary battery cover. The third step is analyzing the best warpage and the influential parameters through applying ABS and PC+ABS respectively in Taguchi Method, and using some production to test and verify the best composition. The fourth step is applying ABS and PC+ABS respectively in short shots experiment of molding the thin wall electronic dictionary battery cover to compare the melt front of ABS and PC+ABS with the predictions of simulation; through 3D numerical simulation, in addition, simulating the variations of melt front of battery cover in three kinds of thickness: 0.2 mm, 0.5 mm, and 1 mm. The final step is utilizing stress viewer and SEM to observe the stress distributions and polymer orientation of part.
The results of the experiments show that the molding window of ABS is larger than the molding window of PC+ABS, and that, via ANOVA analysis, detected the most important manufacture parameter are low melt temperature and high injection speed and high packing pressure which can ensure better warpage. The short shots experiment prove that the simulation and actual shaping have similar melt front, and that 0.2 mm product has hysteresis effect and race effect.
After the enhancement, the production coasts of the thin wall electronic dictionary battery cover can largely lower, which can, on the contrary, largely raise the competition of the companies in this industrial circles.
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