| Summary: | 碩士 === 國立臺北科技大學 === 製造科技研究所 === 106 === In high pressure die casting (HPDC), it always occur the defects of Air porosity and Shrinkage Porosity. These two kinds of internal defects will result the poor product strength. In this study, material tensile tests were conducted first, and correct the appropriate interface heat transfer coefficient (IHTC), use the PQ² curve to find the operating pressure and the operating flow rate of this HPDC machine, ProCAST software was used to reduce the gas formation by find the proper pouring height and delay time. By matching the parameters of the piston speed low and high speed velocity and Transfer position, and determine the defect position, and finally uses local squeezing to the defect location. The results show that the squeezing pressure needs to above 213 MPa, the start and end time of the squeezing is between 0.8 - 2.83 sec, and the extrusion depth is 0.5 mm to effectively improve the internal shrinkage defects, it will obtain the optimization product to achieve the non-porosity products.
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