- 學位論文
澆口設計應用於薄殼鋅合金壓鑄模具之流動研究
The Study of Flow on Gate Design in Thin-Shell Zn-Alloy Die Casting
摘要
摘要 壓鑄模之設計主要之參數含有: 進澆口寬度、位置、形狀與和斷面厚度。本研究以多模穴之薄殼鋅合金件(1.6 )模具，利用實驗設計法及電腦模擬，探討高溫高壓流動金屬成形狀態。在於不同?數下，合金熔液於模穴中的流動情形，並利用熱室壓鑄實驗驗證結果。 由分析結果，流道設計之首要考量以合金熔液流動距離最短，而且以合金熔液最容易充滿模穴者為最佳。並於模流模擬充填過程中發現，前方有阻礙物或厚度變化大時，將使得流動速度減緩。而兩側之流體將會造成超前現象，並會向中央包圍之趨勢，以致產生捲氣或氣孔情形。本研究利用電腦模擬之結果，改變流道形狀及流道尺寸，有效將包封產生之氣體在合金熔液流動的推動力之下，將其推入溢料井區，以減少氣孔之產生。 最後本論文以最佳流動設計模擬分析，配合壓鑄實驗印證，得到結果有：(1)流動最平順，捲氣最少；(2)將氣孔之產生減至最少；(3)兩者相似性約95%之準確度。
並列摘要
Abstract The main parameters of the mould included four variables relating to the gate system: gate size, position, shape, and cross-section. This study aimed to create multi-cavity die casting mould for thin shell zinc alloy parts of maximum 1.6mm thickness, and experiment designs and computer aided simulation to explore flow state of meta in the hot temperature and high pressure. In the different parameters, the flowing situation of the alloy melts in the mould cavities and verify the result using a hot-chamber die casting experiment. Analysis of the results shows that the primary goals of runner design include two things: (1) the flow path of melted metal was shortest; (2) mould cavity was easiest to fill with melted metal. Flow at the sides met obstructions and in some cases became thicker in the filling stage of the simulation. The simulated flow into the middle of the mould was found to be relatively slow but was faster on the two sides. The flow on both sides would gradually surround to the center so that trapped gas or gas porosity was produced. The main objective is to use result of computer aided simulation, and change runner shape and runner size to use analysis software to simulate the flowing condition of the air, which produced air trap. The melting metal motive force pushed air into the cold slug well in order to reduce the production of pores. Final paper is the runner best design to simulate analysis, and verify the result using experiment of die casting. Analysis of the results include three things: (1) the best smooth-going in the flow state, and the best less in the trapped gas, (2) reduce the production of gas porosity, (3) both with a nearly 95% accuracy.