- 學位論文
精密鑄造射蠟成型尺寸縮水率預測
Shrinkage Prediction of Wax Injection Molding for Precision Casting
摘要
精密鑄造成型之產品尺寸精確性取決於射蠟成型階段的製程技術，而在本研究中將針對射蠟成型過程中，製程參數對尺寸縮水率的影響程度及得到正確的電腦輔助分析方法作為本篇研究主要探討主題。 射蠟製程條件包含射出壓力、保壓壓力、保壓時間、射出時間、射出速度、射蠟溫度等因素將影響蠟胚成型的精確性。在第一階段的研究當中先進行模擬分析與實驗的準確率驗證，由於目前模流分析軟體內建材質庫對於蠟材質的建立相當匱乏，也無法由資料庫中直接取得本文研究用蠟的參數，因此，在此階段的研究，須先找出蠟材料物性參數，材料參數取得之後，開始進行第一階段模擬方法的測試與確認，第一階段完成模擬方法確認後才能進入第二階段的研究。第二階段將以第一階段研究為基礎的模擬方法進行田口實驗法，目的是要將影響尺寸縮水率之顯著因子找出，第三階段將以目前量產模具進行驗證，以第一、二階段所獲的研究資料為基礎，利用模擬的方法與實際蠟胚做數據上的驗證比對，尺寸縮水率的模擬誤差能夠控制在1%，利用模擬技術提供模具尺寸縮放係數再配合射蠟製程參數的有效調整，將可大幅提升蠟胚尺寸穩定性及模具蠟計尺寸縮放正確性。
並列摘要
Product size accuracy in investment casting depends on the techniques used in the wax injection molding process. This paper discusses the effect of process parameters on size shrinkage rate and how to obtain an accurate computer-assisted analysis method. The wax injection process includes injection pressure, packing pressure, packing time, injection time, injection speed, injection wax temperature, etc. These related factors will affect the accuracy during the formation of wax embryos. During stage 1 of the research, we perform simulation analysis and testing of the accuracy of experimental results. We need to identify the parameters of properties of the wax elements, but due to the lack on data in the current internal databases of simulation analysis programs, we cannot directly obtain the parameters needed for this research. Once the materials are obtained, we can then proceed with the simulation and testing of stage 1, and only after the simulation process method is confirmed we can continue with stage 2 of the research. Stage 2 uses the simulation method from stage 1 as a basis to perform Taguchi method, with the objective of identifying the significant factors affecting size shrinkage rate. Stage 3 of the research makes use of the research data from stages 1 and 2 to perform evaluation tests of current molds in mass production. It also utilizes simulation methods and real wax embryo data to perform cross over validation, with the expectation of obtaining a size shrinkage rate simulation error of within 1%. By making use of simulation techniques to provide mold size scaling factor and combining with adjustment of parameters during the wax injection process, we can significantly increase stability of wax embryo size and correctness of mold design size scaling.