快速模具精密鑄造製程陶殼模破裂原因之研究

The Study of Quickcast Shell Fracture Mechanism under Burnout Process

李泓原(Hung-Yuan Li) ； 郭崇銘(Chung-Ming Kuo) ； 周岳鋒(Yueh-Feng Chou) ； 楊尚樺(Shang-Hua Yang)

《鑄造工程學刊》 36卷1期 (2010/03) Pp. 17-26

https://doi.org/10.29809/JTFS.201003.0003

摘要

本研究探討精密鑄造陶殼模製程中，使用快速原形取代傳統蠟型時陶殼模受到快速原形燒失期間受熱膨脹所産生的影響，本文以不同的快速原形網狀組織參數爲陶殼模破裂的主要因素，利用有限元素方法進行熱應力分析；研究中以田口氏實驗法探討各因子的影響，控制參數包括快速原形的壁厚、網狀組織跨距和深度與陶殼模層數，在防止陶殼模破裂的情況下，找出快速原形最佳參數與陶殼模的最少層數。經由模擬分析找出最佳化參數並且以實驗進行驗證。最後以最佳化參數製作模仁，進行模流分析與實際澆鑄確認。

關鍵字

快速模具 ； 陶殼模 ； 田口氏實驗法 ； 有限元素法

並列摘要

The objective of this study is to analyze the thermal expansion effect of rapid prototype during the burnout process in the course of investment casting. Conventionally, investment casting wax was applied to be the sacrificial pattern. A major impact rapid prototyping processes have had on investment casting is to replace the wax pattern with rapid prototype part. This replacement enables the possibility to fabricate a complex pattern in a matter of hours and to provide a casting in a matter of days. Another advantage is the low cost of producing castings in medium lot size. However, the thermal expansion condition becomes complicated because the cracking of ceramic shell could occur by rapid prototype expansion.
In this study, Taguchi experimental method was adopted to study various factors causing the ceramic shell cracking. Four controllable factors are the wall thickness of the rapid prototype, span and depth of the webbed pattern inside the prototype, and the thickness of the ceramic shell. Finite element method was used to analyze the thermal stress generated during the burnout process both on the rapid prototype and on the ceramic shell. Experimental runs were also carried to compare with the results from simulation.

並列關鍵字

Rapid tooling ； Ceramic shell mold ； Taguchi experimental method ； Finite element