| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 93 === Metal injection molding(MIM) is a method in metallurgy that combins the benefits from both plastic molding and powder molding. Its advantages include high capacity, high accuracy, low cost for mass production, capability in treating complicated shapes and insensitivity of material using. The removal of binder from the shaped metal or ceramic powder compact is the most consuming step in the powder injection, its many the source of defects in the manufacturing step. In order to reduce the duration of debinding, capillary extraction of the binder by wick powder may be employed. The study utilizes a two-dimensional netwok model to investigate the mechanism of wick debinding by the numerical simulation with a technique combining finite-difference and Monte Carlo methods, a local porosity distribution is quoted in the study, applicable local porosity distribution and typical length scales. Proper theoretical porosity distribution functions are adopted to fit the applicable local porosity distribution, according to the theoretical distribution function, a random number generator is used to generate data of porosity with quantitative randomness for numerical simulations. The typical length scale is an important basis for determining the size of the control volume. The result shows that the contours of wetting wick are irregular and the walking flow edges behave randomly, wick debinding time is proportional to the wick powder diameter and inversely proportional to the compact diameter. As well as the debinding time is proportional to the fractional debinding time.
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