| dc.description.abstract | Wick-debinding in metal injection molding (MIM) is an intricate phenomenon. The motion of molten binder is similar to the fluid flowing through a porous medium in the compact-wick material combination. In the present study, a mathematical model, based on Darcy’s law, is established. To simplify the problem, the assumptions of a single component binder and a fully saturated compact with molten binder are adopted. Body-fitted finite element method (BFEM) is used to calculate the distribution of pressure and other related properties during the wick-debinding of the 2D combination. Additionally, the flow visualization experiment, designed by the Taguchi’s method and a L9 orthogonal array, is qualitatively conducted to describe the process of binder removal. According to the analysis of ANOVA, the optimal control factors can be determined during the wicking process. However, a simple equipment is designed to measure the permeability and the capillary pressure simultaneously. Then the relationships of porosity versus permeability for the simulated porous samples, and the porosity versus capillary pressure for glycerin and R-68 oil are easily obtained. Results show that the prediction of debinding time versus compact thickness squared agrees well to the experimental data. The reliability and accuracy of the present numerical analysis is thus verified. When wicking process is nearly to be finished, the debinding rate increase quickly. Low Reynolds number and low capillary number indicate that capillarity is dominate over other effects, such as inertia force, viscous force, etc. Under the optimal settings, an improvement in the fingering defect and the residual of binder is about 15 dB and 10 dB, respectively. The shape of the flow front of the molten binder and the outer geometry of the compact are found to be closely matched in the final step of wick debinding. | en_US |