Experimental Study on Sintering and Infiltration Process of Metal Part Fabricated by Mold Decomposed Injection Sculpturing

摘要

Mold Decomposed injection sculpturing (Mold DIS) process which integrates injection and sculpturing in layered manufacture is a novel rapid prototyping technique. In this paper a wax mold is fabricated through DIS process, the 316 L stainless steel slurry is then cast into the mold. After curing and drying, the wax mold is melted and the green part is obtained. The purpose of this paper is to study the process of sintering and infiltration of the green part especially which have fine features. Firstly, the solid state sintering was investigated using taguchi experiments. The result shows that sintering temperature gives more effect on the final density than heating rate and holding time. However, when high temperature sintering is adopted, complex shape parts can not be formed without flaws due to the excess shrinkage. Then, copper-infiltration is used to reduce shrinkage and improve mechanical properties. A new infiltration process, named "short-time high-temperature" infiltration, is utilized to form the thin-walled structure. It shows that sintered sample with shrinkage rate of 5.02%, density of 7.56 g/cm³, bend strength of 336.4 MPa and hardness of HV189 is obtained through "short-time high-temperature" copper-infiltration at 1380 °C in vacuum. Finally, a part whose feature size range from 1.6 to 45 mm and a part with complex internal structure are formed without obvious defects.