M Moradjoy - PhD Candidate, Faculty of Material Science and Engineering, K. N. Toosi University of Technology,Tehran,Iran.
H Khorsand - Associated Professor, Faculty of Material Science and Engineering, K. N. Toosi University of Technology,Tehran,Iran.

This In manufacturing industries processing, the fast de-binding of binders in metal injection molding (MIM) is required. In this paper, the shape retention properties and the step-by-step fast de-binding process of the wax-based binder of multi-polymer component (PW-HDPE) binder are studied and compared to those of the wax-based binder of mono-polymer component binders. A systematic considerate of thermoplastic polymer in the wax-based binder is necessary for ensuring the dimensions and mechanical properties of ۳۱۶L stainless steel metal injection molding parts. Metal injection molding (MIM) is considered as a novel technology for producing metal parts with complex geometry. The present work is focused on producing a homogeneous SS ۳۱۶L feedstock for MIM process by optimizing chemical properties of polymeric and surfactant material. Homogeneity of the feedstock was evaluated by DSC and TGA test. The results reveal the injection molding temperature should be set above ۱۳۸ œC in order to improve the rheological properties of feedstock and decrease the degradation of the binder, and the mold temperature should be set below ۶۰ œC. Backbone polymer in the binder start degrading at ۳۶۰ œC until ۵۵۰ œC, which indicates that in the thermal de-binding stage, the temperature should exceed ۵۵۰ œC. Optimum fractional final density of ۹۷.۱۳% of wrought material was achieved with a sintering temperature of ۱۳۵۰ œC, a heating rate of ۲۰œC min−۱ and isothermal heating at ۱۳۵۰ œC for ۹۰ min in a vacuum atmosphere.

Metal Injection molding, feedstock, ۳۱۶L wax-based binder, rheological properties..