Metal Injection Molding Technology: Expectations and Limitations
Berenika Hausnerova, Petr Saha
Tomas Bata University in Zlin, Faculty of Technology, Polymer Centre
Czech Republic

Keywords: Metal Injection Molding, polymeric binder, flow disturbances

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Metal Injection Molding (MIM) technology is a state-of-art process for making metallic items of various uses in aeronautics, automotive, computer and many other industries. This method allows the large-number production of relatively small (corresponding to a weight of around 100 grams) metallic parts of complex shapes with reduced cost and increased efficiency by avoiding the use of extra processes. It combines the flexibility and mass production of injection molding used in plastics with the efficient use of materials employed in powder metallurgy. While at the beginning the research in this area dealt mainly with tailoring suitable polymeric binders to the particular powder and desired application, at present it concentrates to the sophisticated treatment of the critical points of the MIM process. One of such points is injection molding of the MIM feedstock, which depends on a primarily viscous flow of the mixture into the die cavity. Rheology is then of key importance in understanding the flow and deformation behaviour of the MIM feedstock. In this paper we concentrate on the flow disturbances occurring during shear flow of highly concentrated (up to 55 vol.%) hard-metal carbide compounds, showing the possibilities of their reduction or/and full elimination. Such specific rheological characteristics to a large extent limit the possibilities of using Metal Injection Molding technology.