Wall-slip of highly filled powder injection molding compounds: Effect of flow channel geometry and roughness

Abstract

Abstract. The paper deals with the rheological behavior of highly filled compounds proceeded via powder injection molding (PIM) and applied in many sectors of industry (automotive, medicine, electronic or military). Online rheometer equipped with slit dies varying in surface roughness and dimensions was applied to investigate the wall-slip as a rheological phenomenon, which can be considered as a parameter indicating the separation of compound components (polymer binder and metallic powder) during high shear rates when injection molded.

Surface adhesion between ceramic injection molding feedstocks and processing tools

“…Further, we have pointed out that wall slip could be considered as a rheological parameter indicating powder-binder separation absence/occurrence [4,5]. Nevertheless, the conditions, at which the highly filled materials slip at the wall resulting in a plug flow (and thus no separation), are not only feedstock characteristics and processing parameters, but the most important is an interfacial adhesion between the channel walls and CIM feedstock (binder and powder), depending on the surface treatment of the mold channels.…”