A new mold design for qualification of powder/binder separation in PIM technology

Abstract

In powder injection molding (PIM) polymeric binder and metal/ceramic powder are mixed together to create homogenous feedstock. During injection molding stage shear rate gradients in a bulk material are created due to the rotation of powder particles close to the channel walls at the exposed locations. As a result, in these regions a phase separation may occur. Powder/binder separation of multi-component systems is the main quality issue of the PIM parts, and thus an effort has been put to study it with various molding approaches. This paper compares currently employed geometries of mold cavities for determination of phase separation, and proposes a new design of mold, which intercepts majority of possible critical locations.