Influence of Material and Processing Parameters on the Surface Roughness of Injection-Molded Ceramic Parts

Ceramic parts were prepared by means of injection molding and a two-step debinding and sintering process. For four different alumina ceramic feedstocks, the influence of processing parameters like holding pressure, injection speed, melt and mold temperature on the surface roughness was studied. The surface roughness was measured in the direction of flow and perpendicular to it with a tactile cantilever measuring system. A gradient in the surface roughness is detected along the flow path, which ended in a relatively coarse surface section. Smoother and more even surface structures can be generated with higher mold temperatures. In general, larger particle diameters cause greater surface roughness. Lower injection speed and melt temperature show similar effects. However, no significant effect was observed with regard to the holding pressure. Based on these results, the surface roughness could be adjusted in a certain range by changing material or processing parameters in order to fulfill the requirements of a subsequent metallization step.