Molding Micro Parts and Micro Structures Transcription of Small Surface Structures in Injection Molding—An Experimental Study

Abstract

This chapter investigates molding microparts and microstructures transcription of small-surface structures in injection molding. The experiment is carried out with a 2 mm thick ruler-type part with an edge gate and a cold runner in a two plate mold. Opposite the gate end, the cavity has a band with a rough spark eroded surface. The surface roughness is measured on a Talysurf Surtronic 2D mechanical stylus instrument. The experiment reveals that surface transcription consisted of both the hypothesized flow formation and press formation. From the first set of experiments where holding pressure is set to a minimum, it is seen that the transcription is improved progressively with higher injection rate. In the second set of experiments where press formation is investigated, it is evident that higher pressure up to a certain point improved transcription. In both sets of experiments, the increased temperature improved transcription quality and higher temperatures are observed to shift the roughness upwards.