The mass production of carrier devices incorporating membranes as quasi-monolithic devices is often problematic, and a way to produce these devices as an integrated product would offer distinct economic advantages. As these membrane devices are made from both plastic and also metals and/or ceramics, a suitable manufacturing method capable of volume production is required.
Researchers at the Institute of Applied Materials at the Karlsruhe Institute of Technology (KIT) in Eggenstein-Leopoldshafen, Germany, have adapted micro powder injection moulding technology developed previously at KIT to overcome problems in producing µPIM parts with significant differences in wall thicknesses required in the various membrane carrier combinations.
Dr Volker Piotter and his colleagues at KIT reported in the May 2015 issue of Microsystems Technologies (Vol. 21), that in order to produce the integrated membrane carriers containing different wall thicknesses, a demonstrator tool design was developed. This tool design enabled the generation of thin membranes by a controlled piston movement in the injection moulding step. Simulation calculations were used to determine the layout of the runner system, and the resulting filling behaviour and dimensional accuracies of the moulded parts.
The twin-piston moulding tool also enabled the subsequent embossing of the moulded feedstock in the membrane cavity which allows further consolidation and results in a defined adjustment of the membrane thickness in the range from 600 µm to less than 200µm.The combined injection + embossing process could further reduce minimum membrane thickness by a half.