4M Knowledge base - papers

Per Johander (a) , Urban Harrysson (b) , Ulrike Kaufmann (c), H.-J. Ritzhaupt-Kleissl (c)

a IVF Industrial development and production, Argongatan 30, 431 53 Mölndal, Sweden
b Fcubic Argongatan 30, 431 53 Mölndal, Sweden
c Forschungszentrum Karlsruhe, Institute for Materials Research III

Abstract

Layered manufacturing has mainly been used for prototype manufacturing in product development. Direct manufacturing of small components is very favourable due to the scaling effect. The number of components that could be manufactured in one batch grows by the square if the size of the parts is reduced to half. The ceramic material used is yttrium-stabilised zirconium. The structural information is printed by ink jet in powder layers of only 80 μm thickness. The actual part creation is done in a subsequent heat treatment process where a development process takes place. This is an advantage as the machine speed could be increased considerably compared to other layer manufacturing principles. The parts manufactured are impregnated with epoxy and the material properties are comparable or better than injection molded parts. The other option is sintering of the parts to full density. The sintering process has been studied and the shrinkage and material properties evaluated. A cost analysis has been performed comparing direct manufacturing of small batches of components to plastic mouldinginjection.

T. Hanemann (a,b), K. Honnef (b), J. Hausselt (a,b)
a Forschungszentrum Karlsruhe, Institut f. Materialforschung III, D-76021 Karlsruhe, Germany
b Albert-Ludwigs-Universität Freiburg, Institut f. Mikrosystemtechnik (IMTEK), D-79110 Freiburg, Germany

Abstract

Different variants of reaction molding techniques like UV-embossing, UV-RIM, Photomolding, a.o., exploiting the rapid light induced photopolymerization of reactive resins are widely used in microsystem technologies for the fabrication of microoptical components or for rapid prototyping purposes. The solidification based on photocuring limits the suitable materials to transparent resins and yields only plastic microstructured parts. In this paper the further development of micro reaction molding with respect to a rapid prototyping of ceramic and metal parts will be described. As in the different variants of powder injection molding additional process stages have to be considered and individually optimized. First a free-flowing reactive resin based composite with a large filler load (microsized ceramic or metal powder) of at least 45 vol% has to be prepared. The addition of suitable thermal initiators allows the solidification of the composite subsequently after mold filling in a molding tool equipped with microstructured mold inserts. The mold filling and hence the accurate reproduction of surface details depend strongly on the composite’s viscosity, which is a function of the filler load. The further process stages like debinding and sintering have to be optimized with respect to the polymer based reactive resin used and the ceramic filler. Especially an improved process control of the composite formation prior to molding and the thermal debinding is crucial for the realization of ceramic or metal parts carrying a microstructured surface. The development of the whole process chain and some microstructured ceramic or metal parts will be presented.