INDALMIM - Aluminium: Injection molding for industry

Metal injection molding is a popular method to produce precision parts at low cost and with high material utilization. While this works perfectly with stainless steel, titanium and carbides, so far it has been a problem with aluminium.

Al is difficult to sinter (i.e. fusing powder together at high temperatures) due to its stable surface oxides; therefore it has only been possible to injection mold aluminium at the lab scale. For this reason, INDALMIM set out on the mission to develop the required process stages for the industrial application of aluminium metal injection molding, and to refine alloying techniques to the point where implementation by the automotive industry appears realistic. This involved finding solutions to the sintering challenge as well as the recurring problem of surface staining.

Up to 50 percent less material

Aluminium alloys have a particularly low melting point, which is why removing binders by means of traditional thermal methods is difficult since it overlaps with liquid phase sintering, causing melting. This must be avoided at all cost, otherwise carbon is picked up that would prevent sintering.

The researchers have now achieved consolidation by sintering in a nitrogen atmosphere, the debound body containing low oxygen and carbon concentrations. A solution to the unattractive surface layers formed during the cooling phase was also found. In the process of sintering aluminium alloys, particular care must therefore be taken to control the temperature and the partially reactive atmospheres. Thanks to this knowledge, serial production of components by means of industrial injection molding is possible.

The new technology developed by INDALMIM uses relatively coarse, off-the-shelf - and therefore cheap - powders to even allow production of larger components. It can immediately be integrated into existing production lines and saves material by up to 50 percent; in the case of the energy-intensive metal aluminium, this means a significant re duction in energy consumption. A patent for this technology has already been applied for.

Consortium Manager

TU Wien, Institute of Chemical Technologies and Analytics

Other Consortium Partners

• TU Wien, Institute of Chemical Technologies and Analytics
• Fotec Forschungs- und Technologietransfer GmbH
• Rupert Fertinger GmbH
• BASF SE
• Ecka Granules Germany GmbH

Project Coordinator

Herbert Danninger
E-mail: herbert.danninger@tuwien.ac.at