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New material laws for metal filled injection moulding feedstocks

Final Report Summary - MATLAW (New material laws for metal filled injection moulding feedstocks)

The first half of the project was aimed at establishing the shortcomings of mould filling simulation using two demonstrators of small and medium-sized enterprise (SME) partners and aimed at analysing fresh feedstocks made up of various binders and various powders, covering the most important materials processed by the partners. The following properties were analysed using the given instruments. Often, two different instruments were used to find out about the reliability and the possible error of given techniques.

Several methods able to analyse feedstock batch to batch consistency were analysed and tested using fresh feedstock batches of supposedly the same composition from partner MIMITALIA and another series from partner Parmaco.

It was possible to collect reliable data about a range of feedstocks based on different binders and to use them for simulation. At the start of the project, no consistent data had been available which led to simulation results which differed clearly from the moulding conditions being used for the demonstrators. Nevertheless, there already seems to be some correlation between high shear of the feedstock with phase separation (dark spots) on the surface of green parts.

In the second half of the project, the collection of feedstock data continued and also included many experimental feedstocks which had been prepared to check on the new material laws. New insight into the jetting and filling behaviour of the different binders and feedstocks was found experimentally and could be quantified by analysing the limiting shear stress of the materials.

Phase separation of feedstocks was investigated by several methods. It was found that all of them are not able, yet, to determine and to quantify the phase separation in PIM feedstocks, possibly due to very limited occurrence. Nevertheless, important experience was obtained on the methods used and their applicability to the problem. Simulation of mould filling demonstrated the possibility to foresee and to optimise critical mould areas but cannot quantify it.

A tool for easier characterisation of feedstocks was developed. Testing in production was limited due to experimental problems.

It was possible to create a good pool of consistent feedstock data in the end and to use this to simulate the demonstration moulds of all MIM producing partners. The feedstock producers can now offer the simulation to their customers. The simulation software was shown to be improved by the improved data available to characterise the feedstocks and by the description of new material behaviour. The new rheological model for the feedstocks was successfully implemented into the software.

The relevant people of all the industrial partners were trained in the new possibilities of mould filling simulation in a joint workshop.

All partners have expressed their urgent need for these results for their daily work. It seems that more and more customers prefer to have their new moulds simulated before actually producing them. Thus, the industrial partners will certainly use the information from the project to improve their processes.

The dissemination of the results will take place via the feedstock producing partners and via Sigma as they are interested to use the information as extra incentive for their customers. Already, there was a first presentation during the EURO PM2008 in Mannheim / Germany and an exchange with the European project CARCIM in November 2008. All the MIM producers have been convinced that simulation has become a useful tool for every new mould.

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