Sintering is essentially the same process as that used for traditional die pressed powder metallurgy (PM) parts and can be done in continuous (Fig. 7) or batch type furnaces integrated into a complete production line.

It is carried out in protective atmospheres or in vacuum at a temperature well below the melting point of the metal.

The type of sintering process and the sintering conditions are of course depending on the composition and quantities of the materials to be sintered. The parts are placed on ceramic trays or in heat resistant boxes while they are in the sintering furnace.

Unlike die pressed PM compacts, metal injection moulded parts must undergo a large shrinkage during sintering which may require higher sintering temperatures and/or longer sintering cycles.

The continuous binder removal and sintering process mentioned above allows economical mass production of ferrous metal injection moulded parts.

A complete production line is composed of a group of injection moulding presses, a continuous debinding oven for the catalytic process, and a continuous sintering furnace providing a maximum sintering temperature of 1300°C.

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