MIM short report

detail report :

process

plastic injection moulding
sintering

advantages of the MIM

economic efficiency
- positiv
- negativ

construction criterion

Negative effects on the economic efficiency of the MIM process:

• high material costs
• high process costs
• high mould costs

Compare to other cost elements, material costs are the more of consequence the heavier the partis. MIM works with very fine metal powders which accordingly are very expensive. This means that the MIM process is best used with small and extremely small parts, there, the material costs are of comparatively small importance. This disadvantage of high material costs can however be alleviated by the fact that with the MIM process the material can be utilised 100% with no loss whatever, due to the fact that the feedstock can be re-cycled. Usually, the upper weight limit of a parts is in the region of 20g the lower limit being ca. 0.03g.

The process costs also have a strong effect on the end price of MIM produced parts. Understandable, the larger the part is, the fewer will be able to fit the process furnace at one time. This means, as with the weight of the parts, that the costs per part are lower the smaller the parts are. The upper limit of part size is in the region of 400mm. Extremely small parts, with dimensions in the region of 10 to 15 mm are, however, on principle more suitable.

The relatively high initial costs of mould production (as with plastic injection moulding) lead to the necessity to realise a minimal production run. It is however, difficult to define a minimal number as the total costs, and not the isolated mould costs determine economic efficiency. But as a rule, numbers of 10'000 parts per year constitute a lower limit, which can, however, under particular circumstances, such as a very simply mould construction, be crossed.