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HOW
TO CHOOSE THE RIGHT TECHNOLOGY
As long as Metrocast has two different technologies,
we can offer to our customers the opportunity to get always the
most suitable solutions. However it is important to realize that
the two technologies suit different kind of parts, and a component
hardly ever is economically feasible both with MIM and investment
casting. In front of a new part to develop, it is basic to understand
which one of the two processes can give the best solution. In order
to do this (considering that it is always recommanded to contact
our technical dept.) there are some parameters and dimensional limits
which can give some precise advices:
- WEIGHT
First discriminant is weight: with investment casting can be produced
parts whit a weight which varies from a couple of grams up to
3 kgs or more, while with MIM the maximum reachable weight is
50 grams and the best cost-effectivness can be found with components
which weight less than 20 grams.
- ALLOYS
Even if this remark seems to be obvious, it is always advisable
to verify in the material tabs of each technology which are the
available alloys. Materials available for investment casting are
really a lot, while the MIM ones are relatively few.
- MAXIMUM
LINEAR DIMENSION Maximum linear dimension of a MIM
part is 100 mm, while for an investment casting component is 300
mm.
- SURFACE
FINISH Surface finish of a MIM part is generally better
than an investment casting one. Surface roughness normally achivable
with MIM is 1 µm, while with investment casting is 3,2 µm.
- GEOMETRICAL
COMPLEXITY Both investment casting and Metal Injection
Moulding are processes whose cost-effectivness comes from the
opportunity to reduce to the minimum the number of machining operations
to be run on the rough part obtained by the above mentioned processes.
According to that, MIM can provide more design flexibility than
investment casting; only to give you an idea, please note the
following parameters:
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M.I.M.
|
investment
casting
|
| Min.
wall thickness |
1
mm
|
2
mm
|
| Max.
depth of a hole |
10
x ø
|
from
1xø to 4xø depending on ø
|
| Max
depth of a blind hole |
5
x ø
|
from
0,5xø to 2xø depending on ø
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- ORDER
VOLUMES Another significant parameter is the quantity
of parts needed. Metal injection molding is a method of mass production.
Due to the relatively high tooling costs, annual volumes economical
to produce typically exceed 20,000 parts per year. On the other
hand, the minimum batch for investment casting is usually 500
parts (depending anyway on the part).
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