The Shop > Metal Stuff
Anyone tried MIM Metal Injection moulding or sintering?
bry1975:
Any of you chaps,
Had the pleasure of trying MIM Metal Injection Moulding process?
Bry
Lew_Merrick_PE:
Bry, I have designed and made (at other company's sites) both MIM and PM parts. Most recently (which is more than a decade back), the locking bolt for the US Navy SEAL folding knife (designed by me and produced by McCann Industries) was a MIM part. We got a 42 ksi shear strength out of a 4130 MIM part which gave us a "lock failure" at 850 lb-ft of torque applied to the blade pivot. (The civilian version can be seen at http://www.mccannindustries.com/foldair.htm -- though the website is wrong as to the material for the locking bolt.)
While working on a project for Microsoft (which never saw the public light of day) I designed and had made (in China -- according to MS's policies) several dozen MIM and PM parts. From a personal viewpoint, I avoid such things for one-off or small prototype runs as I find it easier and less expensive to either cast or forge a part that might be a candidate for MIM or PM in a production version. It is no small feat to qualify MIM or PM parts if there is any critical loading or cycling involved.
It depends on what you are doing and the requirements that need to be met.
bry1975:
Thanks for the info Lew certainly sounds like an interesting project with the navy seal folding knife.
I take it 4130 means 4130 Chromoly Steel?
42,000psi for shear strength sounds quite impressive.
I mainly asked about the MIM process due to what I heard about Swatch watch case manufacturing it certainly sounds like a useful manufacturing process for certain applications.
Lew_Merrick_PE:
--- Quote from: bry1975 on February 05, 2011, 12:50:59 PM ---Thanks for the info Lew certainly sounds like an interesting project with the navy seal folding knife.
I take it 4130 means 4130 Chromoly Steel?
42,000psi for shear strength sounds quite impressive.
--- End quote ---
Yes, chrome-moly steel (4130). It took us four years from the first Request for Proposal (RFP) to an actual contract in hand. The first MIM'ed bolts were running about 28 ksi shear strength. One of my "magician caliber" heat treaters solved that problem for us. Everything had to pass a 5000 hour salt-fog corrosion test. Yeah, it was "fun"...
--- Quote from: bry1975 on February 05, 2011, 12:50:59 PM ---I mainly asked about the MIM process due to what I heard about Swatch watch case manufacturing it certainly sounds like a useful manufacturing process for certain applications.
--- End quote ---
Quantity would justify it. It would depend on your numbers. Remember that your dieset has to withstand molten metal.
bry1975:
That explains why they were probably aluminium swatch cases a nice low melting point.
So did you have to use a Tungsten die set?
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