Have you had a MIM part break?

[Remo223]

I wouldn't think that just because a part is made using the MIM process it would be inferior to a forged or machined component. MIM parts are made with powdered metal and many exotic metals can be combined in the mix to strengthen it. Maybe some manufatuers are using a poor metal mix (read cheap) to make the parts. S30V blade steel could be considered MIM and it looks to be one of the most desired blade steels out there for a good combination of edge retention and durability. If comparing a part made from MIM 420SS and one made of forged 420SS then yes the forged one will out last the MIM part. If using a MIM from a mix with a end toughness higher than forged 420SS then whats the difference? The process shouldn't be condemned out of hand.

MIM is not even as good as cast. We are talking about sintering...that is metal powder which is heated up NOT HOT ENOUGH TO MELT, but just barely hot enough for the particles to stick together.

So that is right there a basic explanation for why MIM is inferior(for strength)

Now, there's even more to it. The MIM process doesn't start with pure powdered metal. The MIM process starts with a mixture of powdered metal and powdered plastic. the mixture is then pre-heated so that the plastic melts. This allows the powdered metal to be poured or injected as a liquid without actually melting the metal. When the mold is filled, the mixture is heated up hot enough to burn away the plastic leaving behind the powdered metal, which is then heated up enough to make the metal particles soft and gummy, but not hot enough to make them liquid.

Therefore, the resulting metal is porous (since the spaces where the plastic was is still there) and not as heavy as a forged metal part...also the metal particles are not really one solid part but a bunch of grains stuck together since the particles were never really melted together.

The advantage to MIM is the resulting "casting" is very very exact in dimensions. No machining is required to "true it up". Holes do not need to be drilled. They can be cast into the parts extremely accurately.

 

[heeler]

Yes.
Two weeks ago while shooting my very early production Diamondback .380 the trigger bar completely broke.
And to Diamondback Firearms credit they sent me a brand new pistol.
Looking it over I could see several changes that have been made to the pistol.
And supposedly they have upgraded all those MIM parts.
We will soon see.

 

[RSVP2RIP]

MIM is not even as good as cast. We are talking about sintering...that is metal powder which is heated up NOT HOT ENOUGH TO MELT, but just barely hot enough for the particles to stick together.
So that is right there a basic explanation for why MIM is inferior(for strength)

Thats like saying forged zinc is better than MIM. All I'm saying is that MIM as a process does not mean poor quality, the material or the specific steps involved may. By using a press operation after debinding and before sintering you can remove the spaces between the pieces of powder. This step is ofter skipped because of the cost. I can't say what a gun part manufacturer may do exactly but based on what you hear it would be best to buy a firearm with a known track record, no matter what the intenals are made of. Unless Colt is using MIM for firing pins and extractors, it would seem that parts, no matter how they are made can be broken.

 

[Remo223]

Thats like saying forged zinc is better than MIM.

For strength, forged zinc would be better than MIM zinc.

 

[Remo223]

All I'm saying is that MIM as a process does not mean poor quality, the material or the specific steps involved may.

MIM *DOES* mean lower strength.

 

[RSVP2RIP]

For strength, forged zinc would be better than MIM zinc.

I'm not arguing there. Does the MIM parts contain the same material as forged? Then I will agree with you.

MIM *DOES* mean lower strength.

Only if like materials are involved. You could also say cast means lower strength in that context, or machined from bar stock means lower strength than forged.

 

[gohogs93]

none for me. but i replaced most mim parts that see a lot of wear on my 1911. i dont really know what is mim on my XD os Sigs but nothing has broken yet.

 

[Mags]

I notice incredible finish wear on all my Kimber's thumb safeties and slide stops. Never had a failure though just cosmetic finish wear.

 

[orionengnr]

MIM parts are used in the internals of turbofan engines, which are subject to heat and pressure unlike anything your pistol will ever experience.

No, I have never had any trouble with any MIM part, in a pistol or in an engine.

 

[18DAI]

I've had two MIM parts break.

One thumb safety on a Kimber Stainless Target.

One Mag release on a S&W 908.

 

[ForumSurfer]

Ambi Safety on a Kimber Pro CDP II.

I didn't vote, however.

My safety broke because I fell on it...all 185 at-the-time-pounds and the safety took the brunt of the impact against a curb...while holding a couch. I'm guessing a non MIM part would have broke, as well.

Kimber's customer service exceeded my expectations...they sent me a free replacement part despite the Kimber being out of warranty and the incident being "operator error."

 

[MCMXI]

MIM parts are used in the internals of turbofan engines, which are subject to heat and pressure unlike anything your pistol will ever experience.

How is this relevant? How is the use of MIM parts in any application other than firearms relevant to this thread? You can't extrapolate here. Even if Kimber has numerous MIM failures, that's not relevant to the use of MIM in Springfield or any other manufactures unless the parts are made in the same plant, using the same processes and the same QC. All MIM parts are not created equal.

For the poll, I haven't had a MIM part fail yet but I only shot around 500 rounds through my Kimber before I changed the MIM parts. I've shot a few thousand rounds through three SIGs that have three or four MIM parts without any failures. I didn't vote.

 

[Remo223]

You could also say cast means lower strength in that context, or machined from bar stock means lower strength than forged.

I do say that. All the time in fact.