Metal Injection Moulding. How common?

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spykez

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I'm no expert, only got real interested in how swords and knives are made in the past year, but I discovered that perhaps some cheap knives from China are made this way.

[video=youtube;SufKCjYRqh4]https://www.youtube.com/watch?v=SufKCjYRqh4[/video]

How common is this practice?

How can one tell?

Umm... is my Emerson kershaw cqc-6 (made in China) made this way?

This is where I first heard of this process, he mentions looking at the cross section and grain of the blade somewhere in the middle of the video.

[video=youtube;6gspEVFS9-w]https://www.youtube.com/watch?v=6gspEVFS9-w[/video]



Interested in hearing your opinions, gents!
 
I believe Ruger has been using this process for some of their internal gun parts for many years.
 
I only learnt about this today, I'll bet it's common in firearms to make awkwardly shaped small parts.

I have to express complete ignorance till today of such a technology. Ah, well, you learn something everyday.

1. I guess my question is how common is it in knives?

2. Can we tell?

3. What are the implications? Vs forged or stock removal?
 
Ruger has been using this process for a very long time. S&W started using it as well around 1998 as parts come out nearly identical and saves the hand fitting of the various parts. The old time S&W enthusiasts don't like it and prefer the older revolvers made with forged parts and hand fitted together. To stay competitive S&W had to go with the MIM parts and they have proven to be reliable as there guns have a lifetime warranty. Their tolerances are now much tighter with identical parts. Their workforce is becoming parts assemblers instead of craftsman but times change. I can't speak as to how much this is used in the blade industries it seems there is lots of powdered metals used for blades so I would think it is the same general process but I am not a expert on knife blades. On a knife blade I don't think you would be able to tell if it is MIM or forged on a S&W trigger the back side has a cavity and some internal parts have a seam around the middle of them.
 
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Kershaw had a high end folder with a MIM 440c blade. If I recall there were reports of warped blades. I have never seen one outside of a knife case.
 
Buck 110 frames are sintered, the 1st ones were cast, then went to forged, then in the mid 70's went to sintered. Don't know if it's the exact same process
 
As I understand it, MIM actually produces parts in firearms that are stronger than forged or machined ones because there's no directional grain to the metal, so it's equally strong in all directions. By contrast, forged parts are stronger along the flow of the grain, much like wood is, but are weaker vs. cross-grain stresses. Knives tend to benefit from the forging/rolling process (in the case of machined blades) because of their shape and how strain is applied to the blade vs. in a gun.
 


It's not the process that leads to quality issues; it's the overall product. This blade is straight as a laser.
 
FortyTwoBlades said:
As I understand it, MIM actually produces parts in firearms that are stronger than forged or machined ones because there's no directional grain to the metal, so it's equally strong in all directions. By contrast, forged parts are stronger along the flow of the grain, much like wood is, but are weaker vs. cross-grain stresses. Knives tend to benefit from the forging/rolling process (in the case of machined blades) because of their shape and how strain is applied to the blade vs. in a gun.
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Is there a way to readily tell if a blade has been sintered or forged or cut/CNC'ed ?

Are there any signs that indicate sintering?

Sorry for the noob questions there.
 
spykez said:
Is there a way to readily tell if a blade has been sintered or forged or cut/CNC'ed ?

Are there any signs that indicate sintering?

Sorry for the noob questions there.
Click to expand...

Not really, short of industrial testing methods. No simple test for it. Some parts even get cast, then forged to final shape to deliberately impart some degree of grain flow.

In knives, however, it's very uncommon to cast blades. They're overwhelmingly either forged or machined.
 
FortyTwoBlades said:
Not really, short of industrial testing methods. No simple test for it. Some parts even get cast, then forged to final shape to deliberately impart some degree of grain flow.

In knives, however, it's very uncommon to cast blades. They're overwhelmingly either forged or machined.
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I wonder then was the video I linked about the "Winchester" bowie correct at all? Would it make sense for a (presumably) made in China cheap bowie to be MIM'ed or would it just be more sensible to have it machined?

What would be cheaper? What would be actually plausible? Considering that knife seems to have been mass produced.
 
MIM only makes economic sense of the part shape is complex. Most blades are not in that category.

And depending on the alloy, machining and MIM are not the only options for manufacturing.
420HC is popular because the blades can be stamped to final shape.
1095 can also be fine blanked.
 
spykez said:
I wonder then was the video I linked about the "Winchester" bowie correct at all? Would it make sense for a (presumably) made in China cheap bowie to be MIM'ed or would it just be more sensible to have it machined?

What would be cheaper? What would be actually plausible? Considering that knife seems to have been mass produced.
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Molds are very expensive $10 000-$20 000 a copy. And they wear out, and you can only use them one at time. Compare that to having 10-20 machine operators cranking out blades. The advantage to the machine/man combo is that they can be switched to making other gadgets at the drop of a hat or fired.
 
knarfeng said:
MIM only makes economic sense of the part shape is complex. Most blades are not in that category.

And depending on the alloy, machining and MIM are not the only options for manufacturing.
420HC is popular because the blades can be stamped to final shape.
1095 can also be fine blanked.
Click to expand...

I guess that cheap stainless steel bowie I linked in the video in the OP was probably stamped or machined then, rather than sintered as your man in it claimed. That'd be a fair guess, you think?

Ah well, I can't say I did not learn anything today!

Thanks all!
 
MIM is widely used in the 1911 world for hammer, triggers, magwells, slides...
High end gun from big makers (S&W Performance Series, Sig Sauer...) uses it a lot. Or Norinco.
Only the midtech makers (Wilson Combat, Ed Brown...) offer 100% forged parts.
Apparently, it takes 10 times more metal to cast a MIM part.
I dislike the process, I'm a forged guy :)
I won't buy a MIM knife.
 
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