I know this has been mulled over before here but I thought it might be good to narrow the topic to just investment casting v. MIM. Before there was always milled forged parts thrown into the discussion. Really, we can narrow it down further to Ruger’s investment casting v. S&W MIM parts.
Investment casting v. MIM
- Thread starter jski
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MIM is not used by S&W for the same kind of parts that Ruger uses investment casting. S&W uses forgings for things like frames and slides, not MIM. MIM is used for little parts like triggers and hammers. It is possible but not practical to investment cast the kind of small parts that MIM is typically used for. The molds would be too delicate.
The advantage of MIM is consistency of small parts without machining. Without MIM, a comparable part would need to be stamped, die-cast, forged, and then cut with EDM or otherwise machined. It will either produce less consistency or involve lengthy, individual machine processes that consume labor or machine time.
MIM is typically not used for large parts. There have been some aircraft parts made with MIM up to a couple pounds, but most MIM parts are less than 15 grams.
Frames for revolvers or semi-automatics, and slides are CNC machined. The part being machined could either be bar-stock (the most machine time), forged (a lot of machine time), or investment cast (the least machine time). Numerous world-famous, top-class, iconic firearm products have been made with each of these processes. The end product is mostly a result of how well the process is carried out rather than which process is used. In terms of the business, the labor and machine intensive processes have been going progressively out of favor for over a hundred years. S&W has done a lot to cut corners from the days when they made Registered Magnums. Winchester no longer machines everything by hand from bar stock. But today's guns aren't awful pieces of junk. Some of the best, most dependable guns are basically squeezed out of a toothpaste tube.
The advantage of MIM is consistency of small parts without machining. Without MIM, a comparable part would need to be stamped, die-cast, forged, and then cut with EDM or otherwise machined. It will either produce less consistency or involve lengthy, individual machine processes that consume labor or machine time.
MIM is typically not used for large parts. There have been some aircraft parts made with MIM up to a couple pounds, but most MIM parts are less than 15 grams.
Frames for revolvers or semi-automatics, and slides are CNC machined. The part being machined could either be bar-stock (the most machine time), forged (a lot of machine time), or investment cast (the least machine time). Numerous world-famous, top-class, iconic firearm products have been made with each of these processes. The end product is mostly a result of how well the process is carried out rather than which process is used. In terms of the business, the labor and machine intensive processes have been going progressively out of favor for over a hundred years. S&W has done a lot to cut corners from the days when they made Registered Magnums. Winchester no longer machines everything by hand from bar stock. But today's guns aren't awful pieces of junk. Some of the best, most dependable guns are basically squeezed out of a toothpaste tube.
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mcb
Member
What materials?
MIM'ed 4140 is very different than MIM'ed S7 tool steel. Same for castings.
MIM that has been HIP'ed is indistinguishable from a forging if the same material.
This topic is still very broad.
The firearms industry was a very early adopter of the MIM technology and thus its consumers where exposed to the growing pains of a technology. Allot of bad parts got made due to the immature technology and a generation of engineers leaning to use that new technology. The MIM and engineers of today are much much better than it was just a decade ago.
ie some of S&W 380 body guards have barrels made from MIM with zero post sintering machining.
MIM'ed 4140 is very different than MIM'ed S7 tool steel. Same for castings.
MIM that has been HIP'ed is indistinguishable from a forging if the same material.
This topic is still very broad.
The firearms industry was a very early adopter of the MIM technology and thus its consumers where exposed to the growing pains of a technology. Allot of bad parts got made due to the immature technology and a generation of engineers leaning to use that new technology. The MIM and engineers of today are much much better than it was just a decade ago.
ie some of S&W 380 body guards have barrels made from MIM with zero post sintering machining.
From what I heard on Hickok45, the slide for the Ruger SR1911 is not cast. Evidently, it would have been more difficult, more expensive, to have worked out a casting solution. The piece is too complex for a casting and they mill it from bar stock instead.
So a cast solution is not always a less expensive solution.
So a cast solution is not always a less expensive solution.
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