Why do people fear the MIM?
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Jim Watson
New member
There was one early adopter of MIM that sent out a lot of 1911oids with slide stops that would not reliably engage. The best I could tell, they had miscalculated how that 30% shrinkage would affect the working dimensions of an irregularly shaped part like the slide stop. They eventually replaced that $50,000 mold and started sending out guns with slide stops that either worked properly or engaged prematurely. At least that latter fault is easily fixed with a file.
Design process and R+D protocols vary.
When there is a new technology,tell me,where do you hire experts in applying the technology?Hmmm?
Maybe someone has to boldly move forward,try,make some mistakes,take notes,and lead the way.
In the case of an innovative company,there will be some bugs to correct.To be a follower is easier.
Easiest is to be a critic,a xenophobe.
Shrinkage in molding is interesting to deal with.Polymer chains are like spaghetti,and depending on how they orient themselves in a mold,shrinkage varies.A perfectly round gear mold likely will not yield a round gear.
One can laminate a mold so the OD of the gear is through cut in a plate.The cavity may be cut intentionally undersize."Steel safe".A good way would be wire EDM.After molding test parts,these may be evaluated with a Co-ordinate Measuring Machine(CMM) and a virtual model may be compared to the design
database.From there,the cutter path of the wire EDM can be tweaked,and the cavity re-cut to produce a round mold.
Another interesting fact,there are material ref sheets for most every moldable resin produced.Among the specs will be "mold shrinkage".For a crystylline polymer such as polyethylene,polypropylene,or delrin(acetal),a shrinkage range might be .016 to .024 per in.,or so.(30 % would be hard!)
That number is a bit like pressure expectations on a commercial smokeless powder.It means when tested in a mold to make standard shrinkage test bars,one rail car of resin may shrink .016 and the next rail car may shrink .024.
Makes it interesting for a moldmaker to build a tool that will hold + or - .005 over 4 inches.
FWIW,a new tech I was figuring applications for in the 90's was 3D printing.
We were prototyping and making silicone molds with it then,and actually one process ,DTM,used a laser to green-fuse powdered metal.
And one more thought..."powdered metal"...What powdered metal? Regrind Yugos?The stuff from the cutoff saw chip pan?
Maybe.But it is also true that the master chef of powdered metal can apply the same genius that went into the laminated blades of a Samurai sword.
A carbide lathe tool insert is typically a powdered metal product.Hardness,shock resistance,heat resistance,dimensional precision....
When there is a new technology,tell me,where do you hire experts in applying the technology?Hmmm?
Maybe someone has to boldly move forward,try,make some mistakes,take notes,and lead the way.
In the case of an innovative company,there will be some bugs to correct.To be a follower is easier.
Easiest is to be a critic,a xenophobe.
Shrinkage in molding is interesting to deal with.Polymer chains are like spaghetti,and depending on how they orient themselves in a mold,shrinkage varies.A perfectly round gear mold likely will not yield a round gear.
One can laminate a mold so the OD of the gear is through cut in a plate.The cavity may be cut intentionally undersize."Steel safe".A good way would be wire EDM.After molding test parts,these may be evaluated with a Co-ordinate Measuring Machine(CMM) and a virtual model may be compared to the design
database.From there,the cutter path of the wire EDM can be tweaked,and the cavity re-cut to produce a round mold.
Another interesting fact,there are material ref sheets for most every moldable resin produced.Among the specs will be "mold shrinkage".For a crystylline polymer such as polyethylene,polypropylene,or delrin(acetal),a shrinkage range might be .016 to .024 per in.,or so.(30 % would be hard!)
That number is a bit like pressure expectations on a commercial smokeless powder.It means when tested in a mold to make standard shrinkage test bars,one rail car of resin may shrink .016 and the next rail car may shrink .024.
Makes it interesting for a moldmaker to build a tool that will hold + or - .005 over 4 inches.
FWIW,a new tech I was figuring applications for in the 90's was 3D printing.
We were prototyping and making silicone molds with it then,and actually one process ,DTM,used a laser to green-fuse powdered metal.
And one more thought..."powdered metal"...What powdered metal? Regrind Yugos?The stuff from the cutoff saw chip pan?
Maybe.But it is also true that the master chef of powdered metal can apply the same genius that went into the laminated blades of a Samurai sword.
A carbide lathe tool insert is typically a powdered metal product.Hardness,shock resistance,heat resistance,dimensional precision....
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I'll use Glock as an example.
Glocks worked just fine prior to 2008 with a cast extractor, steel striker.
Glock changed to MIM. Why?
Did it make the pistol more reliable or durable? No.
I have seen threads on Glock Talk where a newer pistol that worked fine started throwing brass at the shooters head after 1,000 rounds, perhaps this happened because the MIM extractor wore.
I also saw where a police dept. started getting light strikes because the tip of the striker wore.
I replaced the MIM extractor and striker in my recent Glocks with cast and steel, attempting to make them of equivalent durability as those made prior to 2008.
I would rather Glock have raised the price of the pistols a few dollars and continued to make Glocks as they did for years (prior to 2008) rather than cut cost to keep the selling price lower.
I don't fear MIM, but I am willing to pay more to avoid it, based on the examples given.
Glocks worked just fine prior to 2008 with a cast extractor, steel striker.
Glock changed to MIM. Why?
Did it make the pistol more reliable or durable? No.
I have seen threads on Glock Talk where a newer pistol that worked fine started throwing brass at the shooters head after 1,000 rounds, perhaps this happened because the MIM extractor wore.
I also saw where a police dept. started getting light strikes because the tip of the striker wore.
I replaced the MIM extractor and striker in my recent Glocks with cast and steel, attempting to make them of equivalent durability as those made prior to 2008.
I would rather Glock have raised the price of the pistols a few dollars and continued to make Glocks as they did for years (prior to 2008) rather than cut cost to keep the selling price lower.
I don't fear MIM, but I am willing to pay more to avoid it, based on the examples given.
Did it make them less durable.... No
Started throwing rounds at a persons face... Mim wore... Well cast extractors also did this, specially when people use junk ammo with steel casings.
As far as a police department, which department, do you have sources? Or is this more along the lines of my Uncle's brother Jimbo once met a man at the circus who told him this tale.
No disrespect for LEO's but a lot of them are NOT gun people. They are also sometimes worse with parroting back whatever mis-information they hear about their firearms. I had a LEO a few weeks ago shocked our shop could carry and sell Glock because "thats what we carry"
I had a S&W Rep stop by when they were releasing the M&P auto series tell me they dropped a Glock slide and it broke in two pieces too.
Now I can say Glock yes in need does have issues at time with extractors... but it was not limited to the MIM ones.
HKFan9
"As far as a police department, which department, do you have sources? Or is this more along the lines of my Uncle's brother Jimbo once met a man at the circus who told him this tale."
http://miami.cbslocal.com/2013/05/13/report-raises-concern-about-glock-handguns/
"As far as a police department, which department, do you have sources? Or is this more along the lines of my Uncle's brother Jimbo once met a man at the circus who told him this tale."
http://miami.cbslocal.com/2013/05/13/report-raises-concern-about-glock-handguns/
So that is the article you are using as proof?
It makes no mention of how old the firearms were, what kind of shape they were in, or how many approximate rounds were fired in them.
It uses some unknown gunsmith to make a claim it COULD be the material used in the Firing Pin.
While yet another officer of 30+ years and Glock say it was worn faster due to hotter ammo.
Hmmm..
It makes no mention of how old the firearms were, what kind of shape they were in, or how many approximate rounds were fired in them.
It uses some unknown gunsmith to make a claim it COULD be the material used in the Firing Pin.
While yet another officer of 30+ years and Glock say it was worn faster due to hotter ammo.
Hmmm..
The MIM parts are used by gun companies because it is cheaper. Plain and simple. If the parts are done properly with good quality control they are o.k. for many applications. That's the problem. Quality and cheap often don't go together. They can though. I've had forged parts break that weren't properly heat treated. But much more rare than MIM parts failing. From what I have seen and many gun companies experiences MIM and extractors don't mix well. Less high use parts maybe o.k..
But they are here to stay so what can you do? SIG, HK, and lots of highend guns use them. Again if well made they are fine. Would I rather have a forged part? Yes! Do I want to pay a couple of grand to get it? No.
But they are here to stay so what can you do? SIG, HK, and lots of highend guns use them. Again if well made they are fine. Would I rather have a forged part? Yes! Do I want to pay a couple of grand to get it? No.
Evil Monkey
New member
From what I understand, MIM has a higher rate of incorrect part geometry per lot.
Further more, critical parts like extractors, in which the tip of the material is experiencing high stress, seems to have more problems with wear than machined extractors.
taurus TCP has an MIM slide. Some people have reported the slide breaking in half. They were seriously injured by it.
The SW 380 Bodyguard now has an MIM barrel.
old barrel machined
new barrel MIM
source, http://smith-wessonforum.com/smith-...odyguard-380-new-barrel-design-looks-bad.html
Further more, critical parts like extractors, in which the tip of the material is experiencing high stress, seems to have more problems with wear than machined extractors.
taurus TCP has an MIM slide. Some people have reported the slide breaking in half. They were seriously injured by it.
The SW 380 Bodyguard now has an MIM barrel.
old barrel machined
new barrel MIM
source, http://smith-wessonforum.com/smith-...odyguard-380-new-barrel-design-looks-bad.html
HiBC, you could find someone who knew about guns, manufacturing .failure analysis.That would take care of a lot. Those things I did in my career !! You can't take a just from college guy to do those things.
My comments are not xenophobic but bases on many actual facts and they cover many fields . Research it. Melamine in the milk scandal in China .They sold milk products all over the world .More than one case of pet food killing and injuring many pets. 200 series stainless steel bought by the Aussies - none of it like any standard 200 series. Etc, Etc. easily researched !
The old type of Powder Metal was made by putting powder in a mold ,compressing it . sintering it . Shrinkage is low
.MIM is a mix of metal powder and polymer wax. This if fed into a injection molding system. Heated to melt out the polymer then heated higher to sinter the metal.It does have high shrinkage .
Not being a plastics engineer please explain crystalline polymers ? Polymers have molecular bonds which bond molecules. Metals have metallic bonding which joins atoms ,crystals and grains.
My comments are not xenophobic but bases on many actual facts and they cover many fields . Research it. Melamine in the milk scandal in China .They sold milk products all over the world .More than one case of pet food killing and injuring many pets. 200 series stainless steel bought by the Aussies - none of it like any standard 200 series. Etc, Etc. easily researched !
The old type of Powder Metal was made by putting powder in a mold ,compressing it . sintering it . Shrinkage is low
.MIM is a mix of metal powder and polymer wax. This if fed into a injection molding system. Heated to melt out the polymer then heated higher to sinter the metal.It does have high shrinkage .
Not being a plastics engineer please explain crystalline polymers ? Polymers have molecular bonds which bond molecules. Metals have metallic bonding which joins atoms ,crystals and grains.
Mete,I'm not an engineer.I had machine shop class in high school.Got a job as shop gopher in an evil corporation R+D dept.Was asked to do some simple machine jobs.Those evil corporatist decided if they invested a little patience and training in me,they could exploit me to make profit.
Dad Gum if they did not turn me into a Moldmaker,Modelmaker,Test apparatus builder,...a general "What we need is...." Make it guy.
Along the way I was trained by GE Plastics experts,John Kleese,a brilliant molding science consultant,W D Mold Finishing in Downers Grove,Ill,ParametricsTechnologies Pro-Engineer,Hansvedt EDM,....and maybe a few more.They paid me more than the younger Engineers.
Then I worked for a major Industrial Controls outfit.I wore a few hats there. from manuallathe hand in Limited Production processing quality issues..the "non conforming " parts.
So,no,I'm not an engineer.Just a High School Shop guy.And via those evil,profiting corporatists with non-union shops,I was given opportunity,training,a career,paid for a house,raised a family,Ii have a car,pickup,boat,home and a pension.And no debt.I had decades of paid health care and was up to 4 wks vacation..Oh,yeah!!I was exploited!!!I made them some money.Naive,masochistic pawn that I am,I actually take some Pride in that.
To answer your question,some thermoplastic polymers are crystalline
olypro,Poly E,Acetal,Poly carb,,and,as they cool,crystals are formed.They typically have higher shrink rates...ballpark .016 to .027 per in.The quality of crystal formation and molecular orientation play a part in the success/failure of the product.Good example,the living hinges molded into MTM ammo boxes.
So,gate location /polymer flow influences how the spaghetti molecules are oriented...the "grain",and the cooling system designed into the mold and processing parameters determine the crystalline structure.
The amorphous resins,like ABS,PVC,etc,typically have a lower shrink rate.In some,but not all,materials,these are the solvent bondable materials...like plumbing pipe.
What may happen:Based on inadequacies/failures of an existing part,or bean counters looking for 12 cents or $1.12 cost savings in a part to remain competitive in the market and keep the doors open....
A team gets the job of re-engineering the mfg process for a part.
They have a budget,a deadline,and criteria.
Some are better than others,but typically,the engineer is a product manager who designs nothing ...is an administrator who may research vendors,comply with agencies,etc.
The CAD designers design the parts.They know Pro-Engineer,or AutoCAD,or whatever design and doc software the firm uses.
In the same fashion I learned molding,they learn to apply the tech of the mfg process to their designs...example,uniform wall sections,radii,etc.
Some are better than others.
Guys like me turn ideas into something that can be held and tested.
Which happens.
They have a lot of meetings.The budget is spent or over run.The deadline looms.
The product passes tests,generates data.Someone declares "Success!"
The champagne flows,the bonuschecks are cut.
Then R+D throws it over the fence to Production.
The product goes to the field.There will be problems.They get solved,or they don't.
But look at the history of the Liberty Ship,the B-17,the P-38,the M-16...The 1903...
These endeavors evolve from dismal to great...via being defeated by greater and greater things.
I'm a 1911 guy,but I'm saving for an S+W M+P ...a compact.
Have not made my mind up,Shield,M+P Compact 45...still thinking,but I like the product,and Apex is solving problems...and S+W is paying attention.
It might well be that a sear or hammer hooks are not ideal to a given mix of MIM.
Civil war Hard Tack would break teeth,yet it's made from pretty much the same stuff as your Grannie's breakfast biscuits.
MIM can be as diverse as baked goods.Some is better than others.
Or metamorphic rock.Yes,some MIM sucks,but that is like compring the cast crap at Harbor Freight to Ruger's castings.
World class race cars and motorcycles have sintered gears in the transmissions.re they MIM?I do not know,but its all powdered metal technology.
I'm pretty sure the top line Henkels chef knives...the Cera Max or something like that...series,are a powdered metal blade.Sears and knife blades need to hold edges.
It just occurred to me,reading Clyde Baker's old book on Modern Gunsmithing.and the J.M.Pyne stories in Gun Digest,etc in High School,
had something to do with forming the "Ore" inside me,that my later mentors figured they could work with.
Dad Gum if they did not turn me into a Moldmaker,Modelmaker,Test apparatus builder,...a general "What we need is...." Make it guy.
Along the way I was trained by GE Plastics experts,John Kleese,a brilliant molding science consultant,W D Mold Finishing in Downers Grove,Ill,ParametricsTechnologies Pro-Engineer,Hansvedt EDM,....and maybe a few more.They paid me more than the younger Engineers.
Then I worked for a major Industrial Controls outfit.I wore a few hats there. from manuallathe hand in Limited Production processing quality issues..the "non conforming " parts.
So,no,I'm not an engineer.Just a High School Shop guy.And via those evil,profiting corporatists with non-union shops,I was given opportunity,training,a career,paid for a house,raised a family,Ii have a car,pickup,boat,home and a pension.And no debt.I had decades of paid health care and was up to 4 wks vacation..Oh,yeah!!I was exploited!!!I made them some money.Naive,masochistic pawn that I am,I actually take some Pride in that.
To answer your question,some thermoplastic polymers are crystalline
olypro,Poly E,Acetal,Poly carb,,and,as they cool,crystals are formed.They typically have higher shrink rates...ballpark .016 to .027 per in.The quality of crystal formation and molecular orientation play a part in the success/failure of the product.Good example,the living hinges molded into MTM ammo boxes.So,gate location /polymer flow influences how the spaghetti molecules are oriented...the "grain",and the cooling system designed into the mold and processing parameters determine the crystalline structure.
The amorphous resins,like ABS,PVC,etc,typically have a lower shrink rate.In some,but not all,materials,these are the solvent bondable materials...like plumbing pipe.
What may happen:Based on inadequacies/failures of an existing part,or bean counters looking for 12 cents or $1.12 cost savings in a part to remain competitive in the market and keep the doors open....
A team gets the job of re-engineering the mfg process for a part.
They have a budget,a deadline,and criteria.
Some are better than others,but typically,the engineer is a product manager who designs nothing ...is an administrator who may research vendors,comply with agencies,etc.
The CAD designers design the parts.They know Pro-Engineer,or AutoCAD,or whatever design and doc software the firm uses.
In the same fashion I learned molding,they learn to apply the tech of the mfg process to their designs...example,uniform wall sections,radii,etc.
Some are better than others.
Guys like me turn ideas into something that can be held and tested.
Which happens.
They have a lot of meetings.The budget is spent or over run.The deadline looms.
The product passes tests,generates data.Someone declares "Success!"
The champagne flows,the bonuschecks are cut.
Then R+D throws it over the fence to Production.
The product goes to the field.There will be problems.They get solved,or they don't.
But look at the history of the Liberty Ship,the B-17,the P-38,the M-16...The 1903...
These endeavors evolve from dismal to great...via being defeated by greater and greater things.
I'm a 1911 guy,but I'm saving for an S+W M+P ...a compact.
Have not made my mind up,Shield,M+P Compact 45...still thinking,but I like the product,and Apex is solving problems...and S+W is paying attention.
It might well be that a sear or hammer hooks are not ideal to a given mix of MIM.
Civil war Hard Tack would break teeth,yet it's made from pretty much the same stuff as your Grannie's breakfast biscuits.
MIM can be as diverse as baked goods.Some is better than others.
Or metamorphic rock.Yes,some MIM sucks,but that is like compring the cast crap at Harbor Freight to Ruger's castings.
World class race cars and motorcycles have sintered gears in the transmissions.re they MIM?I do not know,but its all powdered metal technology.
I'm pretty sure the top line Henkels chef knives...the Cera Max or something like that...series,are a powdered metal blade.Sears and knife blades need to hold edges.
It just occurred to me,reading Clyde Baker's old book on Modern Gunsmithing.and the J.M.Pyne stories in Gun Digest,etc in High School,
had something to do with forming the "Ore" inside me,that my later mentors figured they could work with.
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Its been going on since some silly twit came up with the idea of radiusing the corners off the wheel.
It was different so it had to be wrong.
And,it caused problems.You could not just stop a cart anywhere and walk away.
Then they needed brakes,and wheel chocks....
Stone to bronze to iron to steel....Longbow to crossbow to matchlock,,
flint to cap,muzzleloader to breech,single shot to repeater,dang bolt guns!Smokeless powde!!Just get used to a 1903 and the Garand comes along!!
And Scopes!!
Each step was resisted,denigrated and scoffed by the Curmudgeon!
It was different so it had to be wrong.
And,it caused problems.You could not just stop a cart anywhere and walk away.
Then they needed brakes,and wheel chocks....
Stone to bronze to iron to steel....Longbow to crossbow to matchlock,,
flint to cap,muzzleloader to breech,single shot to repeater,dang bolt guns!Smokeless powde!!Just get used to a 1903 and the Garand comes along!!
And Scopes!!
Each step was resisted,denigrated and scoffed by the Curmudgeon!
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Evil Monkey
New member
Some parts shouldn't be manufactured a certain way.
MIM is fine......depending on the part and what it does.
The old powder metal system is an interesting example. If we compare the part to wrought [ 100 % density ] ,they can be made from about 40 % for fluid filters, to pre lubed friction bearings , to mechanical parts to special very close to 100 % for high strength parts requiring a double compression and sintering .This was something Remington specialized in. Various alloys , case hardening etc.
Don't worry. Some folks have come up with a way to end the problems with MIM use in firearms - ban and destroy all privately owned firearms. Then the government will make good guns for its police and military. So let's hear it for Bloomberg, Soros, Schumer, Feinstein, et al., who will save us from MIM.
Jim
Jim
Evil Monkey
New member
dude really?
Rangerrich99
New member
Short story about why I'm not a fan of MIM parts.
I picked up a S&W 1911 SC and 3 yrs. ago, in spite of the fact that I knew it had MIM parts in it. I liked the weight of the gun and the one I'd shot prior was very accurate. Well, right around 250 rounds, the slide stop snapped completely in half while I was at the range. Found both parts and sent the gun and the failed SS in on S&W's dime, and they got it back to me in about three weeks. About two months later I was at the range again, with about 500 more rounds through the gun, when the slide stop failed again. I should've taken some pics, to show the bubbles I found in the piece of the slide stop that I eventually found.
Decided I'd had enough of that, and bought an aftermarket machined slide stop. Approaching 2000 more rounds, slide stop still in one piece.
Now, I'm fully aware that this is not enough data for any kind of analysis, and it's highly likely that that vast majority of the MIM slide stops in S&W 1911s are working just fine. All I'm saying is mine didn't, TWICE. And in a SDG I found that completely unacceptable. I'm in the process of replacing several other MIM parts in that gun with machined parts, even though none of them have failed.
Now, I don't want anyone to get the idea that I don't like this gun, or the other S&W handguns that I've owned, now or in the past. That 1911 is my most accurate handgun, is lighter than any other 4-inch 1911 I've handled, with less recoil than most 5 inchers in my friends' collections. I really like that gun. But if I'd known I'd be replacing half a dozen parts in the gun three year later, would I still have bought it? Maybe. Or maybe I'd have saved a bit more money and gotten a Les Baer instead.
Peace.
I picked up a S&W 1911 SC and 3 yrs. ago, in spite of the fact that I knew it had MIM parts in it. I liked the weight of the gun and the one I'd shot prior was very accurate. Well, right around 250 rounds, the slide stop snapped completely in half while I was at the range. Found both parts and sent the gun and the failed SS in on S&W's dime, and they got it back to me in about three weeks. About two months later I was at the range again, with about 500 more rounds through the gun, when the slide stop failed again. I should've taken some pics, to show the bubbles I found in the piece of the slide stop that I eventually found.
Decided I'd had enough of that, and bought an aftermarket machined slide stop. Approaching 2000 more rounds, slide stop still in one piece.
Now, I'm fully aware that this is not enough data for any kind of analysis, and it's highly likely that that vast majority of the MIM slide stops in S&W 1911s are working just fine. All I'm saying is mine didn't, TWICE. And in a SDG I found that completely unacceptable. I'm in the process of replacing several other MIM parts in that gun with machined parts, even though none of them have failed.
Now, I don't want anyone to get the idea that I don't like this gun, or the other S&W handguns that I've owned, now or in the past. That 1911 is my most accurate handgun, is lighter than any other 4-inch 1911 I've handled, with less recoil than most 5 inchers in my friends' collections. I really like that gun. But if I'd known I'd be replacing half a dozen parts in the gun three year later, would I still have bought it? Maybe. Or maybe I'd have saved a bit more money and gotten a Les Baer instead.
Peace.