CMM questions. O/T

[Thee Dragracer1951]

Off topic sorta, but what the heck

Anyone here know anything about the used CMM market?

I'm in need of a manual CMM. Dea, Mitutoyo, B&S...

Don't wanna spend a million bux. I'm already doin that.

[Don S at Barefoot CNC South]

Jim

Have you looked at a Faro arm and verisurf?

[Thee Dragracer1951]

I have only looked at a faro arm briefly. I think I want something dedicated that isn't portable. I'm not so sure about the faro arm's accuracy and repeatability also.

[J Coulston]

Sent you an email Jim.

[Tim Martinez]

Jim, I sending you an email.

[Tim Martinez]

Jim, did you get our emails?

[Thee Dragracer1951]

I did. Your NW guy is meeting me on Monday I think.

Why are all the days running together??

[Kevangel]

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Anyone here know anything about the used CMM market?

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I talked to another small shop owner a few years back that spent 50K on a new starrett and I asked him why he did not buy a used one (zillions of them around)and he said they have old software that no-one knows how to use, etc. I still have not bought one as gage shop I worked at bought one years ago and never used it. I am curious as to what others say about this also.

[YoDoug®]

We have a Mitutoyo BH303 manual CMM. Its works pretty good. Not as accurate as a DCC CMM. Kevin is right about the software. Ours is running a 10+ year old software that is not very user friendly. We had a demo on Verisurf and were very impressed. Mitutoyo has a newer software that will be an update to the existing hardware. I am trying to get the purchase approved this year. In the mean time it doesn't get used very often because it takes about fifteen minutes to get it started up and do the calibration routines with the old software.

[?Mark]

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they have old software that no-one knows how to use

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True.

We have an older numerex cmm. Few years back the board (box between a cmm and a pc) died. I started searching around for updates and was talking with verisurf to get all necessary hardware/software to get current. Expensive proposition. before I could get a good quote thouh, my boss went ahead and ordered a replacement board that installs inside a pc for $3-4k if memory serves right. The kick is, I couldn't find pc old enough to put it in as it needs to be "win 3.11 " era .

That "upgrade" took us from unimeasure to u-soft 8.5 software (still dos based ) . I'm willing to bet there is only a couple of guys able to run it in colorado and I'm probably one of them

Needless to say, if that pc brakes again we're back to square one.

Most of the quotes I got to update our cmm to modern standards in hardware and software were about 75% of the cost of a new comparable cmm.

Don't know how verisurf people quote would work out though, as I had to pull a plug on this because boss chose to go for a early nineties "technology"

[YoDoug®]

That was the reason we opted to get Verisurf, The hardware conversion. Again I think the software is AWESOME, but the cost to retrofit our old hardware was too costly for the small amount of use our CMM sees. The cost of updating an older CMM can be very costly.

 

Back on topic, Faro has an model that they claim has .005mm repeatability. Thats pretty good for something with six axis being moved manually.

[MIL-TFP-41]

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Faro has an model that they claim has .005mm repeatability. Thats pretty good for something with six axis being moved manually.

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Thats what they advertise for sure, but our company has been through the rounds (sending the arm back more than once) getting it to repeat better than .001. Even our local rep said something was effed up, but Faro insisted that it was OK. Yes, this was their "high end" (platnium model). Basicaly what we found out was that if the arm is used within a small window (8ft arm only being used within 2 ft) it works ok. The further out you extend the arm the less accurate your results. Faro cannot argue with this. All that being said, the Faro arm does get used alot for "on the machine" inspections.

 

CMM's are much more accutate....they hold the same repeatability no matter where you are within their travel.

[YoDoug®]

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CMM's are much more accutate....they hold the same repeatability no matter where you are within their travel.

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Yep, We just bought a Brown and Sharpe DCC CMM for our production facility. Even though the Faro Gage model claims .005mm, we didnt trust that.

[Thee Dragracer1951]

Good stuff guys. Verasurf is comming out next week. We'll see. I am aware of the older software issues. I also see a lot of machines updated with Open DIMIS and PCDIMIS.

What's the difference between them and what are your thoughts?

I also have seen a little B&S machine for short bux...

I'm of the opinion that a CMM is really eye candy for your buyer. I worked in inspection for a good number of years. I can chase that .005 around with you watching and show that the part is good. My customers want to see one on my shop floor.

Are they a good thing? Yes, properly used.

Are they the last word? Nope....

Do I need one? Yup...

[Tim Martinez]

Keep us posted on this, Jim. I would like to know what you decide. Thank you.

[Thee Dragracer1951]

Well Tim. I'd imagine you'll know next week.

I am terrable with names. But your nW guy who is in Port Orchard (I believe) is comming by next week. We'll see. I have a couple of customers that no diddley about machines. But they seen CMM's in shop QC departments. Sometimes ya got to go with what the customer wants ya to have.

We'll see.

[Kevangel]

A friend that owns a shop was told by a new buyer that if he did not buy a 40K CMM they could no longer do business with them (after 20 year relationship) and my friend kept putting them off on CMM and eventually there was a "buyer change" and next buyer could not care less if he had a CMM. I build gages for a measurement company and they said people are almost more concerned about "how" are you going to check these parts, than how are you going to make them anymore. So your QC department is an issue and I do believe in adding some eye candy from auctions, even if it does not work...

[Thee Dragracer1951]

Well Kevin, This is obviously going to work. But I also know that as you said, buyers like to know how you are going to check their part. A CMM will be a valuable addition to my shop. No question about it. On the other hand, I know full well how easy it is to call something good that is not. There's a big difference between buyin parts and sellin parts.

But this CMM will give us faster inspections for first articles. More confidence in what goes out the door, and that'll be a good thing...

One of my customers is a group of Phd Physisist

They like eye candy.

[Guest CNC Apps Guy 1]

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...One of my customers is a group of Phd Physisist They like eye candy...

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ROFL!!! WHen all else fails, make it look pretty.

 

j/k I didn't really mean that, but... I worked in a shop once where cosmetics were more important than dimensions and as long as there were no issues at assembly, it was all good if at assembly things went together. So they would ship discrepant parts on occasion - our QC guy would tag them (per customer request) and send them out. I was kinda going ... if the part fits, why not open up the tolerance a bit more to reflect that??? I know you want to keep things as close to nominal as possible but why so tight if it's unnecessary ??? These parts were .002 True Pos. RFS and we would miss by ±.0002 so we're not talking a bunch here.

[Tim Martinez]

IMHO, it is a matter of ethics. When you start bending the rules, how far do you allow it to bend and how do you stop it before it breaks. I kid about my experience as an inspector questioning why I could hand manufacturing 100 good parts and be viewed as an asset to the company. But the moment I tag something, they want to know how the hell I got my job. Standards are meant to insure quality. Standards are meant to be held, no matter how ridiculous it may sound. If the customer wishes to accept a discrepant part, it is their prerogative to do so. But as a supplier,it is our responsibility to produce the best product, by adhering to our own standards.

 

Thank you. I will now step down from my soapbox and return to my position, which is far from the QC dept. I once worked in.

[Thee Dragracer1951]

And you are correct Tim

My point is that accuracy of a CMM is assumed to be better than it actually is and that very few people will doubt the results and double check themselves by using another method such as a surface plate.

I once had an inspector tell me that she could not inspect a part because we did not have a CMM. I asked her how they would have inspected it prior to the invention of the CMM. She had no idea.

Many buyers are the same.

[Kevangel]

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My point is that accuracy of a CMM is assumed to be better than it actually is and that very few people will doubt the results and double check themselves by using another method such as a surface plate.

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I fight that all the time, people rejecting gages for 10-50 millionths and they used an electronic inspection device and its only rated to .00015 inches. They don't even take a second look before kicking it back.

[Guest CNC Apps Guy 1]

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My point is that accuracy of a CMM is assumed to be better than it actually is and that very few people will doubt the results and double check themselves by using another method such as a surface plate.

 

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I fight that all the time, people rejecting gages for 10-50 millionths and they used an electronic inspection device and its only rated to .00015 inches. They don't even take a second look before kicking it back.

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I did a Turnkey last year for a medical devise manufacturer. 162 probe hits for a profile tolerance check... the tolerance was .0008 on profile (which was a total of 2.4988

in length) , I had 2 points out out of the 162 that were out by 30 millionths. I had to spend 2 weeks getting that last 30 millionths. After I finished the turnkey they changed the policy... you can have up to 10 points out of tolerance as long as they are not out further than 10% in or out. :banghead: Get this... the parts went straight from the machine to the CMM, they didn;t sit for the required 24 hours in the climate controlled room where the CMM is (which was not between the required 68°-72° nor was it at the prescribed humidity level. In other words, arbitrary rule following.

[Thee Dragracer1951]

Ya just gotta love em Eh James?

[Guest CNC Apps Guy 1]

:groan:

 

It's a living... and a good one at that.