Open-Air CMM??? Open to the elements of the shop - Comments Appreciated

[The Quality Kid]

This morning, it was discussed that we may be moving our CMM machine here at our facility. One of the suggestions was to put it in an area of the shop that does not require any walls or enclosures. Basically, the CMM would be out in the open to the elements of the shop. I have never seen this before, and was wondering if there are any constraints to setting up the CMM this way. Are there any rules or regulations that would prevent us from doing this? Please advise.

 

[Jim Wynne]

This morning, it was discussed that we may be moving our CMM machine here at our facility. One of the suggestions was to put it in an area of the shop that does not require any walls or enclosures. Basically, the CMM would be out in the open to the elements of the shop. I have never seen this before, and was wondering if there are any constraints to setting up the CMM this way. Are there any rules or regulations that would prevent us from doing this? Please advise.

CMMs should be kept in temperature and humidity controlled environments in general, but you should find out what the manufacturer says, especially if the CMM is under a warranty or service agreement that could be voided if the unit were kept in a "hostile" environment.

 

[cncmarine]

JSW05 is correct temperature controlled environment is preferred.

I have seen plenty of CMM’s that are out on the manufacturing floor. Normally top-management can not justify the cost of a temp controlled room. But the cost of laser mapping and preventive maintenance will eventually exceed the cost of a new room.

Things do look out for:

1. Encoders will expire on a more frequent basis.
2. A humid environment will cause air hoses to blow off on a more frequently.
3. Ball bearings will become caked if there is oil in the environment.

 

[CarolX]

Definitely check with the manufacture.


Several models are now available for use on shop floor. But if yours is an older piece of equipment, I would reccomend against it.

 

[Claes Gefvenberg]

Several models are now available for use on shop floor. But if yours is an older piece of equipment, I would reccomend against it.

Yes, you should check with the manufacturer. If you stray outside the specified temp, humidity and/or contamination borderlines they will not guarantee that the machine provides you with correct results, and you may also wear the machine down much to fast.

The latter is particularly important if your CMM utilizes air cushion bearings.

Slightly but here's what happened to me with a CMM (in a controlled environment):

On one othewise pleasent morning the machine siezed in one axis during operation. I mean, it really got stuck! Assuming an air bearing had given up I uttered a few unprintable words and called the manufacturer. A service bloke turned up and we had a hard time releasing the siezed bearing (In the end we had to resort to brute force). To my surprise the machine was fully functional when we got it loose.

What on earth was wrong??? The bearing was obviously not damaged. On further examination we found some kind of dried smear on the bearing surface, in spite of the fact that it had been cleaned the previous day. Now what??? Another clue turned up: Small black thingies inside the machine. Mouse poop! We had mice in the CMM :mg:

Well, the smear was not poop, but it turned out that the confounded rodent had chosen that spot to take a leak. Mouse pee! On the bearing surface. That bearing needed 0.005mm of air to run, and the mouse had beaten that.
Soon afterwards a rat trap snapped in the night, and we plugged some well hidden holes in the walls. Calm was restored.... But let me tell you good people: That was one very expensive rodent

/Claes

 

[Jim Wynne]

The best laid schemes o' Mice an' Men,
Gang aft agley,
An' lea'e us nought but grief an' pain,
For promis'd joy!

Robert Burns

 

[bpritts]

Based on Claes' experience, I would recommend that you make sure that any computer console used with the CMM use the keyboard only, no mouse.

Seriously, however, I share everyone's opinion that there are definite risks
to moving the CMM out into a shop environment.

One possible solution - you can purchase "modular offices" - enclosures to put in the shop. One of my customers has one - it seems to me that a 10 x 10
office cost about $10,000 or $15,000 to put in. Probably cheaper than a rebuild of the CMM. Look in a Grainger's catalog-- I think they have them.

Regards,

Brad

 

[H. Majhenich]

H. Majhenich

Another problem with having the CMM out on the shop floor - get any large group of people together, and there will be someone thinking that they know more than they do, and they are apt to 'play'.
With the CMM in a closed environment, it discourages sudden urges of unqualified personnel to touch it.

 

[Rob Nix]

Majhenich reminded me of a very funny incident some time ago.

My CMM operator/programmer (Kevin) was just finishing a routine and hadn't "cleaned it up" yet, so, as a result, there was an extra move taking the probe up into the middle of nowhere, stopping momentarily, then heading for its next hole check.

At the same time, the president was taking some financial executives for a tour of the facility. I, as Quality Manager, joined them and invited them to witness a fully automated 100% inspection on our new CMM (hey, they were new and exciting back then).

During the routine that extra move and pause took place (mentioned above). One of the executives asked what that motion was for. Kevin, without missing a beat said with a straight face, "It's doing a sight check". The executive and his buddies nodded and were neatly impressed, one even saying, "wow, they can do that too". I nearly sprayed coffee across the room.

 

[David Hartman]

One possible solution. Look into a Romer Infinite articulating arm CMM (4ft to 9ft arms available). We recently were quoted less than $50k for a 4ft. with all the bells and whistles. For more info do a Google for Romer articulating arms.