What's new
What's new

Totally confused on older CMM's and what you can or cannot do w/ PD-dmis (for example

countryguy

Hot Rolled
Joined
Jul 29, 2014
Location
Mich, USA
The Son and I started looking on ebay one eve just to see about used CMM prices. I have tried to do some homework, read some basics, and even called a few CMM resellers. I'm confused as a CMM newb on what I could or could not do with (say a) $4 or $5K used CMM from the 80's or 90's w/ some form of ancient PC and (usually) some PC-DMIS version? Say 4.x version (I see 4.3 and 200x listed often for versions ).

I just wanted a primer on what it's high level capabilities are? Anyone have a paragraph in them on what we could do as a father/son start-up w/ a older manual CMM w/ some type of early CMM software package? I also see some others from other vendors but this PC-DMIS seems most common.


Say I want to inspect a part. Plate ID 123: Suppose it is 4" x 8" x 1/4 thick 1018 steel. Has 3 holes. OD.5" 1" and 1.5" inches. I want to test and report on several data points to pass/fail it, record the data on the test, and then print a report (or stuff it into a XLS or DB CSV file). Is that in the realm of this type of buy? again... clueless but seems like some basic that would serve us and save some time and cost ?).

- Could I put the plate down on the manual CMM, pull up (some job ID) on the PC / CMM package indicating we'll check and report on plate ID 123. Maybe a wizard on-screen provides the walk-thru and instructs me through some type of testing routine?

- Can I import DXF (at least) of plate ID 123 and then in some fashion via the PC-DMIS program quickly and w/o a programming degree setup a part test procedure that would get reused over and over.

Just wondered if there is a good reason or not to keep looking at something like this for us?
2 vendors just wanted to stuff me into a full-on used CMM retrofit system w/ crazy $16K starting points and I understand that's cheap in CMM world but we are just not there.
 
I've been programming and operation a CMMs for about a decade.
There are so many different option you can get with a CMM, a lot more info is needed to truly help you.

What size is the CMM?
In my opinion manual CMMs are kinda useless and a pain to operate and not as accurate as DCC machines or portable these days.
It could be very difficult to operate a large manual CMM.

What head is attached?
There are several different head types that can be attached, manual head, fixed head, automatic, continuous...

What level of software?
PC-DMIS comes in 3 distinct favors, PRO, CAD, and CAD++ with different capabilities and there are different modules you can add on too. There are probably a dozen of those.

The last point i have to make is about the price. The company i work for bought a new small (5,7,5) machine last year for 70, 80 grand. What condition do you think a machine that is less than 10% of the original price is in?

I think you should look at portable, romer machines.
 
I just wanted a primer on what it's high level capabilities are?

Your best bet to get those basic questions answered is to ask the folks that sell new ones. They will be the most eager to have you understand that you -need- one, and you need to buy one of theirs. Work backward toward used bargains from there. Share what you learn on this forum. Most any answer or comment you'll get from this forum will be negative with the words "you can't do that" most likely included.
 
I am going to attempt to add some update and color here. See what folks think about some observations. You have a very interesting field. I'm hooked. Seems to be all I read upon of late!

The kid and I have been through several Vendors and several R&R contacts over used CMM's. We learned quite a bit and still it seems it will never be enough.
Question: Brown & Sharp. From MivroVal to Gage 2Ks'.. there are lot of these units for sale. They must have sold many thousands of them! Yet we have been advised from a few to steer away from the B&S aluminum lines. No parts for sale, aluminum, hollow, tube/air, on and on. I also have several gage 2K manual and dcc models in my budget range near me. (under 1 hour drives) Yet I also have some 80's Mitutoyo anchors, and even 2 old & decent Numerex units near me. Sure they need some work but could live again and help start a young mans career (the Son) as a manual CMM for a time.

Again, I just dig the journey and learning & playing as the Engineer. I'll take any info you have for us. + or -

So w/o beating one against the other- Would a B&S gage 2K from the 2000's (say 2000-2005) be a good investment? Offer a Small shop start up quality. with repeatability and some measure of consistency? Seem like $4K to $8K plus unit setup and calibrate and done.

Or... do you grag one of the older heavy 80's units (say the Numerex), spend $2K in repairs and such, then $4-4K for a newer CMM software & package. etc. Seems like we end up in the same place cost wise (more-or-less) but have a (better?) machine to run w/ longer life? Is this even an accurate statement....

Thanks for dropping in if your this far. I get it.. CMM is expensive. But many I have talked to, can and do make it work on a budget and I have talked to quite a few folks since this first post.

Thanks and onward to Tuesday. Warp speed Mr. Sulu.
Peace.
GC.
 
First off, just how accurate do you need to be?

If you are buying used it's caveat emptor. These machines are delicate, because they do delicate things. The upkeep to maintain one to spec is extremely important. Ideally they're kept in clean room at 70 degrees and not operated by some ham-fisted apprentice. What you may come across is one kept on the shop floor and run into with the forklift every other week.
 
About 10 years ago I picked up a used Brown and Sharp Microval from the late 90's I got it from a customer for $7 grand and was able to do work in exchange for it. The machine has QC,5000 software that covers all our needs, Far more powerful than we use it for. It has a touch probe and is 100% manual. Having this machine in the shop has helped a great deal and is worth every penny. We plan to upgrade to a newer machine this year.

Make Chips Boys !

Ron
 
Last edited:
Understood! Is Accuracy to 3-4 tens in the range of these? Most of his work he is bidding is .001 to .005
We (I) have the skills to service delicate gear IMO for now. But parts are one of my worries... Told that Hexagon will not sell parts for microval/ gauge age units

It'll be babied in a separate room and managed withing as controlled an environment as possible. ham-fisted... LOVE that. :D
 
Just to document this a bit... So for a few newb's - Short update for those that come along someday in the same boat:

We did find a Numerex 2424-18 for sale. Owner retiring so off it goes.
single owner, redone in 98 w/ some type of newer interface setup. Has a bad Y axis either scale or head/amp... Plenty of parts out there... sourced already.

Comes w/ PC, Desk, a Printer (dot matrix museum someplace needs one). and something called unimeasure... PC also does not boot. Not sure we'll even try it? Present plan is to get the R&R done, get CMM Manager interfaces (lite or not is another decision) with the correct PC Interface card for USB - Numerex (so I was told we would need).

For transport;
(4.5 hours 1 way) we set a res for a air suspension truck. Only size found over 4 different lease vendors is 26' So we're taking a big truck for about 3'x 4' footprint. :-) Would love to hear that we could do something different... but I was yelled at when I mentioned the goose-neck horse trailer. It is smooth and roomy and. (ok ok... I was kidding).

We have had some help from a Metrology parts house on how to secure and transport. I think it's getting close. Not sure what to do (if anything) about the scales and heads during transport; We read about folks putting tape between scale and head, etc. We'll see what it all looks like when we get there. told Y is exposed (the bad one) and X and Z are inside the unit. Cannot wait to see it.

....so that is the status. decent unit found. Robust in 98 and the right size for us. Options for upgrade/refit's exist and it'll interface to CMM Manager w/ the current output boxes from the scales. (again, so we were told via pictures from the unit owner and a Vendor for the CMM software.

Risk low, spend low. time will tell. I get that's fly by night to many, but rather learn low than spend high.

Everyone stay safe and hope all is well in your space.
CG
 
Last year we bought a 2009 Helmel Phoenix for $12k? I think. We premade a wooden disassemble able "paint by numbers" box. Went there taped as much stuff in place as possible put the machine in the box and filled it to the brim with packing peanuts. Had it calibrated after the move and nothing had to be adjusted, they complimented us on the gentle move.
 
Just to document this a bit... So for a few newb's - Short update for those that come along someday in the same boat:

We did find a Numerex 2424-18 for sale. Owner retiring so off it goes.
single owner, redone in 98 w/ some type of newer interface setup. Has a bad Y axis either scale or head/amp... Plenty of parts out there... sourced already.

Comes w/ PC, Desk, a Printer (dot matrix museum someplace needs one). and something called unimeasure... PC also does not boot. Not sure we'll even try it? Present plan is to get the R&R done, get CMM Manager interfaces (lite or not is another decision) with the correct PC Interface card for USB - Numerex (so I was told we would need).

For transport;
(4.5 hours 1 way) we set a res for a air suspension truck. Only size found over 4 different lease vendors is 26' So we're taking a big truck for about 3'x 4' footprint. :-) Would love to hear that we could do something different... but I was yelled at when I mentioned the goose-neck horse trailer. It is smooth and roomy and. (ok ok... I was kidding).

We have had some help from a Metrology parts house on how to secure and transport. I think it's getting close. Not sure what to do (if anything) about the scales and heads during transport; We read about folks putting tape between scale and head, etc. We'll see what it all looks like when we get there. told Y is exposed (the bad one) and X and Z are inside the unit. Cannot wait to see it.

....so that is the status. decent unit found. Robust in 98 and the right size for us. Options for upgrade/refit's exist and it'll interface to CMM Manager w/ the current output boxes from the scales. (again, so we were told via pictures from the unit owner and a Vendor for the CMM software.

Risk low, spend low. time will tell. I get that's fly by night to many, but rather learn low than spend high.

Everyone stay safe and hope all is well in your space.
CG

We bought a Zeiss CMM with QC5000 software in an auction for $450. I’m the same way that you are. I would rather spend a little and learn more about it, then I’m more experienced when I need something better. This CMM is about 40x30x22. I have some lapped ring gauges from Mitutoyo and when I probe the ID, it’s plus or minus a tenth of what the ring gauge says. So I do trust it within reason. Also, our’s is in an air conditioned shop, but not in a “clean room” so to speak. I personally love to check taper angles, bolt hole centers, that sort of thing. We use it for our own use, not quality control.


Sent from my iPhone using Tapatalk
 
Another update. May as well keep logging some of the adventure and lessons learned. a 26' air-suspension rental truck is a lot of truck! 11 hours there/back, and I'm glad I did the renal in the end.

The Numerex came w/ the PC, controller card, software on floppies, Service/Ops manual, training test pieces. I mean he/they kept everything. A bit like XMas for my Son and I.

I'm in the dog house a bit... New toy in the house and grass can just keep growing today! All I did most of the day was unpack the new toy and then repair the PC (Cmos battery and internal hard drive stickion). I have it all backed up to a 2nd drive. Made backups of all the floppies too. The PC boots to UniSoft 5.1 now


The bad: The Y scale is looked like a mountain range.. all torn up and jagged. in short - destroyed! But.. we knew Y was bad going in. Off to find glass scale parts. Have a source but if folks want to drop a name, or parts house, I will pursue.
The kid is pulling the X and Z covers tomorrow.. just to review the integrity of the glass and inspect.

QQ? Output of linear signals on these older units? Something my kid and I were chatting about in the long truck ride.. is there something rather standard as the output from a linear glass scale/reader? Like the quadrature/diff/ type output some of our CNC equipment on the rotary encoders... Or is that like asking for a favorite hamburger place? Everyone had their own burger
 
Mostly 2 common types of scale output, TTL Quadrature being the most common these days. Either single ended (Channel A, B, and Marker pulse) or with the naught complementary channels (A- B- Marker-) as well. The other most common is Sinusoidal output, which is usually 3 channels of, you guessed it, Sine wave form. Both usually 5vdc output as well. Unless Numerex did a wacky custom wave form or voltage just to either be different, a PITA or both, I'd guess you could source a generic 1 micron scale pretty reasonable. Probably on Ebay even. Keep posting updates!
 
It's usually a given that it's TTL quadrature (3 channel, single ended or differential, as mentioned in the post above) going into the controller, even if the original scales were sinusoidal. Sinusoidal scales go through an interpolator unit that converts to TTL quadrature, so if you happen to have that configuration on the machine, you can either replace the scale like for like, or use a common TTL quadrature scale and bypass the interpolator. You may need to run through a line driver if you need to convert between single ended and differential though.
 
Sin/Cos scales come in differing voltages from 3 to 12 volts. Some based around zero volts, some biased towards all plus.
Scales also come in differing resolutions so it is very important to match this specification.
CMMs often put the sine wave directly into the control board and the interpolation is done on the control board.

First place to start is with the make and model number of the scale, this information usually on the reader head or scale housing.
With this make and model you might find the info needed on the net.

If you have a functional axis you can put a scope on it and decode what type and resolution you have.

Scales come in so many flavors as do rotary encoders. Buying one at random would be like throwing darts with a blindfold on.
With any luck there may be information on the scale in the service manual or even the spec section of the ops manual.
Bob
 
Thanks for the replies on scale output and general methods. A great help. Backgound in EE Technology and Alalog/Digital -So this should be a great fall & winter project. I posted up a few pics. time to start a new Forum post I think? This thread on this was about How-to (done), obtaining.. (done), transporting, (done). Theory, repair - coming soon! I post up often. (fair warning);-)

Would I do it again! Heck ya- But for the newbs that land here... I spent months watching ebay, craigslist, and a few auction sites. Just to find strong candidates for us to buy. Travel/transport is a significant factor that you'll need to sort out case by case. The early forum post to call some Vendors was great advice... but many did not really want to talk unless I was 'buying', and I get that.
Setup and Delivery- Another issue unless you have a real shop. This is a older Farm/ranch home w/ tractors, forks, straps, and 'heavy' is an every day thing here. As I was told often.. Work should be from the neck up first. (always loved that one).

We have a lot to learn about the older unit and will be taking some time over fall and winter to get this operational. For now, I can put the Shop back together... Everything scattered and moved around to get it in the door and a home. Besides, the newly minted Graduate needs to go find some paying CNC work to pay the Dad's Janitor and Repair man bill. :-)


2 quick pics :-)
CMM-up.jpg

IMG-4273.jpg
 
do you think I should just keep this one afloat? Some other places can sometime be little topic touchy.

Just some bullet notes on today's events. Fixing the trailer and hay baler can wait right. Who needs Hay anyway :-)

the kid cleaned the unit today. pulled all the covers. got them painted. ran out for denatured alcohol. He followed the PM guide in the book for cleaning.

We found the Y air bearings were also out of socket last night, and got them inserted and readjusted. (best we could and simply compared tension and feel to X anyway). I am pretty sure well need to square up and Cal the gantry correctly I assume.

Ran air, plugged in the solenoid, and found all air bearings work, unit floats effortlessly. The Y brake does not seems to work? we'll dig into that soon. X and Z brake fine. (which I'm not even sure if 'Brake' is the right word).

PC / Numerex PC card to system connection soon. Advised to hook up and check that it counts on Z and X which is a solid idea. Not going in for more than 1 original glass scale. Else I'll look to DIY upgrade.

Found a service sheet from Zeiss... 1995. Noted a calibration was done and set levels to 18V (sheet is not infront of me... but it's a great tip).

Q for the group: We are wondering what is actually done for a 'certified calibration' on a manual CMM? Clean/Inpsect, signal levels /TP checks, standards measure tests, document and report,... Not trying to trivialize it, but understand the 'big block' diagram here. could not really find anything on the 'what' or the 'how' of an older CMM calibration.

Measured peace,
GC out.
 








 
Back
Top