CMM operators who measure sheet metal parts...Question for you

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  • #16
    Originally posted by Rick Coleman
    I'm in the same situation as Matt. We make dies to make hot & cold stampings. Our product is the die and NOT the stampings falling off the end of the tool. We have not had an issue with collecting and recording temperature data in the CMM lab. Our ISO standards have never called for it. I have a feeling that this may become an issue for me in the future because the lab is on the same heating/cooling system as the wire room; guess where the thermostat is. And to top it off, the wire guy on second shift likes it warm. I've come in in the morning to a room that is 76'. I guess the next step is to put a lock box over the thermostat.
    Dang, Rick, your CMM room is next to the WEDM room? Same here! Two rooms, a door seperating them, one heating and cooling system. And, I run both departments, do you? Until a few months ago, we didn't have an adjustable thermostat, it had a heating module and a cooling module, no adjustments possible, heat up to 68, cool down to 71, no other options possible. BUT, a few months ago, they had to replace the HVAC unit and I now have a regular house 'stat and it can be adjusted. I am not sure how that will work out. BUT, I also finally got LOCKS on my doors to keep the children out when my night guy or I are not in there, so hopefully the 'stat won't be a problem. If it does turn into one, I will put a locking box over it. Oh, the 'stat is in the CMM room, not the EDM room. Good thing too, since we distill the water we use so we don't use up as much de-ion resin, and the distillers are in the EDM room. It can get quite hot in there, even in the winter (like 100+ degrees), when everything is running.
    sigpic
    Originally posted by AndersI
    I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

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    • #17
      I keep the room to 68 degrees +/- 2 degrees. I have the thermostat locked and I have the Key. I know from past years I can let it get up to 74 before the numbers start to look bad from the temp. Some days in the summer it is hard to keep the room at 68 degrees. The air runs all day. I have told the uppers but they just don't understand. If someone asks why it is so cold in here I tell them it is for the machines not for me. I like it about 78 to 80.

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      • #18
        temperature

        Funny thing the temperature. I am not sure why the standard temperature in a lab is 68 as opposed to 72 or so. The machines can be calibrated for most any temperature and will perform well provided the temp is constant.

        It can't really the coefficient of material expansion either as that is not really an absolute number but more of an estimate.

        I seem to remember reading somewhere that 68 degrees was adopted as standard because most deep caves are within a couple of degrees of that and way back before the invention of air conditioning, it was difficult to keep the temperature stable. Some of the length standards developed in Switzerland were kept in deep caves because there was less variation in the temp and the errors in determining the length were minimal.

        H
        Hilton Roberts

        "Carpe Cerveza"

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        • #19
          As for checking the customer required items, that is really NOT part of YOUR QS9000. You put into effect what standards YOU want. That is YOUR QS9000 standard. You customer also has QS9000 standards, that is what THEY want, and part of THEIR standards are what their outsource needs to be able to do. If they are using YOU, then logically, YOU area acceptable by their QS9000 standards, otherwise, they could be using you, right? Right from the beginning of this QS9000 stuff, I said that it was mostly a lot of hooey and I have yet to see anything that has changed my mind. Granted, the idea behind it is a good one, but then that got lost in all the independant companies that sprang up to do the auditing and just about every company has addopted 'standards' that the auditor thought they should have, even if the standard had no real effect on the company. Case in point:

          We build stamping dies, we sell stamping dies, we do not sell stampings.

          The stampings are checked with the CMM to see if the die is producing a part acceptable to the customer, once it is, they buy the tool and we ship it.

          We were Ford Q1 well before QS9000 came along. For whatever reason, Ford wanted EVERY micrometer, vernier, height gage, etc. in the shop checked and calibrated on an annual basis so you could earn the Q1 rating, we did this, even though it took about 1 solid month of work on my part to do all the tools in the shop, 8 to 10 hours a day, so you have to figure that 320 to 400 hours PER YEAR were used checking all these tools. We continued this standard for the QS9000.

          The first time out 'auditor' came in, he said he wanted to see Gage R&R studies done on EVERY micrometer, height gage, vernier, etc. as part of our standard. HUH? Whatinthehell is that about? We told him "NO, We are NOT going to do that, they aren't even used for final product approval!" He kept pushing this for a year and a half before he finally got it through his head we were not going to do it (that is 3 audits, 6 month apart). Then for the next 3 audits (another 18 months) he just wanted to see if we had checked them and calibrated them, and we had. Then, since we had had no violations, we were allowed to go to a yearly audit instead of 6 months. For the next 2 audits, again, everything was just fine.

          Then, at a time when we were so busy we couldn't even scratch, a couple guys tools went out of certificaiton (they were over-due about a month) and the auditor came in. And of course, those guys were the ones he checked to see if the tools were in 'certificaiton'. They weren't. Then, he came to me and asked me WHY they weren't in 'certification' and I told him that I just hadn't had the time to do it, that I had been busy with real work. He then asked, WHY they were part of our standard since final acceptance for the tools came from the CMM? He said that since they were only used for construction that they were technically reference devices and that we didn't need to track them and 'certify' them, that the CMM was the final word and if it said GOOD, that was all that was needed.

          Now, read that all again. Some more facts: We had the SAME auditor EACH AND EVERY TIME. At the beginning, he wanted ABSOLUTELY ridiculous standards, then as time went by, he eventually told us WE didn't even need to track those very items he wanted to go overboard on. Now, does that make sense or does that sound like NEW GUY on a NEW JOB with NEW POWER wanting to run the train instead of just shoveling in the coal? HE wanted THIS and THIS and THIS and THIS that had nothing to do with the type of work we do or the product we make, then as the novelty of his new found POWER tapered off, the BS went away.

          So, with your auditor suddenly asking for something new, that leads me to think that you have a new guy doing the audit this year and that he has discovered his POWER over all these companies that PAY HIM to check to see if they are complying with what they say they do. I swear, these guys that take the auditor jobs are nothing but little Hitler's who couldn't make it in the real job market.

          So, I hope I have preached on enough for you, and remember, YOU REQUESTED IT!
          sigpic
          Originally posted by AndersI
          I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

          Comment


          • #20
            we use temp comp here on a number of jobs but sheet metal does seem to be a very dynamic and ever-changing part if not in the sheer flat blank state. our customers mandate temp control and audit us on it regularly i use a Veriteq Spectrum 2000 monitor and the supporting software. it provides the accuracy and the ability to configure a great number of ways. we used to use the Dickson Circular paper graph then done a study with a Master temp probe and seen some real correlation issues. The Veriteq is cheaper and more accurate. and networkable with live data feeds. hope this helps

            Scott

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            • #21
              So, what is your argument to Y14.5M-1994 1.4(k) ??
              Are your dimensions not applicable? Has the proper compensation been made for measurements at another temp? (playing devils Advocate here)


              I am needing to cross this bridge at my current place of employment.
              Kev
              RFS Means Really Fussy Stuff

              When all you have is a hammer - everything looks like a nail....
              sigpic

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              • #22
                No problem, I have similar experiences and I do not disagree with you. Went thru the exact same argument about GRR. We compromised and did a GR&R on one micrometer, one indicator etc. I put them in a file and have only had to show them once since. We were fortunate in that the auditor we had first and for a few years after was really quite reasonable and knowledgeable. We've had some since that would fit your description to a tee.
                I even had one who wanted all our GR&R files moved from the file cabinet in our CAD room onto the computer where we keep all the certification data. This after the auditor before had said everything was fine. I refused and never heard anymore about it. To this day I believe he was too lazy to get up and walk 30 feet. We could probably devote several pages of this thread to audit horror stories.
                The only reason I mentioned about customer requirements is that we are also audited occasionally by our customers such as GM or Nissan. So if you can incorporate some of their requirements in yours then it doesn't hurt. Did not mean to imply that it has to be part of YOUR procedure.
                When the going gets weird, the weird turn pro. Hunter S. Thompson

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                • #23
                  We have a SOP here (standard operating procedure) booklet that Inspection made for this kind of audit. In the SOP there is a statment that parts have to soak in our room for 24 hrs before measurement. When the fire comes from the floor of having problems that goes right out the window. Yes we also have a locked thermostat and a temp gage. Ours is the same as most 68 degrees +-2. As for the sheet metal stamped parts we make the heatercores and evaporator coils which are .020"material and I have done them right off the press. I do not see a differance in a 24 hour soak period.
                  sigpicRegards,
                  Donald Henger
                  B&S Micro Excel Pfx
                  3.5mr2 & 3.7mr3
                  PHH10MQ, TP20 & TP2
                  Country Rocks,But Bluegrass RULES!!!

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                  • #24
                    AH, but that is not what we are talking about, now is it? QS9000 has nothing to do with that, UNLESS YOU INCLUDE IT IN YOUR STANDARDS. Now, I am not say YEA or NAY to it, I am mearly pointing out what QS9000 requires, which is basically NOTHING!

                    If I set my QS9000 standard to say, "I will make reports that show all parts good, no matter what they actually measure." and as long as I do exactly that, and document that I did exactly that, then I am certified as QS9000. Now, I am not saying that will get me a lot of work, but it CAN get me my QS9000 certification.

                    Now, this IS way over the top, but that is really what QS9000 boils down to. You can DO whatever you want, as long as your standards SAY that is what you will do and then you document that you did do it.


                    As for compensating for tempurate, Hilton said "You can figure 6.5 ppm times the number of degrees from 68 times the number of inches to get an idea of the effect of thermals on your parts if you are checking steel."

                    So, 6.5ppm is part per million or .0000065 X 10 (we will use 10 degrees of temp variation) X 72" (my machine travel) = 0.00468". Now, that is if the part is as long as my machine, 90% (100% right now) are under 48" so that lowers it to 0.00312" TOTAL error. That is as 10 degrees change. I can use my calibration record for temp changes over the last 10 years, fo a total temp range of 5 degrees, max to min. So, that changes it down to 0.00156" for a 48" part. The machine specs are +/-0.0007" both accuracy AND repeatability for a total 'tolerance' of 0.0014". Not much difference than the temperature, now is it?

                    Now, I AM NOT SAYING that tempurature does not need to be monitored. IT WILL all depend on the applications and parts and tolerances you are running. Hilton, I imagine, needs to run a much TIGHTER tolerance so temperature will play a HUGE roll in what he does. I am running +/-0.020" for the tight tolerance and +/-0.080" or more for the loose tolerances. With a 5 degree temp range and the average size of the parts, that is a 5% error, and you remember the 10% rule? The measurement device SHOULD be accurate to 10% of the tolerance being used. The machine is another 5% so that gives me the required 10% accuracy.

                    See, you can be the devil's advocate, and I'll the the advocate's devil!
                    sigpic
                    Originally posted by AndersI
                    I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

                    Comment


                    • #25
                      Temps that affect stampings:
                      I've had one part that was severly affected by a changing environment and it was a very thin part that went into a transmission. It was just a small thin shield. Just falling off of the press shute, made physical changes, then add a change of 10 - 20 degrees in temp and you had a cmm disaster. Therefore if your lab is controlled and production is not, my question:
                      What is the true representation for layout purposes?
                      Right off of the press - like the customer will receive or a chilled deviation of the sample?
                      Then, will the sample be the same in the summer as in the winter?
                      Oh yeah, then take in the material range. One composition ran today, may not be the same next run, but still within the spec, so what is the environment going to do to the dimensions then? Now I remember the reason I like beer,,,,,,,..........
                      A.Gore
                      sigpicA.Gore

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                      • #26
                        you still have to conform to the QS guidelines which is why they have those nice pretty blue books for you to follow.

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                        • #27
                          Advocates devil...Your funny Matt!

                          My bad for semi Thread-jacking...
                          Kev
                          RFS Means Really Fussy Stuff

                          When all you have is a hammer - everything looks like a nail....
                          sigpic

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                          • #28
                            And yet another reason that (so far) I have not worried about temp variation in our parts. Heck, ya know that if you even take the die out of one press and put it in another that you get a different part, sometimes REALLY different. We were doing 3rd party tryout not too long ago for someone who had a die built in (gasp) Korea and we used the stock they gave us. We got it to draw and form and trim like it should (we were NOT responsible for dimensional, we just had to get the die to run without splitting, so I didn't check any parts) and then THEY, the customer bought it off and we shipped it back to them. We used all the stock they gave us running the die off to prove that it no longer split, etc. Then they got it back to their shop, used a different coil from a different batch of steel and all the splits came right back. Both coils of stock were well within the required specs for the production of the part, thickness, composition, etc., yet one coil worked wonderfully, the other was a disaster. This is why production is so much harder in some cases than construction. Every time a new coil from a new batch is put into the die, changes may need to be made to get a functional part. Thus the reason for SPC and continuous monitoring of the process, hour after hour, day after day, week after week, month after month, year after year, well, you get the idea. And this says nothing about shop temps from build source to production source or from winter to summer in the same shop. Not many automotive shops have that kind of climate control (none that I have ever seen). That is a major reason I am SO GLAD I am not in a production shop.
                            sigpic
                            Originally posted by AndersI
                            I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

                            Comment


                            • #29
                              HEY WINSTON, you are right in that you have to follow those guidlines, but they are VERY loose in scope for the most part and allow a LOT of leeway.
                              sigpic
                              Originally posted by AndersI
                              I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

                              Comment


                              • #30
                                temperature compensation

                                A few years ago a DEA tech., the late Kurt Burrell, was in here to work on our machine and he had just gotten back from a repair in Mexico.

                                He said he had to do major replacement of PH9 heads and cartridges.

                                The machine was located in an aluminum foundry and they were bringing castings to be checked right as soon as they could get the castings out of the molds.

                                Kurt told them the parts could not be checked in that condition and they responded they had purchased a machine with thermal compensation.......

                                Turns out the castings were so hot they fried the PH9 head........

                                True story.

                                Hilton
                                Hilton Roberts

                                "Carpe Cerveza"

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