Legacy or Xact Measure

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  • Legacy or Xact Measure

    Have you jumped to Xact Measure or stuck with Legacy?


    If using Xact measure, did you take any training on it. I had a great conversation with Rob last week at the ASME meetings and he's got me leaning to go to Xact. The two things I don't like about it is 1, the value given is a shifted value which is useless for capability. I would have to add a legacy dimension for that and 2, the edit window doesn't show any values, I have to go to the report to see what is reporting.
    69
    Legacy
    84.06%
    58
    Xact Measure
    15.94%
    11
    sigpic GDTPS - 0584

  • #2
    We jumped to Xact Measure (going 3.2 to 4.2). Didn't get training until a year after it was installed. Mainly learned by reading this forum. It was a bit of a learning curve at first, but now I'm pretty confident in most of what it reports.

    Except: True Position reporting in Xact Measure is still a problem. Mainly when nominals just stop appearing on the report, or the position is calculated from dimensions that are not reported. I've learned to watch for this condition and recreate the reporting feature. Annoying, but its what we've got....
    -Rick

    I bring nothing to the table.

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    • #3
      I'm currently running a machine with 3.7 so it's not an issue but when I ran on 4x+ I used legacy for just the reasons resgriggy mentioned. Too many annoying things that you have to watch out for. That and I found it more of a PITA than it was worth trying to explain things to the same people over and over again. At the time I was working tool & die and datum shifts and the like just didn't matter to them all they wanted was "tell me which way and how far I have to move" and I could do that just fine with legacy.
      Last edited by EHines; 05-06-2010, 09:31 AM.
      Saving the world, one bad part at a time.

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      • #4
        I am not voting because the option I need isn't there.

        I have a lot, (hundreds) of existing programs that use legacy. I do not intend to try to change them.

        However yesterday I plunged into 2010 and am also doublewhammying myself because going forward I am going to use Xactmeasure. I decided to this for two main reasons.

        1) Xact measure has been certified mathematically compliant with ASME Y15.4, which legacy is not.

        2) My hope is seeing the actual FCF on my report will help reassure non cmm types that what I am reporting is what is required on the drawing.

        So far my concern is Datum designations limited to "A-Z" & "AA-ZZ". The part I am working with that will be first to use exact measure has Datums A-T with several of those being Datums in ports that appear multiple times, for example Datum D is 3x individually meaning the datum feature occurs at sections A-A, B-B, & C-C and at each location the Datum D is relevant only to that section. Finding ways to clearly name all of these with the limited two character designation is going to be a challenge. I realize the limit is due to the need to fit the defined Datum name into the FCF, it would be very nice if I could add a couple more letters or numbers.


        Is there a thread about this nominal disappearing phenomenon? I don't like the sound of that.

        sigpic"Hated by Many, Loved by Few" _ A.B. - Stone brewery

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        • #5
          Originally posted by Wes Cisco View Post
          I am not voting because the option I need isn't there.

          I have a lot, (hundreds) of existing programs that use legacy. I do not intend to try to change them.

          However yesterday I plunged into 2010 and am also doublewhammying myself because going forward I am going to use Xactmeasure. I decided to this for two main reasons.

          1) Xact measure has been certified mathematically compliant with ASME Y15.4, which legacy is not.
          2) My hope is seeing the actual FCF on my report will help reassure non cmm types that what I am reporting is what is required on the drawing.

          So far my concern is Datum designations limited to "A-Z" & "AA-ZZ". The part I am working with that will be first to use exact measure has Datums A-T with several of those being Datums in ports that appear multiple times, for example Datum D is 3x individually meaning the datum feature occurs at sections A-A, B-B, & C-C and at each location the Datum D is relevant only to that section. Finding ways to clearly name all of these with the limited two character designation is going to be a challenge. I realize the limit is due to the need to fit the defined Datum name into the FCF, it would be very nice if I could add a couple more letters or numbers.


          Is there a thread about this nominal disappearing phenomenon? I don't like the sound of that.

          1) Xact measure has been certified mathematically compliant with ASME Y15.4, which legacy is not.


          Where did you find this?

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          • #6
            Originally posted by Tested View Post
            1) Xact measure has been certified mathematically compliant with ASME Y15.4, which legacy is not.


            Where did you find this?
            PC-DMIS for Windows has received NIST (National Institute of Standards and Technology) Certification. Follow these links for certification information for these versions:
            http://www.wilcoxassoc.com/versions/...cation.php#V43


            Opps, my bad. NIST not ASME. I was told by a ******** that is for Xactmeasure, not legacy.
            Last edited by Wes Cisco; 05-06-2010, 11:38 AM. Reason: opps
            sigpic"Hated by Many, Loved by Few" _ A.B. - Stone brewery

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            • #7
              Thanks for the lonk. I read the documentation and had to splash cold water on my face to bring me back to consciousness. I totally glazed over reading the docs.

              After re-reading them (slowly) from what I can understand, the software calculates GEOMETRY to meet NIST standards; lines, circles yada,yada,yada.

              Why should this make a difference if I report using legacy or xact-meaesure?

              B&S CHAMELEON/PCDMIS CAD++ V2011

              There are no bugs, only "UNDOCUMENTED ENHANCEMENTS!"

              sigpic

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              • #8
                Originally posted by dph51 View Post
                Thanks for the lonk. I read the documentation and had to splash cold water on my face to bring me back to consciousness. I totally glazed over reading the docs.

                After re-reading them (slowly) from what I can understand, the software calculates GEOMETRY to meet NIST standards; lines, circles yada,yada,yada.

                Why should this make a difference if I report using legacy or xact-meaesure?

                Get a big pot of strong coffee. . .

                No, I won't try to get too deep into it, because to be honest, at some point I get lost and I have to take the word of the folks who know a lot more math than I do.

                But the gist is simple enough. If there are material modifiers on Datums, (MMC, LMC), then it gets really ugly math wise. Legacy dimensioning does not handle those situations properly. Xactmeasure does.

                That is the nutshell. I won't try to explain it more completely. I was not bothered by this for years because I rarely see a modifier on a Datum, and usually when I do, I ignore it, knowing that if the part checks good without shifting the Datum, then it is good.

                Knowing legacy has a flaw and now that Xactmeasure has been out long enough it would likely have been found and reported if it had such a flaw, further bolstered by the NIST cert, even though it isn't likely to make much difference in my results, I can't see continuing to use the method I know isn't 100% correct.


                sigpic"Hated by Many, Loved by Few" _ A.B. - Stone brewery

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                • #9
                  Originally posted by Wes Cisco View Post
                  Get a big pot of strong coffee. . .

                  No, I won't try to get too deep into it, because to be honest, at some point I get lost and I have to take the word of the folks who know a lot more math than I do.

                  But the gist is simple enough. If there are material modifiers on Datums, (MMC, LMC), then it gets really ugly math wise. Legacy dimensioning does not handle those situations properly. Xactmeasure does.

                  That is the nutshell. I won't try to explain it more completely. I was not bothered by this for years because I rarely see a modifier on a Datum, and usually when I do, I ignore it, knowing that if the part checks good without shifting the Datum, then it is good.

                  Knowing legacy has a flaw and now that Xactmeasure has been out long enough it would likely have been found and reported if it had such a flaw, further bolstered by the NIST cert, even though it isn't likely to make much difference in my results, I can't see continuing to use the method I know isn't 100% correct.


                  Yup, what he said.
                  sigpic

                  James Mannes

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                  • #10
                    Thanks, Wes and James.

                    So, what you are saying is that legacy dimensioning doesn't calculate datum shift properly and xactmeasure does.

                    Time to grab another cup of coffee.

                    B&S CHAMELEON/PCDMIS CAD++ V2011

                    There are no bugs, only "UNDOCUMENTED ENHANCEMENTS!"

                    sigpic

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                    • #11
                      In PC-DMIS I think (and most other CMM softwares) you have 2 different groups of math calculations.

                      1) Geometry construction. This the math that is used to construct features.

                      2) Feature evaluation. This the math used to evaluate the feature like GD&T

                      Number one is certified by NIST and PTB. Number two uses the math function that is published by ASME as far as xactmeasure but not certified yet. I don't think any one is providing this service yet.
                      sigpic

                      Brain- Pinky, are you pondering what I'm pondering?
                      Pinky- I think so, but where will we find an open tattoo parlor at this time of night?

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                      • #12
                        Originally posted by dph51 View Post
                        Thanks, Wes and James.

                        So, what you are saying is that legacy dimensioning doesn't calculate datum shift properly and xactmeasure does.

                        Time to grab another cup of coffee.
                        That is correct. That being said, here is some more information. Legacy dimensioning will not make a bad part good, but, it will make a good part bad. Legacy doesn't utilize the full amount of "shift" available where Xactmeasure does.

                        If you use Xactmeasure and create a True Position dimension to RFS and then create a Legacy True Position to RFS you will realize the same results.

                        I am unsure of the differences that are output when using Xactmeasure with other types of dimensions.
                        sigpic

                        James Mannes

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                        • #13
                          James - you had me sweating bullets until it dawned on me..... I don't have any parts which allow for datum modifiers. But I learned a valuable lesson for in the future.
                          Thanks to all.
                          sigpic
                          Originally posted by Ironhoe
                          I got something under my sporran for you, take care of it and you got my vote.

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                          • #14
                            At first I was against using XactMeasure it seemed complicated but now I wouldn't use anything else. It reports more closely to the Standard. And if you think about it, Inspection is a reporting department not a fixing department, I do wish it would print the actual values beside the fitted values so there were numbers to give to production, but hey, that could be a enhancement. But I would NOT use XactMeasure unless you are using PC-DMIS 2009 MR1 or higher, it has some issues before that. Now about the nominals disappearing, I've seen it happen but usually you just need to delete the FCF and build a new one and it fixes it. I do HIGHLY recommend Rob's class though, he really puts things in perspective.
                            ______________________________
                            "I find your lack of faith disturbing..."
                            PC-DMIS 2014/MeasureMax/PC-DMIS Gear/Datapage+/Vision/Portable

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                            • #15
                              xact measure is fine if your print gd&t is right.

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