[Da...] Posted April 20, 2018 Share Posted April 20, 2018 Does anybody know how to, or have a problem with not being able to toggle on the MMC modifier for a reference datum in a true position characteristic? I have to relate a width dimension that carries the requirement back to (Datum A) that was scanned as a cylinder and (Datum B) which is a planer flange face. The characteristic does not have a tertiary (Datum C) as of yet, as this is an in-process inspection at the first milling stage of the part. The width dimension is measured using a symmetry plane feature. Does Calypso need a tertiary datum to fully constrain the feature frame, thus allowing the modifier for Datum a to be toggled on? I am pretty much a novice in the software and need this on in order to comply with the customers b/p. Any help would be appreciated. Link to comment Share on other sites More sharing options...
[De...] Posted April 20, 2018 Share Posted April 20, 2018 Try using a symmetry point or symmetry plane. Link to comment Share on other sites More sharing options...
[Aa...] Posted April 23, 2018 Share Posted April 23, 2018 A few points: Yes, you're right to use a symmetry plane feature. I've seen many cases where Calypso ghosts out (or hides altogether) the dropdown for boundary conditions on datum features of size. Unfortunately, I've never seen or heard an explanation why, nor have I been able to pick up on any rhyme or reason on when it happens. I doubt that adding a tertiary datum feature will change this behavior in your case. However, it is still a topic you should consider. In spite of widely held concepts of how Calypso "should" work, reality trumps. Behind-the-scenes, Calypso treats all DRF's as alignments. And it solves using "sequential evaluation", meaning it determines the position/orientation of each alignment before it begins calculating the results of the positions, profiles, etc. that are tied to that alignment. As a result, it does not optimize the unconstrained degrees of freedom. (The exception to this is best fit bore pattern, which only works in 2D scenarios.) If you don't select something to constrain that last degree of freedom, the alignment will simply inherit it from the parent alignment, which is usually the Base Alignment. Link to comment Share on other sites More sharing options...
[Da...] Posted April 25, 2018 Author Share Posted April 25, 2018 Based on the number of views Aaron it looks like quite a few operators have had this situation...Lol. I have had this situation more times than i would like to over my limited time in Calypso. I have version 6.4 , but haven't installed it yet. Maybe that will address this issue a bit better. Thanks for confirming that there is a glitch involving this. Dan Link to comment Share on other sites More sharing options...
[Da...] Posted May 18, 2018 Author Share Posted May 18, 2018 Does anybody else have a clue on this? With almost 27,000 views on this in under a month, it has to be happening quite frequently. 🙂 Thanks, Dan Link to comment Share on other sites More sharing options...
[De...] Posted May 18, 2018 Share Posted May 18, 2018 Uh.. pretty sure all those views are a bug with the forum. I bet there haven't been much more than 27000 views on this entire forum since its been up. That said.. unfortunately this is well known Collapso™ behaviour.. Link to comment Share on other sites More sharing options...
[Me...] Posted May 18, 2018 Share Posted May 18, 2018 Calypso does not support datum shift when a symmetry plane is the considered feature or used as a datum feature. The only time you will have the option to apply coordinate system mobility (MMB) is when the features (considered / datum) are cylindrical and reside in the same plane. Link to comment Share on other sites More sharing options...
[An...] Posted May 22, 2018 Share Posted May 22, 2018 Just trying to tell something about the "Cylinder-Plane" phenomenon.True_Pos_P_7-59_2.pdfTrue_Pos_P_7-59_1.pdf Link to comment Share on other sites More sharing options...
[Ma...] Posted June 14, 2018 Share Posted June 14, 2018 Please sign in to view this quote. +1 Link to comment Share on other sites More sharing options...
[Da...] Posted April 29, 2020 Share Posted April 29, 2020 Please sign in to view this quote. Is this still true for all Calypso versions? Link to comment Share on other sites More sharing options...
[Me...] Posted April 29, 2020 Share Posted April 29, 2020 Yes Link to comment Share on other sites More sharing options...
[Da...] Posted April 29, 2020 Share Posted April 29, 2020 You cant use MMC for Slots, So I just use formulas. It more then likely has to do with MMC of a slot is assessed with Width and Length separately. Link to comment Share on other sites More sharing options...
[Ri...] Posted April 29, 2020 Share Posted April 29, 2020 Please sign in to view this quote. My only problem with using formulas in the tolerance is that capability analysis inside of PiWeb doesn't work correctly when you do that. I like to use Theoretical Circles that pull in the actuals, and then do the evaluation on the circles. That allows me to use the native material condition functionality. Link to comment Share on other sites More sharing options...
[Da...] Posted April 30, 2020 Share Posted April 30, 2020 Please sign in to view this quote. I don't have a solution for that one. I don't use Pie web instead I setup a data transfer to SQL server then use Excel or Minitab. Link to comment Share on other sites More sharing options...
[Jo...] Posted April 30, 2020 Share Posted April 30, 2020 Please sign in to view this quote. This is the method shown in the advanced course I attended. Link to comment Share on other sites More sharing options...
[Da...] Posted April 30, 2020 Share Posted April 30, 2020 Please sign in to view this quote. That is good to know. I was think it was just a workaround and not the best way to do it. Link to comment Share on other sites More sharing options...
[To...] Posted April 30, 2020 Share Posted April 30, 2020 Please sign in to view this quote. Andreas, in #1, it is my understanding that profile should be used on the 20 plane on right, since it is not a feature of size. Link to comment Share on other sites More sharing options...
[An...] Posted April 30, 2020 Share Posted April 30, 2020 You are right. Link to comment Share on other sites More sharing options...
[Me...] Posted May 1, 2020 Share Posted May 1, 2020 Let’s not forget that original question pertained to a modified datum reference. Calypso will only allow modifiers to be applied to datum references when both the datum feature(s) and considered feature(s) are cylindrical. Additionally all must reside in the same measuring plane since the software only allows for “datum shift” in 2d. Also, using the Slot feature within Calypso to verify the position of an elongated hole would be incorrect, if one is trying to maintain the spirit of the Y14.5 standard. This is because Calypso is only looking at the computed center point of the Slot feature and not the boundary. The Slot feature can be used to verify the size components of an elongated hole, but if you're a Y14.5 purist, remember that this is only an approximated LSQ fit. Link to comment Share on other sites More sharing options...
[Da...] Posted May 1, 2020 Share Posted May 1, 2020 Calypso is not to Y14.5 it was made to ISO 1101 Remember that you also have Preassignment for evaluation method If it really is important measurement I used Gage Quality Tools Like True Position Thread Locators and I also use Parallel plates for Datum simulators I also have the CMM granite calibrated so that can also be used. If you have that done and they need to do lapping. Don't lap any part the ballerina leg bearing guide I really like the Prismo that have that area stepped down.Capture.JPG Link to comment Share on other sites More sharing options...
[Me...] Posted May 1, 2020 Share Posted May 1, 2020 Please sign in to view this quote. Interesting…. Can you point me to the proper section for evaluating the location of an elongated hole so that I may learn something new. Please sign in to view this quote. Only option is LSQ for the Slot feature. Link to comment Share on other sites More sharing options...
[Da...] Posted May 1, 2020 Share Posted May 1, 2020 Please sign in to view this quote. An elongated hole (Slot) is not one feature. It is assessed as multiply features. Link to comment Share on other sites More sharing options...
[Da...] Posted May 1, 2020 Share Posted May 1, 2020 The Long side of the slot is completely different then the short side of the slot. I would say your engineers need to take another look at the print if they have a Position of a slot. The only part of a slot that should make contact with the Fastener or Pin is the short sides. Slot length should be great enough that if the parts are in tolerance that it doesn't make contact. Dan Link to comment Share on other sites More sharing options...
[Me...] Posted May 1, 2020 Share Posted May 1, 2020 Please sign in to view this quote. Does this mean that in order to evaluate the position of an elongated hole (Slot) and be compliant to the ISO 1101 standard, one would have to evaluate each face the makes up the elongated hole separately? Please sign in to view this quote. Just so that we are clear, which standard? Link to comment Share on other sites More sharing options...
[Da...] Posted May 1, 2020 Share Posted May 1, 2020 The standard of your print. I guess I don't get your question? Link to comment Share on other sites More sharing options...
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