[Jo...] Posted January 20, 2022 Share Posted January 20, 2022 I a part that is similar to a Ring-gage, ID 1.5 inches, OD 2.733 inches and overall thickness of .75 inches with a composite profile callout, with the top frame .002 to datum B & C, and on the bottom .0003 to datum B at MMC. Here's the detail: featured is the ID, Datum B is one of the flat surface, and Datum C is the OD. How do I know that I'm getting the correct results or if the calculation is correct for a composite profile with 1 or 2 Datum references? The help menu states that all Datum references must be defined or no results. For the Top Frame, Primary is B, and Secondary & Tertiary is C. For the Bottom Frame, Primary, Secondary & Tertiary is B not to mention MMC on a Flat surface. Could the Top frame be considered similar to a True-Position and the bottom one Perpendicularty? Help anyone? Link to comment Share on other sites More sharing options...
[Ro...] Posted January 20, 2022 Share Posted January 20, 2022 I think that they're trying to say that datum -B- is the width between both sides, which is .750, and would be the Midplane/Symmetry of the 2 sides. The thinner it is the more mobility/datum shift you get from -B-. The second tier is "essentially" controlling perpendicularity, but not technically. Link to comment Share on other sites More sharing options...
[To...] Posted January 20, 2022 Share Posted January 20, 2022 Please sign in to view this quote. If that were the case, B symbol would be "inline" with .750 dimension. I'm guessing maybe the mobility comes from the parallelism??? Link to comment Share on other sites More sharing options...
[Ro...] Posted January 20, 2022 Share Posted January 20, 2022 I agree. But parallelism is an orientation control and doesn't have a material condition. You'd have to use the .750. Your guess is as good as mine. 🤣 Link to comment Share on other sites More sharing options...
[Jo...] Posted January 20, 2022 Author Share Posted January 20, 2022 Thanks for the quick response guys. If that's the case, the .750 does have a block tolerance of ±.005, it's basically going to be plenty of bonuses. How would that be entered and which Profile tolerance zone is going to be used? There are a couple. If you could explain each in detail that would help. Thanks. Link to comment Share on other sites More sharing options...
[Te...] Posted January 24, 2022 Share Posted January 24, 2022 There can be no M for datum B because it is not a feature of size at least as shown in the print. When the M is on the datum feature it is MMB which is a shift in the data. Again MMC or MMB can only be applied to a size dimension. https://www.youtube.com/watch?v=cZibPYcXdy8 Link to comment Share on other sites More sharing options...
[Jo...] Posted January 25, 2022 Author Share Posted January 25, 2022 Thanks for the tip. We actually want the MMC to be for the bore diameter. So in this situation, should the MMC be moved next to the tolerance? According the info or video-clip regarding the MMC for Profile, MMC is never allowed on the Profile tolerance. If that is the case moving it to the left-side is not legal either. What' the alternative? . . Also, it seems that you can't applied modifies with Profile callout characteristic on the CMM, un-like Positional callout. . . What's the work-around or if any? Thanks. 😐 Link to comment Share on other sites More sharing options...
[Ia...] Posted January 25, 2022 Share Posted January 25, 2022 Not going to argue whether it's legal or not, but here is a way to apply bonus tolerance. This probably isn't the best method, but I have written a formula in the tolerance portion of the characteristic. Just right click on the empty field. Then make a formula along the lines of: Tolerance + (Actual diameter - MMC diameter) Link to comment Share on other sites More sharing options...
[Ne...] Posted January 25, 2022 Share Posted January 25, 2022 The alternative in this case if you want MMC on bore is to ask that the bottom portion of the profile be changed to perpendicularity. That would allow you to put MMC on the bore. Also for the profile callout, you have bilateral one result, if you change it to bilateral two result it will give you a min and max. Didn't know if you already knew that since you asked about the different callouts. To get a profile result for the BC callout you will have to do what you did which is add C as a third callout. Neil Van Swol Link to comment Share on other sites More sharing options...
[Jo...] Posted January 25, 2022 Author Share Posted January 25, 2022 I totally forgot about using formula on the tolerance because I was so focus about not seeing the Modifier option like for the True-position characteristic. Thanks. Ian. And Neil, that was going to be the other alternative. Having the Top stay at the Profile and the bottom to be Perpendicularity with the MMC. Thanks everyone, I believe the info I have acquired here are very helpful. Hopefully someone will find it useful as well. Until next post, thanks. 😃 -Joseph Khang Link to comment Share on other sites More sharing options...
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