[An...] Posted July 24, 2020 Share Posted July 24, 2020 See attached.Pic_8-18.pdf Link to comment Share on other sites More sharing options...
[Is...] Posted July 24, 2020 Share Posted July 24, 2020 Looks like the diameter tolerance at [18].. then the profile is applied over the actual value. normally we rebuild the geometry with PCM taking the actual values, or best fit in the axis of the diameter (if is evaluated by segments and there are not other toleranced modifiers). What confuse me is that in the picture bellow the diameters are very close to the Start / End cone diameters; however the STD says: Since profile control is used primarily as a surface control, “regardless of feature size” Link to comment Share on other sites More sharing options...
[Me...] Posted July 24, 2020 Share Posted July 24, 2020 I've never liked this particular dimension scheme. I believe it's similar to having a profile of a face and then giving it a width tolerance that is outside the profile tolerance. Not a huge fan of it but according to the ASME Standard and our GD&T experts in this forum, its perfectly "legal". To me, the surface either lays within it's profile or it doesn't so that diameter would not pass with that tolerance. Smarter individuals in this forum have explained this to me in previous posts but I still do not quite understand. Link to comment Share on other sites More sharing options...
[To...] Posted July 24, 2020 Share Posted July 24, 2020 This concept is similar to specifying a gage diameter on a tapered surface. The surface angle and form need to be controlled but the inherent nature of a taper allows for a size variation. The inverse would be to make the diameter BASIC but use a tolerance for the location of the specific diameter. Link to comment Share on other sites More sharing options...
[Cl...] Posted July 24, 2020 Share Posted July 24, 2020 Ran across this scenario a lot with aerospace jet engine parts. Link to comment Share on other sites More sharing options...
[Is...] Posted July 24, 2020 Share Posted July 24, 2020 I work in the automotive and 99% of my CMM programing requests have this condition… Link to comment Share on other sites More sharing options...
[An...] Posted July 24, 2020 Author Share Posted July 24, 2020 Please sign in to view this quote. Yes,this screenshot describes the standard. Question: Is the standard right? Answer: NoPic_8-18_c.pdf Link to comment Share on other sites More sharing options...
[Ma...] Posted July 24, 2020 Share Posted July 24, 2020 Gage point - diameter measured at that basic distance. Link to comment Share on other sites More sharing options...
[Ta...] Posted July 25, 2020 Share Posted July 25, 2020 Hi all, The Drawing says that the Gage point Diameter can be within Minimum (23.8) or Maximum (24.2), Whatever may be the Size, but the profile of the taper surface should be within .02 with respect to the Datum's. "Since profile control is used primarily as a surface control, “regardless of feature size”". Here we need to know that, Profile control is used primarily as a Surface control only, not as the Size control. Profile and Size are different. Link to comment Share on other sites More sharing options...
[Is...] Posted July 26, 2020 Share Posted July 26, 2020 Please sign in to view this quote. ❓ , why is not right? Link to comment Share on other sites More sharing options...
[An...] Posted July 28, 2020 Author Share Posted July 28, 2020 See attached.Pic_8-18_d.pdf Link to comment Share on other sites More sharing options...
[Is...] Posted July 28, 2020 Share Posted July 28, 2020 Please sign in to view this quote. naa… then I must ignore the text in the STD... How should be then the drawing of form in curves when the size is not functional or relevant using ASME?. Link to comment Share on other sites More sharing options...
[Da...] Posted July 28, 2020 Share Posted July 28, 2020 Please sign in to view this quote. You should, for a moment, consider that you misunderstood this particular picture. I understand why this could be misinterpreted, but it is totally correct, because the profile call-out of a cone does not control the diameter of the cone. Link to comment Share on other sites More sharing options...
[An...] Posted July 28, 2020 Author Share Posted July 28, 2020 Please sign in to view this quote. Datum Reference Frame: A I agree Datum Reference Frame: AB I disagree Link to comment Share on other sites More sharing options...
[Is...] Posted July 28, 2020 Share Posted July 28, 2020 Please sign in to view this quote. Datum B limits the displacement in X axis,, but the diameter is in Y axis. … I would prefer ISO standards because have more modifiers than ASME.. Link to comment Share on other sites More sharing options...
[Da...] Posted July 28, 2020 Share Posted July 28, 2020 Please sign in to view this quote. I disagree also. If the diameter of the cone were controlled by the profile call-out, both the 18 and the diameter 24 had to be basic dimensions. Since only the 18 is, there is no correlation between the profile call-out and the diameter 24. We might agree on the fact, that this is an incomplete way of dimensioning a profile or that the diameter call-out tolerance is rather unfortunate, but separate call-outs on the same feature are allowed. Link to comment Share on other sites More sharing options...
[An...] Posted July 28, 2020 Author Share Posted July 28, 2020 So,what Mr. Binder really understands: Having a look at the standard is obviously much more comfortable than having a look and trying to understand the "six-sheets-PDF" of Mr. Binder. Link to comment Share on other sites More sharing options...
[Da...] Posted July 28, 2020 Share Posted July 28, 2020 I'm sorry, I don’t mean to start a fight with you, but I still disagree on that matter. You start off with a wrong prerequisite. The diameter 24 is not a „refinement“ of the profile, the profile is a „refinement“ of the diameter 24. Whatever the diameter at the depth of 18 is, it defines the nominal centerline of the profile, as long as it is within tolerance. It’s kind of a „floating“ centerline. From there, the tolerance of 0.02 of the profile must be held, not the other way round. Those six sheets are full of wrong conclusions and mere assumptions ignoring the given information, and I don’t mean this in a bad way. Over the years I have seen many useful explanations from you, but here, you’re not right. Link to comment Share on other sites More sharing options...
[An...] Posted July 29, 2020 Author Share Posted July 29, 2020 See attached.Pic_8-18_e.pdf Link to comment Share on other sites More sharing options...
[Is...] Posted July 29, 2020 Share Posted July 29, 2020 Please sign in to view this quote. I completely disagree with you.. Link to comment Share on other sites More sharing options...
[Is...] Posted July 29, 2020 Share Posted July 29, 2020 and ASME disagrees with you too. 🤣 Link to comment Share on other sites More sharing options...
[Is...] Posted July 29, 2020 Share Posted July 29, 2020 Also my colleague designers disagree with you.. Link to comment Share on other sites More sharing options...
[Da...] Posted July 29, 2020 Share Posted July 29, 2020 Please sign in to view this quote. This is correct, but it is only fixed when there is a basic dimension from this plane AND a basic diameter at that height. In this particular case, there’s only the basic dimension from the plane B but no fixed diameter, so there is no "fix". There is play around the diameter 24 for the profile center. I don’t think this would be allowed in ISO, but in ASME, there are some examples of tolerated dimensions acting as extended datum features. Link to comment Share on other sites More sharing options...
[An...] Posted July 29, 2020 Author Share Posted July 29, 2020 Please sign in to view this quote. So, what is the meaning of datum B,when calling out Profile 0.02 AB ? And also, what is the meaning of primarily ? (E.o.T.) Link to comment Share on other sites More sharing options...
[Da...] Posted July 29, 2020 Share Posted July 29, 2020 B is the datum for the height 18 (which is fixed after all). It is needed to define the center for the diameter tolerance zone. And the explanation for the word „primarily“ is right there in the next sentence. Although the profile does not control a feature of size (which means there can never be a MMB or LMB on the profile), a material condition can be applied to the datum features (if they are features of size), giving more control of the profile. In this case, however, since B as a plane is also not a feature of size, ASME allows for the modification of the datum by letting the datum float, within the diameter‘s tolerances. It is a solution that would require multiple call-outs in ISO, but can be done in ASME all-in-one. Link to comment Share on other sites More sharing options...
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