[Lu...] Posted July 2, 2020 Share Posted July 2, 2020 Hello, I would like to help me about this matter: Composite Position of bore pattern dimension (ASME Y14.5.M-1994). Here are 5 holes. References : Flat A, Cylinder C. Please look at the pictures. Are these evaluations correct? Thank you for your answers. Regards Lukas1.jpg2.jpg Link to comment Share on other sites More sharing options...
[SH...] Posted July 2, 2020 Share Posted July 2, 2020 Please sign in to view this quote. 1994 is an expired standard, my request is to follow 2018 standard. Link to comment Share on other sites More sharing options...
[Lu...] Posted July 2, 2020 Author Share Posted July 2, 2020 Please sign in to view this quote. Hello, thank you for your answer. Ok, but how to measure these dimensions? Are my setups correct? Link to comment Share on other sites More sharing options...
[SH...] Posted July 2, 2020 Share Posted July 2, 2020 I don't know Germany language. When I work with bore pattern, I usually get some values in X,Y shift and rotation. You don't it. Maybe expert will help you. Good luck. Link to comment Share on other sites More sharing options...
[Ri...] Posted July 2, 2020 Share Posted July 2, 2020 On the top one, what exactly is Datum A & Datum C? What is controlling the clocking (rotation) for the top tier? Link to comment Share on other sites More sharing options...
[To...] Posted July 2, 2020 Share Posted July 2, 2020 Please sign in to view this quote. You really should follow the standard specified on the drawing. Link to comment Share on other sites More sharing options...
[To...] Posted July 2, 2020 Share Posted July 2, 2020 Please sign in to view this quote. Because of the MMC or MMB on datum C, you should allow translation and rotation Link to comment Share on other sites More sharing options...
[Lu...] Posted July 2, 2020 Author Share Posted July 2, 2020 Please sign in to view this quote. There isn´t third reference.... Link to comment Share on other sites More sharing options...
[Ri...] Posted July 2, 2020 Share Posted July 2, 2020 Please sign in to view this quote. Then in the top tier you would allow for rotation, but no translation. The bottom tier you would allow for rotation, and translation. Link to comment Share on other sites More sharing options...
[Ri...] Posted July 2, 2020 Share Posted July 2, 2020 Also, any reason as to why you are measuring the features as Circles instead of as Cylinders? Measuring the features as Circles cuts out one of the controlling evaluations (orientation to Datum A). Link to comment Share on other sites More sharing options...
[Lu...] Posted July 2, 2020 Author Share Posted July 2, 2020 Please sign in to view this quote. Hello, when you open Zeiss ´´Cookbook´´ - section Composite Position of Bore pattern-ASME - you can choose Circles or Cylinders Link to comment Share on other sites More sharing options...
[Ri...] Posted July 2, 2020 Share Posted July 2, 2020 Please sign in to view this quote. This is if the ratio of length to diameter is too small. If this is the case, that is OK. I just wanted to clarify. Link to comment Share on other sites More sharing options...
[Lu...] Posted July 2, 2020 Author Share Posted July 2, 2020 Please sign in to view this quote. Hello, yeah in my case is diameter 4,50mm, lenght 2mm Link to comment Share on other sites More sharing options...
[Lu...] Posted July 2, 2020 Author Share Posted July 2, 2020 Please sign in to view this quote. Hello, i think you have right The Top tier miss third reference => rotation .. The bottom tier is correct => rotation, translation Link to comment Share on other sites More sharing options...
[To...] Posted July 2, 2020 Share Posted July 2, 2020 Please sign in to view this quote. With MMB on Datum C, both rotation and translation are active. Link to comment Share on other sites More sharing options...
[Ja...] Posted July 2, 2020 Share Posted July 2, 2020 The first segment in the composite tolerance is Pattern locating tolerance where Translation and rotational degrees of freedom are constrained, they are not free to translate or rotate. So, we should not activate translation or rotation in the Best fit of bore menu. The second segment in the composite tolerance is Feature locating tolerance where Rotation is constrained, but translation is not constrained. Part is free to translate. So, we should activate only translation in the best fit of bore menu. If in the second or third segment, where no datum is specified, the part is free to translate and free to rotate, so we should activate translation and rotation in the best fit of bore menu. Am i understanding correctly? Link to comment Share on other sites More sharing options...
[An...] Posted July 3, 2020 Share Posted July 3, 2020 This is a typical example of "Over Dimensioning". See attached.Contribution_03_07_2020.pdf Link to comment Share on other sites More sharing options...
[To...] Posted July 3, 2020 Share Posted July 3, 2020 Please sign in to view this quote. Having MMC on the holes, simplifies the design and use of a functional gage. Link to comment Share on other sites More sharing options...
[To...] Posted July 3, 2020 Share Posted July 3, 2020 Please sign in to view this quote. Everyone seems to missing the MMB on the Datum C feature. As the datum C feature departs from its maximum material boundary, the position of the pattern is allowed to shift or translate. And because there is no tertiary datum or "timing" feature, the pattern is allowed to rotate, as well. On the second tier, both translation and rotation are allowed. Link to comment Share on other sites More sharing options...
[An...] Posted July 3, 2020 Share Posted July 3, 2020 Please sign in to view this quote. Having MMC in both tiers complicates the design and does not have any technical reason Increasing the production costs by doing "as much as possible" is not the best choice. Link to comment Share on other sites More sharing options...
[SH...] Posted July 3, 2020 Share Posted July 3, 2020 Please sign in to view this quote. MMC increase production cost??, I was told MMC gives more freedom to manufacturer... Link to comment Share on other sites More sharing options...
[Br...] Posted July 3, 2020 Share Posted July 3, 2020 Please sign in to view this quote. Just to further back up Tom's point here that seems to be getting overlooked--When an MMB(it's still called MMC though in the 1994 standard) modifier is applied in the composite tolerance, in the upper segment or PLTZF(Pattern locating tolerance zone framework), you do want to check those rotation and translation boxes, but you must have MMC selected on the datum feature along with the "View Tolerances" drop down active. This will only allow shift based on the size of the datum feature. Then the lower segment or FRTZF (Feature Relating Tolerance Zone Framework.), you will check all those boxes again, but leave out the secondary datum all together. This will allow the part to shift any amount necessary, completely eliminating any constraints that could be established by the secondary datum. Another thing to keep in mind is the simultaneous requirement that could be invoked here. If there are other tolerances of position or profile with the same exact datum reference frame, and the same modifiers as the DRF in the PLTZF does, there is a simultaneous requirement. So wherever the part shifts within the DRF, all the position and profile tolerances with that same DRF apply at that same shifted location. (Just a note: theres no simultaneous requirement for the FRTZF) Link to comment Share on other sites More sharing options...
[Ja...] Posted July 3, 2020 Share Posted July 3, 2020 Please sign in to view this quote. We can refer to ASME Y14.5 - 2018 Section 10.5.1.8 and figure 10-41 to 10-46. It looks like, rotation and translation will be constrained or not, does not depend on datum's boundary condition. It only depend on, whether it is PLTZF or FRTZF. Link to comment Share on other sites More sharing options...
[An...] Posted July 4, 2020 Share Posted July 4, 2020 The philosophy "as much as possible" increases the costs. A typical example of "Over-Dimensioning": See attached.Contribution_04_07_2020.pdf Link to comment Share on other sites More sharing options...
[Lu...] Posted July 7, 2020 Author Share Posted July 7, 2020 Hello guys, thank you for your answers, but i have final question. What is correct? The Top tier miss third reference => i think the bore pattern rotation should be enable The bottom tier is correct => i think the bore pattern rotation should be enable and bore pattern translation should be enable Do i have right? Regards Lukas Link to comment Share on other sites More sharing options...
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