GD&T: Inner & Outer Boundaries, Virtual & Resultant Conditions
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- เผยแพร่เมื่อ 22 ส.ค. 2024
- I show how to calculate inner and outer boundaries and give an example of use of boundaries for a minimum wall calculation. These are topics you need to know for the certification exam, and many of the explanations I give are not explicit in the standard.
This video is based on ASME Y14.5-2009. The definitions are different in ASME Y14.5M-1994, but the equations are the same.
Yikes. Thanks for your great videos. Goes to show why after 25 years of this it has become ever more complex. Mentoring younger staff incredibly challenging. I can barely grasp it. Used to be 1994 much easier. But, thank you sir.
Another important topic covered precisely! Suggestion for future videos:
1) How to check positional tolerance for projected tolerance zones (Manual measurement).
2) How to calculate the tolerance zone for positional tolerance where MMB and MMC applies.
3) How to detemine the approprieate MMB for features where multiple single segment tolerance applies (like covered in 7.11.6.1 ASME Y14.5-2018).
4) How to check if a hole (with perpendiculatiry error and positional error) matches the print where MMC and MMB applies.
Keep going, Dean! You are doing a great job.
Man-o-Man Dr. Odell --- My college instructor really needs to be "instructed" by your clearly comprehensive examples - if you lived any closer I would buy you lunch buddy -- Xcellent tutorial and so very consistant with all your others - great job !
Thanks so much! I appreciate the support.
I'm currently studying for the ASME GDTP exam and your crystal-clear explanations really helped me grasp the IB/OB & VC/RC concepts captured in this video. Thank you!
Good luck! I’m happy my video was helpful. I made it because these topics are not explained very well in the standard. These questions do show up on the exam, I recommend memorizing the simple formulas to calculate boundaries.
1.080😮
Very clear explanation. It helped me to recall my initial phasase of career
Thank you for explanation! I was trying to understand resultant condition. I almost missed it, but at 17:40, it is stated that
>>>the RC is the condition that incorporates the TST.
That is a great way to visually see why functional gauging can be problematic for RFS and LMC, there would be 0 tolerance in the outer and inner boundaries for RFS and interference in LMC. Maybe using LMC derived no-go guage for a slight interference fit maybe but guessing that's pretty rare? Great video, loved it and feel a little more confident in the topic after viewing.
you are really good in explaining concepts of gd&t, thank you for sharing knowledge, keep it up👍
Thanks so much! I try my best to explain and not repeat what you could read in a book. Thankyou for the feedback.
( 8:37 ) The OB of the external is 1.04 which is the MMC 1.02 plus the straightness tol 0.02 but the IB is the LMC without subtracting the straightness tol because there is no way this external rod would get to 0.96. The min it would be bounded is the LMC which is 0.98 and this means that the rod is perfectly straight. What did I miss here?
Thank you so much for explaining so clearly a complex problem!
Trying to wrap my head around why you add for (OB) or minus for (IB) the total size tolerance. I understand adding or subtracting the geometric tolerance, but not the total tolerance as well. Can you show an example as why we need to do this?? Thanks!!
great video... good explanation
Thank you!
Thanks for a great video, it has definetly helped my understanding! I do want to ask when finding IB & OB for a feature that has a +/- size tolerance and a concentricity geometric tolerance applied, would it be the same as you have explained as LMC/MMC +/- GTOL?
Hi, thanks so much!
Concentricity & runout are treated like position at RFS for the purpose of boundaries, so yes it’s just MMC/LMC and the GTOl without the TST.
i never know its so stupid and complicated. Thank you !
Thanks for watching!
I'm confused as to why/how can the IB of the Ext (pin) be less than the LMC? why take away .020 of straightness?
Hi, I should have used a hole instead of a pin with position or orientation rather than straightness. I used straightness of a pin for simplicity, as I only have so much space on the board. You are correct, the IB of a pin with straightness of a derived median line is just the LMC. Subtracting the GTOL is not correct, but it at least is not correct in a way that makes the design more conservative. Thanks for pointing this out.
Hi Mr Odell, for hole position at RFS, could we use functional gage to inspect the hole position? Such as:
Go gage: MMM-Geo. Tol (VC)
Nogo gage: LMC+Geo.Tol+TST
If my answer as above is wrong, pls could you help to design the functional gage to inspect hole position at RFS.
sir, how to mention thread coating tolerance for a component. before coating the thread, it will go precisely but after coating, it won't.
Nice
🏆
How many of you went for a drink after this😅😅
Me. thanks for watching!