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David Slopsema
เข้าร่วมเมื่อ 15 มิ.ย. 2012
This is a channel about Geometric Dimensioning and tolerancing as specified in the ASME Y14.5 Standard
I have 40 years of experience as an engineer for a large manufacturing company. 9 of those years were creating tolerance stacks full time. I have been teaching GD&T since 2006. I have been teaching and mentoring GD&T full time for the past 7 years.
I am certified Senior level GDTP per ASME, and I am currently a member of the ASME Y14.5 committee.
I have 40 years of experience as an engineer for a large manufacturing company. 9 of those years were creating tolerance stacks full time. I have been teaching GD&T since 2006. I have been teaching and mentoring GD&T full time for the past 7 years.
I am certified Senior level GDTP per ASME, and I am currently a member of the ASME Y14.5 committee.
Runout error on datum features
This video describes how there can be runout error and datum features that are referenced in a common datum reference.
มุมมอง: 12
วีดีโอ
Datum Targets
มุมมอง 147 ชั่วโมงที่ผ่านมา
This video describes what datum targets are and why they are used.
Datum Simulated
มุมมอง 207 ชั่วโมงที่ผ่านมา
This video explains what simulated datums are, where they come from, and their similarities to and differences from datums.
Datum Reference Frames
มุมมอง 117 ชั่วโมงที่ผ่านมา
The video explains what datum reference frames are and how they are the foundation of our dimensioning schemes even though they don't exist.
Datum feature simulators
มุมมอง 77 ชั่วโมงที่ผ่านมา
This video explains what datum feature simulators are and why they are used for measurement even though they are not perfect.
Datum Feature
มุมมอง 129 ชั่วโมงที่ผ่านมา
This video explains what a datum feature is, what its purpose is, and how it is identified.
Datum center plane
มุมมอง 119 ชั่วโมงที่ผ่านมา
This video describes datum center planes and how they are derived from true geometric counterparts.
Datum Axis
มุมมอง 179 ชั่วโมงที่ผ่านมา
This video describes how a datum axis is the axis of a true geometric counterpart.
Datums
มุมมอง 2412 ชั่วโมงที่ผ่านมา
This video describes what datums are and how datums are derived from true geometric counterparts just as simulated datums are derived from datum feature simulators.
Cylindricity
มุมมอง 2012 ชั่วโมงที่ผ่านมา
This video describes cylindricity and contrasts it with cylindricity tolerance.
Coplanarity
มุมมอง 1514 ชั่วโมงที่ผ่านมา
This video discusses coplanarity and contrasts it with coplanarity error.
Go, no-go gages
มุมมอง 10219 ชั่วโมงที่ผ่านมา
This video describes go and no-go gages for regular features of size where rule #1 applies, for regular features of size with a straightness tolerance creating a virtual condition boundary, and for complex surfaces controlled by a profile of a surface tolerance.
Continuous feature of size
มุมมอง 3914 วันที่ผ่านมา
This video describes continuous features of size.
Position tolerance MMC on threaded holes
มุมมอง 14521 วันที่ผ่านมา
Position tolerance MMC on threaded holes
No such thing as true position tolerance or datum feature shift
มุมมอง 118หลายเดือนก่อน
No such thing as true position tolerance or datum feature shift
What are basic dimensions vs reference dimensions
มุมมอง 125หลายเดือนก่อน
What are basic dimensions vs reference dimensions
Calculating RMB per figure 7-24 from ASME Y14.5 2018
มุมมอง 85หลายเดือนก่อน
Calculating RMB per figure 7-24 from ASME Y14.5 2018
Calculating LMB per figure 7-23 from ASME Y14.5 2018
มุมมอง 61หลายเดือนก่อน
Calculating LMB per figure 7-23 from ASME Y14.5 2018
Thank you for the videos David. They are awesome. I hope you will get more subscriber in near future.
Thank you for the encouragement!
Please make a playlist .
I made 3 playlists this afternoon. Thank you for the suggestion!
@ thank you so much sir…
Excellent video, right to the point without any fluff I know nothing of what you speak but i definitely learned something. Good job 👍
Thank you!
Very nice video. I am also of the opinion threads should be toleranced RFS. In the ASME Y14.5 standard there is an example (possibly more than one) where it is shown as a combination of MMC and a projected tolerance zone. I think that a projected zone for a threaded hole makes sense functionally but I don't think that applying it Projected and at MMC (or just MMC) is right. Those recommending it seem to assume the Virtual Condition can be interpreted to apply to the protruding portion of the shank of the mating screw, which would be handy if it was true, for making a gage with fixed size holes. But in fact, the text of the standard doesn't support that interpretation anywhere.
Yes, the standard is not clear about how to handle a position tolerance at MMC with a projected tolerance zone for a threaded hole. I don't recommend using that kind of a callout until the standard clarifies it.
你好。
why isn't the straightness tolerance added to the boundary on option b and c in figure 7-22 and figure 7-23? assumping that the form tolerance is not a refinedment to position and orientation tolerance.
When the datum feature is controlled by a perpendicularity tolerance or a position tolerance at MMC or at LMC, then the straightness error is already incorporated into the perpendicularity error or the position error. The straightness error is not incorporated into the perpendicularity error or the position error when the datum feature is controlled by a perpendicularity tolerance or a straightness tolerance at RFS. When the datum feature has a straightness tolerance RFS, the boundary that this feature of size can occupy with its straightness error can also tilt as allowed by the perpendicularity tolerance or the position tolerance. It is a unique situation because with RFS the axis is allowed to tilt. With MMC or LMB, it is the surface of the feature that is being controlled.
What's your facebook?
你好，你从事过GD&T和CMM工作吗？
I have not operated a CMM. I occasionally talk with people who have.
Hello sir i am beginning to GD & T. Please guide me on how to learn it and how to apply it as a fresher mechanical designer.
Just keep watching my videos. I plan to keep posting. I also have a pretty comprehensive presentation of GD&T on at this URL: www.dimensionalconsulting.com/free-online-textbook.html
C yanlış yerde. C en uzun mesafe olmalı. Rotasyon en uzun yerden yapılmalı.
Thanks David for perfect video. What is the change if we add profile tolerence ? Both of them make same job ?
Profile tolerance without any datum references would do exactly the same thing. Profile tolerance with datum references could do a lot of different things. I'll have more videos coming about that.
Could you please add video also about mathematically defined surface, why we use it ? Usage example etc .( asme 4.13)
Sir, nice lecture. Is this Datum B calledout on surface of cylinder or axis. Also at 1:05 ,what is the gauge size if Datum B( RFS ) and B(MMC).How it is changing in both condition.kindly a replay.
Datum feature B is the pin. Datum B is the axis of the pin.
If datum feature B were referenced MMB, the gage would have a fixed size hole, but we don't have enough information on the drawing to calculate the size of the hole in the gage. As it is, with datum feature B referenced RMB, the hole in the gage is a variable size so that it can exactly surround the pin with no looseness.
@@davidslopsema4374 ok thankyou sir, for valuable replay
You're the legend❤
I love it. Respected sir, please continue this series through a step by step so that fresher mechanical engineer like me learnt it in a practical way. Salute to you 🫡
谢谢！
Not sure I understood this correctly but will rewatch later when i have slept. Nonetheless thanks for the video!
yup
I'm not familiar with this but I love it
Thanks for sharing!
I have some questions regarding pattern as datums. Do you have any socials through which i can contact you?
Amazing Explanation, Thanks Dave>
why the heck would you take a pic of dog crap and put it in a video...sick
How about threaded holes with inserts?
Haló haló??
Hello Sir, Thanks for the explanation. I have one question. What to do if we exceed the stack line. i.e, what to do when I need to add additional stack line after 40 stack lines are consumed ? Please help.
It is not expandable past 40 lines. You would need to divide your stack up into two stacks and add the results.
I know it was not covered probably because the focus of video was something else, but how do they know where to put those holes to begin with? Even if the basic dimensions are put there, we need some another datum feature frame, only for positioning the four holes? No?
Brilliant
Can a pattern of slots be used as datum feature? Thanks
Just sent over an email. Hope to hear back. Thanks for the information on the website.
Good information on tolerance "Stack-up" and that is very useful with "GD&T" and mechanical design-CAD. Thanks for all the work you do! Hope to see more down the road! T J (Tom) Vanderloop, Author, Technology-Instructor & Mechanical Designer; ATEA, AWS & SME Leader/Memberships
Good analogy for the "Dog-Lovers" as shop-workers, the use of Profile is Awesome! T J (Tom) Vanderloop, Author, Mechanical Designer, & Consultant: ATEA, AWS & SME Member
Hmm, ok, let's say I dimension a part with a pattern as datum and then go to assess my real part. Let's say your limited in the same way our inspection department is, and need to use a caliper. I pick one of the four holes randomly. I can check its size, but there's no position requirement yet. Let's say I conclude that the hole size is acceptable. I move onto the next hole. Can that hole's position now vary within its position tolerance, or, within its position tolerance PLUS the position tolerance the first hole could vary within given the single feature control frame??
You consider the first hole to be the center of the universe, and then with the other holes calculate position plus bonus plus datum feature shift. You can avoid a lot of calculations if you can have your inspection department give you hole sizes and locations and you can create a gage in CAD and create the part as measured in CAD and see if the part as measured fits on the gage in CAD. I explain this on my web page here: www.dimensionalconsulting.com/tolerance-of-position.html#cmm Otherwise if you need to do the calculations manually, I explain how to do that on my web page here: www.dimensionalconsulting.com/tolerance-of-position.html#advanced
@@davidslopsema4374 awesome. I'll take a close look. Thanks!
Thanks, this helped me to visualize LMB
What if i have regardless material condition and regardless boundaries call out in gd&t means plz
You will have no bonus and no datum shift, only the position tolerance in the feature control frame regardless of the actual size of the features.
Other than being cleaner and “explaining” the intent better, what are the other quality manufacturing problems that the first examples bring?
I have seen this issue causing confusion when people do tolerance stacks. Other than that, I cannot point to any specific quality problems that it causes. It's just a matter of making the GD&T reflect how the part really functions.
Good tip, but for this example wouldn't you want to use MMC on the perpendicularly & position tolerances to take advantage of bonus (additional) tolerance, & MMB on datum features of size B & C to take advantage of datum feature shift?
Yes you would, if you want to allow bonus and shift, and/or if you want to use fixed size gage pins. If for some reason you could not tolerate the bonus and shift, then you would leave it RFS and RMB. It all depends on your product requirements.
<3
haha...intresting
LOVE the video. One question - despite the side of the feature that the arrow points to, is the number following the U symbol always OUTSIDE of material? Example - what if the scenario was pointing to the inside of the feature? Lastly - if you didn't reference datum features, would the profile become only a feature size control? Thanks!
Yes, the number following the U symbol is always outside the material. So if it were pointing at a hole, the number following the U symbol would allow the hole to get smaller. It can indeed control the size of a feature, but I still would not call it a feature of size. A feature of size always has a coordinate tolerance controlling the size.
Is there a method of reporting profile error using variable data? Historically, the formula used was max - min if crossing nominal or if all positive or negative error is observed, 2*max deviation from nominal.
I am not familiar with a standard method of reporting the data. I am guessing that would be determined by whoever requires the data.
I have used the method of reporting my tolerance / my deviation from tolerance. Example for bilateral would be +/- 0.25 / over / actual result. The result could be anything from + to - 0.25. Also - if you wanted to, you could report in the basic feature box the range that you found. Example: Feature is 40mm and you report 39.8 - 40.22 (all acceptable applying that tolerance). Make sense?
I forgot - when I do report actual readings in comparison to the basic features I do NOT accept or reject that data. The accept reject criteria is reported in the profile callout.
Please visit my web site at www.dimensionalconsulting.com
Please visit my web site at www.dimensionalconsulting.com
Please visit my web site at www.dimensionalconsulting.com
Please visit my web site at www.dimensionalconsulting.com
Please visit my web site at www.dimensionalconsulting.com
Please visit my web page at www.dimensionalconsulting.com
I enjoyed your video, however I can't find where to download the PDF file your talking about. Can you please advise me. Thanks
The "Closed Loop" stack up method is much easier to work with.