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Пікірлер
@danielrafiq51 Күн бұрын
What's the differences between Profile Surface and Flatness, is it gonna be the same thing if we replace it with Flatness 0.01 with respect to Datum A?
@AlexLapugean 2 күн бұрын
I think that there are bigger issues with attempting to control the fillet with a +/- dimension: 1. A fillet is not a feature of size, you do not have opposing points to be able to unambiguously measure, so this type of measurement has an inherent issue of leaving the interpretation to the person doing the measurement, who guess what, will interpret it in a way that is convenientnt to them and you'd have no leverage to tell them they measured in a wrong way. 2. Due to the usually small size of those fillets and having only about quarter of a circle length, measuring the radius is wildly imprecise. You'll most of the time have just 3 points to try to define an arc, whose radius will greatly depend on small variation in the surface. My approach is: never dimension them with +/- size. If they are non functional, a tolerance is usually irrelevant, you just want them to be there roughly in that ballpark (at most you can consider controlling them with edge breaks), if they however are functional, profile tolerance, no 2 ways about it.
@vat_1989 3 күн бұрын
You guys are amazing. Thank you for this 🙌
@odsener 8 күн бұрын
Thank you for the video. I think for the last example "deviated .018" should be "deviated .020" according to formula that resulted .030 total deviation.
@EricIrwin 10 күн бұрын
For the unequal example, if you had a measured high of +.001 over nominal and a measured low of -.001 under nominal, you end up reporting a higher deviation than if the measured values were +.010 and -.000. It seems like this reporting method is favoring the middle of the tolerance zone over favoring the nominal. Also, when the "uneven" modifier is applied, how do you decide which direction to apply the uneven tolerance zone? Is it driven by the basic dimension applied to the feature?
@Gdandtbasics 9 күн бұрын
You are absolutely correct when you say that the reporting method is favoring the middle of the tolerance zone. And that's exactly how it should work. Lets imagine a part that is .030 unequally disposed .030 instead of our example that is disposed .020. In this new example our "nominal" is at the very edge of allowed tolerance, any deviation in one direction immediately results in a failed part. So if the machinist targets the center of the zone, rather than nominal, they have a much higher chance of producing a passing part. For the uneven modifier the value that follows the symbol is the amount of tolerance that exists outside the part. Check out this article. www.gdandtbasics.com/unequally-disposed-profile/
@jefffrodermann5348 10 күн бұрын
Jason, this is one of the most common questions I encounter in GD&T. Thank you for discussing it. I have a request though, by any chance could you follow up by explaining WHY The formula you mentioned is used to report unequally disposed profile. I assume it is to provide an absolute, positive result. Also, could you explain why the result is ultimately not doubled, since the 2X is canceled out by the /2, whereas you suggest the result for bilateral profile is doubled? The reporting and computation of position and profile is an area that I feel the Y14.5 standard could be more clear about, and I field a ton of questions on both.
@Gdandtbasics 9 күн бұрын
That's a great idea for a follow up video. For those wondering, we use this equation because we need a singular value that we can compare to the allowed tolerance value from the FCF. If we simply reported "high to low" or the most deviated point and its absolute value from nominal, we would not be taking into account WHERE our allowed tolerance is at and might accidently report a value that is less than our allowed tolerance but clearly outside the tolerance zone. As you mentioned, when we consider normal profile measurements, we find the most deviated point from nominal and double it (as mentioned at the beginning of this video in the first example) This doubling still occurs in the unequal equation but its taken with respect to the center of the tolerance zone and not necessarily the "nominal". The 2x does not cancel out the /2 but rather the /2 redistributes the tolerance to be centered on offset the zone. This is a tricky topic, hope this helps!
@jefffrodermann5348 9 күн бұрын
@@Gdandtbasics That is a terrific and clear explanation. Thank you.
@dwswanson 13 күн бұрын
At 4:55, it states that this is .010 of deviation. Why is it .010 and not .005? Great video!
@Gdandtbasics 9 күн бұрын
it is .010 because we are locating the surface as well as controlling its form. If we only reported "high to low" or the .005 value, we would only be indicating how much form error there is. If the high point had deviated .006 vertically away instead of .005 it would clearly be out of tolerance, which is why we would report .012 and NOT .006 which would be less than .010 stated tolerance. Hope this helps!
@learntattoo2024 14 күн бұрын
Thanks!
@jeffup8956 16 күн бұрын
To report size from a cmm, do I tell it to give me the max inscribed followed by the min circumscribed? Does minimum circumscribed automatically find the worst 2 opposing points?Would that meet the standard?
@Gdandtbasics 9 күн бұрын
You're definitely thinking in the right direction. Check out this video to help clarify and solidify your thoughts. kzbin.info/www/bejne/l6PMnJ2iZbhmfqc Unfortunately no standard tells us HOW we HAVE to inspect our parts. We are only given the theory of the tolerance and its up to us to interpret inspection results from that frame of mind.
@Brad-y9h 22 күн бұрын
Jason, you mentioned it is "similar" to the ASME Unequally Disposed Tolerance. But how does the ISO modifier differ from the ASME modifier? DO you have a video referencing that?
@Gdandtbasics 9 күн бұрын
We dont have a video that directly states the difference between the symbols however, this video discusses how the UZ modifer works for ISO. The second value in the FCF is the amount and direction of the shift, where as the unequally disposed modifier, outlined in this video (kzbin.info/www/bejne/l6PMnJ2iZbhmfqc) has a second value that represents the amount of tolerance that exists outside the part.
@Brad-y9h 22 күн бұрын
Hello Brandon. I know this is an old video and topic, but I have a question regarding this that I am hoping you can help with or direct me to another video. I completely understand your explanation and how the result would report out to 0.14, in the example with a Bilateral 0.2mm Profile tolerance range (0.1 inside/0.1 outside). My question is regarding an Unequally Disposed Tolerance where if we use the same example as above, but with the inside tolerance being 0.05 and the outside being 0.15? If the result was then 0.07 as you showed above, do you still do the doubling and the result is 0.14 and all still fits in the 0.2 range, so it passes? Or because the 0.07 is definitely beyond the 0.05 range on the inside, there is no doubling, and it fails by 0.02? Does the reporting for an Unequally Disposed tolerance calculate differently than the Bilateral? I really appreciate your feedback. - Brad
@Gdandtbasics 9 күн бұрын
You're in luck! We just created a video discussing exactly that. kzbin.info/www/bejne/l6PMnJ2iZbhmfqc
@ariel59864470 23 күн бұрын
🏆
@sajjadvaezian7308 24 күн бұрын
What about basic dim? What is the tol. of basic dimension when we have profile without datum?
@梅搞七八 23 күн бұрын
basic dim has zero tol.
@sem7207 21 күн бұрын
A basic dimension is a theoretically exact dimension that only sets the location and orientation of tolerance zones, or defines the form and/or size of the "true" (nominal) profile to which a tolerance zone is fixed. So the dimension itself has no tolerance, and you shoudn't measure or report it.
@JonSchmidt-z7n 24 күн бұрын
Spectacular video!
@marcolima89 24 күн бұрын
great video and explanation of the topic
@markstuddock 27 күн бұрын
I'm not sure you answered the question as well as you could have. You picked the 2 and 3 "high points" that conveniently lay close to the theoretical (modeled) datum surfaces. But what if Datum B gets really close to being 2mm out of perpendicular from Datum A? How does that affect the possible positions of the holes? The hole-to-hole spacing seems to be unaffected by the large form and orientation tolerances applied to A and B but what about the 12.70 basic dimension from Datum B? How is that affected when B is 2mm from perpendicular to A? Edit: I think maybe you clarified this for me in the next video (kzbin.info/www/bejne/hJOXZJeoap6Nnrs) by showing how datum features can be simulated.
@Cynthiao-k6l Ай бұрын
Wondering how to set a proper tolerance for the datums. what is the principle for it?
@Gdandtbasics 28 күн бұрын
Setting proper tolerances for datums can be a tricky conversation and it would involve a full understanding of the part and how it functions in the final assembly. Its best practice to allow as much tolerance for manufacturing as possible without allowing too much, resulting in a non-functional part. First steps are to begin understanding envelopes and tolerance effects on each other. Its a great conversation and skill to learn but is unfortunately too deep to get into within the comments section. We cover complex subjects like this in our advanced course. www.gdandtbasics.com/gdt-training/gdt-advanced/
@kaushikiyer9445 Ай бұрын
How is the 2nd case controlling location and orientation of the non datum surfaces without the Datum callout in the FCF? Isnt that only controlling the form of the non datum surfaces?
@Gdandtbasics 28 күн бұрын
Without the the datums in the FCF, the tolerance controls the location/orientation and form of the 5 surfaces and NOT to the datum features.
@kaushikiyer9445 28 күн бұрын
@Gdandtbasics ohhh. I get it now. Thanks
@Jörgen_Volvo Ай бұрын
Noooo... Cylindrical tolerance zone for a surface?
@Gdandtbasics 28 күн бұрын
Definitely not a "legal" thing to do as we point out around 5:50. That diameter symbol should be omitted when applied to a flat planar surface.
@jerryschwarzbach3253 Ай бұрын
Great explanation! Thanks.
@chrisreid8298 Ай бұрын
What would be an example where it would make more sense to use profile of a line vs a surface?
@Gdandtbasics 28 күн бұрын
One example we often talk about where profile of a line would make sense over profile of a surface is in the case of checking cross sectional elements of an aluminum extrusion. We likely care that each cross section is precise, but we dont need to control each cross section with respect to the other cross sections down the length of the extrusion as this would likely be controlled by some other tolerance or guidelines.
@chrisreid8298 28 күн бұрын
@ ahh very good, thanks.
@vasnellgeometrics6381 Ай бұрын
Great video. Thanx for sharing such a basic and important way of using this principle.
@souravdas1751 Ай бұрын
Can i define with profile of a line the pitch of taking the section. If yes. How will is represent it using GD &T
@ariel59864470 Ай бұрын
🏆
@JoshuaReuben-s6d Ай бұрын
You did replace the Position symbol with a Prof. Of Surf. symbol, however, you should have also removed Dat-B & A and kept Dat-C in the RHS flag or perhaps only kept Dat-B is both cases.
@WilliamBurt-g6x Ай бұрын
The basic dimensions are from datum feature B. B would be the primary and C would be required to control rotation around B. A is not required. if you were to keep only C then basic dimension from C would be needed.
@billtaylor3068 Ай бұрын
Id reason that the position call out is illegal to the post tops, as position should only be used on a feature of size. Surface profile more appropriate surely ? Note I'm not up with the most recent standards, so if the feature of size requirement has changed, then ignore me. 👍
@Gdandtbasics Ай бұрын
You're absolutely correct if you are referencing ASME Y14.5. As we mentioned in the video, we would HAVE to use Profile of a Surface if the drawing was utilizing ASME. However, ISO allows for the use of Position Tolerance on flat planar surfaces.
@coltoncyr2283 2 ай бұрын
Can you do an example of SLOTs, from a BC, cut thru the OD. B datum would be the axis of this part. Can you just position the slots (without DIA symbol in the control frame), and keep a non-basic BC? or does the BC have to be basic? How is the slot-to-axis related? My engineering team is debating a basic is/ is not needed for the bolt circle. EX 4 slots, equally spaced on a BASIC 45, and a BC thats nonbasic, should define its location per angle, per related to axis (datum)
@abboberg 2 ай бұрын
Couldn't you just use a flat-faced indicator held at a 45-degree angle and still use the vee block?
@Gdandtbasics Ай бұрын
The issue of the form of the feature allowing the feature to settle into the v-blocks would still be present unfortunately.
@grantrecker 2 ай бұрын
So, in the first example, using the profile tolerance without a datum reference, would you technically need another tolerance to establish the location & orientation of the surface?
@AlexLapugean Ай бұрын
yes. Without a datum, profile tolerances only control form.
@GauravKumar-p6x7o 2 ай бұрын
+kindly tell me why 90 instead of 90+45 from datum?
@antonioferreira2996 2 ай бұрын
5:27 Don’t should be 0.05!? The diameter of the circle is 0.1mm so 0.05mm for both sides.
@QwertyCanada 2 ай бұрын
0.05mm deviation can happen in any direction which results in the outer boundary of +0.1mm.
@johnvmachado 2 ай бұрын
You did not demonstrate how to calculate the deviation from the true position.
@Gdandtbasics Ай бұрын
Please watch this video, as it explains how to calculate diametric deviations. kzbin.info/www/bejne/hnqYh2Z-ir5siNE
@nandhu150390 2 ай бұрын
Useful mate👌
@abdeljelilful 2 ай бұрын
Just why do you insist on higher points to define a plan? I think that the CMM calculates the less square geometry (plan , line,cercle,..) doesn't it or Am I wrong?
@mabilal8067 2 ай бұрын
to establish the datums in CMM we use mini max and Outer Tangential Element algorithms rather than LSQ to be sure the parts well fit together the LSQ algorithm provide a consistent stable result but consistently worng size , form and location .
@AlexLapugean 2 ай бұрын
He just explaine this in the video. If you only select 3 ... 2 ... 1 points to establish your datum system, there is no guarantee that you are going to use the points that will define the proper location, as defined by the standard (the associated feature should be the one that is the closest to the real feature, without going inside of the material). In fact, it is almost guaranteed that you will not. In that way, while you will of course have a working and stable datum system, it will not actualy reflect the functionality of the part in the real environment, so all the measurements you do with respect to that datum are deceiving and do not actually properly tell you if the part is OK or not.
@chrmeiss67 2 ай бұрын
There is a big difference between ISO GPS and GD&T: Association of a simulated planar touch is very different. This example works with a part which ca be orientated four times against specified datum system (it‘s two times symmetric). Under ISO GPS verification can look for the best result. The other orientations must not be ok.
@AlexLapugean 2 ай бұрын
I would argue that you need many more points than 6 to capture all the details of an integral feature. I am not sure in ASME, but in ISO, there is a standard (I can't remember the number out of the top of my head) that explains the extraction process. It is mentioned there how you should choose the point pattern, but also the number of points. While you cannot find an exact number (it would not make any sense), the requirement is that you should choose as many points as needed to capture all macro details of the surface, so that you would be able to accurately reconstruct the surface based on those points. In other words, someone should not be able to find a point outside the ones that you chose, that would change the location or orientation of the associated feature. I think this is something that is missed most of the time by measurement engineers from my experience. You could of course use datum targets to specify a desired 3-2-1 point datum system, but my oppinon is that you should only do that if that is the real case function of the part, or if you have a complicated free-form shape (like a turbine blade), that you need to inspect the surface of and you have no straight surfaces to use as datums.
@marciosilveiramorais6983 2 ай бұрын
Hello, can you share wiht us the number of this standard. Thank you.
@AlexLapugean 2 ай бұрын
@@marciosilveiramorais6983 Hi, I checed on my work computer this morning, it is "ISO 14406:2010 - Geometric product specification (GPS) - Extraction"
@ThePowerhound 3 ай бұрын
Nice video. The only thing I have to say about it is that a size dimension only exists when it’s defining a regular feature of size. It’s not about whether or not it has a +/- tolerance on it. The dimension that controls the step is simply a dimension, not a size dimension.
@brentlackey8316 3 ай бұрын
These are the four fundamental elements. A singular thing is. Multiple things are.
@brentlackey8316 3 ай бұрын
There are self driving cars, but I'm not going to be one.
@brentlackey8316 3 ай бұрын
New York is on Canada's Southern border with the United States.
@brentlackey8316 3 ай бұрын
Where did you get the idea that decreasing the thickness tolerance would improve flatness?
@Gdandtbasics 3 ай бұрын
Decreasing a size tolerance, decreases the amount of form error allowed due to Rule#1 ASME Y14.5 and the envelope priniciple for the ISO GPS standards.
@shawnegan2228 3 ай бұрын
nice video
@marzecm 3 ай бұрын
@Gdandtbasics :)
@abdeljelilful 3 ай бұрын
But the datum C is not the mid plane of the part! Why you translated it to the mid plane?? Many thanks
@Gdandtbasics 3 ай бұрын
Datum C is the midplane of the part since the datum feature symbol is directly in line with the size dimension. This changes the interpretation of the datum to be a feature of size rather than the surface that the extension line originates from. This rule is outlined in the standards.
@SandeepSingh-43 3 ай бұрын
Can you please clarify how datum C is defined as the mid plane. It seems to defy how Datum’s are represented. Thanks
@Gdandtbasics 3 ай бұрын
Datum C is defined as a midplane since the datum feature symbol is directly in line with the size dimension. This is a rule within the standards.
@greggraham2653 3 ай бұрын
Given that Datum C is the midplane: Datum A remains the primary datum, setting the Z = 0 plane, as it represents the main flat surface on which the part would rest. Datum B is still the secondary datum, providing a perpendicular reference plane, which likely sets X = 0 or Y = 0, depending on the orientation. Datum C, as a midplane datum, will establish symmetry about the part's center. This would mean the Y = 0 (or X = 0, if oriented differently) is located at the centerline of the part based on the dimensioned width. With Datum C as a midplane, the (0,0,0) origin will now be located at: The intersection of Datum A (primary datum surface), Datum B (secondary datum plane or surface), and The centerline/midplane established by Datum C. This zero position would likely be positioned at one of the lower corners of the part in the X and Z directions (as defined by Datum B and Datum A), while the Y = 0 axis would pass through the centerline of the part due to Datum C.
@SandeepSingh-43 3 ай бұрын
@@Gdandtbasicsthank you. I will check the standards.
@SandeepSingh-43 3 ай бұрын
@@Gdandtbasicsso does the True Position of 1 get split?
@marcolima89 3 ай бұрын
As a mechanical engineer in Europe, I really appreciated this video about the ISO standard. Thanks
@radon3292 3 ай бұрын
Why does a profile have B datum for secondary? It makes no difference
@Gdandtbasics 3 ай бұрын
You're absolutely correct, none of the features that utilize this profile callout need B as a datum feature, however its still considered good practice to include it just incase that UOS gets applied to a feature in future revisions that DOES utilize it. Basically it doesnt hurt to include it and make all the feature control frames have the same DRF.
@sjsj4998 3 ай бұрын
What is dim. 35 and 18 limits?
@Gdandtbasics 3 ай бұрын
These are defined by the unless otherwise specified profile of a surface tolerance found in the title block. Essentially creating a located ± 0.375 size dimension for these two dimensions.
@MichaelMachado2 3 ай бұрын
I’ve had the exact same question myself! Thanks for answering.
@marzecm 3 ай бұрын
Timestamp: 5:32 => The Limits of Size are applied on diameter. Circularity tolerance defines tolerance zone of two concentric circles offset from each other radially by the tol. value. If LoS were applied on radial basis, it would be 1.0010 to 1.0025. By my understanding, it means that LoS define Circularity of .0015 (instead of .003). Please correct me if i this is wrong.
@Gdandtbasics 3 ай бұрын
The limits of size for a diametric feature should always be applied on a diametric basis and not radial. Rule #1 for a cylinder will always result in form control (cylindricity and circularity) that matches the total size tolerance for the diametric feature.
@marzecm 3 ай бұрын
@@Gdandtbasics Please have a look at Fig. 5-10 in Y14.5-2009, especially the "Means this" section of that figure. It shows that the Circularity tolerance is defined by two concentric circles. These circles ar offset from each other radially by the tolerance value. If we calculate the Circularity from the Limits of Size of the example in the video, it would be (2.005 - 2.002) / 2. This gives the result of Circularity equal to .0030/2 = .0015 (half the value mentioned in video).
@chrmeiss67 3 ай бұрын
It‘s very simple: The two sizes aren‘t based on features function.