ASME Y14.5-xxxx Profile of a Surface - clarification
ASME Y14.5-xxxx Profile of a Surface - clarification
(OP)
I am butting heads with one of our quality department inspectors. He's our lead inspector and we disagree on the application of Profile tolerance of a Surface. I've attached a simple sketch we drew up together to argue over.
He believes that a hole, slot, etc, that intersects the surface being called out, also has a location&size tolerance applied to it BY the Profile Of A Surface tolerance.
The only foundation for his assessment is that is what he was instructed to do in a former position at a well known aerospace manufacturer, and when I slammed by copy of ASME Y14.5-2009 on his desk and told him "Prove it" - all he could come up with was citing 8.2
Those two sentences, he asserts, allows/forces him to check the location and size of a feature at the surface it intersects, if that surface is called out with a GD&T Profile tolerance.
I feel like I'm stuck trying to prove something DOESN'T exist while he stands fast on his status quo.
If I am mistaken, I owe him a sincere apology and a cold drink.
If I am right, I would like suggestions as to how I can further present my case more clearly.
He believes that a hole, slot, etc, that intersects the surface being called out, also has a location&size tolerance applied to it BY the Profile Of A Surface tolerance.
The only foundation for his assessment is that is what he was instructed to do in a former position at a well known aerospace manufacturer, and when I slammed by copy of ASME Y14.5-2009 on his desk and told him "Prove it" - all he could come up with was citing 8.2
Quote (ASME Y14.5-2009 Page 158)
"Profile" where it says: "A profile is an outline of a surface, a shape made up of one or more featuers, or a two-dimensional element of one or more features. Profile tolerances are used to define a tolerance zone to control form or combinations of size, form, orientation, and location of a feature(s) relative to a true profile."
Those two sentences, he asserts, allows/forces him to check the location and size of a feature at the surface it intersects, if that surface is called out with a GD&T Profile tolerance.
I feel like I'm stuck trying to prove something DOESN'T exist while he stands fast on his status quo.
If I am mistaken, I owe him a sincere apology and a cold drink.
If I am right, I would like suggestions as to how I can further present my case more clearly.





RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Like you said, I can't fully explain how he is wrong, because he is making up something that is not in the standard. But, if you follow his logic to it's conclusion, the profile would also apply to the bottom surface, and then up the back (vertical) surface of the part. When he argues that you should only go one surface beyond, ask him to show you that in the standard. Now you have put him in the same position that he originally put you in - having to disprove something that's not there in the first place.
Hope this helps, and good luck.
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
In the paragraph quoted from the standard, it says that "A profile is an outline of a surface, a shape made up of one or more features...." etc.
Well, the callout you show applies to a surface; specifically, a shape made up of ONE feature. To make profile go into the rounded slot (i.e., more than one feature), the callout would have to indicate that.
Here's a statement from the standard that will back up your position: paragraph 1.4(n).
"Unless otherwise specified, all tolerances apply for full depth, length, and width of the feature." (The rounded slot is a different feature.)
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
You are correct.
I agree with what John-Paul said. The onus is on your inspector to provide some evidence to back up his statement.
Evan Janeshewski
Axymetrix Quality Engineering Inc.
www.axymetrix.ca
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
I shot an email to his boss explaining the situation. He agrees with me, and is giving his guy another day to gather evidence to support his belief. If nothing arises, our company inspection policy will be updated. We just got a new quality manager who seems to be very much more on-the-ball than our previous. His agreement with me on this topic only helps me think that way of him ;)
I appreciate the input, all.
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
I did that as well. I showed him where examples in the -2009 standard show the new symbols, and how they directly point to interior features when they /do/ want to call out those surfaces. He is a stubborn man - any inspector should be. He's been cussed out by many machinists, I'm sure, for things he was right on, so I don't expect an inspector to cave without undeniable evidence.
He's a great quality guy, who does good work and provides thorough and complete documentation. I can honestly say this is the only time I've butted heads with him - we've even worked together on providing internal GD&T coursework to train and re-acquaint every employee on these topics.
In a discussion with his boss, whom agrees with me, he's going to re-brief his quality department after giving our inspector a chance to gather any material he feels backs up his decision. I think that's quite fair and respectable.
Thanks for the many second opinions. I do not want to become an "island" in our company, sometimes, if we have no 'other authority' to appeal to, for a greater context.
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Your assessment of the Profile tolerance as applied to the Surface is correct. Moreover for Profile tolerance to control location (level 4) and/or orientation (level 3), Datum Reference Frame is necessary. It is not there in the stated feature control frame. The profile establishes only form tolerance (level 2) as provided.
It would be a good idea to follow the layout of the Feature Control Frame with the Geometric Characteristic Symbol (Profile in this case) to be in the first block of the FCF.
Best regards
Natarajan R.
ASME Certified GDTP - Technologist
Dimensional Management Consultant
www.egs.co.in
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Good catch! In my haste to sketch something up quick-and-dirty in Autocad LT (I normally use NX) I didn't notice my improper ordering of elements in the control frame! I guess that shows what happens when I am spoiled to using canned symbol blocks. I forget how to write it properly the manual-way!
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
I'm a little confused about 'the line' that should not be crossed here...
I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE plants!!
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE plants!!
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
I took part of your diagram and put a grid system on it like you would see on a drawing, A – E and 1 – 5. I labeled this Figure 1. For simplicities sake I took only three points to discuss, B3, C3, and D3. So let’s get on with the inspection, shall we?
First we put the part on a sine block on a surface table such that the surface we want to inspect is parallel to the surface of the surface table. Then we put a suitable dial indicator on a height gauge and adjust it so when it touches the surface we are inspecting, we have one complete rotation of the needle on the dial indicator and adjust it to read zero and lock it in place.
While it doesn’t matter where you start, I will start at point E5 and work in a zig zag pattern across and down the part. When I get to point D3 my dial indicator reads -.001. At this point does this part fail the profile of surface? No, it is allowed to be that far off at that point. I continue and when I get to point C3 my dial indicator reads -.0005. At this point does the part fail the profile of a surface? No, it is allowed to be that far off at that point. When I get to B3 my dial indicator pegs out low and there is space below the indicator point on the dial indicator so the “surface deviation” the indicator is trying to measure is much larger than the .002 allowance we have per drawing. At this point does the part fail the profile of a surface? No, the drawing indicates there is not supposed to be a surface at that location so the dial indicator is supposed to read more than .002. The part still passes at this point.
Now look at the next drawing. I have kept the original figure 1 and added a figure 2. In this case figure 1 is the blueprint and figure 2 is the actual part we are inspecting. Let’s see how we do this time.
We set it up as before on the surface table and adjust the dial indicator as before. We start at E5 and begin our zig zag pattern. When I get to point D3 my dial indicator reads -.001. At this point does this part fail the profile of surface? No, it is allowed to be that far off at that point. I continue and when I get to point C3 my dial indicator pegs out low and there is space below the indicator point on the dial indicator so the “surface deviation” the indicator is trying to measure is much larger than the .002 allowance we have per drawing. At this point does the part fail the profile of a surface? Yes! This part fails at this location because the drawing indicates I should have a surface within .002 and I do not. Let’s keep going. When I get to B3 my dial indicator reads -.0005. At this point does the part fail the profile of a surface? Yes. This part fails at this location because the drawing indicates I should not have a surface at this location and I have one.
What have I just done? I failed a part for profile of a surface, but also demonstrated how profiles do in fact locate features.
As far as the inspector citing section 8.2, what section do you think he should cite??? Section 8.2 deals with (you guessed it) profile of a surface.
As far as it being mentioned only once. Does it become more valid if it is mentioned twice? Will it be even more valid if it is put as a footer at the bottom of each page? NO. It is valid being mentioned only once.
It is interesting that at the top of the forum page on this site there is a banner with a link to Tec-Ease. These people are certified to train people in GD&T and yet not one person so far that has responded has indicated they checked this site out. I checked them out and here is only part of what they have to say on the matter:”. . . There are several geometric tolerances that can be used to locate features. There is only one geometric tolerance that may be used to locate every feature on a part. The geometric tolerance is profile of a surface. Profile of a surface is the only geometric tolerance that controls the location of surfaces. Since every feature on a part has a surface, profile may be used to locate every feature. . . .”.
To find out what else they say, I suggest you go to the site and read it for yourselves. Better yet, ask other qualified, certified schools and see what they say.
In the end, I think you are wrong, and profile of a surface in reality does locate features. You owe the inspector an apology and a cold drink.
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Profile of a surface is used to locate features. I don't think anyone here has argued that it doesn't. I now understand your thought process based on your explanation but it is not accurate. There is not one single thing about the slot that the profile of a surface callout controls. It is only controlling the angled surface and that's it. Your inspection setup is perfect but if there is no material where the print says there should be, it would be failure of another specification, not the profile of a surface spec. If your scenario were real, then the part would fail because the slot is in the wrong place. The profile of a surface callout is not what locates the slot.
You are the inspector in question aren't you?
John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
This profile of a surface idea does not measure whether a surface exists or not at a given point in space. It measures a surface that is there, and sees whether its form meets a given specification. If someone decides to drill a hole where it doesn't belong (or a slot, etc.), that is an error in location for the hole, not an error in the surface that gets drilled through.
Furthermore, even if your explanation were to have some merit, the profile tolerance would have to have datum references in order to even know where that slot is on the part. The sketch in question has no datums, so you can't really impose the grid system anyway because you've artificially introduced datums to establish where the slot should be from the sides.
But again, that point about datums is irrelevant. You are attempting to locate the slot, and that simply isn't part of the surface in question.
And yes, I run a GD&T training company, and have 20 years of full-time experience in GD&T training. I find it really hard to believe that every one of my competitors agrees with you (assuming that the case was properly presented to them).
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Do you have something in writing from any of these schools to corroborate what you say?
You mentioned Tec-Ease. I hate to break it to you but everyone here knows that site and Don's tips are frequently used to illustrate certain concepts and ideas. We don't go plugging his site every time we post though, so just because no one mentioned it doesn't mean we don't know about it. Don even posts here from time to time.
I'm actually okay with this statement but Profile of a surface locates SURFACES. The surface of the slot is not what is being controlled in the OP drawing, it's the angled surface that is being controlled. If there was a PoaS callout pointing to the slot surfaces then we would all be in agreement here.
Using your inspection method--which, upon further reflection, is actually NOT perfect--how would you verify the slot location?
John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Then no profile tolerance applies to the slot.
"every school I have contacted that is qualified to teach the subject matter agrees with my statement"
What statement is that?
Examples:
1) Profile supplies a tolerance on acceptable variations to surfaces and features from ideal nominals.
2) Profile should apply to features it is not applied to.
"it is what they are teaching"
What are they teaching, exactly?
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
I know GD and T is a language, but why bring more complexity into the equation when is not needed?
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Remaining targets are parallelism and perpendicularity, which could be replaced by angularity.
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
I am not asking to replace the flatness with profile --in favor of using profile in GD and T language-- Flatness have its role/usage and profile its own. The same for perpendicularity, parallelism versus angularity. Why more complicated language to be used when a simpler one is available.
I am asking *IN THIS SPECIFIC CASE* (OP) what advantages someone will gain by using profile and *NOT* flatness? Why use profile? What they try to control?
And one additional question: “how flatness is able to control the centerplane variation?” Can you give me an example, or reference a picture in 1994 or 2009 standard? I am not saying is not true, I am trying to learn from this thread.
Thank you
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
However, in general, flatness does not relate the surface to anything else. It can be flat, but be several inches away from nominal location, and be acceptable. If PoaS was applied rather than flatness, it would also have to be located at the correct position in space relative to datums or model based data, if referenced. I imagine if there were no MBD or Datums, that it would be akin to flatness, but I hadn't run into that situation yet and yes, it would be poor practice.
Again, the sketch was simply an illustration of a topic. That is the context and scope of this simple illustration. It's a glorified napkin sketch.
_________________________________________
Engineer, Precision Manufacturing Job Shop
Tool & Die, Aerospace, Defense, Medical, Agricultural, Firearms
NX8.0, Solidworks 2014, AutoCAD LT, Autocad Plant 3D 2013, Enovia DMUv5
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Notice that OP already admitted that the callout he posted is incomplete. For sure datum feature references are missing in profile of surface FCF, unless this face is primary datum feature. And these datum feature references are needed to clearly define orientation of considered surface relative to datum(s). Flatness tolerance, unlike profile, can't use datums inside feature control frame - in other words, flatness tolerance is not powerful enough to control orientation of a feature relative to datum(s). This is the main difference between both characteristics in this case.
If the surface in question was primary datum feature, there would be no difference whether flatness or profile of surface was used.
To be precise, per 2009 standard flatness tolerance can be applied to control form of derived median plane of a feature of size (see fig. 5-9). This is not exactly the same as control of form of center plane, because center plane by definition can't have any form error - it is a perfect plane derived from unrelated actual mating envelope of a feature of size. The whole concept did not exist in '94 version of Y14.5 - straightness tolerance was applied instead (see para. 6.4.1.1.3).
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
In my own experience, parts always seem to have features of varying requirements and a single profile tolerance never meet all of the requirements without unnecessarily restricting features that could have looser tolerances.
“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
I believe I understand the logic behind your assertion, that profile of a surface can control the location of adjacent perpendicular features by the presence or absence of material. By specifying surface profile on one face of a brick-shaped part, you could also control the length and width. While it makes an interesting discussion, I can assure you that this logic is not used by the standards committees or industry in general.
Maybe this will help. ASME Y14.5 (Dimensioning and Tolerancing) and Y14.5.1 (Mathematical Definitions) both define a profile tolerance zone as applying in a direction normal to the true profile at every point on the true profile. This is how a surface profile tolerance locates features - in the direction normal to the true profile. Your argument goes past this, by trying to control the boundaries of the surface in directions that are parallel (not normal) to the true profile. In other words, you're trying to use the profile tolerance to define the extent of the surface. The ASME standards don't do this.
You've also cited the Tec-Ease web site and other "qualified, certified schools" as supporting your opinion. The only evidence you've presented to support this is that they state that profile tolerances control the location of surfaces and could be used to control all of the surfaces of a part. These are both true, but don't support your assertions for JNieman's drawing. In order for the surface profile to locate the other features on the part, it would have to be applied to those other features. Currently the profile tolerance is applied to just the one surface.
Evan Janeshewski
Axymetrix Quality Engineering Inc.
www.axymetrix.ca
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
This thread has actually provided at least two views from qualified, certified trainers that are different from yours. Does this qualify for "in writing."?
To Evan's point; your assertion that profile of a surface can be used to locate features does nothing to support your argument. I'm not surprised that Tec-ease would make that statement since it is true.
I'm interested to know if you still stand staunchly by your viewpoint or if you are actually entertaining the notion that maybe JNieman got it right.
John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Some of the folks who post here are the best of the best when it comes to ASME Y14.5-2009 and have helped shape Y14.5 over the years. They disagree sometimes, but not with respect to this. Take some time and look deeper. They have set me straight on many occasions.
Peter Truitt
Minnesota
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Can you update us on this? Has your company responded positively to our input?
Thanks,
John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Ref: ASME Y14.5 1994 Fig 6-20 and 6-21. Interrupted surfaces
The standard states that a profile control establishes tolerance boundaries.
It is simple enough for me to inspect the surface feature in consideration,
to verify if all of the surface elements lie within the specified boundaries.
The key (IMO) is to inspect the surface that does exist; not, what does not exist.
The slot is a feature that creates an interrupted surface.
The specific Profile Control for the surface in consideration,
does not control the features that interrupt it.
(unless leader lines associate it to the Profile Control frame;
don’t believe that is the case here)
Features that interrupt a surface are simply different features.
They are defined and inspected by their dimensions and geometric controls.
IMO: “Thinking is over rated”. This is being over thought.
Don't:
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Exactly!
You can also back it up by profile definition in Y14.5.1M:
“A profile tolerance zone is an area or a volume generated by offsetting each point on the nominal surface in a direction normal to the nominal surface at that point.” (Para. 6.5)
By definition tolerance zone cannot extend outside of nominal surface, because there is nothing to offset.
So the gap in nominal surface creates a gap in tolerance zone. (See picture)
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
_________________________________________
Engineer, Precision Manufacturing Job Shop
Tool & Die, Aerospace, Defense, Medical, Agricultural, Firearms
NX8.0, Solidworks 2014, AutoCAD LT, Autocad Plant 3D 2013, Enovia DMUv5
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
Inspectors...pfft.
John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
As a professor in a certified college and ASME GDTP S0667, I caution you against using instructors as basis for standard compliance. I know of many other fellow faculty that teach GD&T incorrectly. They have learned it by teaching themselves.
The tolerance zone would not be applied to the slot, a separate FCF is needed to create another tolerance zone, or use the "all over" (2009) symbol.
John
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
the use of 'between' modifier i.e. the double leader arrow.
See 3.3.11 Between symbol
"The symbolic means of indicating that a tolerance
or other specification apply across multiple features
or to a limited segment of a feature between designated
extremities is shown in Figs. 3-11, 3-14, 8-6, and 8-7. The
leader from the feature control frame is directed to the
portion of the feature to which that tolerance applies. In
Fig. 3-14, for example, the tolerance applies only between
G and H. G and H may be points, lines, or features."
fig 3-14 shows application to a profile tolerance.
Although in the case of the attached drawing by JNieman in the opening post, the extent should be unambiguous in my view, using the above solution especially for peripheral profile tolerances would eliminate any chance of misrepresentation.
RE: ASME Y14.5-xxxx Profile of a Surface - clarification
While this argument will probably never be officially resolved due to a lack of response by nwrichard, there's no question in anyone's mind that his notion was incorrect and he's just bowed out rather than acknowledge that he actually learned something. That's the whole purpose of this forum anyway, not to prove who's wrong or right.
John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II