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Y14.5-2018 Published

Y14.5-2018 Published

RE: Y14.5-2018 Published

Thank you pmarc.

I am proposing something: to find mistakes in it. evil

I am sure training companies will update their training material (what is changed, what is new, what is removed etc.) but for us, here on the forum, finding errors is more fun.
What do you think?

RE: Y14.5-2018 Published

(OP)
greenimi,
We can try to find mistakes but at this point I would be more interested to see what others think about the document itself. I know there are different opinions about it.

RE: Y14.5-2018 Published

I got mine last week and have been anxiously awaiting its arrival on the board, I am interested also in what people think.
Concentricity and symmetry gone, plus and minus for location almost gone, and a new dynamic profile?
Frank
Thanks again pmarc

RE: Y14.5-2018 Published

I hate revised standards, just opens more cans of worms.

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: Y14.5-2018 Published

After the extensive public comment period and the way they posted all the issues and proposed fixes I have no doubt this version will be error free. /s

I guess they redefined position to absorb symmetry and concentricity?

I wonder if it has clear support for my contention that a wedge shape can have a flatness tolerance applied to it, owing has to how a wedge has a median plane.

RE: Y14.5-2018 Published

3DDave - I'm curious, how/where did you "find" the posts of the comments to the Draft? I am not a ASME member. Where they only available to Committee members?

I pre-ordered a copy and am waiting for it to arrive.

Certified Sr. GD&T Professional

RE: Y14.5-2018 Published

/s = sarcasm. There's no way they would have an actual, publicly exposed development process.

RE: Y14.5-2018 Published

pmarc and All,

The comments from committee review and public review were discussed and dispositioned in meetings that are open to the public, but these discussions are not published and are not to be discussed publicly. So only those who were there will know what really happened. shockedbanghead hairpull3

The new development that I like the best is dynamic profile. I think that this will be a useful addition to the toolset.

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

RE: Y14.5-2018 Published

Evan,

Quote (axym 21 Feb 19 19:13)

dispositioned in meetings that are open to the public, but these discussions are not published and are not to be discussed publicly
I'm sure everything has its reason, but those two things seem slightly contradictory.. I wish there was more transparency in this regard - seems like this is a commonly shared sentiment from the recent posts/responses.

That being said, I wasn't aware these meetings were open to the public - I guess they would they be posted in the general "committee meetings" (http://calendar.asme.org/home.cfm?EventTypeID=4&am...) portion of the ASME site?

I also share your interest in dynamic profile, I remember you mentioning it a while back and I have been looking forward to see how it is implemented.

RE: Y14.5-2018 Published

Evan,
Which transition you would consider more impactful for a better product definition: from 1994 to 2009 or from 2009 to 2018? Otherwise stated, which standard has more beneficial changes, clarifications, etc: 2009 or 2018?

As for the 2018: I do not like the change in the stabilization procedure for irregularities on datum features applicable at RMB. And that’s probably because I am not understanding it. Candidate datum set has been there for long time and is kind of known (at least for me).
Single solution that minimizes the separation….hmmm.

RE: Y14.5-2018 Published

And one more of my pet peeve: why 2018 version did not put the brakes on using (legally) total runout on a cone?
Just saying the total runout will control cylindricity (in addition to others) is good enough? I remember some discussions where has been concluded that might not be sufficient (in outlaw the practice)

RE: Y14.5-2018 Published

greenimi,

I haven't seen the new standard yet, but recalling the first instance where I heard about dynamic profile in this thread (https://www.eng-tips.com/viewthread.cfm?qid=439427) it was in reference to how it would make the debate over whether total runout is legal for conical features *moot as the new dynamic profile could probably be used instead. See Evan's post on (1 Jun 18 17:05) - are there any examples of this in the 2018 version?

*edit: missing a word

RE: Y14.5-2018 Published

Chez311,
What moot?

My question is: how would you divert people of not using total runout on cones?
Just because you have another method of defining the cones will not be good enough.

Make it illegal would.


RE: Y14.5-2018 Published

Quote (axym)

The new development that I like the best is dynamic profile.
I think that this will be a useful addition to the toolset.
You and me both, Evan. I recall our mutual dislike for Figure 8-18 in the 2009 standard. Maybe it's true that squeaky wheels get the oil!

RE: Y14.5-2018 Published

ASME Y14.5M-1994:  196 pages
ASME Y14.5-2009:   184 pages ( 94% of previous)
ASME Y14.5-2018:   309 pages (168% of previous)
 
I probably shouldn't complain before actually seeing the new standard, but this certainly seems like progress in the wrong direction.

Something written by Antoine de Saint Exupéry comes to mind:

Quote (translated)

It seems that perfection is attained not when there is nothing more to add, but when there is nothing more to remove.

pylfrm

RE: Y14.5-2018 Published

The key isn't making any particular language feature legal** or not; it is providing unambiguous declarations of applicability and clear rules for the expected results of application.

If total runout is described as a control limiting variation as measured by moving parallel or perpendicularly to an axis, as applicable, it automatically rules out cones and arcs and other shapes.

Is there something about dynamic profile that would not have fallen under the composite tolerance rules? Excepting that the '2009 and earlier simply didn't show an example?

**By definition, any language feature as expressed in the language spec is legal, just like any rule in a board game is legal for the game. They may also be ill considered, contradict some other part of the specification, or have some basic defect in the way it reflects the application domain.

RE: Y14.5-2018 Published

Quote (3DDave, 22 Feb 19 02:23)

Is there something about dynamic profile that would not have fallen under the composite tolerance rules? Excepting that the '2009 and earlier simply didn't show an example?

Yes. In the draft, dynamic profile was basically a generalization of total runout to things other than surfaces of revolution. I assume this hasn't changed significantly.

pylfrm

RE: Y14.5-2018 Published

Quote (3DDave 22 Feb 19 02:23)

The key isn't making any particular language feature legal** or not; it is providing unambiguous declarations of applicability and clear rules for the expected results of application.

greenimi,

I meant the argument between whether total runout on cones is legal or not would become moot/irrelevant. However 3DDave hit the nail on the head. I could be wrong, but I don't think the standard spends much time on what is not allowed or specifically stating something as "illegal". Instead it is typically more important to as clearly and specifically as possible define rules and applications for each topic (which, if we're being honest it comes up short in several areas... but no standard is perfect I guess - or at least I'll keep telling myself that).

Take for example the rules for position tolerancing. I don't believe the standard says anywhere "directly toleranced dimensions are not allowed/illegal in combination with position tolerance". Instead it specifically states in 7.2 "Basic dimensions establish the true position from specified datums and between interrelated features" and only shows examples with basic dimensions. The logical conclusion would be that position tolerancing and the definition of true position is only allowed with basic dimensions, and any use of directly toleranced dimensions would violate the definition of position and would have no support in the standard as to how to interpret it.

RE: Y14.5-2018 Published

So, let me ask then what would be the purpose of adding cylindricity to the 2018 version on the total runout definition? To clarify what? Why not keep it the way is it in 2009?

RE: Y14.5-2018 Published

greenimi,

The new stabilization default for RMB datum features will have some impact, but I'm not sure how much. I suppose that this depends on how often candidate datums on a rocking primary datum feature actually come into play. How often do you see a part rocked to an optimal orientation on a surface plate during inspection? I haven't seen that very much. When a part is CMM inspected, the software rarely/never tries different candidate primary datum planes.

Regarding total runout on a cone, I'm wondering what your objection is and why you feel it should be disallowed. Personally, I don't have a problem with it. Regarding the addition of the term "cylindricity", I don't think that this changes anything about the definition itself. It's a description, intended to aid understanding. When applied to a cylindrical feature, total runout limits the worst-case cylindricity error. It's an indirect consequence of conforming to the total runout requirement.

pylfrm,

Some of the additional pages represent new content, but a lot of it is from additional model-based versions of the figures. I also noticed that some of the figures are larger, taking up an entire page.

3DDave,

Total runout doesn't limit variation parallel or perpendicular to an axis. It's often portrayed that way, as this provides a useful description for cylindrical and planar surfaces. Point the indicator perpendicular to the datum axis for cylinders, and parallel to the axis for planes. But the requirement is really that the indicator needs to point normal to the basic surface. So this doesn't rule out cones and curved surfaces of revolution, but it does require that they be defined with basic dimensions and not with directly toleranced dimensions. This has been a sticking point - what to do when the angle of a cone is defined using a directly toleranced angle?

Dynamic profile cannot be covered by composite profile tolerancing - it's something different. Composite profile allows the tolerance zones in the lower segment to translate relative to the DRF. Dynamic profile allows the tolerance zones to "progress" (offset). I agree with pylfrm that this is a generalization of total runout.

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

RE: Y14.5-2018 Published

Evan,

That interpretation of total runout was never supported in previous versions; in fact, the application examples seem to go far out of their way to demonstrate only parallel and perpendicular applications. To say it's often portrayed that was is an understatement - that's the only way the standard portrays it.

There is no means from the stated rules to determine, for a real part, what it means in the absence of anything but a basic profile, what such a measurement might accomplish.

What really perplexes me is seeing no example of what actual driving need was put forward - what industry has long been crippled without this new feature? It seems very much like a language feature that has no engineering need, but would drive a company to have to use a CMM to determine compliance but without similar FEA support, for example, to determine variation affect on function.

On the plus side, there's now new training required and a new compliance check-box for CMM software to make sales differentiation points for sales and marketing; there's no way this is possible for any manual evaluation for the general case, even with dedicated fixturing.

Lest I be cast as a Luddite on this, I had need for essentially including a matrix multiplication into a specification because the desired relationship between two features was not orthogonal and the CMM software was too weak to make the calculation on its own. But I could point to the very real hardware and very real tolerance contribution to justify it.

RE: Y14.5-2018 Published

Dave,

The standard hasn't included examples of total runout on a cone or curved surface (well, at least in the later versions - Y14.5-1966 did have this). Y14.5-2009 makes the following statement on page 180:

"When verifying total runout, the indicator is fixed in orientation normal to and translates along the toleranced surface"

One of the total runout figures (9-3) also mentions "the indicator placed at every location along the surface in a position normal to the true geometric shape without reset of the indicator". Even though the feature in the figure is a cylinder, it isn't a big leap to apply the indicator description to non-parallel and non-perpendicular features.

One of the uses that I see for dynamic profile is to act as a universal form control. When applied without any datum feature references, it controls only form and nothing else.

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

RE: Y14.5-2018 Published

Can anyone tell what is the change introduced to the concept of a feature of size?

RE: Y14.5-2018 Published

Quote (Axym)


The new stabilization default for RMB datum features will have some impact, but I'm not sure how much. I suppose that this depends on how often candidate datums on a rocking primary datum feature actually come into play. How often do you see a part rocked to an optimal orientation on a surface plate during inspection? I haven't seen that very much. When a part is CMM inspected, the software rarely/never tries different candidate primary datum planes.

I've seen (and actually pretty often) in our inspection department. If some holes in a plate are qualified for their perpendicularity to datum plane (and also their mutual relationship) with a functional gage, the inspector is allowed to wiggle the part / rock the part on the gage until he/she is able to fit all the gage pins thru the part into the gage plate. That is how our instructions are reading and are to be understood. But that is again 1994 standard.

Just thinking out loud (and fast forward to 2018 standard) how the inspector is using the same gage when the "single solution that minimizes the separation" is in effect by default. How he/she knows when that single solution is acheieved? Are you no longer allowed to wiggle the part on the gage?

Again, I am not saying that changing the default procedure is not a good move, but I am questioning the implication in the real life/ gaging inspection and even/or simultaneous requirements.

RE: Y14.5-2018 Published

greenimi,

With the new default of a single solution that minimizes the separation between the feature and the true geometric counterpart, the inspector is no longer allowed to wiggle the part on the gage. How the inspector knows that the proper single solution has been achieved is another question entirely. There are definitely some practical implications (unintended consequences?) associated with the new default - these are going to be discussed and debated for the next few years, I'm sure.

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

RE: Y14.5-2018 Published

Evan,

The new default should have been discussed and debated for the previous few years. There should not be any unintended consequences at this point. All implementation questions should have been investigated and solutions included as part of the document that demands them.

RE: Y14.5-2018 Published

Since I don’t like this discussion to die down, I would like to ask what do you think about negative virtual condition which looks like is allowed by the 2018 standard? Some will, probably, say that was allowed even in 2009, but not clearly spell out (or, at least, not to my knowledge)

Or what about, the chart where total runout tolerance has effect on the location of entire surface? Do you think that is correct? I am talking about the wording/verbiage in red.

RE: Y14.5-2018 Published

And one more: what about changing the terminology from "multiple datum feature-primary" to "common datum feature-primary"?
Maybe in the next ASME standard revision we will see "combined datum feature-primary" to align with ISO trend.

RE: Y14.5-2018 Published

I preordered a copy of the 2018 revision. It was supposed to ship on the February 21st. I has not shown up as of this morning. Is anyone else waiting too?

Certified Sr. GD&T Professional

RE: Y14.5-2018 Published

greenimi,

There is a new statement about negative virtual condition, but it isn't in the Tolerances of Position section. It's in 5.9.4.1 Explanation of the Surface Method:

"NOTE: When a geometric tolerance applied at MMC results in a negative VC (i.e. when a 2.0-2.5 internal feature of size has a position tolerance of 3.0, the VC is -1.0), the surface interpretation does not apply."

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

RE: Y14.5-2018 Published

greenimi,

Regarding the statement that total runout controls the location of the entire surface, the correctness of this depends on your idea of what "location" is. Y14.5 doesn't explicitly define what is meant by location, but I would say that the statement is consistent with Y14.5's other descriptions of location. In the context of total runout applied to a cylindrical surface, location relates to coaxiality - the centering of the feature relative to the datum axis. The location of the surface does not relate to the radial distance of the surface from the datum axis.

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

RE: Y14.5-2018 Published

Total runout is a measure of uniformity of displacement relative to rotation about an axis; coaxiality control is a side effect. It is the axis-based version of parallelism vs a planar datum.

RE: Y14.5-2018 Published

Since I do not want this discussion to die (and I am trying to save it AGAIN :) ), I would like to ask another question / another one of my pet-peeve:

Why do you think that committee decided in 2018 edition to “adjust” the definition of the circularity with the unrelated actual mating envelope statement.

Fig 8-10 / 2018 states that each circular element of the surface in a plane perpendicular to the axis of the UAME shall be within……….
The equivalent figure in 2019 2009 states that each circular element of the surface in a plane perpendicular to an axis must lie between …………….

As we talked earlier, there some opinions that the newly addition (UAME) is a mistake.

Is it truly a mistake or an oversight? Or maybe intentionally those words have been chosen specific for cylindrical and conical surfaces .

What do you think?

Edit: I wrote 2019 instead of 2009 which I've been intended.

RE: Y14.5-2018 Published

It appears some of you have received your copies of 2018. Maybe you purchased the download PDF. I am still waiting for my hard copy. Did anyone else get their hard copies?

Certified Sr. GD&T Professional

RE: Y14.5-2018 Published

About the only thing that comes to mind is that UAME is computable by CMM and is discoverable by no other method. I don't know if this is just to be helpful or to plug a perceived hole, but it doesn't seem to me to be any more necessary than it is to require flatness of a width to be in relation to the UAME. Since UAME leads near the word "size" that would exclude cones, so there's that.

RE: Y14.5-2018 Published

greenimi,

Interesting observation about the circularity description and the new reference to planes perpendicular to the axis of the UAME. It's hard to say what they were thinking with that, because there are conflicting indications:
-As 3DDave pointed out, this would exclude cones because they don't have a defined UAME (despite this, Fig. 8-10 includes an example with a cone)
-The circularity section in the text (8.4.3) does not mention the axis of the UAME. It refers to planes described in 3.6 (a) and 3.6 (b)
-3.6 (a) describes planes perpendicular to the axis or spine (curved line)

I would have to say that the cutting planes do not have to be perpendicular to the axis of the UAME, despite what it says in the Fig. 8-10 caption.

Evan Janeshewski

Axymetrix Quality Engineering Inc.
www.axymetrix.ca

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