Individually 1

[Andera]

Does the INDIVIDUALLY note nulifies simultaneous requirement?

Take Fig 7-37 /2009 for example.

If the upper segment (position diameter within 1.4 at MMC) is removed --hypothetical example-- would then the relationship between 3.6 holes still be controlled within 0.4?


Also, how would 40 basic dimension play a role for the upper segment (profile 0.1 INDIVIDUALLY). EDIT: ref fig 8-23/2009.

 

[axym]

chez311,

I agree that with 2X SPF|0.1|A INDIVIDUALLY there would be a simultaneous requirement and it would effectively be the same as SPF|0.1,,,,,,,,,,SPF|0.1 case. This is why I'm thinking that specifying INDIVIDUALLY doesn't make sense when simultaneous requirements applies. The INDIVIDUALLY annotation would have no overall effect, because the simultaneous requirements are not overridden.

Your question about the six D holes raises some interesting issues and questions:
-The 6X is in the "6X DETAIL A" text, and not in front of the 79.4 +/- 0.1 size tolerance. Does it still have the usual implied effect of creating a pattern out of the six tolerance zones?
-In this case, it doesn't really matter if a pattern is created. The A|B|C datum reference frame is fully constrained.
-If we've already said "6X DETAIL A", do we need to specify 6X INDIVIDUALLY beside the datum feature label and the position FCF? Or could these just be INDIVIDUALLY without the 6X?
-The INDIVIDUALLY annotation next to the position FCF overrides the 6X pattern creation from the "6X DETAIL A", but does not override the 4X pattern creation from the size tolerance (at least that is the intent). This is only defined by example - there are no rules governing the constraint on the "pattern of patterns" or the "pattern canceling" of INDIVIDUALLY.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[greenimi]

Evan and Chez311,
Re-reading a little bit the entire discussion, I would go back to the original question asked:

OP asked: “If the upper segment (position diameter within 1.4 at MMC) is removed --hypothetical example-- would then the relationship between 3.6 holes still be controlled within 0.4?”

If I have to answer this question based on the entire discussion (so far) I would say: yes.
Simultaneous requirements still applied even only size dimension (4X Ø3.6±0.1) and second positional tolerance (pos Ø0.4 MMC to A primary and D(MMB) secondary) with 6X INDIVIDUALLY note is shown.
Am I correct in my assessment?

2X SPF|0.1
The 2 zones must be evaluated in the same alignment, because the 2X creates a pattern

So, are you thinking that "no datum" is the SAME DATUM in order to enforce the simultaneous requirement? I read somewhere that there are debates within the experts about this subject. Has it been clarified in 2018 version of ASME? ("Is no datum the same datum")
Just changing the procedure from "candidate datum set" to "a single solution that minimizes the separation between the features and the true geometric counterpart" will give the green light to solve somehow the about issue?

 

[chez311]

I am still in the process of formulating a reply to Evan's multi-pronged post, but greenimi - your questions are a little easier to address.

OP asked: “If the upper segment (position diameter within 1.4 at MMC) is removed --hypothetical example-- would then the relationship between 3.6 holes still be controlled within 0.4?”

If I have to answer this question based on the entire discussion (so far) I would say: yes.
Simultaneous requirements still applied even only size dimension (4X Ø3.6±0.1) and second positional tolerance (pos Ø0.4 MMC to A primary and D(MMB) secondary) with 6X INDIVIDUALLY note is shown.
Am I correct in my assessment?

I would say the converse, no - if the upper segment FCF (pos dia 1.4(M) to |A|B|C|) was fully removed and there was only 4x dia 0.4(M) |A|D(M)| applied to the feature then simultaneous requirements is not applicable (not cancelled, simply not applicable) since each datum feature D is considered individually.

So, are you thinking that "no datum" is the SAME DATUM in order to enforce the simultaneous requirement?

No the 2 zones must be considered together in the example you selected because of the 2X annotation. Evan and I both agreed above that there is no simultaneous requirements enforced with datumless (no datum) FCF's.

 

[greenimi]

if the upper segment FCF (pos dia 1.4(M) to |A|B|C|) was fully removed and there was only 4x dia 0.4(M) |A|D(M)| applied to the feature then simultaneous requirements is not applicable (not cancelled, simply not applicable) since each datum feature D is considered individually.

Ok. So, then my follow-up question (hopefully an easy one): what is controlling the mutual spacing between Ø3.6 holes?

Thank you Chez311

 

[axym]

greenimi,

If the upper segment (position tolerance of 1.4 at MMC) was removed, I would say that the following would apply:
-the 4X and the position tolerance of 0.4 at MMC to D would control the relationship between the 3.6 holes within 0.4, within each pattern of 4 holes
-the [D} 6X INDIVIDUALLY creates six different datum reference frames, so there would not be a simultaneous requirement
-so the 24 holes are not controlled relative to each other within 0.4

For the 2X SPF 0.1, I am not thinking that the "no datum" is the same datum. The 2 zones must be evaluated in the same alignment because of the 2X (nX is a grouping method, as per the definition of "pattern" in 1.3.42). The topic of patterns, grouping, and simultaneous requirements is a very difficult part of Y14.5. It is filled with confusing and misleading terminology, definition by example and implication. I have spent a lot of time trying to sort this out into a reaonably small set of rules and concepts. The only way I have been able to make any progress is to find (or create) examples that isolate a particular effect. Many (most?) of Y14.5's examples have several things going on at once, so it is difficult to pinpoint the effect of each one.

There are still differences of opinion between different experts, regarding whether or not "no datum is the same datum" (in other words, multiple position/profile FCFs with no datum feature references represent a simultaneous requirement because they have identical datum feature references). I do not think this was clarified in Y14.5-2018. The change from a candidate datum set to a single solution applies to primary datum feature references, so that does not affect the case of no datum feature references.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[greenimi]

If the upper segment (position tolerance of 1.4 at MMC) was removed, I would say that the following would apply:
-the 4X and the position tolerance of 0.4 at MMC to D would control the relationship between the 3.6 holes within 0.4, within each pattern of 4 holes
-the [D} 6X INDIVIDUALLY creates six different datum reference frames, so there would not be a simultaneous requirement
-so the 24 holes are not controlled relative to each other within 0.4

Agreed on all accounts.

But, I still say that simultaneous requirements applies between each of the 4 holes (each pattern of 4 holes).
How else, the mutual spacing is kept within Ø0.4 if no simultaneous requirements is applicable?

Quote (chez311)

if the upper segment FCF (pos dia 1.4(M) to |A|B|C|) was fully removed and there was only 4x dia 0.4(M) |A|D(M)| applied to the feature then simultaneous requirements is not applicable (not cancelled, simply not applicable) since each datum feature D is considered individually.

Just curious.

 

[chez311]

But, I still say that simultaneous requirements applies between each of the 4 holes (each pattern of 4 holes).
How else, the mutual spacing is kept within Ø0.4 if no simultaneous requirements is applicable?

See Evan's response, the 4X annotation creates a pattern/grouping of features which is then repeated 6X. You are correct simultaneous requirements would apply inside each individual pattern of 4X features back to EACH of the referenced DRF's |A|D(M)| INDIVIDUALLY, however it is not needed to hold the mutual basic distance WITHIN each pattern of 4X holes due to it being a pattern.

*Edit - to be clear, in my initial response on (20 May 19 17:11) I was referring to the fact that simultaneous requirements did not apply between each 6X grouping as each of the 6X datum feature D is considered INDIVIDUALLY. I was not referring to simultaneous requirements within the pattern of 4X holes, my apologies for the hurried response.

 

[chez311]

This is why I'm thinking that specifying INDIVIDUALLY doesn't make sense when simultaneous requirements applies. The INDIVIDUALLY annotation would have no overall effect, because the simultaneous requirements are not overridden.

I pretty much agree with you here, like I said I can't envision every circumstance but on the whole I don't think it would make much sense and I can't see why one would want to do it.

-The 6X is in the "6X DETAIL A" text, and not in front of the 79.4 +/- 0.1 size tolerance. Does it still have the usual implied effect of creating a pattern out of the six tolerance zones?
-In this case, it doesn't really matter if a pattern is created. The A|B|C datum reference frame is fully constrained.

I would say yes the implied effect of 6X would create a pattern in the "6X DETAIL A" text. In this case, as you noted the DRF is fully constrained, simultaneous requirements is still in effect, and INDIVIDUALLY is applied to the datum feature symbol only (ie: nX is only a number-of-places modifier as it applies to the 79.4 feature when referenced as datum feature D in other FCF's).

-If we've already said "6X DETAIL A", do we need to specify 6X INDIVIDUALLY beside the datum feature label and the position FCF? Or could these just be INDIVIDUALLY without the 6X?

I would say yes that one could just notate this as INDIVIDUALLY without the 6X in front of the datum feature symbol, though I think the repetition of 6X does not confuse the issue and may be wise for explicit clarity. I think the same could actually technically be done on the position FCF on the 3.6 dia holes, but I don't think you would catch me advocating for that since the "pattern within patterns" makes it a little confusing.

From ASME Y14.5-2009 para 7.4.8:
When a detail view
includes a notation of the number of occurrences of that
detail view, then the 6X on the INDIVIDUALLY notation
may be omitted.

-The INDIVIDUALLY annotation next to the position FCF overrides the 6X pattern creation from the "6X DETAIL A", but does not override the 4X pattern creation from the size tolerance (at least that is the intent). This is only defined by example - there are no rules governing the constraint on the "pattern of patterns" or the "pattern canceling" of INDIVIDUALLY.

Actually 7.4.8 (and 10.4.8 in 2018) describe this to some extent. Do you believe this to be insufficient?

From ASME Y14.5-2009 para 7.4.8
The 6X INDIVIDUALLY notation beside
the datum feature D symbol indicates that each of the six
occurrences of the 79.4-diameter hole acts as a separate
datum feature and establishes a separate datum D. The
6X INDIVIDUALLY notation associated with the second
segment of the positional tolerances on the 4X 3.6-diameter
holes indicates that each pattern of four holes has a
tolerance zone framework that is located relative to the
specified datums.

Disappointingly - taking a look at the equivalent 2018 figure 10-38 there is an addition of an MBD example which lacks the detail view of the 2D drawing, adding an additional inference by the person interpreting the drawing that each 4X pattern refers to each 4X pattern of holes around each individual datum feature D.

*Edit: formatting

 

[axym]

All,

I'm noticing something in this thread that almost always occurs in discussions about patterns, grouping and simultaneous requirements. Misunderstandings and confusion often happen, because of different usage and interpretation of the term "simultaneous requirements".

Y14.5 defines the term "simultaneous requirements" in a particular context - multiple position or profile FCF's with exactly the same datum feature references. The effect is described as follows:

"In a simultaneous requirement there is no translation or rotation between the datum reference frames of the included geometric tolerances, thus creating a single pattern."

This same effect also occurs when there is a single FCF with a "grouping method" such as nX, N SURFACES, all around, all over, n COAXIAL HOLES, etc. Some people use the term "simultaneous requirement" in this context as well, and others only use the term in the context of multiple position or profile FCF's with exactly the same datum feature references. So we often get miscommunication between people discussing grouping and simultaneous requirements, because of differences in the usage and understanding of the terms. I believe this happened earlier in the thread, and I also believe that misunderstandings due to vague/loose/imprecise definition of simultaneous requirements have confounded GD&T experts as well. I've seen it firsthand.

Add this to the definition of "pattern", which adds further uncertainties:

"Pattern: two or more features or features of size to which a locational geometric tolerance is applied and are grouped by one of the following methods: nX, n COAXIAL HOLES, ALL OVER, A <--> B, n SURFACES, simultaneous requirements, or INDICATED."

So we are told that features are grouped by the above methods (note that simultaneous requirements is included in the list). However, the meaning of "grouped" is not defined. At least not explicitly - we have to look at the examples involving grouping methods and infer what the exact meaning of "grouped" is and the effect that it has. This literally took me years to figure out. It turns out that the effect of grouping is a lot like a simultaneous requirement ;^).

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[chez311]

Evan,

Those are interesting notes about the nuances of patterns/groupings and I appreciate the insight, I am coming to realize there is quite a bit of complexity to the topic which is not obvious at first look. I am wondering if there is a specific reason though that you laid it out as such? I thought I was following your reasoning pretty well with the differences and interaction between nX, INDIVIDUALLY, SIM/SEP REQT - did I accidentally confuse/conflate any of these?

Y14.5 defines the term "simultaneous requirements" in a particular context - multiple position or profile FCF's with exactly the same datum feature references. [...] This same effect also occurs when there is a single FCF with a "grouping method" [...] So we often get miscommunication between people discussing grouping and simultaneous requirements, because of differences in the usage and understanding of the terms. I believe this happened earlier in the thread

I fully understand these differences, and the way which simultaneous requirements operates (no translation/rotation between DRF) vs groupings such as nX. Agreed on all points.

Unless you think I have an inherent misunderstanding, I am interested to hear what you think about the last two items in my previous post. I have repasted them below:

-If we've already said "6X DETAIL A", do we need to specify 6X INDIVIDUALLY beside the datum feature label and the position FCF? Or could these just be INDIVIDUALLY without the 6X?

I would say yes that one could just notate this as INDIVIDUALLY without the 6X in front of the datum feature symbol, though I think the repetition of 6X does not confuse the issue and may be wise for explicit clarity. I think the same could actually technically be done on the position FCF on the 3.6 dia holes, but I don't think you would catch me advocating for that since the "pattern within patterns" makes it a little confusing.

From ASME Y14.5-2009 para 7.4.8:
When a detail view
includes a notation of the number of occurrences of that
detail view, then the 6X on the INDIVIDUALLY notation
may be omitted.

-The INDIVIDUALLY annotation next to the position FCF overrides the 6X pattern creation from the "6X DETAIL A", but does not override the 4X pattern creation from the size tolerance (at least that is the intent). This is only defined by example - there are no rules governing the constraint on the "pattern of patterns" or the "pattern canceling" of INDIVIDUALLY.

Actually 7.4.8 (and 10.4.8 in 2018) describe this to some extent. Do you believe this to be insufficient?

From ASME Y14.5-2009 para 7.4.8
The 6X INDIVIDUALLY notation beside
the datum feature D symbol indicates that each of the six
occurrences of the 79.4-diameter hole acts as a separate
datum feature and establishes a separate datum D. The
6X INDIVIDUALLY notation associated with the second
segment of the positional tolerances on the 4X 3.6-diameter
holes indicates that each pattern of four holes has a
tolerance zone framework that is located relative to the
specified datums.

Disappointingly - taking a look at the equivalent 2018 figure 10-38 there is an addition of an MBD example which lacks the detail view of the 2D drawing, adding an additional inference by the person interpreting the drawing that each 4X pattern refers to each 4X pattern of holes around each individual datum feature D.

 

[axym]

chez311,

I probably saw the term "simultaneous requirements would apply inside each individual pattern" and launched into my nit-picking. I know exactly what you mean and it's obvious that you understand the details and distinctions, but sometimes Y14.5's terminology is very difficult to work with (technically, Y14.5 defines simultaneous requirements as something that applies between multiple FCF's).

I had not seen the text in 7.4.8 that addresses the use of 6X in the detail views - thank you for pointing that out, it does clarify things. I agree that the MBD example removes an important piece of information and reduces the clarity.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[chez311]

Evan,

Glad I could point something out in the text! Thank you for the enlightening discourse - I think I have a little more appreciation for the nuance of groupings/patterns and I can add the "nX as a pattern of features" vs "nX with INDIVIDUALLY as a number-of-places modifier" to my arsenal of descriptions.

 

[3DDave]

Why would Y14.5 have anything at all to say about MBD? Isn't there a separate standard for that or are they just stamping onto each other's turf? Nothing new there I suppose.

 

[ewh]

MBD standard ASME Y14.41-2012 Digital Product Definition Data Practices defaults to Y14.5 for dimensioning and tolerancing.

"Know the rules well, so you can break them effectively."
-Dalai Lama XIV

 

[axym]

Some of the new developments in Y14.41 (and other standards such as Y14.8) are eventually adopted by Y14.5.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[3DDave]

It should default solely for interpretation, it should not depend on 14.5 for depiction. I guess it makes sense to try to follow the ISO "have to buy it a piece at a time" scheme, but with a monopoly position that seems unfair. Basically it means that, eventually, anyone getting y14.5 certification will be peripherally responsible for Y14.41 as well. Is that where the society is heading?

Still waiting for Y14.41 to include mandatory user interface and data interchange requirements so that anyone can use any compliant software without retraining.