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.

 

[3DDave]

Maybe. It indicates that there will be repeated separate datum features that have identical names and that each reference to them does not apply to all of them at the same time. One can still generate a simultaneous requirement for a group of features relative to each of those separate datum features.

I dislike Figure 7-37 because it splits frames of reference for a single feature in a difficult to calculate manner. Even so, each line of an individual FCF is already separate and acts as if no other control exists for the related feature at the time it is verified.

 

[Andera]

So, would the meaning change if no note INDIVIDUALLY is shown (still considering the upper segment being gone, my adjusted case).

Not sure I get the full meaning and usage of such of note.

 

[greenimi]

I have to disagree with 3DDave.
I do not think INDIVIDUALLY note will offer the license for the simultaneous requirement rule to be canceled.
Not sure why he is even thinking about that.


3DDave,
Could you, please explain a little bit further?

 

[fsincox]

I think it has to, It is a completely different framework established each time, is it not?
Frank

 

[chez311]

It doesn't seem like the standard is too clear on this. I understand that any reference to D such as |A|D(M)| applies to each of the 6x sets of patterns individually - which since each of the 6x datum features D is to be treated as a separate datum feature this can be thought of as nullifying simultaneous requirements**, but does that also apply to the other datum references, ie: |A|B|C| within each one of those 6x patterns of features? My gut says no because the INDIVIDUALLY notation doesn't actually create separate requirements but creates 6x unique datum features, and that any DRF which does not include D would be held in simultaneous requirements unless otherwise stated but I'm interested to hear other thoughts on this.

**which it really isn't since each datum feature D is actually a separate datum feature, which are all being referenced as 6x unique datum features labeled D instead of 6x identically sized/toleranced features separately labeled D,E,F,G,H,I and referenced as such in a multitude of separate FCF in the 6x sets of features shown. I would think of it more like shorthand than truly a form of separate requirement.

 

[CheckerHater]

On Fig. 7-37 Dia 79.4 and Dia 3.6 both have position requirement wrt A,B,C, which creates simultaneous requirement.
Imagine "big" functional gauge that checks all of those features for position Dia 1.4 at once.

Individual requirement controls position within every single detail A.
So imagine "small" functional gauge checking features within every detail A for position Dia. 0.4 6 times in a row.

Two separate DRFs, two separate checks, both must be satisfied.
"Individual" requirement doesn't create simultaneous requirement. Doesn't cancel any as well.


"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[chez311]

Two separate DRFs, two separate checks, both must be satisfied.
"Individual" requirement doesn't create simultaneous requirement. Doesn't cancel any as well.

Well said. I put an asterisk when I said it "can be thought of as nullifying simultaneous requirements" and clarified what I meant but thinking back I shouldn't have even said that. I think I like considering it to be a shorthand way of referencing to "n" times identical features as unique datum features to control associated "n" times features. An entirely separate concept from simultaneous requirements.

 

[axym]

Hi All,

The INDIVIDUALLY annotation has what is sometimes called a "context sensitive" meaning. In other words, it can have very different meanings depending on where it is used.

In Fig. 7-37, it is used to represent a "repetitive" datum feature and datum feature reference. This would save having to label a different datum feature for each of the 6 repetitive collections of features (D 6X INDIVIDUALLY instead of D, E, F, G, H, and J).

In Fig. 8-23, INDIVIDUALLY is used to cancel the effect of the 2X pattern creation mechanism that would require the profile tolerances for both cutouts to be evaluated in the same reference frame. In other words, it allows the rotational/translational shift to be optimized differently for each cutout.

In hindsight, it would have been more clear to define different terms for each of these purposes instead of using INDIVIDUALLY for both.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[CheckerHater]

In 8-23 "INDIVIDUALLY" doesn't "cancel" anything. It has nothing to do with rotation/shift as there is no datum referenced.
All the requirements in the composite frame underneath must be satisfied with or without DRF marked INDIVIDUALLY
You only check the outline of every opening "INDIVIDUALLY".
It may be easier to see if you treat the opening as a pattern of its components. Then you will see that there is no difference - pattern of features is checked individually as many times as many patterns you have.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[chez311]

So I would tend to agree with CH, there is no cancellation or nullification of anything happening in 8-23 either. I would say my "shorthand" analogy still applies - except just drop the part about referencing it as a datum feature ie: it is a shorthand way of referencing "n" times identical features as unique features with its own control/leader line/FCF. Just imagine that instead of a single leader line with the notation "2X" to one feature in the pattern, there was a separate leader line to each feature. In this case simultaneous requirements still applies.

In the case of 8-23, when "INDIVIDUALLY" is applied to the datumless profile tolerance, the tolerance zone is now free to rotate/translate without constraint to any datum features (because its datumless) or other features (because as far as I remember it being discussed previously simultaneous requirements does not apply to datumless FCF - though I would suggest the inclusion of SEP REQT to be most clear on this).

The real question would be if the DRF in the datumless single segment profile tolerance marked "INDIVIDUALLY" were changed to something like |A|B| instead. If I follow my same logic (ie: imagining separate leader lines with 0.1 profile to |A|B| applied individually to each of the 2 features) then while the features would not be considered part of a "pattern" by virtue of the "2X" notation - they would still be held in simultaneous requirements. One would have to add "SEPT REQT" to cancel simultaneous requirements.

 

[axym]

CH and chez311,

So in Fig. 8-23, what effect does the INDIVIDUALLY annotation have on the geometric tolerance in the upper segment? In other words, what would the difference be if the INDIVIDUALLY annotation was not there?

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[chez311]

Evan,

Wouldn't they would be part of a pattern and held in basic location to each other?

 

[CheckerHater]

They are in basic relation, so they would become a pattern.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[axym]

CH and chez311,

Right. I think we're violently agreeing here ;^). We're describing the same thing with different terms.

If the INDIVIDUALLY annotation was not there, the 2X annotation would make the two pockets into a pattern. This would mean that the profile zones for the two pockets would have to be evaluated simultaneously - we can shift the reference frame (alignment) using 3 rotations and 3 translations, but the same best fit must be used for both pockets. A consequence of this is that the relative location (and relative orientation) of the pockets is controlled.

When the INDIVIDUALLY annotation is added it cancels the effect of the 2X annotation, so that the two pockets are no longer treated as a pattern. This means that the profile zones for the two pockets do not have to be evaluated simultaneously - we can shift the alignment differently for each pocket. The relative location and orientation is no longer controlled - only the size and form of each pocket individually. Some people like to describe this in terms of the 40 mm basic dimension no longer applying - I find it easier to think of it as individual optimizations.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[chez311]

Evan,

I think you may be right, we're sort of saying the same thing. The OP was in relation to simultaneous requirements so I was focused on separating the effects of "INDIVIDUALLY" notation from "SEP REQT".

The only mild issue I have is when you said it is "context sensitive". I would say the individually notation effectively does the same thing in each case - per my shorthand analogy. Its just whether its applied to a controlled feature or datum feature.

 

[axym]

chez311,

I was writing another response, to re-assert my view that the INDIVIDUALLY annotation does different things in each case. But the more I tried to explain how it was different, the more it appeared to be similar.

I'm still not prepared to say that it does the same thing in each case, but I think there is more to it than I originally thought. The nX annotation has multiple effects - it acts as a "number of places" modifier, as well as having other implicit effects (that are context-sensitive - sorry!). When applied to a position or profile FCF, nX implicitly creates a pattern (imposes the requirement for all of the tolerance zones to be evaluated in the same alignment). When applied to a datum feature reference, nX implicitly creates a multiple datum feature (n simulators, that act together to constrain the part's degrees of freedom). When the INDIVIDUALLY annotation is added it cancels the implied effect, making the nX only act as a number-of places modifier.

There is still more to this - I need to think it through some more. The effect of INDIVIDUALLY is probably somewhere in between what you were thinking and what I was thinking - it's not the exactly the same thing in each case, but it's not completely different either. It's a means of explicitly overriding whatever implied, context-sensitive requirement is applicable ;^).

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[chez311]

When the INDIVIDUALLY annotation is added it cancels the implied effect, making the nX only act as a number-of places modifier.

Evan,

I like this description, possibly even more than my shorthand analogy. With the application of the INDIVIDUALLY notation, the nX annotation on a position tolerance changes from a pattern of nX features to nX number-of places of individual features, where simultaneous requirements still applies unless noted (or unless FCF is datumless). The nX annotation on a datum feature A changes from a pattern of nX features making up a multiple datum feature A to nX number-of places of individual datum features still called A but considered individually, here simultaneous requirements still applies to the FCF controlling the datum feature A itself - but the concept of simultaneous requirements does not apply to any *FCF controlled by/referencing A, not because it is cancelled but because A is now nX individual (unique) datum features.

Thats a long winded way of essentially repeating what you said, but I wanted to lay it out in explicit terms for my own sake. I will conceed that perhaps there is some more to it than saying that they're the same as the context of whether its applies to a controlled feature or datum feature has some nuanced effects but when describing them they feel very, very similar.

*Edit - changed from "features" to "FCF" because a single feature can have multiple FCF's, I am only talking about the FCF which reference A in the DRF

 

[axym]

chez311,

I'm not sure about the connections to simultaneous requirements here - I think this is very shaky ground.

We have examples in the position section where nX INDIVIDUALLY is applied to FCF's that reference a datum feature that is also nX INDIVIDUALLY. The datum features are considered individually, so simultaneous requirements does not apply.

There is also an example in the profile section (Fig. 8-23) where nX and INDIVIDUALLY are applied to a FCF that has no datum feature references. So simultaneous requirements does not apply here either.

Let's look at different variations of the upper FCF from Fig. 8-23:

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

2X SPF|0.1 INDIVIDUALLY
The 2 zones do not need to be evaluated in the same alignment, because INDIVIDUALLY cancels the pattern creation

SPF|0.1,,,,,,,,,,SPF|0.1 (2 different FCF's)
The 2 zones do not need to be evaluated in the same alignment, because there is nothing to create a pattern and simultaneous requirements does not apply

SPF|0.1|A,,,,,,,,,,SPF|0.1|A
The 2 zones must be evaluated in the same alignment, because of simultaneous requirements

SPF|0.1|A SEP REQT,,,,,,,,,,SPF|0.1|A SEP REQT
The 2 zones do not need to be evaluated in the same alignment, because SEP REQT cancels the simultaneous requirement

2X SPF|0.1|A
The 2 zones must be evaluated in the same alignment, because the 2X creates a pattern and because of simultaneous requirements

2X SPF|0.1|A INDIVIDUALLY
Do the 2 zones need to be evaluated in the same alignment? INDIVIDUALLY cancels the pattern creation, but is there still a simultaneous requirement?

Does it even make sense to specify INDIVIDUALLY in a situation where simultaneous requirements applies?

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[chez311]

Evan,

Apologies if I muddied the water with mention of simultaneous requirements, I was trying to explicitly put into terms how the two relate. It just seems to me that they are always discussed almost in the same breath when someone has a question about the INDIVIDUALLY annotation, the OP of this thread being a prime example.

We have examples in the position section where nX INDIVIDUALLY is applied to FCF's that reference a datum feature that is also nX INDIVIDUALLY. The datum features are considered individually, so simultaneous requirements does not apply.

There is also an example in the profile section (Fig. 8-23) where nX and INDIVIDUALLY are applied to a FCF that has no datum feature references. So simultaneous requirements does not apply here either.

We agree on these two points, I think I said as much in my previous post(s).

2X SPF|0.1|A INDIVIDUALLY
Do the 2 zones need to be evaluated in the same alignment? INDIVIDUALLY cancels the pattern creation, but is there still a simultaneous requirement?

I would say yes. In my mind it would be the same as your SPF|0.1|A,,,,,,,,,,SPF|0.1|A case. Do you believe otherwise?

Does it even make sense to specify INDIVIDUALLY in a situation where simultaneous requirements applies?

This I'm not sure about. Perhaps it doesn't make sense in most cases, but I can't imagine every possible case.

Not to be pedantic - though maybe not what you were referring to, simultaneous requirements still applies such as in the case of of Y14.5-2009 fig 7-37 for the 6x FCF having pos (dia)1.4(M) |A|B|C| controlling the 6x 79.4 dia hole which is datum D. Hopefully that makes sense? I'm not trying to contradict what you or I said earlier/above in regards to this figure and each datum D being considered individually, as I said just being pedantic