Combining Composite and Bidirectional call outs 1

[marshell]

Is it ok to combine a Composite hole location with a Bidirectional call out? I want to allow the PLTZF to have a relatively large X movement, with a smaller Y movement, while at the same time I would like to limit the FRTZH and have it be a diametric control. I could find no examples in Y14.5, nor anything saying I could or could not combine the 2 methods. If it would be cleaner to remove the diameter off the FRTZH and have it be a square zone, I could do that also.

I have included an attachment, because I am sure I have not explained what I am trying to do in a clear way, and a picture is worth a thousand words.
[URL unfurl="true"]http://files.engineering.com/getfile.aspx?folder=babed142-e632-42e5-b7a0-7b2ef3701245&file=Composite-Bidirectional.JPG[/url]

Thank you.

 

[CheckerHater]

I am uncomfortable with having two composites applied to the same pattern.

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

 

[marshell]

CheckerHater,

I am uncomfortable with it also, but it is the closest thing I can think of to achieve the end requirements. Any ideas on a cleaner method would be greatly appreciated.

 

[CheckerHater]

By definition Composite is single control applied to pattern.

Could it be multiple segment:

.100|A|B|
.025|A|C|
.010|A|
?

(Just thinking out loud)

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

 

[pmarc]

marshell,
First, you may want to take a look at fig. 5-41 in Y14.5M-1994 or fig. 7-28 in Y14.5-2009. These figures show proper way of specifying bidirectional position tolerance.

Then, in order to define what you want, just attach additional position feature control frame wrt A to a size requirement.

Side note: It is a FRTZF, not FRTZH ;-)

 

[marshell]

pmarc,

So you are proposing something as this?
[URL unfurl="true"]http://files.engineering.com/getfile.aspx?folder=f93d71f7-d60f-4132-9d20-839d08af40bc&file=Composite-Bidirectional_1.JPG[/url]

It was too early to concentrate too much on my Fritz

 

[pmarc]

Yes, that is what I meant.

 

[greenimi]

Is this composite (the position shown) or multi-single segments?

 

[Woosang]

It would be similar to multi-single segments requirement.
In composite position tolerancing, FRTZF can float around inside boundary of PLTZF, being orientation controlled by datum referenced in the lower segment.
In multi-single segments tolerancing, FRTZF cannot float freely inside PLTZF since datum referenced in the lower segment also constrains the location of tolerance zone.

In the second attached drawing,location of Ø.010 tolerance zone, though Datum B and C are not referenced, would be fixed in its true position.

 

[greenimi]

Are we talking about Y14.5 - 1994 or 2009 ?

 

[Woosang]

I wrote based on 1994.
Looking over 2009 chapter 7.5.2, it doesn't look quite different, except that the terms FRTZF and PLTZF are no longer applicable to multi-single segments.
As I understood, main difference between composite and multi-single segments is whether the lower segments constrain the location of tolerance zone or not, in other words, basic dimensions from referenced datums are effective or not.

 

[greenimi]

Okay. Thank you Woosang.

 

[greenimi]

So , I guess the OP question should be “ multi-single segments” instead of “composite, right?
I don’t see where composite is shown in the pictures attached. Am I missing something?

 

[marshell]

Greenmini,

My intent is to have the call out along the lines of a composite. I want to allow the hole pattern to float in a large, rectangular zone, but I want to ensure the hole to hole location of the pattern stays tight in a normal circular zone. Basically I am mounting something on a rail, and I want to allow a large float of a tight pattern along that rail. Allowing more tolerance along its length, while limiting its side to side movement on the rail.

Thank you.

 

[pmarc]

marshell, greenimi, Woosang,

As long as we are talking about single pattern only and the positional callout defining cylindrical tolerance zones is wrt A only, there is no geometric difference between composite and two single segments callouts.

 

[greenimi]

pmarc,
I agree. But what is shown in the sketch is not composite..... (as the OP title states).
Do you agree?

 

[Woosang]

pmarc,
You mean that since neither datum B or C is referenced, they can't restrict the position of the hole pattern, don't you?
I might have been confused with that.
Thanks.

 

[pmarc]

greenimi,
If you are talking about the second sketch posted by OP - the one where he modified his original sketch according to my suggestion - then yes, this is not composite callout.

Woosang,
Yes, no reference to B and C in the position callout means hat callout does not control location of the pattern. The only locational relationship controlled is spacing between the holes.

 

[Gilmiril]

I want to allow the hole pattern to float in a large, rectangular zone, but I want to ensure the hole to hole location of the pattern stays tight in a normal circular zone.

The |Ø.010(M)|A| refines the orientation (perpendicularity) relative to datum A, so it seems to me that you haven't (yet) refined the hole-to-hole location. Or did I misunderstand what you mean by hole-to-hole location?

 

[pmarc]

Gilmiril,
Notice that the |Ø.010(M)|A| callout is Position not Perpendicularity, thus hole-to-hole location is controlled (in addition to perpendicularity).