Composite position on non-patterned features 1

[DanieJones]

I have a threaded gland with a flange and a bore. I am trying to position the threads, I want the primary datum to be the flange and the secondary to be the bore. I want to then refine the orientation to the flange.

I want to use a composte position, but I am not sure if I can beacuse the feature isn't a pattern.

Is it legal to use composite position control on a non-patterened feature?

 

[CheckerHater]

Technically it’s not, but Multiple Single-Segment Feature Control Frames (could we call it MSSFCF?) may be your thing.
First frame will loosely locate to [A] and , than second will tighten location to [A].
Haven’t seen it done on threads (what are you locating; MD, PD?). So, I am really curious what others have to say.

 

[DanieJones]

checkerhater,

It is the PD, we usually put an MMC modifier on the position so a functional gauge can be used.

 

[SeasonLee]

On a single feature of size, multiple geometric controls can be used to control the location and orientation to different tolerance values, for example:

|POS|Ø.010(M)|A|B(M) and refine by
|PERP|Ø.005(M)|A

SeasonLee

 

[fsincox]

IMHO, The trick would be in establishing the concept of the pattern of features. In my past work I would establish a pattern of multiple bearing bore centers in a gear case as a pattern of features. The bores may be of varying sizes so it was not a "right out of the book" kind of thing, but, it served the functional condition. This is assuming you do not want to invoke the "simultaeneous requirement" as the others have mentioned, which I was not fond of and is not universal.
Frank

 

[MechNorth]

Unfortunately it is not directly supported in the Y14.5 standard. To me, it's an extension of principles and no reason it shouldn't be applicable to single features as a composite profile would be.

Jim Sykes, P.Eng, GDTP-S
Profile Services

http://www.profileservices.ca

TecEase, Inc.

http://www.tec-ease.com

 

[Belanger]

Agree with SeasonLee. You can't use composite position because the lower part of the callout is not position. Use two separate feature control frames.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

http://www.gdtseminars.com

 

[SeasonLee]

You may find out many multiple geometric control application examples from chapter 6 on ASME 2009 standard.
Fig.6-5~6-9, Fig.6-12, Fig.6-14 and Fig 6-15

SeasonLee