Has anyone ever used a "design parameter drawing"?

[drdherl]

My Saga continues.

I'm sure the economy will be booming before this gets behind me.

I'm wondering if I'm getting stuck in terminology, semantics or just beaurocratic bs.

I had posted a question not long ago, stating that my dftg department is now mandating that we not put hard dimensions on our interface drawings. Despite never doing this in past, they are now mandating that we put reference dims and ref tols on Interface dwgs. After much debate, I'm now being told that if I change the title of my dwgs from interface dwgs to design parameter dwgs, I can leave the hard dims. Something seems amiss. It seems like no value is added to the argument to just call the dwg a different name.

I'm wondering whether we've been misusing the term Interface control dwgs for eons.

Does an interface control dwg typically define both halves of the interface or does it only define one half? I typically see only one half of the interface except for occasional notes "shall mate with p/n xxx".

If I want a dwg to define one half, am I really trying to create a design parameter dwg?

Remember...my initial intent is to have a single drawing that defines (and puts under config control) the binding form, fit requirements of one half of a mated assembly. I'd like my requirements database to say...."widget shall conform to dwg xxx". Since supplier is in same company, I cannot callout SCD or part no of part being ordered.

I do not want drawing to be used as primary inspection mechanism for production, as I would prefer that parts be inspected on lowest level fab dwgs. I do want ability to use it for inspection for sampling design verification.

Basic question....What are examples of when one would create an interface Dwg vs a Design Parameter dwg?

drdherl

 

[KENAT]

drdherl, do you have ASME Y14.24-1999, if not I think you really need to in order to see for yourself what you need.

Looking at Y14.24 section 13.11 it seems that a DPD is similar to an interface drawing but is used to help define requirements during the design stage, before hardware exists rather than describing the interface of an existing part - if that makes sense.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[drawoh]

drdherl,

It sounds like you are implementing one of my suggestions, using terminology that your drafting department has not worked out strict rules on. "Design parameter drawing" is a much better idea than my other suggestion of naming the drawings after somebody's cat.

I do suggest that you leave the word "drawing" out of your drawing titles. You want your titles to be as short as possible. Images on paper or on computer screens and things on drawing lists obviously are drawings.

KENAT's suggestion has merit if you can get your drafting department to read ASME Y14.24-1999, understand it, and take it seriously.

It sounds a lot like you have some weird office politics going on at your site. Do you understand how your drafting department's mind works? Using terminology out of a manual or standard gives them the opportunity to work out rules on it. Some people out there are completely rule driven, and have little or no capacity to work to objectives. You are working to an objective.

JHG

 

[KENAT]

drawoh, the standard says you have to put the notation "DESIGN PARAMETERS DRAWING" adjacent to the drawing title block, it doesn't necessarily have to be part of the drawing title as such though.

Thinking about your situation drdherl, it almost seems like the drawing would start out as a DPM and then once the item exists might become an Interface drawing to continue to control the interface.

Which brings you back to the initial problem of your drafting department not wanting tols on the interface drawing.

The example in 14.24 clearly shows tolerances on dimensions, I'd be interested in hearing your drafting departments view on that, unless you have a company DRM that overrides it. Either way does seem to definitely start to fall into the BBS category.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[KENAT]

Don't normally do this and will probably RF it.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[EdMcCabe]

from DRM

"An interface control drawing shows physical and functional interface engineering requirements of an item which affect the design or operation of co-functioning items. These drawings are used as design control documents, delineating interface engineering data coordinated for the purpose of: a) establishing and maintaining compatibility between co-functioning items; b) controlling interface designs thereby preventing changes to item requirements which would affect compatibility with co-functioning sub-systems; c) communicating design decisions and changes to participating activities.

REQUIREMENTS:

An interface control drawing shall delineate, as necessary:

1. Configuration and all interface dimensional data applicable to the envelope, mounting and mating of the items.
2. Complete interface engineering requirements, such as mechanical, electrical, electronic, hydraulic, pneumatic, optical, etc., which affect the physical or functional characteristics of co-functioning items.
3. Any other characteristics which cannot be changed without affecting system design criteria.
4. The notation INTERFACE CONTROL DRAWING shall be shown, adjacent to the title block in .25" high letters."

Therefore, I would say your drafting dept. is wrong.