Contolling Electronic Cad Data

[macduff]

Happy New Year Everyone!

I was wondering if there and ASME specification for controlling electronic data. Looking mostly for a generic drawing note.

Here's my dilemma:
For our complex parts we make drawings with only critical dimensions applicable to the design and have a drawing note referencing the cad model as follows:

THIS DRAWING SHALL BE MAINTAINED AND REVISED ELECTRONICALLY
THROUGH THE 3D SOLIDMODEL AND SHALL HAVE THE SAME REVISION
LETTER. THE 3D MODEL MAY BE USED FOR RAPIDPROTOTYPING OR
ANY OTHER CAD SERVICES NEEDED FOR PRODUCIBILITY OF THIS PART.

My co-workers want to use this note:

GEOMETRY OF PART PER SOLIDWORKS FILE USE FOR MANUFACTURING AND DATA VERIFICATION. MODEL: XXX-XXXX-XX.SLDPRT PART MODEL
TAKES PRECEDENCE OVER DRAWING PART IS MODELED AT NOMINAL DIMENSIONS.

A couple of things......one; I don't like the p/n in the note because it's just one more thing to edit and miss revising a drawing. two; our quality system hear requires us to buy and inspect hardware to drawings, not electronic data. I'm referencing ".....PART MODEL TAKES PRECEDENCE OVER DRAWING....." which conflicts our quality standard.

What your take on this? Also, any aerospace spec referencing controlling electronic data would be helpful.

All the Best,




Colin Fitzpatrick (aka Macduff)
Mechanical Designer
Solidworks 2009 SP 3.0
Dell 490 XP Pro SP 2
Xeon CPU 3.00 GHz 3.00 GB of RAM
nVida Quadro FX 3450 512 MB
3D Connexion-SpaceExplorer

 

[MadMango]

I like the fact that some of you have the reference model features as Basic. Related to this, our standard note is "This drawing shall be used with <CAD file> for complete product definition. This document controls all unspecified dimensions and features." We also invoke Y14.41 in another note.

"This document" refers to the drawing itself, which doesn't make sense to me as written. Should this read "This document controls all unspecified dimensions and features of the model." Here, the 2D document is used for QA acceptance.

"Art without engineering is dreaming; Engineering without art is calculating."

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[KENAT]

MM, still seems a bit confusing to me but it may depend how you're using the drawing. Are you saying that some dimensions and features are unspecified in the model? By that you mean things like notes & tolerances, not geometry, right? Are you saying some of these things are specified in the model?

Most of the parts we use MBD on are curvy plastic or cast parts. So generally the drawings have very few if any dimensions on, at most just the mounting hole patterns. However, they have all the tolerance information, notes etc. as most of the time our vendors get sent dumb step or igs or parasolid files without any PMI information.

I don't get the hang up about needing a full drawing becuase that's what your QA procedures say is used to inspect against. If the drawing explicitly says to invoke the model, surely you can use the model as your primary product definition without violating your procedures? Don't get me wrong, I can see a drawing may be more usefull for inspection in some cases, I'm just questioning the concern with auditable procedures. Do you fully spec things like threads on drawings? I'm guessing not, you reference another document on the drawing and your QA procedures are find with that. So why can this principle not be extended to the model?

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[ajack1]

Glad to see you are finally coming around Kenat.

 

[KENAT]

You made a convincing arguement ajack;-)

Actually, while there were aspects that concerned me the concept of hybrid MBD (Model + partial Drawing) seemed appealing to me long ago.

It was the pure MBD with no drawing at all which still seems problematic in many ways.

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[MadMango]

KENAT, yes, mostly just notes and tolerances, as we too usualy send parasolid files to our vendors (molded and cast parts). I guess out drawings are mostly detailed, since it is the drawing that is used for first article inspection.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[MechEng2005]

Ok, I see the value of using a model for manufacturing. However, the original post indicated hardware was to be bought and inspected per drawings. Even if the quality system were allowed to use the model, I find it hard to imagine something that can be inspected but not put on a drawing. If you can't dimension it on a drawing, how could you inspect it?

I appolgize that the rant went somewhat off-topic, and am glad that the other replies have not followed a topic that has already been debated, as Kenat pointed out.

However, the point of my first post was to share that I personnally do not think the model should take precedence over the drawing, which was part of the original topic.

-- MechEng2005

 

[KENAT]

MechEng, I believe some CMM systems allow you to compare the model to actual hardware. Don't ask me the details but they were starting to do it nearly 10 years ago at my old employer.

Also, full blown MBD allows annotation of the model. I'm not convinced how easy this is/will be to work with but the idea is in existence and being used.

Posting guidelines faq731-376

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

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[ajack1]

I find it hard to imagine something that can be inspected but not put on a drawing. If you can't dimension it on a drawing, how could you inspect it?

Think of any major car body panel and no they are radii. As for measuring it you use a CMM against the model using a surface profile.

 

[ewh]

Our procedures reflect that of ajack1's; the CMM software locates the model in 3D space then a probe is used to compare the physical part to the solid model.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[fcsuper]

CMM has limitations adn will not work with all scenarios. However, if there is a way to make the part and inspect it, with it being FULLY detailed in a 3D CAD model, the I would see that as a candidate for drawingless environment. There is a lot of setup work to get this kind of process going too. From my experience, it's not as simple as just sticking a part into a CMM and having it know everything it needs to do. It's harder to teach a machine to inspect than a person (at least so far).

Matt Lorono
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[MechEng2005]

Ok, maybe I should have kept my mouth shut, since the places I have worked have no real quality control to speak of, much less a CMM. I would still say that the drawing takes precedence. Then I would put a note on the drawing with instructions or indication of how the part was to be inspected (which would allow use of the model where required). I would personnally include as much as possible on the drawing, and require the model for as little as possible. However, they is only my (ignorant) opinion.

-- MechEng2005

 

[fcsuper]

I mostly agree with you, Mecheng2005. It just depends on the work environment.

Matt Lorono
Lorono's SolidWorks Resources & SolidWorks Legion

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