Proposal for adopting ASME Y14.5M-1994

[ModulusCT]

So, after mentioning to the engineering VP where I work that adopting the ASME standards for our drawings would improve things here, he said that he's all for effeciency, and that I should write up a proposal which outlines the benefits of the move as well as any training that would be required and any other important points.

Anyone here have any information regarding the benefits of adopting a drafting standard like this? Specifically, benefits that would apply to the drafting side of things?

Our VP is concerned that people in our assembly dept. won't be able to understand the drawings, but I told him that if anything, they will have fewer problems.

 

[KENAT]

I was part of a team brought into this company to improve product definition including introducing Industry best practices, managment speak for ASME drafting standards.

While I'm a strong advocate of industry standards your VP may actually have a point about the impact of strict compliance in assy drawings. There isn't that much in the standards about assy drawings, ASME Y14.24 has a section and that's about it. If they are used to drawings that are more like work instructions, with detailed step by step instructions of what/how to do then they may struggle with more conventional drawings.

To my understanding a more conventional assy drawing effectively defines the end item requirement, it doesn't detail specifically how to get there. This is an issue we've struggled with, and for us it's compounded by the fact they like a 'flat' BOM structure without lots of levels of sub assy drawings so we have fairly large assemblies with lots of parts.

To try and get around this we tried to formalize the distinction between classic assy drawings & detailed work instructions. However people, perhaps understandably, question having 2 documents.

I've made a few posts on the topic over time, maybe take a look, the 2 below are the first I found.

thread1103-157857 thread1103-192933

There are also lots articles on line about the advantages of GD&T.

http://findarticles.com/p/articles/mi_qa3618/is_199402/ai_n8728937/

http://www.engineersedge.com/training_engineering/advantages_geometric_dimensioning_tolerance.htm

http://www.geometricguru.com/gd&t benefits.htm

http://books.google.com/books?id=GQ...jqCQCg&sa=X&oi=book_result&ct=result&resnum=6

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[KENAT]

Forgot to say, from my point of view the major benefit of following ASME drafting standards is that done properly it reduces ambiguity/improves definition.

Adoption of GD&T, which is at the heart of 14.5 has additional benefits relating to better defining, and making better use of, available tolerance.

KENAT,

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[ModulusCT]

Great thanks Kenat... I'll check out those threads in a bit.

I think that the way this is going to go is that we'll adopt the standards for drafting first, so that we can reduce the number of engineering hours spent redlining prerelease documents and discussing the best way to describe design intent on our detail drawings.

If that goes well, than we may be able to adopt the GD&T portions of the spec and train some of the more inexperienced drafters and inspection persons to interpret and apply the ideas properly.

Our assembly drawings would most likely not be controlled by the spec, except for in the most superficial sense (placement of leaders, balloon styles, etc.). We control the process of assembly with an additional document we call a traveler. So even with the more conventional method, I think that assembly would be OK. This change would mostly affect, drafting, inspection and our vendors.

 

[KENAT]

OK, your place actually understands the concept of a travelor, in that case you will probably be OK with a more conventional assy drawing. I'd made an incorrect asumption that based on what you said that youd didn't use them or similar, sorry.

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[drawoh]

ModulusCT,

The benefits of meeting drawing standards depends on the current state of your organization. If your documentation is complete and clear, a rigorous program of ASME conformance may be a waste of time. Add in some office politics, and it could even make thing worse.

Can your assembly people make sense of your drawings?

Can your fabricators make sense of your drawings?

Do you send drawings out to vendors? In-house, you can work out your own unique standards that precisely address your requirements. Once the drawings goe out, ASME, ISO, DIN and JIS allow everyone to speak the same language. When you issue a PO, your drawings are a clause in a contract. They cannot be ambiguous.

Another advantage of standards is that you can hire people who understand them. The more exotic your in-house system is, the longer it will take new people to learn it.

Are your drawings crap? If so, is it because your people do not understand the standards, or is it because they are lazy, stupid and uncommunicative. If your CAD operators have no design or problem solving capability, standards training will not help.

Don't be a solution in search of a problem.

JHG

 

[ModulusCT]

drawoh,

Currently, our main problem seems to be that we have few standards controlling our documentation. We are given no in-house design / drafting specifications and we our told by word of mouth that U.O.S. we are to interpret our drawings per ANSI. Unfortunately, no one but myself and one of our drafters is familiar with this... We spend a fair amount of time going back and forth between our documentation manager, engineers, drafters and quality trying to best quantify our design documentation.

Unfortunately, what happens is our drawings are inconsistent, from drafter to drafter and from drawing to drawing from the same drafter.

We are in a period of expansion (new hires, recent ISO cert., facility expansion, etc.) and I think this could be the best time to adopt a new best practices manual.

Thanks guys, for your input... Further discussion is always appreciated.

 

[fcsuper]

I believe the term is Level 3 assembly drawings, which details step by step drawing assembly instructions? Anyway, it's not ASME, but umm..DOD? I would still move towards adopting ASME, but if assembly drawings are your concern, you may want to formulate your own internal rules.

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[KENAT]

fcsuper, I don't believe so.

I don't believe any of the industry or govt standards require/expect step by step assembly instructions as the drawing. On all the US & UK govt standard drawing packs I've seen there were not step by step assembly instructions. They were adequate views, including sections, (in the assembled condition with maybe one exception that had an exploded view) to allow all parts to be ballooned/identified with the numbers from the Parts list. They'd have notes detailing explicit requirements.

They complied with the spirit of ASME Y14.5M-1994 1.4(e) "The drawing should define a part without specifying manufacturing methods. ..."

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[ctopher]

I had a director ask me to do the same proposal. I told him that I don't believe in writing proposals to follow industry standards. I told him to read our contracts with our customers, they all indicate that we must follow the standards and writing a proposal is wasting my time. He agreed.

Chris
SolidWorks 08, CATIA V5
ctopher's home (updated Aug 5, 2008)
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[drawoh]

fcsuper,

I forget where Levels 1, 2 and 3 were defined. My very crude understanding is that level[ ]1 means you have made some attempt to generate documentation. Level[ ]2 means your documentation is good enough that you can manufacture the thing. Level[ ]3 means your documentation is good enough that someone else can manufacture it. Googling Thomas Morse Aircraft may provide some useful history on the concept.

JHG

 

[KENAT]

drawoh, that's about it as I understand. There have been threads that touched on this before and there may even be quotes/links on those.

KENAT,

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[KENAT]

Veering of the OP's topic a bit but here you go thread1103-170033

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[ModulusCT]

I like the cut of your jib, ctopher... But I don't think he even knows what GD&T is, so telling him that it's an industry standard might be seen as a somewhat empty endorsement.

Adoption of the spec will be primarily for detail drawings and designs. It's probably best to do our assembly work the way we have been... With a drawing to show items, part numbers and locations of mating parts, and a traveler for define the actual assembly processes.

Thanks for the input everyone.

 

[KENAT]

Modulus, while you haven't gone into much detail, what you do for your assy drawings follows ASME specs from what I see.

For whatever reason our place can't/wont do the travelor thing. So we get our selves into a pickle, especially given how large most of our assemblies end up being due to their not liking sub-assy's.

KENAT,

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