Dawing Revisions

[ozzy1]

What are the rules for drawing revisions. I am head of QC Mechanical and work with design engineers who release a drawing without a revision and will make the first change a Rev A and others that start with Rev A when releasing the drawing.

 

[drawoh]

ozzy1,

This question belongs in forum1103.

I suggest you red flag this post, and repost there.

--
JHG

 

[KENAT]

Actually drawoh, some might argue it belongs in forum781 however that forum is a bit quiet.

What standards do you work to ozzy?

From memory it's not explicitly clear in ASME Y14.100 series - Y14.35M-1997 section 5.1 says "Initial issue of a drawing does not constitute need for a revision letter and may be indicated by the use of a - (dash)."

It's been discussed before so you might find something with search e.g..

thread1103-116296 thread1103-113692 thread292-278425 thread1103-279441

Posting guidelines faq731-376

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

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

 

[KENAT]

Oh, forgot to say while either option appears to be allowed by Y14.35 I'd suggest at least picking one and making it standard at your employer - which I'd guess is what you're trying to do.

Posting guidelines faq731-376

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

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

 

[LittleInch]

This is usually deinfed in a company or client procedure as I've seen everything excpet a blank revision no - some start at 0,1,2, some A, B or start with letters and/ or numbers (a1, A2, A3...) then move to the other when it's issued for construction.

As head of QC I would hope you access to your company QC standards where this should be specified as a default, but can be subject to client requirements.

I would always start with a revision numbe ror letter so that it can be recorded, tracked, transmitted and referred to properly.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[mcgyvr]

The problem you have is there is no clearly defined standard company procedure so confusion does/could arise..nothing else.

I'd hope there are NO rules in the industry that are set in stone..other than a consistent process that must be used to indicate revision changes. Heck you can use "A" for your first rev and "Z1" for the next as long as the revision process is documented and can be followed.

 

[ozzy1]

Actually we do not have any specific standards here. Everybody is allowed to do their own thing on the engineering design side even though our print notes start with "Interpret Drawing per ASME Y14.5-1994". The trouble with that is 90% of our engineers no nothing about GD&T. Our VP of engineering will yes you to death and then nothing happens.I asked the original question because we have 2 directors of engineering that we work with that do it 2 different ways. The one thing we generally agree on is numbers are used for pre-production letters for production.

 

[LittleInch]

So why don't you write one - Go to the head of QA and see how you can introduce it - one page should be enough. Write it, follow the QA procedure for how to write and approve procedures then send it to the head of Qa and get him (or her) to do some work / take the flak. Then issue it ansd send / give to everyone. In about a years time you might have a procedure ;-)

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[1gibson]

If you don't call the first revision "A" then how do you refer to it, just by the drawing number?

"Please send me drawing 12345."

Well do you mean the original revision, or did you just forget to specify and you actually want the most recent revision?

"Received part from vendor, it is made per drawing 12345 instead of drawing 12345 rev.C"

Whoops.

 

[Metalfixer]

Our first drawing was REL.for release to production. We used letters, skipping I and O to avoid confusion for revisions. On our drawings we also had the customer's revision level to update, as well as our own production drawings. As an example we might make parts to Chrysler's revision level "D", and our revision level might be "G". We were very carful with our drawings, as they were in effect a legal document.
Larry

 

[ozzy1]

Those that use a blank just refer to the drawing number.We do not have customer numbers since we are the design authority.We have other issues here where half of the product line has part numbers aswell as drawing numbers. That half starts with "A" for released drawings and numbers for pre-prod or any prototype. Right now I have one on my desk that is at Rev level E5. This has gone through 5 changes on a design change and will eventually be released as Rev F.

 

[drawoh]

ozzy1,

I guess the discussion is staying here.

I strongly prefer that my initial release of finalized drawings is revision[ ]A, because I release preliminary drawings as part of the design discussion. I need a clear description of which drawing I have sent out at any given time.

--
JHG

 

[Cockroach]

Typically the practice of revisions vary between companies. The usual practice is to put a triangular letter beside the revised dimension or statement and then make reference to that in a revision block on the print. The previous dimension is listed in description with the initials and date of the cat doing the revision. The whole purpose is to track legacy changes to design evolution on the part relative to the overall assembly.

This is mandatory in my company. But there are others who employ different methods that allow approved vendors to their website and dictate own us on that vendor to check for latest revision compliance. So only the vendor and parties having privileges can access revised drawings. I find this extremely controlling and unnecessarily a make work program, but it is ISO compliant with state of the art QC/QA policy.

I believe the print should stand alone and have information relating to that manufacturing detail. My employees know that if a machinist needs to ask someone, stop his work to reference a book or other document, then the print has failed. That is my policy, period.

It works quite well, I may add.

Regards,
Cockroach

 

[RajuKanumuri]

It varies with company to company
Our procedure is we need to start the DWG rev with A,B ,C and so on until the DWG is ready for PE stamp / issue for construction (IFC).
Once it is PE stamped / Issued for construction (IFC) the rev numbering need to change to 1,2,3 and so no..
One more thing whenever you change rev. need to cloud the changes for easy identification.
once construction completed, the DWG need to be prepared as built DWG with final rev number.

 

[IFRs]

Here's what I do:
first release is rev A entitled original issue.
subsequent releases are rev B, C, D.
when issued for construction it is changed to Rev 0 issued for construction and all previous revs are removed.
when I say removed I really mean layers frozen or off.
the drawing only ever shows one set of Rev numbers and clouds - the latest one.

 

[MadMango]

Where I work, prototype drawings are marked rev X1, X2, etc, and released drawings are rev A. Sometimes the ERP/PLM system can dictate prototype revision levels, as in our case our system only recognized alpha revs and not numerical ones.

Ozzy1, if you are the "head of QC Mechanical" then don't you have the luxury of laying down the law?

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

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

 

[urkson]

For prototype and pre-production we use numbers e.g. Rev 1 Rev 2 etc. then change to letters. What do you guys do if you have a design change to a part that may be at Rev D. We add a number e.g. Rev D1, Rev D2 etc. Then once sealed we would rev it up to Rev E.

 

[looslib]

We use numeric revsions starting at 0 for pre-production releases and letter revsions starting at A for production releases.
In PDMLink, all designers work in the Design State. We then release ro Pre-Release state all numeric revisions. When it moves to production, the state is Released. PDMLink prevents a designer from modifying any files at either Pre-Release or Release state.


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

 

[urkson]

As head of QC Mechanical I only control Quality not Design Engineering and even then Engineering can overule us unless we deem it, and can prove that a particular problem would be a product liability.

 

[Sparweb]

Whatever you do Ozzy1, don't do what is seen at our workplace, where the first release is at "IR" as in "Initial revision".
Files get sorted on the hard drive in alpha-numeric order so strange things happen.
It hasn't happened yet, but some rookie is going to come along and forget the other rule that you skip revision "I" between rev "H" and "J", and the confusion will get even worse.

My personal preference is to make sure the revision is a letter, and keep drawings ordered solely by number. If the drawings are organized with alphabetic designations, then a number to track the revisions stands out more. Letter drawing names invites wild imagination into file name conventions so avoid it. Make sure to use computer file names that equate the file name to the drawing number and revision. Do it in a way that the operating system can naturally sort them in a reasonable order. Do this even if you have a data management system or database that tracks this for you, because somebody has to manage the database.

It is not difficult to create a system that tracks, and isolates, the preliminaries that have been released before the drawings are approved. If the company has a data management system database, this may be an impediment to issuing prelims, but on the other hand, the prelims don't have to be made distinct from the approved drawings, if there is a "master drawing" or list that defines at what revision status each drawing becomes approved. Implying that any earlier revisions were not approved, just drafts.


STF