Pre-Production Drawing Revision Symbols 3

[thegardener6]

Hello,

The company I work for is currently reviewing our drawing release and revisioning processes.

I know that it is widely acceptable to have 2-3 different release levels such as preliminary, prototype and production. I also have seen different schemes for differentiating between these release levels by the revision letter or symbol. However, I need something a tad more concrete than what I have seen or done inorder to submit the idea.

I am looking for a standard or spec that explicitly approves or shows the use of diffent revision symbols to differentiate between pre-production and production revision levels. Can anyone point me in the right direcion?

 

[ctopher]

I'm not aware of revision 'symbols'. Revisions are numeric, alpha, or alphanumeric.

Chris
SolidWorks 09, CATIA V5
ctopher's home
SolidWorks Legion

 

[fcsuper]

If by symbols, you mean the marks you place next to the location of the revision on the drawing, then I would say that the standard you should look at is ASME Y14.35M-1997. It establishes the use of revision symbols. The only symbol shape it mentions is a circle with the revision contained within. It also allows arrows to connect the revision symbol with the changed item.

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

 

[thegardener6]

Sorry, I should have been more clear. I did mean revision letters instead of symbols.

I can't seem to find any other option for revision designation other than letters in ASME Y14.35M. You stated that revisions can be alpha, numeric or alphanumeric, which I agree because I have seen and done the same. However, I am looking for something that shows this being done -- a standard, spec, drawing manual, etc.

I think that the Drawing Requirements Manual might have something about this. I do not have access to that manual, but I know that most everything in it is based on some standard or other which I can access.

 

[drawoh]

thegardener6,

We add a version number to prelimininary documents that are not ready for issue. eg:[ ]A.3.

Once they go out for fabrication, why differentiate at all? Preliminary, prototype and production should be the contents of a pull down menu on your PDM profile card. If your part is released as preliminary and you do not modify it as you go to prototype and then production, you should not change the revision letter.

Your fabricator needs to know that you want parts fabricated, and they need to know if and how you changed your drawing since last time. Document status is a document control issue.

JHG

 

[fcsuper]

First, when multiple changes occur within a single revision, you can add a revision sequence number at the end of the revision letter according to ASME Y14.35M

Second, to how the status of release, it is common practice to use numbers for development or engineering release levels, and to use letters for production release. For preliminary, I currently use a 0.X scheme.

Third, you are "allowed" to do this by the ASME Y14.100 paragraph 1.2: "Application of this Standard may necessitate tailoring to exclude unnecessary requirements." As long as your documentation system clearly defines exceptions to the Standards (and the exceptions are readily available to your interior supply chain ...up and down stream), you will be in compliance.

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

 

[ewh]

According to my copy of the Drawing Reqirements Manual, revision letters are alpha only. The only documents it refers to are DOD-STD-100 and ANSI Y14.5 (you can tell it's an old version).
I have always used "alpha only" revisions to cover the complete change, while using alpha-numeric to differentiate between changes in that revision.
That said, I would rely more on the specific current standard than on the manual.

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

 

[MintJulep]

I've never quite understood why people feel it's necessary to differentiate between preliminary and production drawings by revision level.

Build the function into your documentation control system, not into the drawings themselves.

 

[swertel]

A Level I drawing is a sketch or concept drawing.
A Level II drawing is a prototype drawing.
A Level III drawing is a production level drawing.

The biggest difference between the 3 is the level of detail required to define the part/assembly of the drawing. Subsequently, the approval process is often different. Concepts are just napkin sketches being built with the engineer's or designer's authority. Prototype drawings have at least been reviewed by quality or manufacturing. Production drawings have been fully checked, i's dotted, t's crossed, and all Classification of Characteristics incorporated.

So the OP's question could be restated - How does one differentiate the drawing level? Most do it by drawing prefix:
SK is for sketches
X is for prototpe
<blank> is for production.

SK12345 gets redrawn to X12345 and redrawn again to 12345 as the part progresses from concept to prototype to production. I have seen companies use numbered revisions for pre-production and then letter revision for production level drawings. This allows them to keep the same drawing number through the entire development process. Read up on the key words "Baseline Release."

--Scott

http://wertel.eng.pro

 

[thegardener6]

drawoh,

Your example of version number or something like X0, X1, X2... to designate preliminary or prototype (or pre-production as it's called here) is what I am looking for. We do not operate in a PDM system (yet) and fabricators would know to build parts via a purchase order.

My main point of this post is about drawing revision practices and possible standards to look for. I have Y14.35M and that is what we currently use. I don't think that this is a new idea as I have used and seen this used elsewhere. I have managed to get some buy in, but I am being asked to show some standard or spec or something that says or shows how this is done on a drawing. I am starting to suspect that there are none and that this handled by a company standard.

The reason for this is that external companies procure to our production level drawings. Therefore, it has been determined that they need to approve release and changing of production drawings. So, if everything is released as production then everything needs to be approved by a combersome and not always clear approval process. The unclear part is that drawings released for production are not always production builds and it takes planning some time to research who needs to approve the release or the change. This slows down the release and revisioning processes extremely. We do not have a concrete way to differentiate between prototype and production builds -- everything is released or not released. It has become so combersome and time consuming to release or change a production drawing that a method of creating "not released" drawings was adopted as a work-around for the process time.

There is hardly any control over "not released" drawings. The only thing on the drawing that says "I am the current drawing, use me" is an electronic date stamp (latest date wins). There is no revision history placed on "not released" drawings -- just the date stamp. Old versions are kept, but what good does that do the fabricator who needs clear revision history to determine his disposition. These "not released" drawings also do not follow any ECO process. We send "not released" drawings out for quote and have parts built in low qty's to particular dates of "not released" drawings.

Having relatively uncontolled "not released" drawings has created some problems. My suggested approach is to have drawings at REV X0, X1, X2... be designated pre-production and drawings at REV A, B, C... be designated production release.

The idea would be to find middle ground between having at least minimum control over pre-production release drawings and not having to go through the entire production release process. Revisions can be controlled via a lesser ECO process, and revision history would be kept on the drawing. Only when drawings are ready/required for production, do to they need then go through the bureaucracy of the production release process.

Theoretically, everone gets what they need. Fabricators get clean revisions and revision history. There are minimal version mix-ups. It would also become easier for approval and planning because the release level would dictate who needs to approve it and where the drawing needs to be routed. The revision on the drawing would tell what release level the drawing is. There would be some bureaucracy, but only to the minimum extent required.

 

[ewh]

I have also seen similar schemes used. We got around the Level III standards by including the scheme in our DRM and by producing data packages (for customer use) with no preliminary revisions included.

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

 

[thegardener6]

Thank you all for your input

swertel,

That's the idea, except it is impractical for us to change drawing numbers. Our method is that drawing numbers and part numbers are the same. Our part numbers are on parts lists provided to the customer and on contracts. In fact, most of the time we produce parts lists for the customer before the majority of drawings. So by the time we produce drawings, most of the part numbers are set in stone or at least very combersome to change.

MintJulep,

I know this is primarily a document control issue and can be handled by a MRP or PDM system, but like I said I am looking for drawing practices. Some companies may never have the need for different release levels or to indicate that on a drawing. We have neither a suitable MRP nor a PDM system. All work is done on forms and on drawings. Even CM information is kept in the revision history block of the drawing. So, as complicated as it may sound by modifying the revision letters to indicate a release level, it is pale in comparison to what current practices are.

fcsuper,

First, I understand how to accomplish multiple changes in the same revision.

Second, I understand that it is common practice to use numbers for preliminary releases and letters for production releases. This is what I want to be able to do. I have done this before. I just need to show something.

Third, I understand that ASME Y14.100 may be tailored to exclude unnecessary practices, but management has a hard time with this. This is why I need to have something to show.

 

[swertel]

If you can find yourself and old copy DOD-STD-100, I believe it shows the method of revision control you are looking for. Good luck on that hunt!
No, not MIL-STD-100 and not DOD-STD-1000, DOD-STD-00100D(AR) is the latest "release" I know about back in 3 Apr 1987.

Appendix E - Revision of Drawings

Method A
--Utilizes "X" revision letter system. Uses "X0" (zero) for first entry when drawing is prepared. "XA", "XB", etc. are used until Product Baseline release which is a dash "-". Next revision will be "A", "B", "C", etc.

Method B
Same as Method A but includes an Allocated Baseline revision.

Method C
Revision begins with "A" during initial document preparation and continues alphabetically. Product Baseline is only noted within the sequential revision description.

Method D
Initial release is the Product Baseline and the revision description states that it is a Product Baseline as revision dash "-". Subsequent revision are alphabetical "A", "B", "C", etc.

Method E
Concept drawings are Revision "1", "2", "3", etc.
Prototype drawings are "X0" (zero), "XA", "XB", etc.
Production drawings, as defined by the Product Baseline at revision dash "-" and continuing through revision "A", "B", "C", etc. If not prototype revision, may skip from concept revision to product baseline.

Method F
Alternatives to Methods: A, B, and C. Allows removal of all prior revision history upon creating the Product Baseline. But, a note is left in the revision block stating old revision history has been removed.


--Scott

http://wertel.eng.pro

 

[thegardener6]

swertel,

Thank you, that is exactly what I was looking for.

 

[drawoh]

swertel,

I thought that all that Level I, II and III stuff was a description of the entire documentation package. I think we are discussing individual drawings here.

JHG

 

[drawoh]

... The reason for this is that external companies procure to our production level drawings. Therefore, it has been determined that they need to approve release and changing of production drawings. So, if everything is released as production then everything needs to be approved by a combersome and not always clear approval process. The unclear part is that drawings released for production are not always production builds and it takes planning some time to research who needs to approve the release or the change. This slows down the release and revisioning processes extremely. We do not have a concrete way to differentiate between prototype and production builds -- everything is released or not released. It has become so combersome and time consuming to release or change a production drawing that a method of creating "not released" drawings was adopted as a work-around for the process time. ...

Maybe you should not worry about the standards so much as your business requirement.

When your drawing goes out to a vendor, you need to generate a requisition listing the document number and its revision. If you revise the drawing, you need to describe the change on the revision block, so that the vendor can review his quote (it's only fair) and review his fabrication process. Your inspector must inspect incoming stuff using the drawing revision the vendor used.

I play fast and loose with my drawings during my design phase. My drawings have the word "PRELIMINARY" on them, along with the latest revision date. Once I freeze my drawings and send them to outside parties, I need to log changes. To me, drawings either are a work in progress, or they are finalized.

The distinction between finalized preliminary, and finalized production release tells you who approves ECRs. If you use the revision codes to indicate this, you are going to have to revise each and every drawing you release to production, and explain the revisions to your vendors.

JHG

 

[swertel]

drawoh

Level I, II, and III typically do refer to the entire Tech Data Package. But most tech data packages are simply drawing packages and all drawings tend to coincide. In other words, you don't have some parts of your end-item deliverable being defined as a concept (drawing) and the rest as production.

I'll have to review the spec that actually defines the levels... I have it here somewhere, to know for sure. But I think right next to Level definitions is the catch all that states these can all be tailored per contract or order.

--Scott

http://wertel.eng.pro

 

[KENAT]

Bit late, but I think we do similar to Drawoh.

Basically, for real initial concept stuff we don't really have any rev control, I'll often have an automatic printed date stamp included in the "Preliminary Draft..." stamp/watermark but use of this isn't formalized.

Once (still during development) drawings start going out externally, or sometimes internally to other departments etc, we start using numeric revs. The reason we use numeric revs is that we don't fully enforce standard revision rules of "backward & forward compatible" during development. Rev control at this stage is very loose, basically it's up to the Engineer/Designer to keep track.

Once ready for formal release for manufacture they get released at rev A etc. (On the rare occasion true revisions need a "prototype" first article then the "prototypes" of rev B are B1, B2 etc. However, chances are if this is required then we're fudging the "backward and forward compatible" golden rule of revisions. Possible exception is when we update an old drawing to bring up to current standards with GHD&T etc, a first article is often required but the parts are (more or less) still interchangeable.)

In the UK defence system I used to work with we used letter revs during development and numeric once the design was "frozen" for manufacture. The distinction being that while in development we used our internal change process. Once frozen and effectively under the governments control we had to use their change system. In theor when the design was "frozen" we should have gone thru the entire pack changing everything to rev 1, but we rarely bothered and the customer rarely wanted to pay for it. Not sure which def-stan this was to, maybe 08-10.

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