Revision callouts on Drawings

[GuinnessDraft]

I hope this is the right forumn.

There seems to be a little issue here on what the proper or best practice is for calling out revisions on the face of the drawing, in the drawing formats.

Should each and every revision including pre-production and post release revisions be listed in the revision block or should we only list the current released revision.

Note, all revisions and what they entailed is documented in another form in addition to the drawing.

Note also that on the face of the drawing, only the current revision is flagged to point out the item revised.

Thanks

 

[swertel]

The first question is to what standard does your company follow? Is it ANSI/ASME, ISO, JIN, or MIL?

If you don't follow a standard, then do whatever you please. If you follow a standard, maybe we can point you to the section that answers your question.

--Scott

 

[swertel]

By the way, I did realize that this is posted in the ANSI forum, but I wanted the clarification anyway.

 

[GuinnessDraft]

Let me try this again (it died on me the first try).

First let me thank you for replying.

now to answer your question: This place has no set standard per sey but they have asked me to set one up. Of course we need to go by ANSI standards and tweak them to our needs.

One issues that has hit a wall is the revision call out issue. For some odd reason here they demand every drawing is done on an "A" size (8.5x11&quot format. I'm looking to change that too. Currently they callout every revision and every aspect of that revision and list them in the upper right hand corner of the format. Problem being with the requirement of an "A" size format, this eats up valuable graphics space. They also list each revision during pre-production along with post production. The problem surfaced when I noticed one part literally running out of space for the next revision.

My arguement being the next revision will cause a complete draw thus eliminating the previous revision call outs due to space...but that goes completely against their "standards". On top of this there is a complete paper trail of the revisions in ECN format. Thus there is always a way to find out what was changed, when and by who. This, in my book is an overkill and provides a reason why NOT to list nothing but the current revision on the face of the drawing.

If I can get a few more "outsiders" to back my arguement up, I'll have something to fall back on and might be able to get them to change this process.

 

[swertel]

Your place sounds like the one I quit. They too did everything on 'A' size paper, and that included parts that were 11-12" Dia and 24+ inches long. We had to use 1/8 to 1/10 scale for the overall and then create loads of detail views to show the very critical .050" reliefs. And sheets 2-4 were reserved for in-process views (milling step, lathe step, and another milling step) so we couldn't even use a second sheet for clarity. I tried to get my boss to at least switch to allow 'A' and 'B' size but he was "emotionally attached to the 'A' size because it is so easy to carry around and fax to customers." We weren't even allowed to fax these to customers. What a moroon! But I digress.

Where I work now we follow DOD-STD-1000/DOD-STD-100, which is similar to MIL-STD-100 which has been cancelled and replaced with the ANSI standards. You will want to get a copy of ANSI Y14.35(M) "Revision of Engineering Drawings and Associated Lists." If you can't get the ANSI standard, get a copy of an older revision of MIL-STD-100 which can be found for free at

http://assist.daps.dla.mil

and click quick search.
The current, and final, revision was G. You will probably want rev E or sooner to get the full standard. Sometime around F and G it started to drop sections and just refer to the respective ANSI standard.

Finally to the point.
Your revision history in the upper right corner of the drawing face should only be one line that states "Incorporated changes per ECN #XXXXXX" and have the rev block signed and dated by the final approver when the changes are accepted. The ECN should have a place for the full signatures: Designer, draftsman, approvers, etc. and a full description of the entire change.
The revision block on the drawing should maintain a list of all the previous revisions until you are forced to do a complete redraw. Then you can erase the previous revision histories from the face of the drawing and the rev description will be "Complete redraw with changes per ECN #XXXX." Make sure the original signatures in the title block remain for the new drawing, and keep an archived copy (scanned image, pdf, whatever) of the revision prior to the redraw. Depending on the extent of the redraw, you may need to supersede the old drawing with a new number.

Good luck. Sorry for such a long post. Let me know if you need any further clarification.

--Scott

 

[GuinnessDraft]

Thanks Scott,

It sure does sound like I work at the same place you quit.

We also have parts that can reach a dia of about 12" or more and be about 18" long for the complete assembly. Not to mention all the details required for the machining , etc. As you said they want all this on an "A" size and to top that off, they NEVER used multiple sheets prior to my arrival! That's right, they put everything on one sheet. Needless to say they didn't document everything...they claimed "the guy in the shop knows what to do". I went ballistic!

We are now in the process of putting together a "B" size format but the one they want is, get this.....take a "B" size and divide it so you have the graphics window of an "A" size, the rest of the drawing (the right side) is nothing more than the title block, tolerances, notes and revision block, all located in the vertical. So it's a "B" size paper but you still only have an "A" size graphics window to work in. Ugh!

Anyways, thanks for the info. It's gonna be an interesting day...

 

[MadMango]

Since you have a an ECN process in place, I don't see the harm in just having the latest revision information on the title block. My last company did this, and this was a medical company. You can understand they were very strict with procedures and standards and "paper trials", especially considering that we made devices that had to be approved by the FDA and could cause a loss of life if there was a failure (insulin pumps).

My current company only keeps the latest rev and the previous rev for history. This way you have the information handy n case you want to check the previous revision history. We don't describe our rev changes either. Our Rev Block in the upper RH corner just lists Rev, ECN#, Date and Approved By.

As for the paper size issue, I really feel for you. At teh medical company we were restricted to only A and B size drawings. Some of my parts that were injection-molded drawings were 8-10 B-size sheets, with easily 6 sheets being nothing but detials and section views. I think a good approach would be to try to sell your company on not listing the changes on the drawings, and maybe keeping a minimum of only 3 revision lines, 2 for history and 1 for current release.

I am assuming that you work in a company that does mostly machining. It's been my experience that machinist like the A-size, because they are easier to handle on the shop floor. There's something to be said for this, but just remember the drawing should clearly dictate the design. If you don't have room to fully detail your parts, then there is a problem. Besides, the manufacturing process (i.e. machinist liking A-size) shouldn't drive the documentation of the part. "The attempt and not the deed confounds us."

 

[testy]

This is a bit off the original subject of revisions, but I have some input on drawing size. At my company everything is on D-size but is printed on 11x17 paper. This is a nice compromise because the paper is manageable but still legible. As an ex machinist I can confirm what a pain it is to handle large drawings. The manufacturing process is one of the main aspects of part documentation.

 

[Hush]

We also draft almost everything on D Size but use larger dimension text (.16&quot so it reproduces easily as an A Size.

We list all the revisions in a small block but it only references the Rev Letter & ECN. All other information is contained within the individual ECNs.

Printable drawings and ECNs are kept in electronic format in a database accessible to everyone (that needs access) for easy reproducibilty. One hardcopy of each is signed and maintained for audit purposes.

 

[IanIV]

Every revision, in my opinion, should be listed on the drawing. It is an easy way of following up on changes and can be readily documented for reference. A triangle with the appropriate number / letter is adjacent to the modification, and an explanation is shown some where on the drawing listing that change in detail, along with all the others. This works for me.