Recording changes on a 2D Print 5

[SDETERS]

What is the industry standard, or standard on recording of what changed on a 2D drawing? For example, if we modify our print, we record every dimension and or note that gets changed on the print. This results in the tedious task of going in and ensuring you get everything recorded correctly.

 

[Brian Malone]

For the past 20 years the company I am at has not used a revision history tabulation on drawings. The revision is used to get the redline and ECN from the ERP database where everything is scanned/converted or directly saved as a PDF. At first this seemed a little odd, but soon it showed it is very efficient and effective with absolutely no downside. A PDF of the redline is supplied to any fabricator/machine shop that asks for specific change details. Very few of our shops ask for the PDF and in 20 years we have had zero errors attributed to a mismanagement of a change/configuration. Dropping the revision block saves editing time, errors of typing, and provides more space on a drawing to place views. I would not go back to using an on-drawing revision history block.

 

[Brian Malone]

Title block with signatures/department approvals were eliminated also. Title block has the component name, rev, standard tolerances, and number sheets, and a standards reference (if applicable). All signatures/approvals are electronic approval and do not appear on the drawing. This has saved space too. Some items of traditional drafting form and style are dogma. If no major benefit is provided, some items are a waste of time and effort to do and maintain.

 

[geesaman.d]

If you have a good document storage system, the chore of bubbling revisions all over the drawing is mostly for the readers' convenience. The document storage system covers past revisions. The ECR/ECN system covers the thoughts and specifics of the revisions. For example, if a casting drawing was revised to include draft angles that did not have before, then putting a revision bubble next to every drafted surface edge is silly. The ECN only needs to say "added draft angles per sand cast vendor <vendor name> actual practice".

When a drawing gets more than a few revision bubbles, I sometimes note it as "general revision" and that essentially warns the reader to re-read / re-process / review the entire newly revised drawing. That's not done often (partly considering the definition of new drawing vs. revision being a change in form/fit/function). But sometimes it's the right thing to do.

 

[Brian Malone]

Another change that has worked well where I work: all drawings are on 'B size' sheets. No C, D, E size allowed. Occassionally, an A size is used for a presentation or manual illustration. B size is printable on all the office printers/copiers and can be filed in standard filing cabinets, etc. PDFs of the drawings can be viewed easily without extensive zooming and panning. If more sheets are required to provide the necessary views/clarity, then sheets are added. We don't stress about adding views - CAD simplifies view/detail creation/projection. For the type and size equipment we make - blood separation and freezing systems, this works perfectly. The systems range from lab bench-top to large floor-standing gear. The B size requirement is enforced even with contract engineering firms - some who initially scoffed at the requirement or tried to continue to supply drawings on C,D, and E sheets. But once they worked with our system, they got it and realized why it works so well. Just another part of traditional drafting that I have found is no longer a benefit in this age of powerful and flexible CAD. 20+ years on this and no issues found - started doing this with ProE 17 or 2001 and have continued with all versions of Solidworks and Inventor, and AutoCAD.

 

[geesaman.d]

^ I think most engineers at my company do that already (use an A or B unless it simply won't fit) but it's interesting to see that as a policy.

 

[Brian Malone]

I highly recommend consideration of the B size limit. Unless you have a large format printer/copier (or budget for outsourced printing) to allow printing a C, D, or E size sheet full size then the perceived benefit of the large sheet sizes is lost once you print the drawing to fit on standard office size paper. All the text and details are too small to see without magnification or you will end up printing sections of the drawing full-size just to be useful. And when viewing the drawing on a monitor constant zooming and panning will be necessary to be able to see details and read text.

 

[SDETERS]

Brian Malone, what limits the scale of your views when you toss everything on your B size print? Do you have a standard text size that you use, What is the text size, Just curious how this works. Kind of an interesting concept.

 

[drawoh]

SDETERS,

2mm fonts work on A[&nbsp;]sized prints. 2.5mm fonts work on B[&nbsp;]prints.

--
JHG

 

[Brian Malone]

SDETERS we don't have limits to view scale. The scale is chosen for convenience of viewing and reading to minimize secondary need to zoom or pan. So for most machine components for the equipment we make, the general overall view scale may range 1:2, 1:1, 2:1, etc., sometimes 1:10 for a larger system. But the fabrication views and details are scaled as needed to show the required information. We use .10 inch text for all dims, notes, etc. This size is easy to read on most monitors without zooming and likewise prints very readable. Views are added as required and if a projection does not fit on the sheet it is generated from, it is moved to a following sheet with appropriate naming. Most parts for us are one to two sheet drawings but some have 9 to 12. This has caused no issues because the view/details are clear and traceable. The text is readable and the view scale for the views is chosen for clarity when printed on 11 x 17 inch paper. Even when printed to fit on 8 1/2 x 11 inch paper the drawings are very readable. Many shops just print on 8 1/2 x 11.

 

[Brian Malone]

Review your process and decide if all traditional drafting and drawing control process hold up with review for efficiency, security, cost of operation. With electronic file control and electronic signature approval, a lot of sections on traditional drawings, such as approval blocks and revision history do very little and take up time and space. I have long-term experience that shows those elements can be eliminated with no detriment.