Need help developing title block verbiage for undimensioned drawings 2

[blades741]

Hello all, and thank you in advance for the help I know I'll receive here. You've collectively been so helpful in the past, and I thank you for that!
I work for a company who's core manufacturing process is laser cutting & bending sheet metal parts. For the sake of this question, we can disregard the sheet metal bending aspect. Most of our parts start out as a flat pattern of a bent part. These flat patterns can be complex in shape, and also contain complex shapes cut out of them. Fully dimensioning them is neither practical nor necessary, as we deal with the DXF files for use in laser or water-jet processing. I know I can add a SURFACE PROFILE note or title-block tolerance that can control the outer profile of the part, but can this same profile tolerance control the interior profile shapes (slots, holes, complex contours, etc.)as well as the location of these various cutouts within the part? Would a "CAD IS MASTER" note along with the general surface profile tolerance note be sufficient to convey the intent of both the profiles and location of the profiles?

 

[3DDave]

Kenat,

"I haven't seen anywhere near the amount of confusion"

In contrast, I have.

I have also seen companies that supplied deficient parts because the supplier got an updated drawing with a contract, but since the contract said nothing and the drawing didn't supply any indication of the exact CAD data, they just went with the model they had gotten for a previous revision.

Execution of a contract should not depend on one guy on the shop floor knowing the phone number of another guy in the drafting department to get data.

I think it is better to fix the system so it works right instead of being complacent and hoping it doesn't go wrong. If procurement doesn't care to talk with engineering about how a product will be procured, adding a non-specific note to the drawing isn't the patch that is required, because, as noted above, procurement often doesn't read drawings.

If the drawing is incomplete it needs to specify exactly what is required to complete it - use "Filename.Extension, Revision, xxxxx Bytes, Dated YYYYMMDD.HHMM to complete", and not a general purpose note.

 

[pylfrm]

"Filename.Extension, Revision, xxxxx Bytes, Dated YYYYMMDD.HHMM to complete"

Such information is often unreliable or invisible (if embedded in proprietary CAD format) by the time it gets to the end user.

A possible alternative is to include the supplementary data as an attachment within a PDF drawing. That PDF file could then be included as an attachment within a PDF contract. For extra assurance, digitally sign everything.


pylfrm

 

[3DDave]

Already said that "It needs to be spelled out somewhere and building the drawing and the model file as attachments to a contract via PDF keeps them all together."

What I called out was the text that would be applied to a note in the field of the released drawing, not invisible at all.

 

[pylfrm]

3DDave,

Sorry, I missed that.

I didn't mean that the note itself might be unreliable or invisible though. I meant information in the file you're trying to identify with the note. Sometimes the vendor doesn't have the right software to read the metadata, and is left with just a filename.


pylfrm

 

[3DDave]

Typical file transfer will keep the last modified date and the file size. So will using the Zip format, so these are available to the operating system. Rev may not be, but with name, date, and size, the file should be adequately identified to prevent getting the wrong one.

 

[drawoh]

3DDave,

Our POs specify the revision number of the fabrication drawing.

A better process is to follow design change rules that do not allow changes to parts. Any change to form, fit or function results in a new part number. Revisions correct spelling mistakes and bad drafting.

--
JHG

 

[3DDave]

What happens is someone sends several suppliers a part file for them to look at, ahead of the contract, as a preliminary. They get comments, other things happen, changes are made and the drawing is finally released. No one tells drafting that contract has been let and nothing tells supplier that changes were made. Hilarity ensues.

 

[berkshire]

One thing that caused confusion in the ordering chain is the PDF.
If a model is modified using a cad program the drawing updates, the drafter may have to update the revision letter manually.
Unless the PDF is overwritten it just sits there like a landmine , waiting for purchasing to send out the wrong one.
B.E.


You are judged not by what you know, but by what you can do.

 

[KENAT]

Sure there are configuration control & doc control issues that need addressing along with the note on the drawing, but It generally works here.

Posting guidelines faq731-376

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

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