Associated lists, on-the-drawing-BOM

[cadmunky69]

i have my req in for asme y14.34 just to be safe, but would like to query the experts. i've done very little work at companies that require on-the-drawing-boms and would like to hear some of your recommendations. fyi, we are mostly an ASME pressure vessel house, kinda young.

i'm being slated into the cad admin position here, and have been tasked with setting up a process for drawing standards. my gut instinct is to make this bom table as simple as possible and only show index/find no., qty, desription, and drawing/ref number. currently, the users are split between wanting material called out in it's own column in the table (which can get lengthy because of some of these compositions), and calling it with the description (lengthier still). personally, i'm accustomed to having detailed material callouts in the general notes, which we aren't using at all now. any suggestions/recommendations? one concern is having blank cells for items with no material callout (valves, regulators).

also, being unfamiliar with the asme pressure vessel reqs, if anyone can point me to any other info required on vessel drawings, i would be most appreciative.

Ed Lee
Sr. Designer
H2Gen
Alexandria, VA

 

[SnTMan]

cadmunky69, I would offer the following OPINIONS based on my shell and tube experience.

1) Each line on the BOM should include material, and references to any required notes such as NDE, chemisrty restrictions, etc. A sample line might look like:

P/N Qty. Desc. Matl Note Rev P.O.
1 1 Plate: 1/2x24x24 Sa-516-70 1 1 123456
2 etc.

Notes:
1)Impact test per UG-84

The P.O # is usually written in by the buyer on his copies and does not necessarily make it to the formal BOM.

2) I would NOT place individual BOM's on individual drawings. I would place all material on a separate BOM, whether a drawing of multiple sheets or another document. Reason is that with a seperate bill, you can order out the long lead items WITHOUT having a complete set of detail drawings. You order them on a preliminary BOM, and just continue to revise as necessary to add more levels of detail. Narurally, when doing this you have to keep track of what has been previously ordered so you don't repeat by mistake. If you are into automation, use a suitable format and document type.

3) I am not aware that ASME requires anything in particular to be on shop drawings. They should contain all the info you need to build the vessel such that it conforms with the design and fab requirements and NOT ANOTHER THING.

4) Start simple

FYI, the shell and tube shops I am familiar with do not follow any formal drawing standard. They kind of use their own standards which they have developed over a period of years. After all, the drawings are just for building the unit.

I will not mention customer-driven drawing content.

Hope you get some use from this.

Regards,

Mike

 

[cadmunky69]

Thanks mike, I can use some of that. I won't have the PO or rev in there, although you've touched on another discussion I’ve had with engineering here about the material ordering process.

I’m of the school that we try our best not to build or order from any preliminary documents. but I’ll have to get along with it for now, as our process dictates we order materials before designs become released. it appears to me we have an unnecessary step wherein we order piping/tubing, inspect and stamp for asme at receiving, cut stock to usable lengths giving the stock an internal p/n. then when the stock is machined for assembly, oft times it needs to be re-stamped for asme as the first stamp can be obliterated by machining features.

I’d like to see materials called out as form and composition in the general notes section just like any other welded assembly, but I’ve been told this is the way asme likes it for pressure vessels. I still have a sea of specs and requirements to go through, but still welcome any heads-up I can get.

also found this previous discussion.


Ed Lee
Sr. Designer
H2Gen
Alexandria, VA

 

[SnTMan]

cadmunky69, you may just have to live with the re-stamping.

Every industry is a little different, but often ordering from preliminary documents is a must. For example it is common in S & T for customers to approve the outline drawing and mechanical calculations. So you generate these, which are checked documents, and order long lead stuff off a pre-bill, which is also checked. Detailing usually waits til return of docs by the customer, at which time all details and a final BOM are made.

You might visit with your AI to get his input as well, it might help you identify what you need.

The good news is whatever you come up with, it only has to work for YOUR company.

Good luck.

MIke