Drawing BOM usage

ehill · ‎Nov 29, 2012

Hello All,

We are continuing to work on globalization of CAD methodology. This week's topic of discussion is the display of a BOM on an assembly drawing. Some of our business units have always shown the BOM on the drawing, some have not, and some have done it both ways at some point in time. We are trying to evaluate the pros and cons of showing the BOM on the drawing, and I am hoping the user community can help with any feedback of their experience on how it is done at other companies, and why.

This is a subject of debate, because historically we have always fixed our BOM index numbers. Thisrequires some extra work with the drawing BOM, as well as cross-referencing those items numbers to the BOM in our ECOs.This is needed to use BOM balloons effectively, which we plan to continue. The other main issue is whether downstream users (manufacturing, vendors, etc.) need to print a separate BOM fromour ERP system or some other source.

Any feedback will help, thanks in advance!

Eric Hill
Staff Engineer
ASM America

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MikeLockwood · ‎Nov 29, 2012

Windchill product structure is for this purpose - we have been struggling for a few years now with the various related decisions on this. Making progress but not all that smooth yet.

A CAD drawing table should be parametric with the CAD model; this info is a report of what the data management system already "knows" and is available elsewhere as a table. Product Structure should generally be CAD-driven, but there are many reasons for exceptions.

Think of the BOM as being essential to the overall company; engineering creates it but many use it - from more than one computerized system for more than one purpose.

Create the master once and have all uses / displays of it / references to it dependent on the master such that all are in synch. Clearly define where the master is and how to make changes.

proed · ‎Nov 30, 2012

Hi

That's a good question, and something we've discussed often with different product lines. We tend to head for this:

- Use the PDM BOM as the master, it's auto-printed on every Part PDF
- Keep a simple BOM table in CAD for the purpose of fixing BOM balloons to the correct index to match the master BOM
- Place this table 'off-page' - so it doesn't print or show in PDFs

Some groups still show the full BOM Table on the CAD drawing as well as maintaining their PDM BOM, but I explain how this is just extra work for engineering, since they spend a lot of time correcting the CAD attributes for titles, part numbers, etc, that show in the BOM table. However, there are always traditions... 🙂

Hopefully at some point, PDMLink can talk to CAD BOMs and fix the index of each balloon automatically?!

I look forward to others input on this.

Regards
Edwin

In Reply to Eric Hill:

Hello All,

We are continuing to work on globalization of CAD methodology. This week's topic of discussion is the display of a BOM on an assembly drawing. Some of our business units have always shown the BOM on the drawing, some have not, and some have done it both ways at some point in time. We are trying to evaluate the pros and cons of showing the BOM on the drawing, and I am hoping the user community can help with any feedback of their experience on how it is done at other companies, and why.

This is a subject of debate, because historically we have always fixed our BOM index numbers. Thisrequires some extra work with the drawing BOM, as well as cross-referencing those items numbers to the BOM in our ECOs.This is needed to use BOM balloons effectively, which we plan to continue. The other main issue is whether downstream users (manufacturing, vendors, etc.) need to print a separate BOM fromour ERP system or some other source.

Any feedback will help, thanks in advance!

Eric Hill
Staff Engineer
ASM America

davidlawrence · ‎Nov 30, 2012

I've used both. I personally like an integral BOM, all the info is in the drawing. Of course I'm biased I look at drawings. Purchasing and planning finds it easier to look at a list. The most important thing is that there is a single database for all users.

David W. Lawrence
Mechanical Engineer

Sigma Space Corporation
4600 forbes Blvd.
Lanham, MD 20706 USA
301.552.6000 (Main)
301.552.6028 (Direct)
301.577.7383 (Fax)
www.sigmaspace.com
301.552.6000

ehill · ‎Dec 18, 2012

Thanks to all who replied. The reponses shown here are pretty much all I received, so I won't repeat them. Our decision is pending some more feedback from our manufacturing division, product support department, and outside integration houses. We may swing in favor of eliminating the BOM if we can get rid if item numbers in SAP and BOM balloons (using part numbers only instead). Otherwise it looks like we will be using a drawing BOM, since we will have already done all the work required to configure the item numbers to match SAP.

Eric Hill
Staff Engineer
ASM America