written standard for bill of material structuring - best resource?

[rmetzger]

I'm looking for a document to define the standard practices for BOM structuring.

Typically I've always followed the practice to structure a BOM as the items were assembled in manufacturing to best represent the development of the finished assembly. We currently have a mixed bag of BOM's sub assy's that fall into two groups: Some are set up as the assembly is made (sub assy's containing the parts that make up the sub assembly). Others just to group parts together that get used together often in other assemblies that are combined with other parts to make a finished good (IE - subassy of seals, misc mechanical parts, circuit boards, packaging and labeling... that are further put into a higher level subassy with the rest of the parts that make up the real product). We're looking for a better definition of industry practice as we seem to have made up out own standards often in the past that don't coincide with industry standards.

 

[ctopher]

What you describe is good. I have seen various ways, but whatever works for your company. You need Config & Quality Control on your docs. What is your industry?

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Apr 30, 2008)

 

[rmetzger]

We manufacture/design sensors for fluid measurement and analysis.

Typically we have 10-20 assemblies that are identical other than cable length or other small deviations which has lead to the multiple methods in use.

 

[KENAT]

Generally I'd agree with what you put about "structure a BOM as the items were assembled in manufacturing to best represent the development of the finished assembly".

However, my current place also has issues, they like relatively 'flat BOM' so as few subassy levels as possible. Apparantly this helps them with routings etc however it's a pain from a documentation point of view as the assemblies we do have tend to be large and complex so are a bit of a pain to fully detail in a conventional assy drawing. You then end up needing a detailed assy work instruction and then you have arguements over why you need both...

What you say about having 20 almost identical assemblies except for one or two details makes me think of - numbers. Is this something you'd be able to use?

KENAT, probably the least qualified checker you'll ever meet...

 

[fcsuper]

Yeah, it really does depend on your company (size, industry, etc). It also depends on what you put into stock. If you have subassemblies in stock, for example, then those shouldn't be broken down on the top level BOM. Also, if you are maintaining 3D CAD files, you should keep their structure in mind and now that impacts the form/fit/function of hte product. I've seen situations where Manufacturing will flatten out BOMs (even though they have an MRB system that recognizes phatom boms), which cause the engineering department to lose its ability to maintain revisions of the product 3D CAD models because the removed fundemental subassemblies where no longer being controlled by the ECO process.

So it depends on what you are looking for and how your system is set up.

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[KENAT]

fcsuper raises good points that I didn't go into detail on.

Generally having what are effectively 'kits' of things like fasteners, seals etc seems to end up causing problems unless they are actually supplied to the customers as kits.

Also bear in mind things like spared sub assemblies etc.

KENAT, probably the least qualified checker you'll ever meet...