BOM Standards for multiple configurations

[trinhhle]

Hello All,

How many part numbers are allowed to be assigned to a Find Number or Item Number? I have attached an example BOM where FN 2 and FN 4 have two part numbers assigned to them. For FN 2 and FN 4, the material may be different for the plate and bracket or they have slightly different features. In a large BOM, this is very useful to group components that would change based on the configuration.

I looked at ASME Y14.34-2013 section 3.17 and did not find any information regarding this issue.

ASME Y14.34-2013
3.17 Find Number or Item Number
find number or item number: a reference number assigned to designate an item on the field of the drawing, in lieu
of using the item’s part or identifying number. It is entered as a cross-reference to the line of the parts list where
the item’s actual part or identifying number and description are given.

 

[3DDave]

That's different. Usually each unique item gets a unique item number; the exception is if there is a 1:1 substitution, which this scheme apparently does not. It is my experience, though not a general law I suppose, that the different items get multiple balloons with a dash number indicator on the field of the drawing.

In drawings for some DoD branches there are no item numbers at all, the part numbers are directly on the drawing and a separate drawing is created for each configuration because there are no dash numbers allowed.

So, as long as everyone can manage to keep it straight, there's a range of workable solutions.

What you have is approaching what I call a kit; a subset of parts that work together that, as a group, perform a function and which have parts that are incompatible with members of other groups that perform the same function.