This is a basic question about part numbers and revisions. I have a three level BOM structure (e.g., assembly, subassembly, and component). If I change the component (i.e, different part number) and the change has no impact to the form, fit or function of the subassembly, for document change control purposes, the revision of the subassembly BOM is incremented (e.g., rev A to rev B).
Essentially, different revisions for the same part number mean they are completely interchangeable, and for all intents and purposes, can occupy the same inventory bin. A FIFO policy would ensure all rev A subassemblies are consumed before rev B, but that’s technically not required. If two parts are not interchangeable, they must have different part numbers.
My contention is that there should be no change to the BOM of the assembly because any demand for the assembly can be satisfied without concern for the revision of the subassembly.
This suggests that, in general, component revisions need not be listed on any BOM because they are inconsequential to the assembly being built. Or if component revisions are listed on a BOM they should be considered for reference only and can be ignored when building the actual assembly.
Here’s my problem: I am told that in M2M job orders and inventory of an assembly built with a rev A subassembly have to be managed separately from an assembly built with a rev B subassembly. If that is really true, then what we are dealing with is two different part numbers masquerading as the same part number with different revisions.
Can M2M assemblies be component revision indifferent?