Hi everyone,
What is considered an industry best practice when it comes to building a bill of material for a complex product?
1) Is it necessary to rename the part #s from suppliers to internal part # (e.g. with a company prefix followed by a serial numbering system)
I'm not sure there is an industry best practice for this. I am accustomed to having the bill of materials be part of the device master record. There is no requirement that you have one bill of materials. You could have a materials list for each subassembly instead.
1) My opinion is that it is better to have your own part numbers just in case two different suppliers use the same part number.
I have a cautionary tale about using supplier part numbers for the references to a BoM as part of a Device Master Record. I have had some experience with a (less than mature) medical device manufacturer that chose to use supplier PNs for both commercial and custom components. This manufacturer would tie itself into knots trying to keep BoM up-to-date as well as trying to keep 'control' over suppliers.
It may not be completely self-evident what the full extent of the problems were, as working within that system was quite traumatic for me!
For commercially available parts, the practice of using supplier PNs led to confusion when the supplier of the component altered the PN. Sometimes this would happen because of an acquisition, sometimes it would happen because of the supplier's own inventory system, sometimes it would happen because the supplier changed packing or distribution methods (e.g. tape and reel instead of tubes for integrated circuit components). Generally, for commerical ('off-the-shelf' or 'out of the catalog') devices an ME manufacturer shouldn't be constrained such that these types of PN changes affect a BoM, even though the purchasing department does need to know which authorized parts to purchase.
For custom components the manufacturer I am thinking of got itself into a serious twist because they fell into a trap of revising the custom part every time they would update the methods used at either incoming or in-process inspections (at the manufacturer, not at the supplier). There is a need to keep revision levels synchronized between suppliers and the manufacturer (to know the level of controls implemented at the supplier for a given part) but revising a custom part for purely internal reasons that don't affect the supplier (as opposed to making a design change to the part) led this company to delay changes because of the process of notifying the supplier about the (purely internal) changes that drove the revision change.
For both commercial and custom parts, it became very confusing for that manufacturer to allow for the use of the same part (in the same finished good) from alternate suppliers.
I don't know that any of the issues I describe would have been avoided by using a separate PN for the parts used in the DMR versus the purchased parts, but I do think it would have helped that manufacturer better understand where the different types and levels of controls were appropriate. That particular manufacturer had trouble distinguishing between design, supplier, and in-process controls... I feel like the implemented part numbering scheme did not help the situation.
