I was thinking of creating a few new parts in our schematic library, like BOX and BOX/1Lead and BOX/2Lead maybe. Each will be just a box on the schematic and not have a layout decal. The leads allow the object to be grounded or whatever.
The idea is that I can use them for heat sinks, tie-downs, even the bare PCB itself, things that would not usually be on the schematic but we want to remember to put on the BOM.
Yes, it would be a visible dummy schematic symbol, but would have the attributes that cause a part on the schematic to appear in the BOM.
One attribute of any part is its MAX number, namely the stock number in our material control system. When we buy a part, we create a bin and assign a 7-digit stock number and declare the manufacturer(s) and their part numbers that are acceptable buys. Every part on a schematic has a MAX number attribute, and the schematic generates the BOM. But we have been manually adding the non-electronic parts, like the PCB itself!, to the BOM and that's a nuisance, especially for board revs. I thought it would be cool to put the non-electronic parts on the schematic too.
We already have schematic symbols for a few sizes of screw holes, like for mounting screws and scope grounds, but they don't include the screws themselves.
What do other people do about adding non-schematic parts to the BOM of a PC board?
Have a separate mechanical diagram for the PCB assembly, et al. In some cases, the core drawing number is the same, and different three-letter prefixes differentiate PCB schematic from PCB mechanical design. And there is a document tree (itself a drawing) that defines how it all fits together.
Part of the reason for this is that schematics use one set of electronic design tools, and mechanical assemblies a different tool, and so on.