We do some pasting as reference for "make from" materials so that our PMD BOM's are accurate, as those get directly uploaded into our ERP system.
Another idea is to make an "empty" solidworks file, ie no geometry, but with all required metadata, and insert those into your assembly.
I have used both of Corey's methods and both are a great way to manage BOM data. In addition, over the years I have concluded when working with BOM's, one decision between 2 methods of managing the BOM needs to be decided upon:
- Better for smaller organizations - BOMs are on the SolidWorks drawing face solely and NOT maintained in EPDM or the ERP system. The shop floor builds according to print but with every change, a new "drawing" REV has to be controlled. Assembly instructions are maintained on the face of the drawing also.
- Better for larger organizations - BOMs are removed from the SolidWorks drawing face and are maintained solely in EPDM as either computed or named then uploaded to the ERP system and the shop floor builds according to an ERP BOM with the "aid" of an assembly drawing for visuals. When the drawing changes, the "drawing" does not necessarily need a REV but an ECN/ECO is generated against the BOM in the ERP system. Assembly instructions are maintained in a separate document or 3DVia.
Otherwise, the BOM is 1/2 in one area and 1/2 in the other and BOTH have to be synchronized (lots of detail) or worse in both areas and keeping both synced is a document control nightmare.
- #1 is "heavy" in my opinion with regard to document control because it is a one stop shop for all drawing needs (visual assembly and part list) but is not too friendly with ERP systems so this approach may work well in shops without an ERP system.
- #2 lends itself to more generalized drawings with only visual assembly information which can be used as assembly guides. Assembly instructions are generalized and separated also from the face of the drawing and managed by document control or production planning. BOMs are updated through an ECN/ECO in the ERP system against the ERP BOM. 3DVia can be used for managing visual assembly instructions using the SolidWorks assembly. If an ECN/ECO requires a visual change to the assembly or assembly instructions then these are listed as one of the documents to be changed under the ECN/ECO. I see this as the once the BOM is inside the ERP, that is where is lives from then on. Engineering hates this idea The goal is to compartmentalize the scope of required work anytime a change is required which limits the amount of labor required for change thus reducing operating costs.
These process boundaries need to be defined for which system owns the data at which part in the product lifecycle.
Hope this helps,
Thank you Corey and Tim for your comments. We're actually a very small company and don't have an ERP system, so the current plan is to do as much BOM work as possible in EPDM. So far this seems to be working well but to get all the detail correct in CAD could take a long time and many Rev changes!
From my previous experience in large companies I definitely agree with Tim's #2 method. It also allows non-CAD uers (but still engineers) to make changes to our BOMs and so will speed up ECRs.
Question... For scenario #2, it seems there would still be work to be done if an item changes in an assembly, because the SolidWorks assembly model would need to be updated to reflect the change to the references. So, not showing the BOM on the drawing means a BOM change can occur in ERP, but the model still needs to change in the vault to reflect the reference changes. We always keep our models and drawings at the same rev level, so a change to one necessitates a change to the other. Would the change to that assembly file then be handled as a version change and not a rev change?
Also, when companies operate under scenario 2 (as we do), do they show item numbers on the drawings? We show the item numbers on the drawing, hide the BOM on the drawing, and ensure the ERP system has the correct BOM and that the item numbers match from ERP BOM to drawing in the vault (currently workgroup). I've been wondering lately if we just let the balloons on the assembly drawings call out the item's part number and don't show item numbers at all on the drawing. When item numbers are used on the drawing, all that seems to happen is that they point to another document, just to find a part number. I wonder if shop floor personell should just be able to see the part number ballooned right there on the drawing. The ERP BOM would contain the total list of items and their quantities. This method, however would necessitate a change to the drawing if the BOM changed.