Short answer: Decide per component whether it is a deliverable item. Parts that aren't deliverable, such as envelopes, fixtures, mock-ups and layout sketches, should be marked Exclude from bill of materials (or set as envelopes) in SOLIDWORKS, so they stay in the model but leave the BOM. Customer-supplied or by-others items usually stay in the BOM, with a clear flag. Document the rule so everyone applies it the same way.
Steps
1. List the categories found in your assemblies: deliverable parts, purchased parts, customer-supplied items, by-others items, reference or envelope geometry, and temporary fixtures.
2. Choose a treatment per category.
- Reference or envelope geometry and fixtures: exclude from the BOM, or insert as an envelope.
- Customer-supplied or by-others items: keep in the BOM with a "supplied by" property, so the interface is visible.
3. Apply it in CAD. Use the component's "Exclude from bill of materials" property. Note that this can differ per configuration.
4. Add a custom property column, such as "Supply," to the BOM table template.
5. Check exports. Confirm that the ERP or PDM export honors the same flags.
Worked example (generic)
A gas cabinet assembly includes a wall-envelope part used for clearance checks and a customer-supplied gas cylinder model. The envelope is excluded from the BOM. The cylinder stays in the BOM with Supply = "Customer," so purchasing doesn't order it and installation still sees it.
Common mistakes
- Deleting reference parts to clean up the BOM, which loses clearance checks.
- Excluding customer-supplied items entirely, which hides interfaces.
- Setting the exclusion in one configuration and forgetting the others.
- Using description text ("REF ONLY") instead of a property that filters reliably.
More steps: setting the rule up properly
1. Write the rule in the CAD standard: a short table of categories and their BOM treatment.
2. Add a "Supply" or "BOM role" custom property to the part templates, with fixed values (for example Make, Buy, Customer, By others, Reference).
3. Set exclusion per configuration deliberately. In SOLIDWORKS, "Exclude from bill of materials" is set on the component in the assembly and can differ between configurations. Decide which configurations it applies to.
4. Use envelopes for pure reference volumes, such as keep-out zones, service clearance boxes and cleanroom wall positions. They are visually distinct and excluded by default.
5. Filter the BOM table in drawings on the BOM role property where you need separate purchasing and installation views.
6. Test the ERP or PDM export once with a sample assembly that contains every category.
Edge cases
- Fixtures that ship with the machine. A lifting fixture used in the factory and shipped to site is a deliverable. Don't exclude it just because it isn't part of the function.
- Consumables pre-loaded at the factory. First-fill gaskets or filters ship in the machine and belong in the BOM.
- Customer-supplied parts you modify. If you machine or weld a customer-supplied part, it needs a made-part entry or a rework operation, not just a customer flag.
- Placeholders for parts not yet selected. A placeholder block should be flagged as "TBD," not excluded. Otherwise it disappears from both the BOM and the open-items review.
- Reference parts inside library subassemblies. A vendor subassembly may contain its own reference geometry. Check that it is excluded at the source, or it will show up in every project.
A second worked example (generic)
A frame assembly contains a forklift-pocket keep-out envelope, a lifting fixture that is used in the factory and shipped with the frame, and a placeholder block for a pump that hasn't been selected.
- The envelope is excluded (envelope type).
- The lifting fixture stays in the BOM as a deliverable with Supply = Make.
- The pump placeholder stays in the BOM with Supply = TBD, so it shows on the open-items list until the real pump replaces it.
Before release, a compare between the full component list and the BOM shows only the envelope missing, which matches the rule.
FAQ
Exclude from BOM vs envelope?
Envelopes are for reference volumes and are excluded by default. "Exclude from BOM" works on any component.
Will excluded parts still show on the drawing?
Yes, in the views, but without balloons tied to BOM rows.
How do I check nothing important was excluded?
Compare the CAD BOM with a parts-only export that includes excluded items. A BOM compare makes the difference obvious.
Do excluded parts affect mass properties?
Yes, unless they are envelopes or you exclude them from mass calculations. Check your mass property settings.
Can PDM read the exclusion flag?
It depends on the PDM configuration. Test the export with a known sample.
Should I exclude cosmetic models, like a cleanroom wall?
Yes. Use envelopes for that kind of reference geometry.
How do I check that nothing was excluded by mistake?
Before release, export the full component list and the BOM, and compare them. Every component that is missing from the BOM should match a category your rule allows to be excluded.
Who owns the rule?
Usually the CAD or engineering standards owner, with input from purchasing and production. Review it whenever the ERP or PDM export changes.
Should excluded items still appear on drawings?
They can appear for reference, for example in phantom line style. Label them so nobody orders them.