BOM scrubbing before an RFQ should establish which components the selected build actually needs and how many pieces to request. Check repeated reference designators, fitted and DNP states, and the quantity basis before sending the list to suppliers. Keep the source file intact and refer design discrepancies to its owner.
This review comes before comparing quotations. The BOM sourcing guide covers the broader request. Here, the task is to prevent a drawing or export ambiguity from becoming a purchasing quantity.
Start with the released build variant
Record the BOM revision, assembly variant and planned build quantity. Confirm whether the file covers one variant or consolidates several. A consolidated export can contain parts that are fitted in one version and omitted in another.
Check the meaning of the fitted-status fields in the originating system. Altium's documentation explains that an export can retain components marked Not Fitted for the selected variant and show their quantity as zero. The selected variant and export settings therefore matter when interpreting a row. Altium BOM finalization documentation
Use the released assembly information to confirm DNP, or “do not place,” rows. Preserve those rows in your review copy and mark how they were treated in the supplier-facing request.
Investigate repeated designators
A reference designator identifies a component instance, such as R1 or C7. When the same physical designator appears twice within the same assembly and variant, flag it for investigation. Also check whether the quantity column agrees with the intended fitted instances.
First establish what the export represents. Multi-channel designs can repeat logical designators while assigning unique physical designators to the actual component instances. Altium documents both that export issue and genuine duplicate physical designators. The design owner can establish which case applies. Altium duplicate-identifier guidance
Record the source row, affected designators and exact question. Ask for a corrected released export or a documented clarification before changing the purchasing quantity.
Confirm the quantity basis
For a simple single-level BOM expressed in pieces per assembly, the fitted requirement is:
Confirmed quantity per assembly × number of assemblies to build
Check the units and file instructions before using that calculation. Some exports already contain extended build quantities. Others use a base of several assemblies or quantities expressed in another unit. Preserve the original value and label the calculated quantity separately.
Keep any assembler-agreed setup or attrition allowance in its own field. The resulting sourcing request can then show how the design requirement and additional production allowance were established.
A hypothetical review before an RFQ
A buyer is preparing a request for 250 assemblies of one released variant. Three rows need review.
Source row | Initial observation | Action before quoting |
|---|---|---|
Resistor line | Designators read R1, R2, R2; quantity per assembly is 3 | Ask whether a designator is missing or an entry was repeated |
Capacitor line | C7 is marked DNP for the selected variant, but a copied quantity field shows 1 | Ask the design owner to confirm the fitted state and correct export |
Connector line | J1 is fitted; quantity per assembly is confirmed as 1 piece | Calculate 1 × 250 = 250 pieces |
The design owner supplies a corrected release confirming two fitted resistor positions, R1 and R2, and C7 as DNP. The buyer records a fitted requirement of 2 × 250 = 500 resistor pieces, zero fitted pieces for C7, and 250 connector pieces. Any production allowance remains separately identified.
The review copy retains the original observations and the correction reference. The RFQ uses the confirmed quantities for the selected variant.
Frequently asked questions
Is the same MPN on two rows always a duplicate?
It can legitimately serve different component positions. Check the designators, variant and quantity basis before combining rows. Keep the source references so the relationship to the released BOM remains visible.
Should I delete DNP rows?
Preserve their status in the review record. Once the released variant confirms the parts are omitted, exclude them from its purchasing requirement while retaining enough information to explain the exclusion.
What if a row has no reference designators?
Ask the source owner what the row represents and how its quantity is defined. It could be a non-placement item or a grouped entry. Resolve that basis before applying a component-count check.
Can I treat a blank quantity as zero?
Obtain clarification. A blank field leaves the required quantity unresolved. Record it as an open question and keep it out of any claim that the purchasing list is complete.
Does a scrubbed BOM include enough parts for setup losses?
Confirm that separately with the assembly provider. Record the requested additional pieces and their basis alongside the fitted requirement. Avoid applying one assumed allowance to every component.
Once the design questions are resolved, use your material-planning process to establish which quantities still need purchasing. The partial BOM quotation guide explains the separate task of tracking open sourcing requirements. Keep the review record with your approved BOM revision.