Review an assembly BOM as a build instruction: each fitted position needs an approved part, quantity, supply owner and substitution decision.
Identify the exact assembly variant
Start the BOM with the assembly part number, board revision and fitted variant. Two products can use the same bare board while populating different parts. If the variant is described only in an email, it can be lost when the BOM is forwarded to purchasing or production.
State whether quantities refer to one board, one panel or the complete order. A line showing a quantity of four is ambiguous if its reference designators identify four parts per board but the purchasing team interprets it as the total order quantity.
Review every populated line
| Field | Decision it supports |
|---|---|
| Reference designators | Which physical positions receive the part? |
| Manufacturer and part number | Which exact orderable item is approved? |
| Quantity per assembly | Does the count match the listed positions? |
| Supply owner | Is the part purchased by the assembler or supplied by the customer? |
| Alternates | Which replacements are already approved, and which require review? |
Descriptions are useful for a human check, but they should not silently override the manufacturer part number. If those fields conflict, resolve the line before release. Package names also need enough detail to distinguish parts that share an electrical value but do not fit the same land pattern.
Keep do-not-populate decisions explicit
Mark DNP positions consistently and explain whether they are excluded from procurement and placement files. A blank manufacturer field is a poor substitute for an intentional DNP instruction: it can also mean that the BOM is unfinished.
For example, if R10 and R11 select a product option, record the actual fitted state for the released variant. Do not leave the assembly team to interpret a schematic note about possible configurations.
Control substitutions
Separate a suggested alternate from an approved alternate. The review should consider the circuit requirements, package fit, assembly consequences and any product-specific restrictions. Document who can approve the substitution and whether the approval applies to one order or future production.
A short supply situation should produce a visible engineering decision, not an undocumented change in the purchased part. Record the accepted alternate against the original line and update affected test or programming instructions where needed.
Run a cross-file check
Compare BOM designators with the assembly drawing and placement data. Investigate missing and duplicated positions, verify variant markings, and retain a clean release copy. Use the BOM service guide to prepare the inquiry and the assembly file checklist to complete the handoff.
Move from reading to a build-ready project
Use the fabrication and assembly checklists to prepare drawings, production files and test requirements.
Open the DFM checklist