How do we build a bill-of-materials review into a charger OEM project?

Main answer · Wecent Editorial Team

Short answer: Make the BOM part of the project plan with set review points: at quotation, before sample approval, before mass production and whenever the factory proposes a change. Ask for the critical parts, brands and part numbers, compare them with the test report, and agree that no part can change without your written approval.

What a BOM review is for

The bill of materials lists every part in the product. A review checks that these parts match the approved sample, the test reports and the price. Many quality and compliance problems begin with a silent part change.

When to review

1. At quotation. Ask for the BOM or at least the critical parts list, so you can compare suppliers fairly.
2. At sample approval. Check that the sample matches the BOM.
3. Before production. Confirm the final BOM against the certification report.
4. After any change. Review proposed substitutes.
5. Periodically. Compare production units with the BOM.

What to check

• Critical safety parts, such as the transformer, capacitors, fuse, optocoupler and plastic.
• Controller and GaN chip: brand, model and package.
• Connectors and cables: type, rating and supplier.
• Materials: plastic grade and flame rating.
• Markings: label content and certification marks.

Match against the test report

The report lists critical components. Every one should appear in the BOM, with the same manufacturer and model. Differences need a change record.

Set rules in the contract

• The factory must name the brand and model of critical parts.
• Substitutions need written approval.
• A copy of the current BOM is kept with the order.

Use a simple tool

A spreadsheet with part, supplier, model, certificate reference and last check date is enough. Add a column for approved alternatives.

Keep it light

You do not need to review every resistor. Focus on safety-critical, performance-critical and high-cost items.

Quick summary

Review the BOM at quotation, sample approval, pre-production and any change; focus on critical parts; match to the certificate; and ban silent substitutions in the contract.

Example schedule

Week 1: ask for the critical-part list. Week 3: compare it with the first sample. Week 6: compare the final BOM with the test report. Each production order: confirm the BOM version number. A simple calendar like this takes little time and catches most surprises.

Where this answer says to confirm with Wecent, the detail is not published on the product page and has to come from the datasheet or the factory. General facts come from the regulators, standards bodies or device makers named in the text.