ENGINEERING ANSWER
Board color, surface finish and a silkscreen label cannot prove that a board uses RO4350B. A useful traceability chain connects the purchase order, laminate lot, fabrication traveler and delivered board identification.
What to decide before release
Ask the supplier what evidence accompanies the shipment. Match the exact grade, core thickness, foil and any approved substitutions to the drawing. Keep acceptance coupons and test reports associated with the lot when RF performance is critical.
Checks to put in your design brief
- Request material certification or traceable supplier records
- Prohibit unapproved substitutions
- Link test reports to the production lot
Important distinction
A photograph on a supplier page is an example of a construction, not a certificate for your order.
Sources & basis
Material facts follow the cited source. Design checks are preliminary guidance, not supplier process instructions.