Component Substitution Risks in China Manufacturing
1 resources tagged with "Component Substitution"
Component substitution is the quiet failure mode of China electronics production: a factory hits a shortage or wants margin, and swaps your specified MOSFET or capacitor for a cheaper 'equivalent' that passes a power-on test but fails under thermal or transient load. It goes beyond AQL sampling — catching it requires engineering-level review of the actual parts populated on the board against your BOM, sometimes with X-ray or decap on suspect lines. A board can pass functional QC and still be quietly substituted in ways that surface only as field returns.
When you control substitution, you lock MPNs on the BOM and require written approval for any deviation, then verify the populated board matches at first-article and during inspection. The common pitfall is relying on a functional test alone — many substituted parts work at the bench but fail on lifespan, temperature range, or voltage margin.
Guides (1)
FAQ
How do I stop a factory from substituting components?
Lock every MPN on the BOM, state in the PO that no substitutions are allowed without written approval, and verify the populated board at first-article inspection. An approved vendor list with named alternates removes the factory's excuse to substitute silently.
Can normal QC inspection catch a substituted component?
Standard AQL visual sampling usually can't — a substituted part often looks correct and passes power-on. Catching it requires comparing markings against the BOM, and for high-risk parts, X-ray or decap to confirm the die matches the labeled part.
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