Counterfeit Components: Detection and Avoidance

What Makes a Part Counterfeit

A counterfeit part is one that is misrepresented: a recycled device sold as new, a lower grade sold as a higher one, a different manufacturer relabelled, or a device that was never made by the brand printed on it. The category also includes parts that are functionally the same but outside the manufacturer’s specification, such as components rejected at test and resold, and parts that have been re-marked to a higher temperature grade. The common thread is that the buyer’s records say one thing and the part is another, which makes traceability the core defence.

How Counterfeits Enter the Supply Chain

The usual route is the open market. When a part is short, brokers appear with stock that no authorised channel can confirm, and the pressure to keep a line running makes those offers attractive. Recycled parts come from scrapped boards, where components are removed by heating, cleaned, re-balled and re-marked so that they look new; the rework damages the part in ways that are invisible and that shorten its life. Other counterfeits are genuine dies in unauthorised packages, or clones that fail at temperature. Because the shortage is what creates the opportunity, the risk rises exactly when the schedule pressure is highest, which is when discipline matters most.

Visual and Documentary Checks

The first line of defence is cheap: check the paperwork and look at the parts. Documentation should trace back to the manufacturer through authorised distribution, and the date codes, lot codes and packaging should be consistent across the shipment. Visually, the signs include a blacktopped surface that hides the original marking, laser etching that is too deep or too shallow, text that is not aligned, mismatched fonts between the part and the logo, solder residue on leads that indicates removal, and re-balled terminations with an uneven finish. A microscope and a controlled light source make these checks practical, and a reference sample of a known-good part makes the comparison objective.

Electrical and Physical Test

When the paper trail is weak, testing answers the question. Curve tracing or a semiconductor analyser compares the device against a known-good sample and catches gross differences and many re-marked parts. X-ray fluorescence checks the plating and the lead finish, which often gives away a part from a different source. Decapsulation removes the package and exposes the die, whose marking and layout identify the true manufacturer. X-ray inspection shows the bond wires and the die attach, where a recycled part shows rework. Electrical test at temperature is the most convincing check for grade claims, since a commercial part re-marked as industrial will drift outside specification when it is hot or cold.

Standards and Programme

There are recognised standards for this work. AS6081 sets out the requirements for counterfeit electronic parts avoidance and the inspection and test methods used to detect them, and AS5553 covers the same ground for the broader supply chain. A workable programme combines authorised sourcing as the default, an approved supplier list with audit records, incoming inspection that is risk based, and a quarantine path for suspect parts so that nothing suspicious reaches the line. Training matters as much as the procedure, because the inspector has to know what normal looks like before an abnormality is visible.

Risk Based Incoming Inspection

Not every shipment needs the same scrutiny. Inspection should scale with risk: parts bought from the manufacturer or an authorised distributor are low risk and can be sampled, while parts from the open market, from an unknown broker or from a shortage situation are high risk and warrant the full check. The risk rating should consider the part type, since a programmable device or a high value analogue part is more likely to be counterfeited than a common resistor, and the history of the supplier. Recording the outcome builds a picture that directs effort toward the shipments where it will actually find something.

If a Suspect Part Is Found

A suspect part must be controlled before it is investigated. Quarantine the whole lot, including the parts already issued to the line, and hold the assemblies that contain them. Notify the supplier in writing and preserve the evidence, since a returned part that has been handled loses much of its value as evidence. Screen the affected assemblies, decide disposition with the customer where the requirement calls for it, and check whether the same part number from the same source was used on other builds. The countermeasure is not only the replacement lot, it is the change to the sourcing rule that let the part in.

Authorised Channels and Broker Risk

The single most effective countermeasure is to buy through authorised distribution, because a part that arrives with a traceable chain from the manufacturer to the buyer is not counterfeit. That is easy to say and harder to do when a line is down and an authorised channel quotes twelve weeks. The practical compromise is to keep a small allowance for open market purchases but to route every one of them through the same inspection, to require the supplier to certify the source and the lot, and to refuse any shipment whose paperwork cannot be verified. A broker who will not state where the parts came from is a broker whose parts should not be used.

FAQ

What is a counterfeit component? One that is misrepresented: recycled, relabelled, re-marked to a different grade, or not made by the brand it claims.

Why are shortages dangerous? They create the demand that brokers and counterfeiters fill, and they push buyers toward unauthorised sources.

Which test finds counterfeits best? No single test does. Documentation, visual inspection, XRF, X-ray, decapsulation and temperature testing are combined by risk.

What is AS6081? A standard for avoiding counterfeit electronic parts, defining inspection and test methods and programme requirements.

What should I do with a suspect lot? Quarantine it and the assemblies that contain it, preserve evidence, notify the supplier and review your sourcing rules.

Conclusion

Counterfeits are a sourcing problem before they are an inspection problem, so buy from authorised channels and reserve testing for the cases where the trail is weak. A risk based programme with clear quarantine rules is what keeps a suspect part off the line. Incoming control belongs to quality management, the build sits within PCB assembly, and the sourcing policy is part of PCB manufacturing. First builds that stress these controls are handled in prototype PCB assembly in 2026.