The warranty claim arrived three months after the batch left your assembly room.

Automotive technical cleanliness failures follow a consistent pattern: the contamination event occurs during assembly, the functional failure occurs in the field, and the investigation concludes with “assembly environment contamination” as a probable cause — without the data to be more specific. Fuel injection valves, ABS solenoids, EPS gears, and transmission bearings fail in service because a single particle of the wrong size was present at the wrong surface at the moment of assembly. The critical particle size for a fuel injector needle seat is around 50 μm. That particle is invisible to standard quality inspection and passes every functional test until it causes a field failure.

VDA 19.2 defines the framework for technical cleanliness in assembly: the Illig value, calculated as the weighted sum of depositing particles per size class normalised to 1000 cm² per hour, classifies the assembly environment from SaS0 (uncontrolled) to SaS3 (cleanroom-equivalent). Most automotive assembly lines operate at SaS1 or SaS2. The conventional method for verifying this classification is a sediment plate: a passive collection surface read out once per shift, once per day. This method reveals that a contamination event occurred. It does not reveal when, during which process step, or from which activity — this is the information required to prevent contamination.

APMON Automotive delivers the Illig value continuously, every four minutes, at the assembly location. Every deposition spike is timestamped and stored. When a warranty event is investigated, the assembly environment condition during the production of that specific batch is recoverable from the event log. SUMON completes the picture by measuring the particle fall-out level on workbenches, tool trays, jigs, and transfer surfaces — the contact surfaces where direct transfer to the component occurs, bypassing the air entirely and invisible to any environmental monitor.