Your product has a cleanliness requirement. Your process may not know it yet.
Any product with a functional surface that can be harmed by a depositing particle has a contamination risk that can be quantified — and a monitoring need that follows directly from that calculation.
Particle contamination affects every industry where products have functional surfaces exposed during manufacturing. The framework is the same regardless of the sector: identify the critical particle size, the vulnerable surface area, the acceptable contamination limit, and the exposure time. From these inputs, the maximum allowable deposition rate follows from ISO 14644-17. The cleanroom environment, the assembly process, and the monitoring program are then evaluated against that limit — not against a generic ISO class that was not derived from the product.
In precision optics, a single particle on a lens surface or optical coating causes a point defect that is detectable in final inspection and irreversible after coating. The critical particle size is often below 50 μm; the exposure time during assembly or inspection can be measured in minutes. The deposition rate limit for an optical surface is frequently tighter than the cleanroom classification implies. APMON measures whether the actual operational environment meets that limit during the actual assembly operation, not during the classification audit. SUMON measures whether the fixtures and carriers that handle the optical components have been cleaned to the required surface cleanliness before the component is placed.
In pharmaceutical manufacturing, contamination control for non-sterile solid dosage forms focuses on cross-contamination between products and on particle contamination of equipment contact surfaces. In sterile manufacturing, particle deposition rate monitoring in fill-finish environments provides continuous evidence of the contamination barrier during the most critical processing steps. In printhead manufacturing — Koos Agricola’s original application domain at Océ Technologies — the cleanliness control method was developed for exactly this situation: a functional surface (the printhead nozzle plate) with a defined critical particle size and a manufacturing chain that required contamination control from component fabrication through final assembly.
The product-oriented approach
