Why does the actual filtration precision (micron rating) vary for screens with the same mesh count?

Mesh count only indicates openings per inch, while precision is determined by the wire diameter. According to ISO 944, aperture size is a function of both; for instance, a 100-mesh screen with 0.10mm wire yields 154μm, whereas 0.15mm wire reduces it to 104μm. Technical selection must prioritize the micron rating to avoid insufficient interception efficiency caused by wire diameter variations.