Use aperture dimensions
State the required opening in millimeters or micrometers where possible. A mesh count alone is not a complete aperture specification because wire diameter also matters.
Define the desired fractions
Specify what should pass and what should be retained. Include the allowed amount of misplaced material and how separation performance will be assessed.
Discuss mesh condition
Screen wear and blockage affect separation. Include inspection and cleaning access in the equipment discussion.
Confirm against actual material
The desired opening is one input to selection. Feed rate and particle behavior also influence the observed result.