Nep Origin Tracing
topic
Nep tracing methodology: (1) Measure neps at each stage using AFIS fibre tester: raw cotton (typically 100–250 neps/g), after blowroom (80–180/g), after card (60–120/g), after combing (if applicable: 30–60/g), sliver (50–100/g), roving (60–120/g), yarn (classified by Uster CLASSIMAT +200%). (2) Nep removal ratio per stage — carding should remove 50–60%; if removal <40%, check card clothing, flat setting, and cylinder speed. (3) Nep generation post-carding: check aprons, pressure rollers, and any fibres under tension.
Role
Nep tracing is the diagnostic methodology that identifies where neps are generated vs where they should be removed, enabling targeted machine adjustment. Without stage-by-stage measurement, nep problems are typically addressed by changing ring frame settings — which cannot remove neps generated in carding. Understanding nep tracing methodology prevents months of ineffective corrective action on the wrong process stage.