Yarn Defect Classification — CLASSIMAT
topic
CLASSIMAT testing (Uster Classimat 5) classifies yarn defects by cross-section increase and length, producing a 23-class defect matrix (short thick: A1–D4; long thick: E,F,G,H; long thin: I,J) and counts defects per 100 km. Critical classes (D4 — very thick, very long, causing winding breaks; H — long thin) are specified in yarn contracts. Periodic faults (systematic defects at regular intervals) are separately classified. CLASSIMAT testing identifies: splice quality, periodic faults, and spinning origin defects.
Role
CLASSIMAT is the bridge between spinning quality and weaving/knitting performance. It quantifies the defects that cause winding breaks, weaving stops, and visible fabric faults at the exact commercial specifications used in yarn trading. A yarn lot with excessive D4 class faults will cause winder stop rates that triple autoconer costs — making CLASSIMAT testing before shipment a direct cost management tool for both producer and customer.