Standard Operating Inspection Protocol for Four Point Greige Scoring
ASTM D5430 four-point scoring normalises greige defects per 100 square yards, capping penalties at four points per yard to decide lot acceptance.
Drop Wire Failure
Signal Interruption
Mechanical malfunctions within the loom safety system prevent the machine from stopping when a yarn breaks. A drop wire failure occurs when the metal leaf responsible for monitoring yarn tension becomes stuck or fails to make electrical contact. This prevents the warp stop motion from receiving the signal required to halt the motor.
Detection Failure
Friction or lint accumulation often causes the wire to remain suspended even after the thread it supports has snapped. During this drop wire failure, the loom continues to cycle and creates a major flaw known as a missing end. If the electrical bar is oxidized or dirty, the circuit remains open and the stop command is never issued.
Regular cleaning of the stop motion assembly is the primary preventative measure in a weaving shed. Technicians use compressed air to clear the debris from the contact points during routine maintenance cycles.
Production Loss
Fabric quality suffers immediately when the machine runs with a broken warp end. Because a drop wire failure allows the weaving to proceed, the resulting cloth contains a long gap that runs parallel to the selvage. This defect is usually unrepairable and results in the fabric being downgraded to second quality or waste.