Dynamic Tension Control and Dobby Shedding Parameters for Flax Warps
Active tension control and asymmetrical dobby dwell minimize stress spikes on low-stretch flax warps to prevent end breaks and starting marks.
Shedding Mispicks
Fabric Defect
Weaving faults occur when the mechanical elements of the loom fail to execute the programmed yarn interlacing pattern correctly. The incidence of shedding mispicks arises when a warp yarn is either raised or lowered at the wrong time, causing the weft yarn to float over the wrong ends. This defect is identified during the grey fabric inspection on the mill viewing table, where inspectors log each occurrence on the roll quality sheet.
Such errors disrupt the visual uniformity of the linen fabric and can lead to downgrade classifications.
Machine Causation
Mechanical wear in the dobby drive or incorrect tension in the heald return springs causes the harness frames to lag behind the loom cycle. In relation to shedding mispicks, this lag prevents a warp yarn from clearing the path of the incoming weft pick. Mill technicians must check the alignment of the shedding cams and the tension of the harness cords to correct the issue.
On modern electronic looms, sensors detect these lag events and stop the machine before the wrong pick is locked in by the reed.
Inspection Grading
Uncorrected defects reduce the batch value and require the mill to downgrade the roll. Quality standards set a strict limit on shedding mispicks per run of fabric. Excessive faults lead to total rejection by the buyer.