Optimizing Shed Height Settings for Air Jet Linen Fabric Construction
Optimizing air jet linen shedding requires asymmetric harness levelling at 26 millimetres to balance relay nozzle clearance with tension limits.
Crossed Shed Timing
Mechanical Interval
Weaving efficiency and yarn friction on high-speed rapier or air-jet looms depend on the specific angular position of the crankshaft where warp yarns transition between shed configurations. This specific coordinate is known as crossed shed timing, which governs the precise moment of yarn crossover relative to the beat-up action. In linen weaving, selecting an early timing reduces warp tension at the beat-up but increases abrasion against the reed.
Operational Impact
Poorly synchronized yarn crossings generate excessive abrasion on the delicate, low-elasticity flax fibres. Adjustment of crossed shed timing prevents early yarn-to-yarn contact while the weft is being inserted, which protects the single-twist linen warp from fraying. A late timing maintains a wider shed opening for a longer duration, reducing the frequency of weft-way stops during high-speed air-jet weaving.
When yarn hairiness is high, typical of wet-spun flax yarn, keeping the shed open longer prevents clinging warp threads from trapping the pick midway through the reed width. This setting reduces the rate of warp breaks caused by mechanical interference.
Process Adjustment
Mill operators modify the loom settings to match the specific characteristics of the flax warp batch. When weaving dense linen fabrics like heavy sailcloth, a technician adjusts the crossed shed timing closer to 300 degrees to lock the weft pick firmly into the fell line. This configuration prevents warp yarns from clinging to each other and ensures clean yarn separation.