Pneumatic Propulsion
Insertion of the filling thread in air-jet weaving looms relies on the kinetic energy of compressed air released at precise intervals. Adjusting the main nozzle pressure dictates the acceleration and velocity of the weft yarn as it enters the warp shed. This setting is calibrated according to yarn count, composition, and twist level.
It ensures the yarn reaches the opposite side of the loom within the available timing window.
Weft Transport
Air velocity inside the nozzle dictates the drag force acting on the surface of the yarn. Increasing the main nozzle pressure allows heavier or hairier yarns to cross the shed without stalling. This force must be carefully balanced with the timing of the profile nozzles across the machine.
It determines the efficiency and speed of the entire weaving operation.
Yarn Quality
Excessive force during insertion can cause yarn structural failures or surface damage to delicate fibres. When main nozzle pressure is too high, the yarn suffers from high tension spike risks, causing end breaks and machine stops. This damage often appears as weft defects or frayed ends in the finished fabric.
Proper pressure control prevents filament separation in textured yarns.
Operational Window
Low tension during insertion can lead to loop formation or short pick defects in the woven structure. Insufficient pressure results in a slow flight time, causing the yarn to collapse before it is secured by the selvedge. This defect causes fabric rejects and machine downtime.
