Quantifying Primary Trim Scrap in Rapier Weft Insertion
Primary rapier trim scrap depends on insertion geometry rather than fabric width, requiring exact tail length modeling to prevent yarn yield deficits.
Weft Accumulator
Yarn Feeder
Auxiliary yarn delivery devices are installed between the supply package and the loom’s insertion mechanism to store a metered length of yarn. The weft accumulator unwinds yarn from the package at a continuous, low tension and winds it onto a storage drum, from which the loom pulls it during insertion. This decoupling of the unwinding and insertion processes prevents yarn breaks and tension spikes.
It is an essential component for high-speed industrial weaving.
Mechanical Process
Inserting yarn across wide looms at high speeds requires a rapid, low-resistance release of the weft thread. The weft accumulator stores several coils of yarn on its stationary drum, allowing the rapier or air-jet to pull the yarn off the end of the drum with minimal resistance. This drum is equipped with sensors that monitor the yarn supply and activate an electric motor to replenish the coils as they are used.
In linen weaving, flax yarn is prone to slubs and irregular diameter, which can cause erratic drag when pulled directly from a supply package. The accumulator smoothens this drag, ensuring a consistent and gentle feed that prevents the yarn from breaking during the high-acceleration phase of the insertion cycle.
Weave Efficiency
Uniform weft tension is a critical factor in reducing loom stops and achieving a uniform fabric surface. By minimizing tension variations, the weft accumulator allows looms to run at higher speeds with fewer interruptions. This device is particularly important when weaving linen-cotton blends, where the different elasticities of the two fibres must be managed.
It maintains fabric quality while maximizing loom productivity.