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.
Tucking Mechanism
Edge Finisher
Mechanical devices are integrated into shuttleless looms to tuck the protruding ends of the weft yarn back into the subsequent shed. The tucking mechanism forms a clean, secure, and fringe-free selvedge by bending the cut yarn ends into the fabric edge during the beat-up. This creates a double-thickness edge that prevents the fabric from unravelling.
It is used to produce high-quality linen fabrics with finished borders.
Operational Details
High-speed selvedge formation requires precise mechanical and pneumatic actions during the yarn insertion cycle. The tucking mechanism uses a needle or an air jet to grasp the protruding weft tail and bend it back into the warp shed before the next pick is inserted. This action occurs immediately after the weft has been cut by the loom shears.
For linen weaving, where flax yarn is stiff and can resist bending, the tucking device must use sufficient force and precise timing to ensure the end is fully tucked. This action double-picks the outer edges, requiring a specialized warp yarn arrangement to handle the extra density without causing uneven fabric thickness.
Processing Benefits
Fabrics with tucked-in selvedges perform better during downstream industrial processes. The tucked edge eliminates the need for trimming auxiliary selvedges, which reduces yarn waste and simplifies finishing. This durable border can withstand the high tensions of scouring, bleaching, and stentering without fraying.
It is preferred for premium linen fabrics used in tablecloths and bedding.