Woven and Knitted Fabric Structural Construction Specifications
Fabric specifications mandate exact finished thread densities, stitch lengths, and test conditions to enforce supplier compliance and control landed costs.
Weft Picks
Weaving Element
The transverse yarns are inserted across the width of a loom and interlaced with the longitudinal yarns to create a woven fabric. These individual filing threads are called weft picks, and their frequency per unit length determines the density of the weave. They do not include the warp threads or the selvage reinforcement yarns.
Insertion Mechanism
During weaving, the loom creates an opening in the warp threads and inserts the filing yarn using a shuttle, projectile, rapier, or jet of air or water. The inserted yarn is then pushed tightly against the previously woven fabric by a moving reed in a process called beating-up. This mechanical action locks the yarn into the structure, with the number of these insertions per inch controlled by the loom’s take-up speed.
Slower speeds result in a higher density of filing threads, creating a heavier and more compact fabric. The insertion rate determines the overall production speed of the loom.
Fabric Properties
Weavers adjust the frequency and type of these filling threads to modify the weight, drape, and breathability of the finished textile. A higher count improves the cover factor and reduces the porosity of the fabric, which is useful for down-proof jacket linings. This setting is critical for achieving the desired hand and flexibility.
Element Limit
The number of filling threads can vary slightly along the length of a fabric roll due to tension fluctuations during weaving. These variations are normal but must be kept within tight tolerances to prevent visible bands or shading.