Effect of shed geometry on starting mark of woven fabric

Abstract

This paper aims to analyze the formation of starting mark on loom and the effect of shed geometry formed by warp yarns under various conditions. The actual cause of starting mark in woven fabric is variable pick spacing and cloth-fell displacement due to the relaxation nature of the warp yarn and fabric and the loom’s dynamic characteristics after restarting. Herein, nine woven fabrics of different constructions, compositions are used on an air-jet loom with a series of settings. Three shed angles were selected for specific warp yarn count, and other loom settings like heald frame height, back-rest height and depth, air pressure, take-up correction, automatic start offset, stop position were triggered to change the shed geometry, and then the effect of starting mark on fabric was checked. The pick spacings were then measured from fabric using a projection microscope, whereas various plots were generated utilizing the obtained data to check the pick spacing variation after a certain period of loom stoppage and restarting. Finally, the experimental results were analyzed with standard deviation, coefficient of variation % analysis using the IBM SPSS statistical program.