VALUE ADDED AND HIGH-VOLUME COTTON PRODUCTS AND PROCESSES
Location: Cotton Chemistry and Utilization Research
Title: THE CURRENT STATUS OF SIZE-FREE WEAVING RESEARCH AT USDA
Submitted to: International Conference on Composites Engineering Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 5, 2006
Publication Date: August 1, 2006
Citation: Sawhney, A.P., Singh, K.V., Sachinvala, N.D., Condon, B.D., Pang, S. 2006. The Current Status of Size-Free Weaving Research at USDA. International Conference on Composites Engineering Proceedings. p. 831-832.
Interpretive Summary: The weaving sector is by far the largest component of textile manufacturing industry worldwide. Woven cotton fabrics almost always are produced using sized warp yarns, because the sizing improves tensile and abrasion resistances of the yarns and consequently enables efficient weaving. However, since warp sizing and the subsequent (mandatory) fabric desizing are costly, complex and environment sensitive, the textile industry obviously would like to eliminate the underlying process of sizing. Size-free, or size-less, weaving of cotton fabrics on a modern high-speed weaving machine was never explored until 2005, when the Agricultural Research Service (ARS) of the US Department of Agriculture (USDA) first investigated the feasibility of such weaving.
A size-free weaving trial was conducted on a modern flexible-rapier machine operating under almost mill-like conditions, using the best available materials and methods for producing a 100% cotton twill fabric of light construction. As a pleasant surprise, more than 100 m of cloth without warp sizing and without any yarn breakage or mechanical failure. This certainly is a great encouragement and a significant milestone toward progress in size-free weaving. For the first time ever, the research at least demonstrated the mechanical feasibility of size-less weaving on a modern high-speed weaving machine. However, fabric quality is not satisfactory yet, mainly because of numerous tiny fuzzy balls that most likely were formed due to the warp yarn abrasion in the “red-sweep” zone. Efforts to minimize yarn abrasion and thus improve fabric quality are underway.
After achieving a mechanically successful size-free weaving trial on a conventional fly-shuttle loom, the size-free weaving research was directed towards a modern high-speed weaving machine. A good quality rotor-spun combed cotton yarn, 30-tex (20/1 Ne), was produced for both warp and filling. The warp set was transformed into a loom beam on a so-called “dummy slasher,” by simply passing the yarn through a bath (size box) of boiling water containing a non-ionic wetting agent and a rice soap (optional), followed by drying on seven (7) steam-heated cylinders. A ½-twill fabric of relatively low/light construction was woven at speeds up to 500 picks per minute on a modern flexible-rapier weaving machine, partly using a conventional reed and a ceramic-coated reed. It is very encouraging to report here that, for the first time ever, more than 100 meters of size-less fabric of varying pick density have been produced at various weaving speeds without any yarn failure. Although it certainly is a pioneering research development and a significant milestone in cotton utilization research, the fabric quality is not yet acceptable. Numerous, minor (tiny) slubs, most likely caused by warp yarn abrasion in the reed sweep, appear on the fabric surface and are highly objectionable. Research efforts are continuing to assess/quantify the yarn abrasion and explore ways and means to minimize it and, thereby, improve fabric quality. As per the current status on size-free weaving research at ARS-USDA, it can be cautiously reported that size-free weaving on a modern high-speed weaving machine is at least mechanically feasible for certain types and styles of fabrics.