Warp Preparation Process Warping, Sizing & Draw-in Dr. Jimmy Lam Institute of Textiles & Clothing

Production processes in woven fabric manufacture Raw Material ( cone yarn ) Warping Warp Sizing Weaving Drawing-in Fabric Inspection Finished Product ( woven fabric )

Warping Process The purpose of warping is to arrange threads in long length parallel to one another for further processing. The primary operation of warp making in which ends withdrawn from a warping creel, evenly spaced in sheet form, are wound onto a beam to substantial length. There are two warping methods: the first is direct beaming, the second is section warping

Direct Beaming

Direct Beaming Direct beaming is the winding of the total number of warp ends in full width in a single operation from a creeled bobbin, either onto a weaver’s beam or onto a sectional beam. The system is for large scale mass production

Section Warping

Section Warping Section warping is a two-stage-machine method of preparing a warp on a beam, consisting of firstly winding a warp in sections on to a reel, and then beaming-off the complete warp from the reel onto a weave’s beam. The sectional-warping system is used for shorter runs on high class goods.

Warp Sizing Process

Warp Sizing ( Slashing ) The weaving process requires the warp yarn to be strong, smooth and elastic or extensible to a certain degree. To achieve these properties on the warp yarns, a protective coating of a polymeric film forming agent ( size ) is applied to the warp yarns prior to weaving. This process is called slashing or sizing. After the fabric is woven, the size materials will be removed from the fabric during the finishing process which is called desizing.

Main Purposes of Warp Sizing to increase the strength of the yarns to reduce the yarn hairiness that would cause problems in weaving process to increase the abrasion resistance of the yarn against other yarns and various weaving machine elements to reduce fluff and fly during the weaving machine process for high speed weaving machines.

Appearance of Sized Spun Yarn The picture on the right side shows the appearance of a properly sized spun yarn used as warp in weaving process. The protruding hairs are bound to the yarn body with a thin coating of adhesive material applied to the yarn in the sizing process.

Draw-in Process

Drawing-in Process Drawing-in is the entering of yarns from a new warp into the weaving elements of a weaving machine, namely drop wires, heddles and reed, when starting up a new fabric style. Stop motion Control Fabric density control

Drawing-in Process

Discussion Define the direct beaming and section warping for warping process Discuss the advantages of sizing on weaving process What is draw-in process in weaving