WARPING FOR DENIM WEAVING

WARPING

The first process in the manufacturing of denim is warping.

INTRODUCTION

Warping is the process of transferring multiple yarns from individual yarn packages onto a single package assembly. Normally, yarns are collected in a sheet form where the yarns lie parallel to each other and in the same plane onto a beam, which is a cylindrical barrel with side flanges. This is known as beam warping. For ball warp denim, the yarns are brought together and condensed into a rope before being wound onto a relatively short cylindrical barrel (sometimes called the shell or log) that has no end flanges.. In both cases, the supply yarn packages are placed on spindles, which are located in a framework called a creel.

Ball Warping:

In ball warping (Figure 5), 250 to 400 yarn ends are pulled from the creel. The yarns then pass through a comb-like device (sometimes called a hack or reed), which keeps each warp yarn separate and parallel to its neighboring ends. At intervals of every 1000 or 2000 yards (or meters), a lease string is placed across the sheet of warp yarns to aid yarn separation for the re- beaming operation, which will occur later. The yarns then go through a funnel-shaped device called a trumpet or condenser, which collapses and condenses the sheet of yarn into rope form. This device is located at the base of the warper head and traverses back and forth, guiding the newly formed rope of yarn onto a log. The rope must be wound at a constant tension to keep the yarns from tangling.

BEAM WARPING

Beam warping maintains the yarns in an open sheet form and winds the yarns parallel to each other onto a slightly wider flanged beam. These yarns will not go through the rope indigo dye range, but are left “natural” and will end up either slasher dyed or in an undyed fabric, which can later be piece dyed, garment dyed, or left natural. Another option would be to beam dye the yarns using a dye other than indigo.

COMPONENTS OF MACHINE

1. Creel
2. Rods
3. Chain System
4. Control Devices
5. Sensors
6. Head stock
7. Expansion Comb
8. Dust and fly accumulation unit
9. Showering assembly

PROCEDURE OF WARPING:

The creel stand has maximum capacity of five cones per stand. The yarn from the cones is unwounded and passes from rod by cross wound, holed by a catcher guided to the tensioning zone when cone rotates anticlockwise. There are three types of tension in warping i.e. catcher tension, rod tension, and sacker tension. Magnetic tensioner is used for yarn tension. Then the yarn comes to the winding zone or headstock. Combs straighten the yarns towards pressure drum, which supports beam, and yarns in an alignment so that each andevery yarn end can wound separately. Static charges due to friction of yarns on metal surface cause static charges, which are removed through an antistatic device. Then the yarn is wounded on beam in this way for a required length if beam is changed after one filling of beam then knotting of yarns is made. Similarly if cones are finished on one frame side then trolley system of cone changing is used in this way chains rotates the whole frame of empty side and new filled side of frame is forwarded again knotting is done between the new cones yarn and already winded yarn. Extra yarn is then removed through cutting. Sensors sense any type of yarn breakage and in case of yarn breakage knotting is done.