PREPARATORY PROCESS IN WEAVING:-

Warping process:-

We know that woven fabrics is made by two sets of yarn , warp and weft. Warp yarns run along with the length of fabric and WEFT yarn go across the width of the fabric. Warping is the preparation of yarn to weave fabric. It is the transfer of many yarn from the creel of single package to a beam. The yarn will form a parallel sheet of yarn wound on to the beam. The basic objective of warping is to built a package where yarn ends remain in uniformly set parallel and continuous form & there by to eccelarate the next process either sizing or drawing.

Fig schematic diagram of warping

Object of warpig:-

The main objective of Warping is to prepare a warp sheet of desired length contains a desired number of yarns that are wrapped on a flanged barrel (roll) in such asnnet that the tension in each yarn and density of yarn mass in the cylindrical sssembly are maintained within a given tolerance level through out the warping of the warp beam. By warping process yarn quality increase, wound up fixed length of yarn on weaver's beam. Increase the weaveability of yarn. In this process small package can re-use . After all increase the production. The process of warping is dedicated to the conversion of cone into a beam of given specification.

TYPES OF WARPING:-

There are two types warping are popular in textile industry for preparing warp yarn for power loom driven high speed loom or handloom. These are, 

1) Direct warping or Beam warping .

2) sectional Warping.

(1) DIRECT WARPING OR BEAM WARPING:-

When the yarn are drawn from the single package on the creel direct warping . It is also called high speed warping or Beam warping . Direct warping is used to make smaller beams which are combined later in skashind to produce the weaver's beam . Direct warping is used to manufacture greige towels that will be dyed full bleached during wet processing. Modern beam warping machine have creel moveable that cone can be creeled in reserve when one set is working in the machine.

Image of beam warping machine:-

(2) SECTIONAL WARPING:-

When the yarn is wound on to the beam in sections starting with the tapered end of the beam , then it is called sectional warping 

 Sectional warping is used for weaving a towels containing stripes . Multiple colors of yarn can be incorporated in the weaver's beam by using sectional warping . The drum of the beam has a cone which has a slight angle that will prevent the yarns from slipping off. sectional warping important for making stripe towels.

Apart fro these two , direct and sectional Warping there are also used (i) Draw warping and (ii) Ball warping method.

(1) DRAW WARPING:-

A process in which a number of thread lines , usually 800 to 2000 ends of POY feed, are oriented under essentially equal mechanical & thermal conditions by stretchimg stage using variable speed rolls , the directly wound on to the beam . Draw warping process give uniform end to end properties. 

Imag Fig. Draw warping process

(2) BALL WARPING:-

Ball warping is the process in which warping is performed in rope firm on wooden ball . It involves cterling multiple ends of yarn (between 350 and 500 ends ) and collecting them into untwisted rope for dyeing . The rope is wound on to a long cylinder called loh on a machine called a ball warper.

WARPING PROCEDURE 

The flow chart of warping is give be low.

FLOW CHART OF WARPING, 

                       I

              CREELING

                       I              

                DENTING

                       I  

     EMPTY BEAM FEEDING     

                       I

                ROLLING

                       I

               WARPING

                       I

               LEASING

                       I

           END CUTTING

                       I

                DOFFING.

WARPING OPERATION:-

Warping procedure for terry towels is not at all different from the Warping procedure of traditional weaving. The warping procedure is described below in brief, 

1) The first operation of warping is CREELING i.e. to feed the yarn package of yarn in creel among different types of creel provided in warping machine, the V creel is mostly used .

2) Then the yarn end passes through the dents of the comb of the reed . This known as denting .

3) Then the yarn from the yarn package wrapped on to an empty beam.

4) As the warp beam wraps a predetermined amount of yarn ; a lease yarn is inserted that helps to separate each yarn from each other during sizing. 

5) Finally the full beam is doffed out from the machine .

Purpose of Warping or What Warping should do?

A) To form a predetermined number of single end package a continuous sheet of yarn of specific length and width.

B,) The individual yarn ends of the sheet should be spaced uniformly across beams ful width.

C) All the yarn end sheet should be wound at almost uniform tension.

D) The density of wound yarn on beam should be uniform across the width, all from start to end of winding the sheet .

PROBLEM OF WARPING:-

Following are some of the normal problems during warping,

1) Variation in tension within and between beam.

2) Missing ends.

3) Cross end .

4) Poor quality of beam .

5) Production less due to some cone running out early.

6) Pattern not proper.

7) Lost ends

8) Section Mark.

9) Draw back.

           Ref:-https://textileblog.com