Warping Process in Weaving | Importance | Types

Warping

The parallel winding of warp ends from many winding packages (cone and cheeses) onto a common package (Warp Beam) is called warping.

Importance of warping:

Constructions of beam warp yarn.
Constructions of a parallel yarn sheet.
Modifying the faults of yarn like thick and thin places large knots etc.
Winding the predetermined length of yarn.
Combination of small packages.
Finding the long length of warp yarn.

Types of warping:

Direct warping- Beam Warping
Sectional Warping- Patterns band or drum warping

The fundamental difference between the direct and indirect system of warping is that the indirect system provides a means of making a loom warp on one machine and the direct system of warping requires two.

Direct warping denotes the transference of yarns from single entry and packages round packages directly to a beam in a one-step process.

This means that there is an equal number of packages in the grill area as there are ends on the beam, except in the case of a magazine creel. A magazine creel connects the tale of one wound package to the beginning of a new wound package for an easy package transfer from the wound packages in the creel.

Beam warping:

A weavers beam may have up to 10,000 ends and if this were to be produced directly it would be necessary to have up to 10,000 packages such an arrangement would be very difficult to accommodate and manage, consequently it is normal practice to produce warper's beams which may contain up to about 1,000 ends and these are combined at the slashing (sizing) stage because of the difficulties involved in combining the ends, patterned warper beams are seldom produced on the direct system and any pattern that is produced is achieved by combining beams of various colors at the later stage of slashing, this imposes limitation which can only overcome by changing to pattern weaving.

Sectional Warping:

In sectional warping sections are made sequentially and because of this the process is rather slow it is the practice, therefore, to produce do more than is required to fill a single weaver's beam.

The result is that sectional warping is used mainly for short-run or complex color patterns.

Quality of good warp:

Sufficiently and uniformly strong
Uniform in cross-section
Uniform warp tension
Uniformly sized
Less hairy and clean
Minimum number of knot
Proper or standard sizes and types of knots
Free from neps slubs and loose fiber
Parallel arrangement of warp yarn in the weavers Beam.

Requirements of warping:

The tension of all wound ends must be uniform and possibly constant during all the time of withdrawal from supply packages otherwise the rate of breakages will be increased and the structure of ready cloth will be impaired.
Working should not impair the physical and Mechanical properties of yarn the tension should moderate to elo the yarn to completely written its elastic properties and strength. The yarn should not be subjected to sharp abrasive action.
The surface of working package must be cylindrical therefore the spreading of yarn throughout the whole width of working must be as uniform as possible
A predetermined length of working should be observed.
The production rate of working should be as high as possible.

Basic Requirements of Warping:

The yarns in the sheet should be in a uniform spacing.
The yarns in the sheet should be in a uniform tension.
The yarns in the sheet should be of a predetermined length.
The sheet should be containing a predetermined number of ends.
There should be no broken end in the beam.

Warping process involves:

Cone from winding
Creeling
Control system
Reed
Measuring device
Winding on beam

Assessment of quality of warping Beam:

Warping is said to be the barometer of weaving preparatory. The quality of the beam has also considerable effects on the subsequent processes.

The following are the important aspects of assessing the beam quality:

Incorrectly mended broken hands

When a and brakes on a working machine if the machine does not stop within 1 to 1.5 revolution of the drum the broken and on the beam gets buried inside the succeeding layer of warp. The warper then find difficulty in locating this end. When there is a high incidence of Britishers on working there is every possibility that the wall may become negligent on performing his duty of locating the broken and properly and tie into the corresponding end from the creel. This broken ends if incorrectly mended then they create a problem of lappers for migratory ends on sizing process. Therefore to avoid these defects proper setting of brakes stop motions and frequent control over the operator practices are necessary to avoid about faults.

Uniformity of yarn tension

In case of warping system uneven distribution of tension on individual ends across the width take place. The tension distribution depends on the type of trading system employed at the creel of the warping machine.

Depthwise threading system:

This system is employed on semi high speed machines. The important drawback of this system is that the coefficient of variation of tension is generally on the higher side for the system.

Vertical threading system

In this system the trading ends comes from a vertical Bank of cones in the adjacent dents of the back reed. In this system gradual rise in tension from the centre of the beam towards the extreme part of the beam. However the magnitude of variation is of a smaller order as compared to that with the depthwise threading system. The non-uniformity of a tension across the width of worksheet involving leads to stickiness in dyed varieties of warper's beams. More duty more uneven tension on working in the ends may become less extensible which ultimately cause migration of ends at sizing. Also more breakages may take place at weaving process. It has also been observed that more streakiness is observed on the beams prepared with depthwise threading system as compared to beams prepared on vertical threading system. Therefore tension variation at working stage do cannot be eliminated but should be minimised to reduce problem on subsequent process.

Bulged/Sunken selvedge ends

This type of fault occurs when the setting of expanding comb is done incorrectly. The formation of bulged selvedge agents take place when expanding comb setting is wider than the beamwidth whereas Sankalp cell which ends are formed when the expanding comb setting is shorter than the beam width or when the flanges of warpers beams are not true and they are out. Both these problems lead to unwinding problems at sizing. The best cell which ends give rise to see like ends whereas sunken sale which create entanglements of ends and tight ends during unwinding at sizing process. Therefore proper attention and care should be taken at the time of expanding Chrome settings and correct and proper condition of beam flanges.

Condition of beam flanges

If the empty beams are carelessly handled during loading doping transport or storage the Beam flanges get damaged. Either Dev sittings fittings or the condition of beam flanges become true to this damage flanges causes breakages of selvage during unwinding of a beam. Therefore the housekeeping of beams must be given priority. Their condition must be changed regularly and to avoid further damages the protecting annular metal disc can be fitted over the flanges but proper manhandling is the most important factor in maintaining the good condition of beams.

Slough offs, wild yarn on warper's beam

Sometimes slug of wild yarn etc get formally attached to the warp sheet, the GATE forms reattached due to pressure applied on wallpapers Bheem during successive working layers and get more firmly attached due to application of size paste. Therefore when this type of end reaches the splitting zone they cause excessive-end breaks. If these embedded ends remain in the sized beam, then they certainly cause multiple breaks at weaving by getting jammed in the heald eye and reed dents.

To avoid faults the most preventive action to be taken at spinning winding warping so that the above defects can be minimized.

Damaged beam surface

The important causes for this defect are excessive friction between beam and drum of the warping machine, damaged drum surfaces and improper handling of beams during transport, and improper storage. The damage to beams causes excessive breakage in the sizing process, it also leads to excessive hard waste.

Uneven beam density

The beams should be firm and compact, inadequate pressure between the beams and the drum causes soft beams, therefore adequate pressure should be kept by making suitable mechanical adjustments

The main causes of this fault are:

Mix up of yarn counts
Improper condition of expanding comb
The uneven surface of the driving drum
Uneven yarn tension.

Provide initially about defect proper adjustment and alignment of purpose beam with drum must be set correctly and most care to be taken towards adequate pressure between the beam and drum.