Weaving Preparatory Process

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Weaving preparatory Process There are three main steps of weaving preparatory process. 1. Winding 2. Warping 3. Sizing

Flow chart of weaving preparatory process

Winding

• Transferring yarn from one type of package to other which is more suitable for subsequent process.

Warping

• Transferring a number of yarns from a creel of single end packages, forming a parallel sheet on to a beam

Sizing

• Application of size material on the warp sheet, to induce desired properties

Winding Winding is a process in which yarn from ring bobbins are wound into convenient form of package. Transferring a yarn from one type of package, more suitable for subsequent process is also called winding. It occurs both in spinning & weaving. Main objectives of winding include:    

Increase package size according to the requirement of subsequent process Clearing yarn defects like slub, thick and thin places, neps, etc. Package dying Doubling

Winding rate

Winding rate is the speed at which the yarn is wound on package surface. In case of parallel package; traverse is very slow, so winding rate is approximately equal to the surface speed.

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Production of Winding Machine

Production of winding machine can be calculated by the following formula:

Flow chart of Yarn Passage Through winding machine:

Magazine

Stop Motion

Splicer

Baloon Breaker

Waxing

Cradle

Pre Cleaner

Tension Device

Drum

Warping Warping is the process of transferring a number of yarns from a creel of single end packages, forming a parallel sheet on to a beam. The main objectives of warping are:   

To get the required number of ends as per set calculation. To get the required length of yarn on each beam of the set. To wind a specific type of package required by subsequent process.

Types of Warping Machines

   

High speed Warping Sectional Warping Ball Warping Draw Warping 2

1. High speed Warping:

In direct warping, the yarns are withdrawn from the single-end yarn packages on the creel and directly wound on a beam. 2. Sectional Warping:

Sectional warping is a two stage machine method of preparing a warp on a beam, mostly used for yarn dyed fabrics. 3. Ball Warping:

Ball warping is the process in which warping is performed in rope form onto balls. A ball warped beam is prepared for subsequent process. It is suitable for denim fabric manufacturing, involving rope dyeing process. 4. Draw Warping:

Draw warping is combining the drawing of filament yarns with heat setting and warping process to achieve uniform stretching and heating for improved dye uniformity, end to end. It is used for weaving of thermoplastic yarns.

Flow chart of Yarn Passage through Warping Machine

Creel

Warp sheet on to comb

Guide Roller

Spindles

Headstock

Warping Beam

Tension Rods

Stop motion sensor

Pressing Drum

3

Sizing The weaving requires warp yarn to be strong, smooth and elastic to a certain degree. To achieve these properties, protective coating of a film forming agent is applied to the warp yarns prior to weaving. The application of size material on the warp sheet, to induce the desired properties is called slashing or sizing. Sizing is to produce Quality Fabric economically and efficiently. Objectives

The main objectives of sizing are as follows:     

To get the required number of ends To increase the strength of yarn To cover the hairiness of yarn To maintain flexibility in yarn To make yarn surface smooth and pliable.

Parameters Affecting Performance of Sized Yarn