Loom introduction
Loom is the machine that is responsible for fabric formation from the yarn.
In loom machines, numbers of yarn are fed as raw materials and the end product is fabric. This is done by the weaving process.
The weaving process is the process of interlacing two sets of yarns.
In a loom machine, warp and weft threads are used to produce the fabric.
Warp threads are vertical threads or run along the length of the fabric while weft threads are horizontal and run along the width of the fabric.
The interlacements between these two threads make the fabric and this is done with the help of the specified motiones and mechanisms.
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| Loom Machine |
Weaving motion and basic terms
PRIMARY MOTION
without primary activity, the production of cloth is not possible. All three motions should be present in sequence as shedding, picking, and beat-up.
Shedding – Shedding is the motion in which the upward and downward movement of the heald shaft is done. This is provided through the Heald shaft to Heald-eye by a specific mechanism for raising and lowering of warp to insert a pick.
Picking- Picking is the insertion of a weft thread into the shed using the shuttle or by any other medium.
Beat up – Beat up is the movement of the reed that carries forward the inserted pick towards the fell of the cloth.
SECONDARY MOTION
The tension should apply to maintain the warp in a stretch position, so let-off and take-up are necessary. Also, there is a change in tension due to shedding which should keep in mind.
Let-off motion – to control the tension in the loom using speed is known as take-up motion.
Take-up motion – to wound the cloth on the cloth-roller uniformly to maintain the tension is known as take-up motion.
AUXILIARY MOTION
This motion improves the inefficiency and end-product quality of the loom.
Warp stop motion – to stop the loom when the warp thread is broken.
Weft stop motion – to stop the loom when the weft is broken or the pick is missed.
Warp stop motion – to stop the loom and save the warp threads from damaging when weft fails to reach, and box properly into either the winder during picking.
- The warp threads are divided into two overlapping groups or lines that run in two planes, one above another, so the pick can be passed between them in a straight motion.
- After one pick passes the upper group is lowered by the loom mechanism, and the lower group is raised (shedding), allowing the pick to pass in the opposite direction, also in a straight motion.
- Repeating these actions form a fabric mesh but without beating up, the final distance between the adjacent wefts would be irregular and far too large.
- The principal parts of a loom are the frame, the warp-beam or weavers beam, the cloth roll (apron bar), the heddles, and their mounting, the reed.
- The warp beam is a wooden or metal cylinder on the back of the loom on which the warp is delivered.
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| Weaving motion |
Essential passage of weaving machine
First, the weaver beam is placed on the backside of the loom in a specific place.
The weight is provided on the roller to keep the warp in tension and control the speed of letting the warp unwound and this is known as let-off motion.
It contains approximately 3000-5000 warps end. The number of ends depends on the width and EPI of the loom and cloth respectively.
All ends are parallelly unwound from the beam and go for the weaving process.
Then comes the backrest, which gives firm warp holding by creating tension.
From there the warp ends are passed along the lease rods that distribute the warps into two or more than that section so that the entanglement of warps can be prevented when shedding is done.
Warp is then passed through Heald's eye which is raised and lowered to form the shed for the passing of weft for interlacement.
The raising and lowering of the Heald shaft are known as shedding and the insertion of the weft is known as picking.
Reed – Each warp is passed between the reed bars as per the density of the cloth set. It is mounted on a sley and transferred the weft to the ‘fell of cloth’ where we can say that cloth is formed from warp sheet. The process of transferring weft is also known as the beat-up process.
Temple – it has work to grip the cloth firmly from both edges so that the cloth doesn’t shrink.
Front rest/breast beam – It guides the cloth and creates tension.
Emery roller – Its surface is rough so it holds the fabric and helps to wind cloth on the cloth roller.
Guide roller/measuring roller - it prevents slippage in winding by applying tension on the cloth and measures the quantity of cloth wound on the cloth roller.
Cloth roller- cloth is wound and it is driven by an emery roller with the help of friction. The winding motion of cloth is known as the take-up motion.
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| Passage of yarn in loom |
Questions -
- What is a loom?
- What is the working of the loom?
- A detailed description of the loom.
- What are the weaving motions of the loom?
- What are the basic terms of the loom?
- What is the primary motion?
- What is the secondary motion?
- What is the auxiliary motion?
- Draw the passage of the loom.
- Explain the passage of the loom.
References
Diary, J. (n.d.). BASIC LOOM MECHANISM. Textileschool4u.blogspot.com. from http://textileschool4u.blogspot.com/2013/11/basic-loom-mechanism-general-passage-of.html
Patwary, E. M. Z. (2012, June 23). What is the loom? Textile Fashion Study; Engr. Mohammad Zillane Patwary. https://textilefashionstudy.com/classification-of-loom/
Safwan, A. A. (2016, November 19). Study on passage diagram of warp yarn through shuttle loom. Blogspot.com. https://diutestudents.blogspot.com/2016/11/study-on-passage-diagram-of-warp-yarn.html
Sayed, A. (n.d.). Definition, classification and parts of the loom. Blogspot.com. from https://textileapex.blogspot.com/2014/01/loom.html
Textile School. (2010, October 27). Types of fabric weaving loom. Textile School. https://www.textileschool.com/360/types-of-fabric-weaving-looms/
textile-tutorials. (2018, June 3). Parts of the loom and their functions in textile weaving. Textile Tutorials. https://textiletutorials.com/different-parts-of-loom-and-their-functions/
The Editors of Encyclopedia Britannica. (2013). loom. In Encyclopedia Britannica.
Understanding weaving: What are looms? (n.d.). The Sustainable Fashion Collective. from https://www.the-sustainable-fashion-collective.com/2014/10/14/what-are-looms
Writer - DSPAT Team
