Principles of loom motions

Principles of primary, secondary and auxiliary loom motions

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FABRIC PRODUCTION 1
ND 1 LECTURE SERIES
ON
OPERATIONAL PRINCIPLES OF LOOM MOTIONS
BY
Muhammed Raji, Abdulwasiu.
Department of Polymer & Textile Technology
Yaba College of Technology, Lagos Nigeria.
Correspondence: [email protected]
REFERENCES
1. Lord, P.R., Mohamed, M.H., (1992). Weaving: Conversion of yarn to fabric.
Durham, England: Merrows Publishing Co. Ltd.
2. Gokarneshan, N., (2004). Fabric Structure and Design. New Delhi, India:
New Age International (P) Ltd, Publishers.
3. Gordon, S., Hsieh, Y-L, (2007). Cotton: Science and Technology.
Cambridge, England: Woodhead Publishing Ltd.
4. Adanur, S., (2001). Handbook of Weaving. Pennsylvania, USA: Technomic
Publishing CO. Inc.
5. Marks R. and Robinson A.T.C. (1976). Principles of Weaving. Manchester,
UK: The Textile Institute.

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LOOMS/WEAVING MACHINE
A loom is a device that causes interlacement of two sets of threads, namely, warp
and weft threads, to form a fabric. The very first loom in history is the pit loom.
Subsequently the handloom was developed and then the power loom. After the
advent of power looms, a number of developments have taken place.

The chart below shows the broad classification of the various types of looms.

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DESCRIPTION OF IMPORTANT PARTS OF A LOOM
1. Heald Shaft: This is made of wood or metals such aluminium. It carries a
number of heald wires through which the ends of the warp sheet pass. The
number of heald shaft depends on the warp repeat of the weave.

Handloom Power loom
Shuttle loom
Shuttleless loom

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WEAVING
Weaving is the process of mechanically interlacing two sets of yarns at right angles
to one another in a designated order. In a woven fabric, the longitudinal or warp
yarns are called ends and the transverse or weft yarns are called picks. The order or
pattern of interlacement of ends and picks is called the weave or fabric design. The
most basic and extensively used woven fabric is the plain weave in which the warp
and weft (filling) yarns are interlaced in alternate order. Woven fabrics differ
according to interlacing pattern and yarn structure and composition.

LOOM MECHANISMS/MOTIONS

The basic mechanisms in any type of loom can be classified as follows:
(a) Primary motions
(b) Secondary motions, and
(c) Auxiliary motions.
The primary motions can further be divided as shedding, picking and beat up
motions. Shedding opens the warp sheet into layers to facilitate passage of shuttle.
The figure below shows a shed.




Figure : A shed

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The picking motion causes the shuttle carrying weft to be propelled from one end
of loom to another.


Figure : Picking


SHUTTLE: The filling yarn is inserted through the shed by a small carrier or
device called a shuttle. The shuttle is normally pointed at each end to allow
passage through the shed. In a traditional shuttle loom, the filling yarn is wound
onto a quill or pirn

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Figure : A shuttle with quill or pirn.

The beat up motion lays the previously laid weft to the fell of the cloth ( i.e.
pushing the newly inserted length of weft, known as the pick) into the already
woven fabric at a point known as the fell.

Figure : Beat up/Beating-up

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The secondary motions comprise of take up and let off motions. Take up motion
helps to wind the cloth on to the cloth roller and also influences the pick density in
the cloth.



Figure : Take up/Cloth control.

Let off motion helps to let the warp from the weaver’s beam ( i.e. delivers warp to
the weaving area) at a uniform rate thus maintaining the warp tension constant
throughout the weaving process. Figure below: Let off

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The auxiliary motions consist of the warp stop motion, weft stop motion and
warp protector motion.
The warp stop motion is used to stop the loom in the event of warp breakages.
This is necessary to prevent fabric defects such as missing ends and floats. Weft
stop motion is used to stop the loom in the event of weft exhaustion or weft
breakages. This is necessary to prevent missing weft threads called
cracks in the fabric. The warp protector is used to prevent multiple warp thread
breakages in the event of shuttle getting trapped in the middle of the warp sheet