Transcript Weaving Principle

Introduction (1)
Weaving Principle & Shuttle loom
Dr. Jimmy Lam
Institute of Textiles & Clothing
Learning Objectives
Weaving Principles
 Different types of weaving machines
 Production calculations
 Discussion
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– To explain how woven fabrics are produced
– Primary motions and auxiliary motions of weaving
looms
Introduction
This is a process of interlacing two or more
yarns at the right angles to each other to
produce a woven fabric.
 The yarn runs lengthwise is called warp
(end).
 The yarn runs crosswise is called weft (pick).
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Weft (Pick)
Warp (End)
Basic Plain Weave Fabric
Weaving Principle (I)
Basic Motion of Weaving Machine
There are Six motions on a loom (weaving
machine).
 The first three are called primary motions and
the second three are called auxiliary motions.
 Primary motions are: shedding, picking and
beating up.
 Auxiliary motions are : let-off, take-up and
pattern.

Basic Weaving Mechanism
Yarn Movement
Hardness controls up/down movement of warp yarn
Shuttle inserts weft yarn into the shed to form a cloth
Weaving Principle (II)
Primary Motions
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The function of primary motions is to separate warp
yarn and form an opening so weft yarn can be passed
inside the shed.
1) Shedding: raising or lowering of the warp yarns by
the hardness (wire) to make an opening for the weft
yarn to pass through.
2) Picking: the passage of the shuttle or other device
across the loom to put a weft yarn in the shed.
3) Beating-up: the pushing of each loose weft yarn
into the cloth by the reed, after the shuttle has moved
through the shed.
Weaving Principle (III)
Auxiliary Motions
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The functions of auxiliary motions are to continue
supply the warp yarn to the weaving loom and takeup the cloth onto the cloth roll.
4) Warp let-off: Unwinding of the warp beam to supply
more warp yarn as the cloth is woven.
5) Cloth take-up: the turning of the cloth roll to wind
up the cloth as it is woven.
6) Pattern: the vertical movement of the boxes in
shuttle box loom
Weaving Loom
Air-jet,
shuttless loom
Cloth
Hardness
Warp Let-off
Warp Yarn
Warp yarn is
delivered to the
loom
Discussion
Discuss the functions of Primary motions and
Auxiliary motions of weaving machine.
 How can you increase the weaving machine
production?

Weaving Machine
Weaving Machine
Shuttle Loom
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Looms that use a shuttle to insert the weft yarn in the
shed is called shuttle loom.
A shuttle is a wooden, boat-like device with a bobbin
placed inside.
As a shuttle is thrown across the loom, the weft yarn
unwinds from the bobbin, leaving a trail of yarn
behind.
When the weft yarn inside the shuttle is almost
exhausted, a full bobbin is automatically inserted into
the shuttle, which allows weaving to continue without
stop.
Shuttle for Weaving Loom
Weft yarn is placed inside the shuttle. The whole shuttle is
passed through the warp shed to form a fabric.
Pirn-changing for shuttle loom
Pirns for refilled the empty shuttle
Shuttle Loom
Disadvantages
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Shuttle loom needs a pirn-winding (to re-supply the
weft yarn in the shuttle).
The shuttle is big and heavy in weight. The loom is
therefore slow in speed and noisy in operation because
of the dynamic problems created by picking and
checking mechanisms.
In addition, the shuttle sometimes causes abrasion on
the warp yarn as it passes over them and may cause
thread breaks.
A weaver attended a stopped loom caused by yarn breakage
The cloth rolls doffed off from the looms were delivered to
cloth inspection room for inspection and quality grading.
Weaving machine
Shuttle loom
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The use of shuttle loom is the slowest and least
efficiency power weaving.
Explain why and how to improve them?