Introduction (1)Introduction (1)Weaving Principle & Shuttle loomWeaving Principle & Shuttle loom

Dr. Jimmy LamDr. Jimmy Lam

Institute of Textiles & ClothingInstitute of Textiles & Clothing

Learning ObjectivesLearning Objectives

�� Weaving PrinciplesWeaving Principles

�� Different types of weaving machinesDifferent types of weaving machines

�� Production calculationsProduction calculations

�� DiscussionDiscussion

–– To explain how woven fabrics are producedTo explain how woven fabrics are produced

–– Primary motions and auxiliary motions of weaving Primary motions and auxiliary motions of weaving

loomslooms

IntroductionIntroduction

�� This is a process of interlacing two or more This is a process of interlacing two or more

yarns at the right angles to each other to yarns at the right angles to each other to

produce a woven fabric.produce a woven fabric.

�� The yarn runs lengthwise is called warp The yarn runs lengthwise is called warp

(end).(end).

�� The yarn runs crosswise is called weft (pick).The yarn runs crosswise is called weft (pick).

Warp (End)

Weft (Pick)

Basic Plain Weave Fabric

Weaving Principle (I)Weaving Principle (I)

Basic Motion of Weaving MachineBasic Motion of Weaving Machine

�� There are Six motions on a loom (weaving There are Six motions on a loom (weaving machine).machine).

�� The first three are called primary motions and The first three are called primary motions and the second three are called auxiliary motions.the second three are called auxiliary motions.

�� Primary motions are: shedding, picking and Primary motions are: shedding, picking and beating up.beating up.

�� Auxiliary motions are : letAuxiliary motions are : let--off, takeoff, take--up and up and pattern.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)Weaving Principle (II)

Primary MotionsPrimary Motions

�� The function of primary motions is to separate warp The function of primary motions is to separate warp yarn and form an opening so weft yarn can be passed yarn and form an opening so weft yarn can be passed inside the shed. inside the shed.

�� 1) Shedding1) Shedding: raising or lowering of the warp yarns by : raising or lowering of the warp yarns by the hardness (wire) to make an opening for the weft the hardness (wire) to make an opening for the weft yarn to pass through.yarn to pass through.

�� 2) Picking2) Picking: the passage of the shuttle or other device : the passage of the shuttle or other device across the loom to put a weft yarn in the shed.across the loom to put a weft yarn in the shed.

�� 3) B3) Beatingeating--upup: the pushing of each loose weft yarn : the pushing of each loose weft yarn into the cloth by the reed, after the shuttle has moved into the cloth by the reed, after the shuttle has moved through the shed.through the shed.

Weaving Principle (III)Weaving Principle (III)

Auxiliary MotionsAuxiliary Motions

�� The functions of auxiliary motions are to continue The functions of auxiliary motions are to continue supply the warp yarn to the weaving loom and takesupply the warp yarn to the weaving loom and take--up the cloth onto the cloth roll.up the cloth onto the cloth roll.

�� 4) Warp let4) Warp let--offoff: Unwinding of the warp beam to : Unwinding of the warp beam to supply more warp yarn as the cloth is woven.supply more warp yarn as the cloth is woven.

�� 5) Cloth take5) Cloth take--upup: the turning of the cloth roll to wind : the turning of the cloth roll to wind up the cloth as it is woven.up the cloth as it is woven.

�� 6) Pattern6) Pattern: the vertical movement of the boxes in : the vertical movement of the boxes in shuttle box loomshuttle box loom

Weaving Loom

Air-jet,

shuttless loom

Cloth

Warp Let-off

Warp Yarn

Hardness

Warp yarn is

delivered to the

loom

DiscussionDiscussion

�� Discuss the functions of Primary motions and Discuss the functions of Primary motions and

Auxiliary motions of weaving machine.Auxiliary motions of weaving machine.

�� How can you increase the weaving machine How can you increase the weaving machine

production?production?

Weaving MachineWeaving Machine

Weaving MachineWeaving Machine

Shuttle LoomShuttle Loom

�� Looms that use a shuttle to insert the weft yarn in the Looms that use a shuttle to insert the weft yarn in the shed is called shuttle loom.shed is called shuttle loom.

�� A shuttle is a wooden, boatA shuttle is a wooden, boat--like device with a bobbin like device with a bobbin placed inside.placed inside.

�� As a shuttle is thrown across the loom, the weft yarn As a shuttle is thrown across the loom, the weft yarn unwinds from the bobbin, leaving a trail of yarn unwinds from the bobbin, leaving a trail of yarn behind.behind.

�� When the weft yarn inside the shuttle is almost When the weft yarn inside the shuttle is almost exhausted, a full bobbin is automatically inserted into exhausted, a full bobbin is automatically inserted into the shuttle, which allows weaving to continue without the shuttle, which allows weaving to continue without stop.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.

PirnPirn--changing for shuttle loomchanging for shuttle loom

Pirns for refilled the empty shuttlePirns for refilled the empty shuttle

Shuttle LoomShuttle Loom

DisadvantagesDisadvantages

�� Shuttle loom needs a pirnShuttle loom needs a pirn--winding (to rewinding (to re--supply the supply the

weft yarn in the shuttle).weft yarn in the shuttle).

�� The shuttle is big and heavy in weight. The loom is The shuttle is big and heavy in weight. The loom is

therefore slow in speed and noisy in operation because therefore slow in speed and noisy in operation because

of the dynamic problems created by picking and of the dynamic problems created by picking and

checking mechanisms.checking mechanisms.

�� In addition, the shuttle sometimes causes abrasion on In addition, the shuttle sometimes causes abrasion on

the warp yarn as it passes over them and may cause the warp yarn as it passes over them and may cause

thread breaks.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 machineWeaving machine

Shuttle loomShuttle loom

�� The use of shuttle loom is the slowest and least The use of shuttle loom is the slowest and least

efficiency power weaving. efficiency power weaving.

�� Explain why and how to improve them?Explain why and how to improve them?