textile techniques

8/7/2019 TEXTILE TECHNIQUES

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TEXTILE TECHNIQUES

A loom is a device used to weave cloth. The basic purpose of any loom is to hold the warp

threads under tension to facilitate the interweaving of the weft threads. The precise shapeof the loom and its mechanics may vary, but the basic function is the same.

Weaving

Weaving is done by intersecting the longitudinal threads, the warp, i.e. "that which is

thrown across", with the transverse threads, the weft, i.e. "that which is woven".

The major components of the loom are the warp beam, heddles, harnesses, shuttle, reed

and takeup roll. In the loom, yarn processing includes shedding, picking, battening and

taking-up operations.

y Shedding. Shedding is the raising of the warp yarns to form a shed through whichthe filling yarn, carried by the shuttle, can be inserted. The shed is the vertical space

between the raised and unraised warp yarns. On the modern loom, simple and

intricate shedding operations are performed automatically by the heddle or heald

frame, also known as a harness. This is a rectangular frame to which a series of

wires, called heddles or healds, are attached. The yarns are passed through the eye

holes of the heddles, which hang vertically from the harnesses. The weave pattern

determines which harness controls which warp yarns, and the number of harnesses

used depends on the complexity of the weave. Two common methods of controlling

the heddles are dobbies and a Jacquard Head.

y Picking. As the harnesses raise the heddles or healds, which raise the warp yarns, theshed is created. The filling yarn in inserted through the shed by a small carrier 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,

which in turn is mounted in the shuttle. The filling yarn emerges through a hole in

the shuttle as it moves across the loom. A single crossing of the shuttle from one side

of the loom to the other is known as a pick . As the shuttle moves back and forth

across the shed, it weaves an edge, or selvage, on each side of the fabric to prevent

the fabric from raveling.

y Battening. As the shuttle moves across the loom laying down the fill yarn, it alsopasses through openings in another frame called a reed (which resembles a comb).

With each picking operation, the reed presses or battens each filling yarn against the

portion of the fabric that has already been formed. The point where the fabric is


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forme

s c

e

e fe

Conventional s

ttle loomscan operate at spee

s of about

150 to 160 pic s per minute [1]

With each weaving operation, the newlyconstructe

fabric must be wound on a cloth

beam. This process iscalled taking up. At thesame time, the warp yarns must belet off or

released from the warp beams. To become fully automatic, a loom needs a filling stop

motion which will brake the loom, if the weft thread breaks.[1] An automatic loom re uires

0.125 hp to 0.5 hp to operate.

Typ s ofloo

Back st ap loo

A back strap loom with a shed-rod.

A simple loom which has its roots in ancient civilizationscomprising two sticks or bars

between which the warps arestretched.One bar is attached to a fixed object and the other

to the weaver usually by means of a strap around the back. On traditional looms, the two

main sheds are operated by means of a shed roll over which oneset of warps pass, and

continuousstring heddles which encaseeach of the warps in the other set. The weaver

leans back and uses her body weight to tension the loom. To open theshed controlled by

thestring heddles, the weaver relaxes tension on the warps and raises the heddles. The

other shed is usually opened bysimply drawing theshed roll toward the weaver. Both

simple and complex textilescan be woven on this loom. Width is limited to how far the

weaver can reach from side to side to pass theshuttle. Warp faced textiles, often decorated

with intricate pick-up patterns woven in complementary and supplementary warp

techniques are woven by indigenous peoples today around the world. They producesuch

things as belts, ponchos bags, hatbands and carrying cloths. Supplementary weft patterning

and brocading is practiced in many regions. Balanced weaves are also possible on thebackstrap loom. Today, commercially produced backstrap loom kits often include a rigid

heddle.

arp w i ht d loo

Main article:Warp-weighted loom


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Thewarp-weighted loom is a vertical loom that may have originated in theNeolithic period.

Theearliest evidence of warp-weighted loomscomes from sites belonging to theStarevo

culture in modern Hungary and from late Neolithicsites in Switzerland.[2]

This loom was

used in Ancient Greece, and spread north and west throughout Europethereafter.[3]

Its

defining characteristic is hanging weights (loom weights which keep bundles of thewarp

threads taut. Frequently, extra warp thread is wound around the weights. When a weaver

has reached the bottom of the available warp, thecompleted section can be rolled around

the top beam, and additional lengths of warp threadscan be unwound from the weights to

continue. This frees the weaver from vertical sizeconstraints.

Drawloo

A drawloom is a hand-loom for weaving figured cloth. In a drawloom, a "figure harness" is

used to control each warp thread separately.[4]

A drawloom requires two operators, the

weaver and an assistant called a "drawboy" to manage the figure harness.

Handloo

Ele ents ofa foot-treadle floorloo

1. Wood frame2. Seat for weaver3. Warp beam- let off4. Warp threads5. Back beam or platen6. Rods used to make a shed7. Heddle frame- heald frame-

harness

8. Heddle- heald - theeye9. Shuttle with weft yarn10.Shed11.Completed fabric12.Breast beam


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Hand loom at Hjerl Hede, Denmark, showing grayish warp threads (back) and cloth woven

with red filling yarn (front).

Theearliest looms[citation needed]

were wooden vertical-shaft looms, with theheddles fixed in

place in theshaft. The warp threads pass alternately through a heddle and through a space

between the heddles (theshed), so that raising theshaft raises half the threads (thosepassing through the heddles), and lowering theshaft lowers thesame threadsthe threads

passing through thespaces between the heddles remain in place.

Haute lisseand basse lisseloo s

Looms used for weaving traditionaltapestry areclassified ashaute lisse looms, where the

warp issuspended vertically between two rolls, and thebasse lisse looms, where the warp

extends horizontally between the rolls.

Powerloo s

Main article:Power loom

A power loom used in Ettayapuram

13.Batten with reedcomb14.Batten adjustment15.Lathe16.Treadles17.Cloth roll- takeup


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A Picanol Rapier Loom

Edmund Cartwrightbuilt and patented a power loom in 1785, and it was this that was

adopted by the nascent cotton industry in England. A silk loom was made byJacques

Vaucanson in 1745, which used thesame ideas but it wasn't developed further. The

invention of the flying shuttle byJohn Kay had been critical to the development of a

commerciallysuccessful power loom.[5]

Cartwright's loom was impractical but the ideas

were developed by numerous inventors in the Manchester area in England, where by 1818

there were32 factoriescontaining 5732 looms.[6]

Horrocks loom wasviable but it was theRobertsLoom in 1830[7]

that marked the turning

point. Before this timehand looms had out numbered power looms. Incremental changes to

the three motionscontinued to be made. The problems ofsizing, stop-motions, consistent

take-up and a temple to maintain the width remained. In 1841, Kenworthy andBullough

produced theLancashireLoom[8]

which wasself-acting or semi-automatic. Thisenables a 15-

year-old spinner to run six looms at thesame time. Incrementally, theDickinson Loom, and

then theKeighley born inventor Northrop working forDraper in Lowell produced the fully

automaticNorthrop Loom which recharged theshuttle when thepirn wasempty. The

Draper E and X model became the leading products from 1909 until they werechallenged by

the different characteristics ofsynthetic fibressuch asrayon.[9]

From 1942 the faster and moreefficient shuttlelessSulzer Looms and therapier looms were

introduced.[10]

Modern industrial loomscan weave at 2000 weft insertions per minute.[11]

Today, advances in technology have produced a variety of looms designed to maximize

production for specific types of material. The most common of these are air-jet looms and

water-jet looms.

HORIZONTALLOOM:

A structure on which woven cloth is manufactured, comprising a frameset horizontally

acrossvertical supports. The warp threads were tied across the frame from frontto back so

that theycould be wound out as weaving proceeded. The warp was usually arranged so that

alternate threadscould be raised and lowered, thus allowing the weaver to pass a shuttle

containing theweft thread from side to side across the warp. The horizontal loom was

developed later than theupright loom and provided the basis for the development of

mechanical looms during later medieval andpost-medieval times.


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VERTICAL LOOM:

The vertical beam loom was developed in Syria or the region of the aucasian Mountains

around 2400BC. This type of loom is still used today for making rugs and tapestries.

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