chapter 5: woven fabrics Flashcards
woven fabrics are?
Weaving fabrics consists of:
-interlacing yarn at right angles to each other
Warp yarn
- The length wise yarns
- Runs parallel to the salvage
- Yarns are usually thinner ( for less abrasion weave process)
- usually more warp yarns per inch which makes the fabric stronger in the length wise direction
Weft yarn
- The width wise yarns
- Also known as filling yarns
- Runs perpendicular to the salvage
- Can be thicker, weaker, and have less twist
- Novelty yarns may be used in the filling direction
- Filling yarns will be used as the stretch in woven fabric
What is a loom?
- A device for holding a set of threads or yarns in sequence, parallel, and under tension so that other yarns may be interlaced with them at right angles ( the weft). This process is called weaving.
- Produces woven fabrics by
1) Wrap beam winds warp yarns
2) Warp yarns pass through the harness
3) harness raised produces the shed
4) Filling yarn is inserted in shed
5) Reed pushes filling yarn in the shed
Types of looms
Shuttle loom: uses a shuttle (the wooden boat like device that carries filling weft/ filling yarn across warp yarns)
Types of production looms
4 types
1) Projectile loom: Suited to regular, heavy and bulky yarns
2) Rapier loom: Is capable of weaving with fine, delicate weft/filling yarns. A wide range of fabrics can be made with them.
3) Jet loom: 2 types- air jet and water jet
4) Multiphase loom: Uses multiple sheds. Filling yarns can be inserted faster than a shed loom. used for for high production but only good for basic twill and rib weave.
Grain
The grain of the fabric is a direction parallel to either the warp or filling yarns
On grain
Is used if a fabric has been cut parallel to either the warp or filling yarns
if the has been cut not on the grain then it is considered off grain or bias
Salvage
Lengthwise edge of the fabric. Main purpose is that fabric will not tear when going through finishing processes.
Face and back
Face: has the better appearance and is usually the visible side.
Back: Is the plain side with a faded colour.
Top and bottom
Some fabrics have a top and bottom on the face side.
YPI
Yarns Per Inch
- used to determine quality of fabric
- high YPI means fabric is stronger, better abrasion resistance and improved hand
- Is expressed numerically
ex: 85x60 = 85 warp yarns by 60 filling yarns per square inch
Floats
- When one yarn doesn’t interlace with the next but passes over 2 or more adjacent yarns.
- Floats on the surface increase the amount of luster
- If the float is too long snagging problems may occur
3 basic weaves
- Plain weave
- Twill weave
- Satin weave
Plain weaves
- The simplest and most widely used weave
- Fabrics are reversible unless one side is made the face by printing or finishing
- Have firm construction wears well and offers good surface for printing
- Low surface interest so special yarns or finishes can be used to produce texture
- Tearing strength is lower than any other weave
- Has no floats
other types of a plain weave
Ribbed Plain weave:
- Has a ribbed surface because the filling yarns are thicker than the warp yarns
Basket weave:
- A variation of the plain weave but uses 2 yearns are in the warp and filling direction
- Decorative weave, made with relatively few yarns per inch and low twist yarns
- Not durable and shrink easily when twisted
Twill weave
- Characterized by a diagonal pattern formed by the weaving
- Extremely durable and strong, more compact and heavier
- In a right hand twill the diagonal run upward to the right and left hand twill the diagonals run upward to the left
- Example= Denim
- A balanced twill would have the same size and number of warp and filling yarns per inch
- Most twills are either warp face or balanced
Other types of twill weaves
Broken twill weaves:
- Combining left and right hand twills
- Twills run in one direction for a desired # of yearns and then the direction of the twills is reversed for the same # of yarns and then the pattern repeats
Satin weaves
- smooth and lustrous because filament yarns are used
- Weaves have long floats
- The face yarns are very fine and closely packed
- Strong due to floats
Other types of satin weaves
Sateen fabric:
- Is cotton fabric with filling face satin weave
- Not as lustrous because spun yarns are used
- Not as drapable
Crepe-back satin:
- Warp yarns are fine and filling yarns are highly twisted
- Face of the fabric is almost all warp yarns, the back is almost all filling yarns
- Common end uses
Special fabric weaves
- Leno weave
- Pile weave
- Double weave
Leno
- Warp yarns twist in pairs around each filling yarn
- Used to reduce yarn slippage in fabrics that require yarns spaced far apart
- Used for mosquito netting, curtains and summer clothing
Pile weaves
- Woven pile fabrics are material with raised hair or fur like surface
- Surface is made with an extra set of yarns (pile)
2 basic types of pile weaves
Warp pile- has an extra set of warp yarns
Filling pile- Has and extra set of filling yarns
Double weave
- Double cloth: 2 fabrics held together by a separate set of yarns
- Some of these fabrics are designed to be cut into 2 separate fabrics and some are to remain together
Woven designs with a textile
- Made with long and short floats and placement of interlacing
Dobby Pattern: Simple geometric forms or motifs. Made on a dobby loom
Jacquard pattern: Characterized by complex woven- in designs. Made on a Jacquard loom and is the most costly
Clip spot pattern: Extra yarns are used to make designs, long floats in between patterns are often cut away
Colour and weave effect: Pattern made in a fabric using different coloured yarns in both warp and filling direction
Factors that affect cost of woven fabrics
Fibre content: Cost of fibres
Yarn type: Cost of yarns are based on fibre content and the type of yarns
Construction: The type of weave used
