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