Exam 2 Flashcards
Simple yarns are:
Smooth
Complex yarns are:
Irregular
The steps of ring spinning are:
1 opening
2 cleaning
3 blending
4 carding
5 combing
6 drawing
7 roving
8 spinning
The opening step of ring spinning is:
When a hopper machine breaks open the compact bale of fiber and fluffs them on to a conveyor belt
This is the first step that comes before cleaning and blending
The cleaning step of ring spinning is:
When the dirt is removed in a centrifuge
This comes after the fibers are opening and before the fibers are blended
Carding is:
When the fibers are further cleaned and aligned by wired cards that remove the shortest fibers and forms a mass that is pulled into a rope called a sliver
This step is after cleaning and blending and before combing
A sliver is:
A rope like strand pulled from A webbed mass of fibers created by carding
Combing is
Carded slivers are fed to the breaker- drawing frame, where several card slivers are combined and combed to further allign the fibers and creates new combed slivers.
This step is after carding and before drawing
What is the difference from a carded sliver and a combed sliver?
Carded slivers are
-looser
-have 20% more shorter fibers
-less aligned
-not finalized
-removes a majority of impurities
-more absorbant
-used in napped fabric
Combed slivers are:
- the final sliver
-contain longer fibers
-made with finer combs
-more twisted
-further aligned
-smoother
-uniform
-formed from several carded slivers
-removes the rest of the impurities
What is drawing?
This is the stage where fibers can be mixed . Slivers from carding or combing unit are processed through drawing or drafting frame and combined.
This step comes after combing and before roving
What is roving?
Slivers from drawing are then taken to the roving frame where each sliver will be narrowed to 1/8 the original diameter
●A slight amount of twist is given by the roving frame to increase the strength of roving
This step comes after drawing and before spinning
What is spinning?
Roving is attenuated (narrowed) to the desired diameter called final draft
●More twist is introduced
●New final draft is fed to the spinning area
-a machine called the traveler twists the yarn in a u shaped guide on a bobbin via a spindle turning
-this step comes after roving and is the final step in ring spinning
What is rotor spinning
Also called open ended spinning or break spinning. Rotor spinning is A faster, ring-less system of twisting yarns by feeding a sliver into a funnel that breaks the sliver into fibers that are fed into an open end that creates the yarn
-less strong than ring spinning
-better uniformity and blending
Z twist
Twist direction for cotton yarn
S twist
Twist direction for wool yarn
Z + S twisting
One will be more twisted and one will be more unwound
Low twist yarn
Used in knits
More:
-soft
-fluffy
- breathable
-better hand
-dirt penetrates
Less
-strong
High twist yarn
-More strength (to a point)
-smoother
-Too much can create an
uneven surface that kinks and
-lacks luster and be
-unbalanced
-pilling of fabric
-dirt can’t penetrate
Balanced and unbalanced yarn
Unbalanced yarn is over twisted and tends to coil and kink when it hangs
Balanced yarn hangs straight
Torque
Internal force built as yarn is twisted
TPI
Twists Per Inch
Twist-less yarns
●A roving frame is made and drawn to a fine strand
●Adhesive is applied by rollers
●Heat is used to set the adhesive and bond the fibers
Differences from ring-spun yarns
●Stiffer
●More luster
●Less elongation
●Better covering power
●More uniform
-softer
-more absorbent
Filament yarns
Ie. silk and synthetic
-stronger than other fibers of same diameter
-force slides staple fibers apart
-force is applied evenly on filament fibers
Self twist yarns
-formed directly from fibers
-reduced space and cost
-higher production speed
-4 rollers occelate and spin with 2 yarns fed into two sets of rollers
Higher yarns per inch means
More:
strength
Weight
Better hand
Reduced yarn distortion
Abrasion resistance
Cost
Yarns per inch
Filling X warp
F epi X W ppi
Filling is the yarns per inch
Qualities of plain weave
Poor luster
Good snag resistance
Flat surface
Low tearing strength
Poor wrinkle resistance
Qualities of twill weave
Fair luster
Good snag resistance
Twill line surface
Medium tear strength
Fair wrinkle resistance
-compact
Qualities of satin weave
Good luster
Poor snag resistance
Smooth surface
High tearing strength
Good wrinkle resistance
-unbalanced
-warp or weft facing
-minimum interlacing
-dense
Qualities of ribbed plain weave
-Filling yarns are thicker
-Filling can have lower twist or staple fibers
-less wear
Basket weave
-reversible
-decorative
-low twist
-poor durability
-shrinkage
-yarn distortion
Fewer interlacings mean
More yarns per inch
Wales
Columns of stitches in knits
#of wales = needles per inch
Courses
Rows of stitches in knits
Purl stitch
-reverse knit stitch
-course faced
Miss stitch
-When needles don’t move to accept yarn
-yarn floats on back of fabric (float stitch)
-can create designs
-increases weight
-reduces stretch
Tuck stitch
-Needle holds old loop while receiving a new yarn
-collects two loops
-elongated stitch
-inverted “v”
-increases width and weight
Warp knit
Used in lingerie
Diagonal
-each loop has own yarn source
Qualities of weft knits
-4 way stretch
-more stretch in width
-may run or ravel
-can create shaped garments
-can create finished edges
-curls at selvage
-shrinks in wash
-fast, easy and cheap to make
Qualities of warp knits
-limited stretch
-does not run or ravel easily
-slower and more costly
-produces yardage only
-zig zag on back
Tricot fabric
-warp knit
-flat production
-used in lingerie
-fastest production speed
-mesh
Raschel fabric
-warp knit
-uses compound needles
-can use large number of yarn guide bars for variation
-lace
Differences between tricot and raschel fabric
-heavy yarns, open spaces, lace, surface effects = raschel
-fine yarns, no or simple design, mesh = Tricot
Differences in recovery and wrinkling between knits and woven
-Knits recover faster
-can’t be sharply creased
-knits are good for traveling
-easier care
Differences in insulation and warmth between knits and woven
-knits are good insulators but are poor in wind
-tightly woven fabric provide better wind resistance
problems with knits in comparison to woven fabric
Knits tend to stretch out of shape and snag more than wovens
Knits with with higher stitch density are
-stable
-rigid
-tends to shrink less
-have less stretch
-better recovery
Knits with lower stitch density
-stretch easily
-less rigid
-more poor recovery
-snags easier
-shrinks easier
-yarn distortion
-consumes less yarn
-faster to produce
-shape retention compromised
Factors that limit production in ring spinning are
-Spindle speed
-amount of twist desired f
Rotor spinning is
- an open ended way of spinning in a funnel that is faster than ring spinning
- slivers from roving are broken apart into individual fibers
Advantages of open ended spinning (break spinning) are
-Better regularity
-uniformity
-distribution
-absorption
Disadvantages of open ended (break) spinning are
-can’t spin fine yarn
-only able to spin course-medium yarn
-less strength than ring spun yarn
Spun yarns
-made from staple fibers
-fibers are made parallel then pulled and twisted together
-twisting introduces surface friction by pressing fibers together which adheres them to each other
Comparison of spun and filament yarns
Uniformity
Smoothness (spun is fuzzy)
Luster
Strength
-filament generally wins out on these categories
- filaments can slip and slide in fabric and out of seams
-spun fibers slip less because they adhere to each other with friction
-filaments break completely while only some fibers break or slip in spun yarn
Spun yarns provide
-warmth
-softness
-lightweight
Ideal for :
-blankets
-sweaters
-T-shirt’s
Filament yarns provide
-smooth uniform surfaces
-luster
-finer diameter
Used in:
-Lining (easy to slide on and off)
-outer wear surface (tightly packed yarns offer less wind penetration)
TPM
Turns per meter
Crepe fabric
-Made from highly twisted filament yarn
-combines Z and s twist
-pebble textured surface
Napped fabric is
Fabric with a surface texture resulting from fibers being brushed out and raised from the surface
- fleece
-denim
-suede
-woolen
Woolen yarns are
-carded
-fuzzier
-uneven
-bulkier
-insulating
-less twisted
-napped/felted surface
Worsted yarns are
-combed
-smoother
-more uniform
-tighter twist
-firmer
-denser
-holds shape
-shows weave clearly
-tends to shine with ware
-used in suits
Shuttle loom
-filling yarns are enclosed in a shuttle and passed through the shed of warp yarns
-produces narrow fabric
-slow production
Shuttleless looms
-filling yarn is NOT held in a shuttle
-filling yarn comes from cones (yarn packages) at side of loom
-other mechanisms for filling include: projectile, rapier, air/water jet
-more compact
-faster production
PPI
-picks per inch
-determined by rate of warp through loom (inches per minute)
-also determined by the rate filling yarns are inserted (picks per minute)
PPI = (picks per minute) / (inches per minute)
Warp per inch calulation
(#of warp yarns on beam) / (width of fabric) = warps per inch
Rapier
-filling yarn mechanic of shuttleless rapier loom
-rods that pull the filing yarn across
-produces high quality silk and wool
-can use fine delicate filament or heavy weight course yarn
Projectile loom
-projectile with is shot across warp, pulling the filling yarn behind it
-can make wide fabrics (carpets)
-can’t use delicate yarns
Jet loom
-air or water jet propels thread across warp
-is the fastest loom
-no abrasion to weft
-can’t produce very wide fabric
-can’t use bulky or heavy yarns
5 features of woven fabric
-selvage
-warp and filling yarn
-face and back
-top and bottom
-yarns per inch
Selvage
-ensures the edge of fabric won’t tear
ways to make selvage stronger include:
- heavier warp yarns
-more warp yarns per inch
-greater twist
-different weave
Identifiers or warp yarns in fabric
-warp is thinner than filling
-more twist
-more yarns per inch
-stiffer
-plied
Strongest weave
Satin
-floats and less interlacing allows for more density
Leno weave
-warp yarns twist back and forth in pairs around each pick
-warp yarns can slip
-yarns can be spaced apart (see through)
Pile fabric
-cut pile or uncut pile
-warp pile or filling pile (extra set of yarns)
Double cloth
-way to produce pile fabrics
-pile yarns interlace and connect two sets of ground warps and wefts
-interlaced yarns are cut, producing the pile and two sheets of fabric
Clip spot weave
Extra warp or weft threads are woven in floats on fabric and cut in certain spots
Wire cut method
-extra warp is raised in loops to create pile
-wire is inserted through the shed of pile and pulled to cut the pile
Warp/filling pile fabrics
-5th set of yarn is woven into ground fabric
- can be cut or uncut
Looped pile fabric
-Terry cloth method
-based on tension
-uncut pile fabric
-extra warp yarn is raised by wire
- pile is created in both sides
-pile yarns are highly twisted
Tufted pile fabric
-loops are inserted into pre-constructed fabric using needles and a looper to pull the piles of yarn
-can be cut or uncut
Flocking
-tiny fibers are sprinkled on adhesive coated fabric and static points the fiber up
Advantages of pile fabric
-pleasant hand
-higher absorption
-greater abrasion resistance
-thicker
-warmer
Disadvantages of pile fabric
-staining due to high surface area
-care
-long drying time
-loss of piles
Advantages of weaving
-Strength
-durability
-unlimited variety / tightness
-launders well
-any finish can be applied
-resistant to abrasion
-can be cut and draped
Disadvantages of weaving
-must be cut (involves waste)
-cost due to time/production is higher than knitting
-not as flexible and drapable as knits
-wrinkles
-not as form fitting
-not as elastic
- slippage at seams
-subject to shine
-not as porous as knits
Triaxial weaving
-interlaced at 60 degree angle
-uses three sets of yarn
-warp beams are located above weaving area
-a set of 2 filling yarns are inserted horizontally
-no selvage
Gauge
Number of needles per inch
Steps in weaving
1shedding
2picking
3beating
4letting up
Shedding is
-The first step in weaving
-when the harnesses move apart to create space (shed) between the warps
-step before picking
Picking is
-The second step in weaving
-filling yarns (picks) are passed through the shed of warps
-after shedding
-before beating
Beating is
The third step in weaving
-reeds in the beater push filling yarn into fabric
-closes the weave
-before letting up
-after picking
Letting up is
The fourth and final step in weaving
-warp yarns advance through loom
-fabric is rolled up on cloth beam
-after beating
Slashing is
Applying starch to warp yarns
-prevents breaking in loom
-smooths fuzzy ends
