oral exam Flashcards
Burn test
- Melting or burning
- Characteristics, oddor of fumes, appearance of residue after burning
Acetone testing
- Acetate will dissolve
Chlorine bleach testing
- Silk or wool will disintegrate
alternative to wool
acrylic
sun yarns
- Can be untwisted
- Longer fibres
- Provide warmth and softness
Filament yarns
- Made of manufactured fibres or silk
- Made and marketed by chemical fibre producer
- Good for when you need smoothness and luster since yarns are finer
Compassion of sun and filament yarn properties
Yarn uniformity:
SPUN- Less uniform
FILAMENT- More uniform
Yarn smoothness & luster:
SPUN- Less smooth and dull with slight surface fuzz
FILAMENT- Smother and more luster, Yarns have no fuzziness due to short fibres
Yarn strength:
SPUN- SOme fibres break and others slide away from each other
FILAMENT- Stronger than spun yarns of the same diameter because it requiers more force to break all the fibres
Comments:
SPUN- More twist will increase strength of spun yarn
FILAMENT- Smooth surface can cause yarns to slip and slid in a fabric
Mono filament yarns
Single filament
- used in nylon hosiery, fabric webbing for patio chairs
Multi
- Many filaments
- Makes fabrics that are softer and more flexible
Yarn twist
- Spun and filament yarns are made by twisting together fibres
- The amount of twist is designated as turns- per- intch or TPI of the yarn
Knitting
Is the process of making cloth by the interlooping of yarns
- A single yarn is looped through itself to make a chain of stitches
- A knitted loop is referred to as a stitch when it is pulled through another.
Weft Knits
Yarns run horizontally, from side to side, across the width of the fabric.
Warp knits
- Yarns run vertically in the length of the fabric.
- Warp knit fabrics can be identified by the clearly defined knit stitches running vertically, but slightly angled from side to side.
Wales
- the vertical rows of stitches that run in columns along the lengthwise direction of the knitted fabric. (similar to warp in a woven fabric).
Courses
the horizontal rows of stitches in a knitted fabric. They run from side to side in the knitted fabric (similar to the filling in a woven fabric).
Wales and Courses per inch
Fabric weight, hand, insulation, shape retention, drapability and cost.
Wales per inch depend on the number of needles used per inch
Courses per inch depend on the height of the stitch loop.
Cut
refers to the number of needle slots in a knitting machine.
Higher the cut = more closely knit fabric
Lower the cut = coarser knit fabric.
Gauge
refers to the closeness of knit stitches. It also refers to the needles per inch in the knitting machine
Types of Knitting Stitches
- There are 4 principal stitches in knit fabrics:
- KNIT, PURL, MISS, TUCK
Knit Stitch
the basic knitting stitch. Also called plain stitch
Purl Stitch
The reverse of the knit stitch
Miss Stitch or Float Stitch
A miss stitch (see fig.6.12 ) is a floating unknit yarn on the back of the fabric. It’s used to create color and patterns in knitted fabric. It’s prone to snagging
Tuck Stitch
The stitch is elongated and appears as an inverted V on the back of a fabric
Basic Weft Knit Fabrics
Jersey knit, Rib knit, and Purl knit
Jersey knit: Smooth face with vertical ribs (wales) on right side of fabric and horizontal ribs (courses) on the back.
Characteristics of Jersey knit:
Fabrics made with jersey knit: sheer, light weight hosiery, men’s underwear, t-shirts, knit terry, knit velour.
