Yarns Flashcards
What must fibres be turned into before they can be woven or knitted into a fabric?
Into yarns
What is Yarn?
Continuous length of fibres that are interlocked and used to produce fabrics
What do twist do to a yarn?
Hold fibres together & give it strength
Compare a low level twists & a high level twists:
- what are each type of twist more suitable for?
- what type of twist should be used for a brushed fabric? why?
Low level twists:
- allows fibres to slip apart= yarn will be weak
- yarns will be thicker and rougher to the touch
- more suitable for knitting
High level twists:
- increases strength
- gives a smoother, denser yarn= more expensive
- more suitable for weaving
Brushed fabric= low level twist= so fibres can be teased apart easily to form the raised nap
Staple yarn:
What are they?
- what can be chopped to create this yarn?
- what is the surface like? what does this cause? (property)
- what kind of fabrics will they make?
- what else can these fibres do?
(2nd property)
- these yarns have more …? what does this cause it to look like? (3rd property)
Yarn made from short staple fibres that are twisted together to form a yarn
- filament fibres can be chopped into short staple fibres
- hairy= good at trapping air between fibres= good insulators
- fabrics that are warm
- can trap moisture between fibres
- more texture compared to smooth yarns= duller in appearance
Filament yarn:
What are they?
- what is the surface like? what does this mean? (property)
- what do they look like in appearance compared to staple yarns?
Yarn made by slightly twisting one or more filament fibres together
- smooth= don’t trap air between fibres= not good at insulating
- more lustrous
What is the difference between a single yarn and a plied yarn?
- what does it mean if a yarn has more plies?
- what do the plies do?
- why are single yarns twisted together in the opposite direction to the direction that they were spun? (2 reasons)
Single yarn= staple or filament fibres twisted to make one single yarn
Plied yarn= made by twisting single yarns together (e.g. 2-ply= two strands)
- more plies= more durable
- plies hold the fibres together
- yarn= even thickness & no weak spots
A fabrics weight, flexibility, handle, texture and appearance determined by?
The thickness and tightness of the yarn
How is blending achieved?
- what does this allow the fabric made to be?
- what must be done to the fibres for a successful blend? why?
e.g. what must be done to a filament fibre to be blended with a staple fibre?
- what are they mixed together in?
Spinning two or more fibres together to make a yarn
- better suited to the product
- fibres must be same length= so they can be mixed together before spun into a yarn
e.g. must be cut into a staple fibre
- different proportions needed for the yarn
What does a Monofilament yarn consist of?
A single continuous filament
What does a multifilament yarn consist of?
- what are they sometimes referred to as?
- give an example
two or more filament fibres which may or may not be twisted together
- plied yarns (folded)
- e .g. polyester & nylon
What are Core spun yarns?
- what do they consist of?
- what are the important in the manufacture of? why?
- what can the core provide if the outer fibres are weaker due to aesthetic purposes?
(Give an example of a type of core and covering fibres & what this would be used to prevent?)
Multicomponent yarns
- Core at centre of yarn covered by other fibres
- stretch yarns & sewing threads
- core provides strength (e.g. metallic yarns)
EXAMPLE:
Synthetic filament core (polyester)= strength
covering fibres (cotton)= prevent machine needle from overheating during high-speed machining
How can the characteristics of continuous filament fibres be changed?
- why is this done?
By introducing crimps, crinkles and snarls into the filaments
- done so the filament can no longer lie close to each other= able to trap air= better insulators
What are the 2 different types of yarn?
- Textured
- Fancy yarns
Fancy yarns: what do they do to fabrics?
Give texture and interesting effects
Fancy yarns: what do they have added to the length of the yarn?
Irregularities & other effects added to length of the yarn
Fancy yarns: what type of fibres can they be made from?
Any fibre
Fancy yarns: Are they made from continuous filament of staple form fibres?
BOTH
Fancy yarns: What is the most common form of a fancy yarn? (what do they have)
Have 3 different parts to the yarn
Fancy yarns: What are the 3 common parts to the yarn and how do they work? (2 steps)
- why are the threads often different thicknesses
- A fancy
- A base
- A tie thread
- fancy effect thread is twisted around a base thread
- a tie thread is then used to hold the two together
- to create the special effect
What are the 2 common types of fancy yarns?
- Slub yarn
- Chenille yarn
Fancy yarns: How is a Slub yarn usually made?
- what is the result?
- spinning thicker and thinner sections of yarn at irregular intervals
- results in yarn giving fabric a similar texture and appearance to linen or wild silk
Fancy yarns: what do Chenille yarns have?
- how is it produced?
- what is the result?
- fibres projecting from all around a central core of threads
- by weaving an open net-type fabric which is cut afterwards
- chenille fabrics are soft & bulky
Textured yarns: what are fabrics made from textured yarns like? and why?
More interesting
