Experiment No: 04 Date:02-06-2014

Experiment Name:Analysis the Basic Structure of weft knitting fabric.

Theory: All weft knitted structures are classified into four groups according to the arrangement of loops in their courses & wales.Four Primary structures are given below—

1.Single Jersey/Plain knit structure.

2.Rib structure/Double knit structure.

3.Interlock structure.

4.Purl structure.

Single Jersey/.Plain Knit structure:

The simplest & most basic structure is the “Plain Knit” which is also called “Single Knit”.

A) Appearanch: The fabric is unbalanced, because each side of the fabric exhibits a different appearance.Within each side, the loops on all courses & wales are identical.Each side of the fabric is made of a single type of loop.The top & the bottom of each loop occurs on the fabric back & the centre(leges) of the loop appears on the fabric face.So the face of the fabric is smooth & shows the side limbs of the loops as a series of interlocking “V”s.The reverse is rough & looks like columns of interlacing semicirxles.

B) Extansibility: The fabric is stretchable although not always elastic.Usually, the fabric can be stretched much more in the width then in the length.The fabric is extansible in a course wise direction & in a wale wise direction.However,the degree of extansibility is different when pulled top to bottom from when pulled side to sideThe degree of recovery from stretch is not a property of the construction but depends on the nature of the raw material & yarn construction.It has potential recovery of 40% in width after stretching.

C) Edge Curling: This fabric curls at the edge when the fabric after cut relax state.It has a tendency to curl towards the back at the sides and towards the front at the top & bottom.The difference in construction between the two faces causes strees in the structure so that the fabric tends to curl.

D) Unroving: The plain knit structure can be easily unraveled from the edge which was knitted last.This selvedge is the top edge when the fabric is held upright.The ability of the structure to unravel from both bedge is demonstrated.

E) End uses of plain knit structures: Plain knit structures are used for basic T-shirt,under garments,mens vest.ladies hosiery,fully fashioned knitware etc.

F) Notation Diagram:

G) Graphical Represantation :

Rib Structure:

Rib is also called :Double knit” is the second family of knit structures.Rib requires two sets of needles operating in between each other,so that wales of face stitches and wales of back stitches are knitted on each side of rhe fabric.

A) Appearanch: Same appearanch in both sides.Both sides of the fabric will show face loops since the fabric is produced on the needles of both needle beds.Taken of the needles, the fabric contracts immeadiately in a widthwise direction. The fabric looks as if it is made only of face loops on both sides,named as right/right,double face or double knit.

B) Extansibility: Elastic structure with good widthways recovery after it has been stretched because the face loop wales move over and in front of the reverse loop wales.

C)Edge Curling:

The fabric being in many cases symmetrical on both faces is not exposed to unbalanced strees & therefore does not curl,it lies flat,when curl.

D)Unroving:

Rib structures can be easily unraveled from the edge knitting last.Rib fabric can not be from the edge knitting first.

E) End Uses of Rib structures: Rib structures are used in waist brands,cuffs , caller types, bottom of the fabric,skirt belt fancy boards,under wares,sweaterwares etc.

F) Notation Diagram:

G) Graphical Represantation :

Interlock Structure:

Interlock is another rib variant structure which is produced on specially designed m/c. These m/c possess two sets of needles in both cylinder and dial and at least two feeders.

A) Appearanch: Interlock has the technical face of plain fabric on both sides,But in smoorh surface can’t be stretched out to reveal the reverse meshed loop wales because the wales on each side are exactly opposite to each other and are locked together.

B) Extansibility: This interlock is a elastic structure with good width ways recovery after it has be stretched.

C) Edge Curling: The fabric being in many cases symmetrical on both face is no exposes to unbalance strees.

D) Unroving: Interlock structure can easily be unraveled from thr edge knitted last.E) End Uses of Rib structures: Interlock atructures are used for

underwear,shirts,suits,trouser suits,sportsware,dresses etc.

F) Notation Diagram:

G) Graphical Representation:

Purl Structure:

The another structure is purl structure.As with rib structures,it requires the participation of both needles beds for the production of the loops.Purl fabrics are knitted on m/c with special equipment,which are double ended latch needles & special devices of drive them.

A) Appearanch: Each wale can be made of a combination of face and reverse loops.Each course can be made up of a combination of face and reverse loops.The face loops are covered so the needle and connection arches typical of reverse loops show on both sides.

B) Extansibility: Fabric made of the above basic purl structures have,due to contraction,a horizontal rib effect which makes them elastic in the length direction.

C) Edge Curling: The fabric is usually balanced and does not tend to curl.This however depends on the arrangement of the loops on the face & reverse side of the fabric.

D) Unroving: Purl knit structures can easily be unraveled from the knitted last. Basically purl structures in which each courses is made only one type of loop,behave like plain kniys when unraveling is concerned.Tjey can be unraveled from both ends.

E) End Uses of Purl Structure :Purl fabrics are widely used for baby wear,childrens clothing,sweater,knitware,thick & heavy outerware, under garments etc.

F) Notation Diagram:

G) Graphical Representation: