KNITTING AND NONWOVEN TECH. TXL419 KNITTING AND NONWOVEN TECH. Weft knit

Weft knit products Popular products: T-shirt, socks, sweaters infant/baby wears etc.

Warp knit products Popular products: swimwear, lingeries, curtains, football jersey, lace fabric etc.

KNITTING TERMINOLOGY A Stitch is the basic unit of a knitted fabric which is commonly called ‘loop’ If the feet (c) are below the binding points and the legs (b) are above, then the TECHNICAL FACE of the loop  is being viewed. If, on the other hand, the feet (c) of a loop lie above the binding points at the base, and the arms (b) lie below  then the loop is being viewed from the TECHNICAL BACK side.

Course There are two distinguished loops: WALE & COURSE Wale - vertical column of loops formed by a single needle. Wales run lengthwise through out the fabric and in that sense as similar to the warp in a woven fabric. Course horizontal rows of loops. Courses run widthwise from side to side of the cloth, and in that sense as similar to the weft in a woven fabric.

Unit for Wale: The number of wales per cm or wales per inch Unit for Wale: The number of wales per cm or wales per inch. This depends on upon the closeness of the needles and their thickness. The use of thinner needles can result in higher wales per unit length. Unit for Course: The number of course per cm or course per inch. It is dependent upon the height of the stitch loop.

Stitch density = wpcm x cpcm The stitch density is actually a total number of stitches (loops) per unit area of the fabric eg: stitches/2cm. The higher the stitch density the thinner the fabric and vice-versa.

Cut and Gauge are expressions of fineness and coarseness of stitches in knitted material. The number of needles in the slot of the machine per unit length is called CUT. GAUGE is referred to the closeness of the needles in the machine. The higher the gauge number, the finer the fabric.

Needle bed Needle slot gauge needle

Needle in action

Knitting Element – needles There are three types of needle: i. LATCH ii.SPRING BEARD iii. COMPOUND

Variations of latch needle

Flat Knitting Machine

CIRCULAR KNITTING MACHINE Yarn supply Knit fabric

KNITTING MACHINE – THE PIONEER BY REV.LEE WILLIAM - 1589

EXAMPLE OF YARN PATH DIAGRAM

Types of knitting stitches i. KNIT STITCH It is produced whenever a new loop is intermeshed as a single loop through an old loop. ii.TUCK It is produced when a needle holding its loop also receives the new loop which becomes a tuck loop. Used mainly for design effect.  iii. MISS The miss yarn floating freely on the reverse side of the held loop.

Single Knit Fabric The fabric is produced from one set of needles. They can be produced from flat or circular machine. The fabric is unstable and thinner. Types of single knit fabric: i. Plain Jersey or Stockinette ii. Purl

STRUCTURE OF SINGLE KNIT FABRIC PLAIN JERSEY PURL

Single knit fabrics 1. Plain Jersey or stockinette. Products: The jersey knit is unbalanced and have the tendency to curl at the edges. It stretches approximately equally in both the length and width direction. Products: - T-shirts, - underwear, - panty-hose, - knit terry,etc. Limitation: if one yarn breaks, it causes an unraveling of adjoining stitches called run.

Simplest Knitted Fabric Plain Knitted Fabric

Technical Face and Technical Back Fabric Properties: Extensible Curls

Fabric Curling The top and bottom curl in towards the face of the fabric and the sides towards the back of the fabric.

Fabric Unraveling The constituent loops of plain fabric can readily be disconnected from the structure, course by course, by merely pulling at the most exposed thread. This can take place either from the end first knitted or the end last knitted.

Purl Fabric Produced by knitting alternate courses in opposite directions using double-ended latch needle. Because of the double hooked needle, the purl machine has the capability of producing a knit and a purl stitch in the same wale. Made on link-link knitting machine which use double headed latch needle. Purl fabric lie flat and do not curl. Famous for infants and children’s wear.

Technical front Technical back Purl Fabric Purl or “links-links” fabrics differ from plain knitted fabrics in that the loops are not all meshed in the same direction. In the simplest purl fabric alternate courses are meshed in opposite directions so that the appearance of the fabric is the same from front or back. Technical front Technical back

Rib v/s Purl

Purl Beds Flat Circular

Knitting Action of the Purl Machine

DOUBLE KNIT FABRIC

DOUBLE KNIT FABRIC ii. Interlock Types of double knit fabrics: Produced from two sets of needles and can be produced on rib and interlock machines. These fabrics are close stitch, which provides good stability, and thicker, heavier than jersey. Types of double knit fabrics: i. Rib knit fabric ii. Interlock

Double knit fabric Rib Knit Fabrics Produced from two sets of needle positioned at right angles to each other. Rib-knit fabrics have a very distinct lengthwise rib effect on both sides of fabric. Rib knit lie flat and do not curl at edges. It has greater elasticity in their width than their length. Products: sweater, waistbands, knit cuffs, knit hats, men’s hosiery etc.

Structure for rib fabric

Interlock fabric Columns of wales are directly behind each other. It is a variation of rib knits made on the interlock machine. Columns of wales are directly behind each other. Interlock is smoother, more stable, better insulators and more expensive. It does not tend to stretch easily. Fabrics are popular for blouses, dresses, and dress T-shirt.

Structure for interlock

Machine Type Single Bed Double Bed

Machine Type Single Bed Double Bed

Rib Gating Interlock Gating Needle Gating Rib Gating Interlock Gating

Loop Configuration Technical front Technical back Single Jersey Rib

Fabric Appearance Single Jersey Rib Face Back

Ribs do not curl When the fabric is relaxed and under no strain in the direction of the courses, it collapses to a situation of alternate wale touching one another. The face loop wale tend to move over and in front of the reverse loop wale.

Ribs are thicker Hence a rib is theoretically twice as thick and half the width of an equivalent plain fabric, but it has twice as much width-wise recoverable stretch.

Interlock Fabric

The interlock fabric is a variation of the rib fabric, resembling two separate 1 x 1 rib fabrics inter-knitted. The fabric is relatively firm and smooth. Interlock has the technical face of plain fabric on both sides but its smooth surface cannot 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

Machine Type Single Bed Double Bed

Rib Gating Interlock Gating Needle Gating Rib Gating Interlock Gating

Needles & loops in interlock gating

Loop Configuration Technical front Technical back Single Jersey Interlock The fabric has technical face of plain fabric on both sides

Each interlock pattern row requires two feeder courses each with a separate yarn which knits on separate alternate needles producing two half-gauge 1x1 rib courses whose sinker loop cross over each other, thus odd feeders will produce alternate wale of loops on each side and even feeders will produce the other wale.

Interlock fabric properties The positioning of one set of ribs between the other gives a smooth surface and prevents the relaxed fabric from contracting in width like a 1x1 rib so that thickness is obtained without widthwise contraction. It is obvious that the fabric will have these additional properties: Surface smooth Does not curl; fabric lies flat Heavier and narrower than rib

Interlock Cam System