Weft knitting

weft knitting and types

1. Prepared by Rasmin Thahani Z, Assistant Professor, Syed Ammal Arts and Science College, Ramanathapuram . TEXTILE SCIENCE WEFT KNITTING

2. WEFT KNITTING Weft knitting is the simplest method of converting a yarn into fabrics. Weft knitting is a method of forming a fabric in which the loops are made in horizontal way from a single yarn and intermeshing of loops take place in a circular or flat form on a crosswise basis. In this method each weft thread is fed, more or less, at right-angle to direction in which fabric is formed.

3. WEFT KNITTING – contd.. Each course in a weft knit builds upon the previous knitted course. Most of the weft knitting is of tubular form. It is possible to knit with only one thread or cone of yarn, though production demands have resulted in circular weft knitting machines being manufactured with upto 192 threads (feeders).

4. Types of Weft Knitted Fabrics

5. PLAIN KNIT If a weft knitted fabric has one side consisting only of face stitches , and the opposite side consisting of back stitches, then it is described as a plain knitted fabric. It is also frequently referred to as a single jersey fabric (single fabric). Plain knitted fabrics are produced by using one linear array of needles. As such all the stitches are meshed in one direction. These fabrics tend to roll at their edges. PLAIN KNIT

6. PLAIN KNIT – contd.. They roll from their technical back towards the technical front at the top and lower edges. They also roll from their technical front towards the technical back at their selvedges (the self-finished left and right-hand edges of the fabric ). The structure is extensible in both lateral and longitudinal directions, but the lateral extension is approximately twice that of the longitudinal extension.

7. PROPERTIES Single jersey is composed of a number of identical loops, all pulled through the preceding loops from the back of the face of the fabric. This stitch is mostly employed in single jersey weft knitting machine. This stitch is the simplest one & the process is rapid. The fabric produced with this stitch have flat vertical lines on the face of the fabric and the dominant horizontal ribs on the back side.

8. PROPERTIES Plain knit can be unravelled from the course knitted last. Here the height and width of loop is equal. This fabric has the maximum covering power and has a potential recovery of 40% in width after stretching. This stitch is used for preparing ladies stockings, banians, men's and ladies shirts. Its production rate is high because of stitch simplicity. Plain knit fabric tend to curl.

9. USES Sheets Sweaters Terry robes T-shirts Men's underwear Dresses Hosiery and pantyhose Fully fashion garments

10. PURL KNIT If on both sides of a relaxed weft knitted fabric only reverse stitches are visible , then this is defined as a purl knitted fabric . Purl fabrics are produced by meshing the stitches in adjacent courses in opposite directions either by using special latch needles with two needle hooks or by transferring the fabric from bed to bed between each knitting action.

11. PURL KNIT When the fabric is stretched lengthwise, then the face stitches are visible. The fabric shrinks more in the direction of Wales, and once it is released, it relaxes to hide the face stitches between the courses. The interlooping of the stitches of adjacent courses in opposite directions results in the courses of a purl knitted structure closing up. The structure, therefore, has a large longitudinal extensibility.

12. CHARACTERISTICS Slowest of the knitting machines Both side similar appearance More expensive Good stretch in all direction Stretches out of shape easily Crosswise stretch less than a jersey knit Thicker than jersey knits Does not curl Can be unrove from either end

13. USES Infant and children's wear Sweaters Scarves Fancy garment parts PURL KNIT

14. INTERLOCK KNIT Interlock knitted structures could be considered as a combination of two rib knitted structures. The reverse stitches of one rib knitted structure are covered by the face stitches of the second rib knitted structure . On both sides of the fabric, therefore, only face stitches are visible, and it is difficult to detect the reverse stitches even when the fabric is stretched widthwise. The geometry of the yarn path influences the stretch behavior of the knitted fabrics. INTERLOCK KNIT

15. INTERLOCK KNIT The change of direction of the meshing of the stitches in adjacent wales results in the wales of a rib knitted fabric closing up giving it better stretch properties widthwise as opposed to other basic knitted structures. The combination of two rib knitted structures in the interlock structure gives very little or no room at all for the wales or courses to close up and therefore the interlock fabrics shows relatively poor stretch properties in both directions.

16. INTERLOCK KNIT

17. CHARACTERISTICS Reversible It does not curl Firmer fabric Costlier fabric Better insulator Less extensible as compared to other jersey fabrics Heavier and thicker as compare to rib It unrove from the course knitted the last

18. USES Outwear fabric Dress wear Skirt Blouses T-shirts

19. RIB KNIT Rib, 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 the fabric. Rib fabrics are knitted on machines with two sets of needles. Rib knits have a very high degree of elasticity in the crosswise direction.

20. RIB KNIT – contd..

21. RIB KNIT – contd.. To produce rib stitch, it requires two sets of needles operating in between each other in a knitting machine. A rib structure is also known as double jersey structure. Rib knit fabrics have alternating lengthwise rows of plain and purl stitches constructed so that the face and back of the fabric appear alike. This may be produced either on a flat rib machine or a circular rib machine.

22. RIB KNIT – contd.. In both machines, one set of needles pulls the loops to the front and the other set pulls the loops to the back of the fabric. Each set of needles alternately draws loops in its own direction, depending upon the width of the rib desired. For example, rib stitches can be 1x1, 2x2, 2x1, 3x1, and so on.

23. PROPERTIES It is a reversible fabric that means it has the same appearance on face and back of the fabric, both sides showing face loops only. The back loops can be seen only if the fabric is stretched width way. It has the excellent widthwise extensibility. As there are face loops and the back loops side by side, the fabric does not curl at the edges.

24. PROPERTIES Wale lines on ribs run lengthwise on both sides can be seen prominently. No course lines are seen. It is not ready to unravel the structure from start. It only unravels from the end knitted last. Rib knits are warm. Rib is expensive than plain and it is a heavier structure. Output is less. Rib knitted fabrics are costlier.

25. USES Collars and cuffs Necklines Bottom edges of sweaters Double knits jackets Knit hats Men's hosiery Rib knits are usually found on the lower edges of sweaters, sleeves of the wrist line and at neck line, cuffs, stockings, socks, etc.

26. DIFFERENCE BETWEEN PLAIN KNIT AND RIB KNIT FABRIC

27. PLAIN FABRIC & MACHINE RIB FABRIC & MACHINE 1. Face side and Back side of fabric are different 1. Face side and Backside of fabric are same. 2. Less expensive 2. Expensive 3. Lighter fabric 3. Heavier fabric. 4. Produce by S/J m/c. 4. Produce by Double Jersey m/c. 5. The m/c. contains no Dial. 5. The m/c. contains Dial. 6. The m/c. contains Sinker 6. The m/c. contains no Sinker

28. PLAIN FABRIC & MACHINE RIB FABRIC & MACHINE 7. The m/c. contains one set of needles 7. The m/c. contains two set of needles 8. Extensibility: a)      Length wise – 10 to 20% b)      Width wise – 30 to 40% 8. Extensibility: c)      Length wise – 50 to 80% (for 1´1 rib) d)     Width wise – 30 to 45% (for 1´1 rib) 9. Thickness & Warmth: Thicker and wormier than plain woven made from same yarn. 9. Thickness & Warmth: Much thicker and wormier than plain woven made from same yarn. 10. Curling: Tendency to curl 10. Curling: No tendency to curl 11. End use: Ladies stocking, fine cardigan, men and ladies’ dresses, sweater etc. 11. End use: Socks, cuffs, warm outerwear, under wear etc.