Derivatives of Warp Knitting

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Fabric Science- II Derivatives of Warp Knitting An Effort By:- Vikash Kumar DFT-IV NIFT Chennai

Transcript of Derivatives of Warp Knitting

Page 1: Derivatives of Warp Knitting

Fabric Science- II

Derivatives of Warp Knitting

An Effort By:-Vikash KumarDFT-IVNIFT Chennai

Page 2: Derivatives of Warp Knitting

Introduction

• Forms by interlacing loops of yarn, but vertically down the fabric in contrast to weft knitting

• Yarn zigzags along the length of the fabric

• Follows adjacent columns "wales" of knitting, rather than a single row "course“

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Derivatives of Warp Knitting

• Double Tricot Structure

• Locknit Structure

• Satin Structures

• Reverse LocknitStructures

• Shark Knit Structures

• Tulle Fabric

• Warp Knitted Knotless Nets

• Queen S Cord

• Net Structures

• Laying-in Structures

• Raschel Knit

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Double Tricot Structure

• Lapping movement– Front & back guide bars 1

and 1 lap in opposite directions

• Threading arrangement– Front & back guide bars

fully threaded

• Fabric characteristics– Light weight fabric; splits

very easily if a yarn breaks or a stitch drops

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Locknit Structure

• Lapping movement

– Front guide bars 2 and 1 lap

– Back guide bar 1 and 1 lap in opposite directions

• Threading arrangement

– Front & back guide bars fully threaded

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Conti…

• Fabric characteristics– Good elasticity– Due to free-floating underlaps the fabric has a smooth

back, which is very pleasant to touch.– Light weight– Non-splitting– Edge curling towards the technical back– The structure contracts in the lateral direction after leaving

the needles by about 67% (the structure was traditionally knitted on E28 machines but today knitting on E32 - E40 is becoming popular)

– Generally used to produce ladies lingerie

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Satin Structures

• Lapping movement

– Front guide bars 3(4) and 1 lap

– Back guide bar 1 and 1 lap in opposite directions

• Threading arrangement

– Front & back guide bars fully threaded

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Conti…

• Fabric characteristics– The fabric shrinks after leaving the needles. This is

due to the long underlaps

– Good elastic properties

– Very comfortable to wear

– Edge curling towards the technical back

– As the length of the underlaps increases, the structure exhibits a smooth and shiny technical back, but at the same time the structure becomes heavier

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Reverse Locknit Structures

• Lapping movement– Front guide bars & bsp 1 and 1 lap

– Back guide bar 2 and 1 lap in opposite directions

• Threading arrangement– Front & back guide bars fully threaded

• Fabric characteristics– Not so stable as locknit

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Shark Knit Structures

• Lapping movement

– Front guide bars 1 and 1 lap

– Back guide bar 3(4) and 1 lap in opposite directions

• Threading arrangement

– Front & back guide bars fully threaded

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Conti…

• Fabric characteristics

– The trapped longer underlaps restrict the fabric shrinkage

– Rigid and very stable structure (more stable than other structures)

– Rough technical back; the reason for the name

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Queen S Cord

• Lapping movement

– Front guide bars pillar lap

– Back guide bar 3(4) and 1 lap in opposite directions

• Threading arrangement

– Front & back guide bars fully threaded

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Conti…

• Fabric characteristics

– High degree of stability

– Minimum lateral shrinkage after leaving the needles; i.e. final width of the fabric is closer to that of the knitted width

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Net Structures

• Net structures can be classified into the following groups:– 1. Net structures in which the distance between

the wales is determined by the gap between the needles used to knit the structure. Generally the yarns of a second set of yarns are used to bridge the gap between the wales. The shape of the opening is determined by the lapping movement and by the tension in the yarns. If the yarn tension is high it would cause the wales to distort, but generally the pillars are vertical or almost vertical.

– 2. Net structures that are formed by interconnecting pillars. The side connections are achieved by inclining and distorting neighbouring wales. The typical openings of these nets are diamond shaped. It is also possible to produce nets with other openings.

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Laying-in Structures

• A guide bar is used to insert yarn ends into the fabric structure. The laid-in yarn end is not knitted into the structure, but it is held in the structure between the stitches (in the technical front) and the underlaps (formed by other yarns in the technical back).

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• Basic principal of laying-in

– Laying-in is achieved using a back guide bar. Generally, at least one fully threaded guide bar in front of the laying-in guide bar(s) produces the ground structure.

– A laying-in guide bar can be fully or partially threaded. Fully threaded laying-in guide bars increase the fabric stability. Partially threaded laying-in guide bars are utilised for patterning purposes.

– The laying-in guide bars carry out only the underlaps.

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• Advantages of laying-in– Laying-in technique allows one to knit yarns that are otherwise

difficult to knit

– Any yarn which is capable of passing freely through the guide eye and between the needles can be inserted into the fabric

– Laid-in yarns contribute very little towards the fabric weight because of the lack of loops

– Saves on patterning yarn, which is usually more expensive, i.e. a commercial advantage

– Designers can use this technique to enlarge the range of designs by laying-in yarns with coarser counts (up to thousands of dtex) and yarns of different texture. Laying-in technique is used in creating lace and curtain fabrics.

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Tulle Fabric

• Tulle is a lightweight, very fine netting, which is often starched

• It can be made of various fibres, including silk, nylon, and rayon

• Tulle is most commonly used for veils, gowns (particularly wedding gowns), and ballet tutus

• Tulle comes in a wide array of colors and it can also easily be dyed to suit the needs of the consumer. It is readily available from most fabric stores and through special order.

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