ADVANCEMENT in WARPKNITTING

INTRODUCTION‘KNITTING’→ Constructing textile structures by forming a continuous length of yarn into columns of vertically intermeshed loopsWARP KNITTING →A row of stitches are made simultaneously using many threads which form loops in the general direction of fabric growth

Tarrat is credited with developing the first efficient treadle-operated warp knitting frame in 1785

TYPESUsually two type of warp knitting machines are available…

TRICOT

SINGLE BAR DOUBLE BAR

RASCHEL

Difference of principle :The role of Sinker Tricot sinkers combine the functions of holding-down, knowing over and supporting the fabricRaschel Sinkers only perform f holding down the loops when needless rise

ADVANCEMENT TRENDIncrease productionFlexibility in terms of design and material handlingBetter controlNew TechnologyCombination of Technology

MEANSThe new generation warp knitting machines are having

Electronic Control system, mainly servo controlElectronics in place of Mechanical-electric devicesDesign versatility using CAD/CAMImproved Machine gaugeUse of Digital process control and Data analysisNew concepts of Products and designsControl of fine and elastic yarnImprovement of needle material, gauge

ADVANCEMENT TREND

Dynamic servo motors, the newest electronic control systems opened extreme probabilities for produces and designers of advanced lingerie lace, with an entirely new patterning system

In 2003, the new generation machines in the warp knitting were displayed at ITMA, Birmingham. The machines were equipped with individual motors to feed thread, fabric take-up and rolling-up, with all easy navigation. All machines had network systems with latest computers

ITMA 2011 : Karl Mayer Textilmaschinenfabrik GmbH, Germany, exhibited a 50-gauge (needles per inch) tricot machine, HKS 2-3 E, operating at 3,200 rpm and producing elastomeric fabric using 20-decitex spandex and targeted for the lingerie market

This is the first and finest-gauge tricot machineProduces 20,800,000 loops per minute with 130-inch width, 50 gauge and, 200 rpm

Electronic SOGGING

The summary driveThe Karl Mayer electronically-controlled SU guide bar shogging arrangementElectromagnetic type

Each pattern bar has its own unit consisting of six eccentric cams that, although mounted on six separate continuously rotating shafts, are not fixed to rotate with them. On either side of each cam is an electromagnet that, when it receives a signal from the microprocessor, locks the cam onto its shaft causing the cam to rotate, moving its push rod forward like a piston so that the roller in front causes the vertical segmented bar to move upwards. At the top of the bar, the vertical movement is transformed into a horizontal shogging motion.

Sogging is the Heart of PatterningElectronic Sogging is mainly based on Servo Mechanism

Electronic SOGGINGSteel comb Shogging systemServo Control Electromechanical Type

The guide needles that the force are controlled by servo motor, which moving according to the patterns, and the directions are by dint of the air compressor and the mechanical power

Piezo-JacquardA piezoelectric jacquard device which is composed of consists of 1.Piezoelectric bimorph2.Guide holder3.Exchangeable Jacquard guide needle

Type Electromagnetic Jacquard

Piezo Jacquard

Working Speed

400r/min 1300r/min

Power (Per Set)

8kw 1.5kw

Capability Easy To Be Destroyed Reliable

Volume Large 1/8 Of Electromagnetic Type

Can ld be used on Jacquard raschel machineMulti-bar Raschel machineDouble-needle bar Raschel machineHigh-speed tricot machine

Compared to the conventional Jacquard techniques, no displacement takes place with the Piezo-Jacquard System(PLS) but, instead, the Piezo element is activated by a current impulse

ESS DEVICEAccurate Feeding Of Delicate Yarns

Karl Mayer has recently optimized its two-bar tricot machines by developing a special tension bar for processing fine-count elastane yarns more efficiently with the name Elastane-Security System (ESS)

The rubber-coated surface, the precision grinding of the tubular guide, and an additional pressure roller guarantee the non-slip transfer of the peripheral speed to the yarns

This system guarantees a uniform yarn feed. A prerequisite for this is that the yarn tension between the warp beam and the guide causes the yarns to adhere at the tube. However, as the yarn count decreases, the maximum yarn tension that can be achieved also decreases

In order to achieve these low yarn tension levels at fine counts during processing, a modified tubular guide belonging to the new ESS is actively controlled via its own EBA drive

COMPUTER-AIDED PATTERN

Integral knitting machine manufacturers, such as Shima Seiki, have associated CAD software that will accept virtual body images such as those producible with body scanning technology, and then virtually simulated on a 3D image for accurate placement of knit structures

The development of a system to integrate design with production would enhance the performance, comfort, fit, and desirability of knitted garments

KAMCOS® SYSTEMIntegrated and a essential system for all Karl Mayer Warp Knitting Machine

Three Major componentMOTION CONTROLPATTERN CONTROLOPERATOR INTERFACE

Higher PRODUCTIVITYHighest efficiency during production and resource management, minimum downtimes, extremely short set-up times.Improved QUALITYTop-quality guarantee due to excellent reproducibility, monitoring, visualization and signaling facilities.More FUNCTIONALITYJust-in-time management of a flexible production of different amounts of articles, despite of highest versatility of products

Additional components:Warp break sensorFabric defect detection

Motion ControlA well-tried and perfected technology exactly controls the following functions, via electronic drives:

Motion of the main shaft for inching speed and rapid motion Control of the yarn quantity of the individual warp beams via different yarn let-off programsControl of the fabric take-up Control of the batching devices

PATTERN CONTOL

The Pattern Control computer belongs to the technical equipment of machines with electronic control of ground guide bars, pattern guide bars and Jacquard bars. This Pattern Control computer meets all the requirements of rapid pattern change and extensive repeat functions

LASERSTOPEND BREAK DETECTOR FOR WARP KNITTING AND RASCHEL MACHINES by Protechna Herbst GmbH & Co. KG

The laser light barriers operate with a visible red-light laserThe highly homogeneity of the light beam guarantees a

constant sensitivity over the full working widthWhen a broken thread comes out of the warp sheet, it will

break the laser beam. The resulting impulse will be digitally processed and the production machine will be stopped immediately

Fast and safe detection of broken threads from 12 dtex in the warp sheet or at the needle position

Vibration insensitive receiver

SCANNERTHE NEW KNITTED FABRIC SURVEILLANCE DEVICE SCANNER 5390

by Protechna Herbst GmbH & Co. KG

The scanner head travels at a speed of 1-2 m/s at a distance of approx 6-7 cm above the knitted fabric. In this manner the fabric can be scanned directly after it has been formed by the needle bar.

Working principle is Laser light barriersIt can exactly determination of the

position of the fault in the fabricFast reaction time minimizes lengthy faultsIt can Immediately stop the machine even

at high speedsSelf-diagnostic system assists in fault

finding and repair in case of a technical problem

Automatic evaluation of the measured data by means of modern microprocessors

PROCAMPROCAM 5310-AUTOMATIC OPTICAL INSPECTION SYSTEM FOR TEXTILE MACHINES by Protechna Herbst GmbH & Co. KG

Can be used as online surveillance device for warp knitting and weaving machines

Advanced evaluation systems and a special image processing software detect virtually all textile faults exactly at the place they occur

As soon as a fault is detected, the machine is stopped immediately

Extremely short fault lengths even with difficult to see faults due to the permanent surveillance of the complete fabric width

Control of the weft threads on weft insertion machines

SEAMLESS WARP KNITTING

A shaped knit product has advantages over the traditional cut and sewn product in terms of raw material savings, high productivity, higher quality and performance

DJ machines from Karl Mayer Seamless warp knitting technology uses two opposing needle bars equipped with compound needles, which are fed yarns by moving guide barsKnitting commences with the knitting of three tubes side by side (sleeve/ body/ sleeve), which are created by knitting on both needle bars and by closing each tube at the edges by knittingThe shoulder shape of the garment is created by joining of the knitting of both needle bars in a predefined pattern within the tubeWhen the neck opening has been reached, the cycle starts over again to commence knitting of the next garment upside-down

Santoni also offering is named SWD4/2J double needle-bar raschel knitting machines capable of producing sportswear, lingerie,hosiery

AUXETIC TEXTILES

Auxetic textiles belong to a class of extraordinary materials that become fatter when stretched and are increasingly attaining some prominence in many applications of technical textiles

These warp knit structures have been constructed from wales of chain and inlay yarns.

The wales are knitted from open loops using thicker, low-stiffness filaments, and a high-stiffness filament is inlaid around the underlap loops

Such a construction exhibits auxetic behaviour upon stretching due to the straightening of the high-stiffness filament that becomes fully aligned and causes the open loops formed by the lower stiffness filament to wrap around the straightened high-stiffness filament

CIRCULAR WARP KNITTING

The yarns are threaded through radially perforated rings The shogging movement becomes a

rotation of these ringsA pattern chain comprises a number of

rotational movements of the rings in synchronization with the main mechanism responsible for reciprocating the needles vertically.The rings must perform two distinct

rotations and two dwells during a machine cycleThe larger the number of rings, the

greater the patterning possibilitiesThe cylinder diameter is not critical for the

netting applications; this varies in the range of 75-100 mm for the stockings applicationMedical application fabric can also be

produced

CIRCULAR WARP KNITTING

Mechanical design Servo control mechanism

Patterning Mechanism of Circular Warp Knitting

TECHNICAL WARP KNIT

WEFT InsertedWhen the needles are in the lowered position during the warp knitting cycle, a so called ‘open shed’ effect is created at the back of the machine. It is then possible for a weft yarn, laid across the full width of the machine

The weft pins are attached to the needle bar so that the two descend together, releasing the full-width weft at the moment when the weft bits, one above every alternate sinker, advance over the lowered needle heads to insert the weft

In this way, narrow-width fabrics suitable for dish-cloths can be produced

WEFT InsertedMagazine weft insertion

18 or 24 ends of yarn from a stationary creel to an insertion carriage, with a weft insertion speed of 6500m/min is inserted

Actually the speed of the weft yarn will be only 320 m/min because multiple wefts are simultaneously being laid onto thec onveyor to be fed individually to the knitting machine.

The chains convey the weft to the weft insertion bits at the rate of one weft per knitting cycle

BI-AXIAL WARP KNITTED

Bi-axial warp-knitted (BWK) composite is a kind of textile composite produced with BWK reinforcement which consists of cross plied 0⁰/90⁰ straight fiber tows (warp and weft yarns) and knitted loop yarns (tricot yarns)

Structural feature provides not only high tensile modulus and strength in both weft and warp directions for the composite, but also good assistance against impact

MWKWarp Knitting is an inherently fast process to produce non crimp Multi-Axial Warp Knitted Fabrics

In Mayer and LIBA machines, θ can range from 30 to 90 . Besides the ⁰ ⁰oriented fibers or yarns, this process also allows the incorporation of non-woven fabric layers. One limitation of this process is the damage to the in-plane fibers due to the penetration by the knitting needles

Multi-axial warp knit (LIBA) system

diagonal weft thread layer can be laid at any adjustable angle from 60⁰–45⁰ or 90⁰–45⁰

Working width up to 245 inchesProduction speed of 1200 courses /min

Many More….

HD 6/20-65: High performance Raschel machine for high-distance spacer fabric by Karl-Mayer

Stitch Bonded Nonwoven

CONCLUSIONThe warp knitting industry has become in

recent years, one of the fastest growing industries

With the advancement of the digital process control technology may mechatronic principle using high end computers are being used in this technology in place of many mechanical mechanism

These technologies are giving the rise of production speed, better quality control, and value for the money to the customers

The new technologies like circular warp knitting, multi axial warp knitting are also being capable of producing new types of composites fulfilling the technical textile market demand

REFERENCES1. Spencer, D. J., Knitting technology: A comprehensive handbook and practical guide (3rd ed.). Cambridge, England; Lancaster, Pa.: Woodhead Publishing Limited, 2001 2. Mermelstein, S. P., Hale, D., Acar, M., Jackson, M. R., Roberts, K., Patterning Servo-mechanism for a circular warp knitting machine, Mechatronics ,Vol. 11, 2001, p 617-630. 3. Pearson, G. J., Pearson, A. W., Ball, D. F., Innovation in a mature industry: a case study of warp knitting in the U.K, Technovorion, Vol. 9,1989, p 657-679.4. http://www.fibre2fashion.com/konghong/products.asp [Konghong Corporation Limited, China, Leading Piezo Ceramic Application Manufacturer]5. http://www.warpknitting4u.com 6. Lamar, A. M. T., Powell, N. B., Chapman, L. P., Integrated System to Design/Produce Engineered Knit Garments, NTC Project: S09-NS02, National Textile Center Annual Report: November 2010, Project Website: http://www.ntcresearch.org/projectapp/?project=S09-NS027. http://www.karlmayer.com/internet/docs/Kamcos_0908.pdf, KARL MAYER Textilmaschinenfabrik GmbH, Brühlstraße, 2563179, Obertshausen.8. Gupta, S., New advances of seamless and warp-knit technologies, ATA Journal for Asia on Textile & Apparel, April 2010 issue, 2010.9. Ugbolue et al., The formation and performance of auxetic textiles. Part I: theoretical and technical considerations, Journal of The Textile Institute, vol. 101, No. 7, July 2010, p 660-667.10. Ugbolue et al., The formation and performance of auxetic textiles. Part II: geometry and structural properties, Journal of The Textile Institute, vol. 102, No. 5, May 2011, p 424-433.11. Jin, L., Hu, H., Sun, B., Gu, B., A simplified microstructure model of bi-axial warp-knitted composite for ballistic impact simulation, Composites: Part B, 41, 2010, p337–353,available in Science Direct.12. Kamiya, R., Cheeseman B. A., Popper, P., Chou, T. W., Some recent advances in the fabrication and design of three-dimensional textile preforms: a review, Composites Science and Technology, Vol. 60, 2000, p 33-47.13. Bailey, D. L., Grow, J. L., (2000): 4. Knitting Overview, Textile Progress, 30:1-2, 41-50.14. Little, T. J., ITMA Technology: Circular And Warp Knitting, Textile World Asia, December 2011, directly from http://www.textileworld.com15. www.karlmayer.com

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