ADVANCEMENTS IN WEFT KNITTING TECHNOLOGYPreeti Taterway Nidhi Mishra

YARN FEEDING ARRANGEMENT

MANUAL AND MECHANICAL SYSTEMS

y Tension assembly provides optimum amount of

tension to the yarn y Tension arm compensates for the irregular nature of the movement created by the traversing carriage

y Very similar to manual machine y Yarn breakage stop motion which stops the

machine y Knot catcher which detects irregularities in the yarn

COMPUTERISED SYSTEM

y The complete bobbin stand can be moved forward above the

knitting area providing easy access to all bobbins y An electronic quality control unit incorporates two major components two thin metal plates and an arc metal bridge

Auxillary Yarn Feeding Devicesy Designed to increase productivity and to improve fabric

quality y Allows yarn to be positively driven into the knitting zone with the minimum required tension y Also a system of side tension arm which detects the yarn breakage much faster

NEEDLE BED

MANUAL SYSTEM y 2 needle beds 48 inches wide. y Gauge ranges from 2.5 needles per inch to 14 needles per inch y Each trick is fitted with a spring which is used to prevent the needle from sliding down and out of the cam tracks

MECHANICAL SYSTEMy Milling of the needle tricks enables the

production of higher quality and wider needle beds y Immediate advantage of this improvement is the ability to knit more than one panel across the machine simultaneously

COMPUTERIZED SYSTEMy Needle beds are 230cms wide to conform with

the required sizes of modern garments and for higher production y Precision tricks are cut and polished in each needle bed to accommodate the various knitting elements required for selection and knitting y Electronic selection system enables the individual selection of the raising jacks and needles

CARRIAGE ASSEMBLY

MANUAL SYSTEMS

y The cam box in one section of the carriage operates the

needles of the front needle bed. The other section rigidly connected to the first, operates the needle of the rear bed

MECHANICAL SYSTEMSy Carriage is connected to the driving chain y Cams of the mechanical machines are activated by strike bars y Cam box consists of one primary raising cam and one

secondary raising cam

COMPUTERISED SYSTEM

y Carriage includes two camboxes one operates

the knitting element of the front bed while the other operates the rear bed y Four knitting cam systems are accommodated in the cam box y In other modern machines, movable carriage is provided with a needle bed that is provided with a cam plate facing each needle bed

FABRIC TAKE DOWN ASSEMBLY

MANUAL SYSTEMS The fabric is weighted to keep it down

MECHANICAL SYSTEMSy Automated fabric take down allows for the

production of connected panels in a continuous form

COMPUTERISED SYSTEM

y Positively driven, computer controlled fabric take down

mechanisms designed to produce the optimum knitting condition y Take down shaft is coated with a high friction material to provide slippage free operation y Electric motor used to drive main shaft is computer controlled and turns to provide the required pre-determined fabric tension. y Take down values can be programmed in 100 stages from no tension to max tension to suit the type of yarn used, the knitting structure , the knitting quality etc.

FURTHER ADVANCEMENTSy Fabric take-down mechanism is provided with stitch stripers y The fabric is passed into the comb gap between the needle

bed by means of the needle stripers and the take down hooks engage the edge of the fabric beneath the needle beds y This avoids the necessity for having accurate spacing between the take down hooks and allows for the use of a smaller number of take down hooks than needles