Knitted fabrics are made using two methods namely warp knitting and weft knitting, both of which yield a wide range of knitted fabrics. Weft Knitting Warp knitting Plain Tricot Purl Milanese Rib Rachel Interlock Crochet Knit
The most common sort of knit fabric is jersey knit. It has a visible flat vertical lines on the front and dominant horizontal ribs on the back of the. As a result, this fabric is often known as single or plain knit. Among the types of knit fabrics, this one is easy to distinguish because of its unmistakable right and wrong side of fabric
Properties of Plain Knitting Elastic Comfortable Fits well Definite right and wrong side Warm to wear Lightweight Different patterns can be created using just plain knit Many different colours available Different weights can be achieved depending on the yarn Edges curls up easily when pulled
End Uses of Plain Knitting Knitwear Hosiery Underwear T-Shirts Pyjamas Sportswear Baby clothes
Purl Knit Fabrics have the same appearance on both sides. Many attractive patterns and designs can be created with the purl stitch. Bulky sweaters and children's apparel are frequently made with it. Purl knits are known for their slow production speed.
Properties of Purl Knitting Can unravel easily The fabric does not curl and lies flat Lightweight Comfortable Warm to wear Available in Various colours It is more stretchable in length direction Purl Knit Fabrics look the same on both sides of the fabric Many attractive patterns and designs can be created with the purl stitch
End Uses of Purl Knitting Knitwear Cardigans Hosiery T-Shirts Clothing Sweaters
Rib knit, is characterised by elevated textured lines. Plain weave differs from Rib weave in that Rib weave uses one heavyweight yarn. Depending on whether the heavier, thicker yarn is used for the warp or the weft, the end result is a fabric with elevated ribs running horizontally or vertically down the cloth. Rib knits are used to create the “ribbing” seen on the lower edges of sweaters, sleeve cuffs, and necklines.
Properties of Rib Knit Fabric Characterised by raised lines either horizontally and vertically Edges don’t curl up when pulled Not so smooth unlike plain knit Heavier compared to plain knit Generally very stretchy crosswise After being stretched, it generally recovers very quickly
End Uses of Rib Weave Fabric Turtleneck clothes Bottom edges of sweaters Cuffs Necklines on clothes Rugs
Interlock knit fabric is a type of double knit. Both the front and back sides of the interlock knit fabric are ribbed. These knits have a smooth appearance on both sides and have minimal flexibility in the width but plenty in the length. These fabrics are created by interlocking two ribbed fabrics made from a single yarn each.
• Are firm and keep their shape compared to plain knit • Creases are quite tough to get rid of • Very little shrinking • They are not prone to curling at the rough edges. • It is extremely soft, firm, and absorbent making it ideal for active wear • Have great amount of stretch
• T-shirts • Tops • Sportswear • Legging
Raschel Knit Fabric is a type of warp knitted fabric manufactured with yarns from the warp beam in a specific knitting machine. The fabric contains slightly inclined vertical knitting loops on the face side and inclined horizontal floats on the backside. Raschel knits are made from various weights and types of spun or filament yarns.
Has good draping qualities Have great dimensional stability They do not ravel Do not stretch significantly and are often bulky
Backpacks Jackets Coats Straight skirts
Filament yarns are used in tricot knits because uniform diameter and high quality is essential for usage with the ultra-high-speed tricot knitting machines. Fabrics made with a tricot knitting machine are typically plain or feature a simple geometric pattern. The fabric's front surface contains vertical wales that are clearly defined, and the rear surface has crosswise courses.
• Its ideal for close-fitting comfort stretch apparel • Excellent elasticity • Shape stability is good, and there is little change in shape after washing • The texture is soft, and the fit is perfect • Resistant to wrinkles and creases because of its porous nature, it is breathable
Innerwear Sports wear Lingerie Sleepwear Swimwear
4.3 Explain the operations of a weft knitting machine 4.3.1 Explain the basic principles and structures of : a. Straight bar frame b. Flat bed machine c. Circular machine
Straight bar frame is a sort of weft knitting machine that comes with a bearded needle. Operating speeds of a hundred courses per minute are possible with this equipment. The machines are noted for their production of high-quality garments as a result of the gentle knitting action and low fabric tension.
Movement is controlled by the accurately constructed cam system. Divisions are equally distributed along the length of the machine in a number of heads. Each knitting head can knit in a uniform manner along the garment panel independently.
A flat bed machine has two flat needle beds forming and upside down “V” formation. This machine is capable of producing complex knit patterns and sophisticated stitching.
Flatbed knitting machines are divided into two categories which are : V-bed machines It has two rib gated, diagonally-approaching needle beds. The needle beds set at between 90 and 104 degrees to each other. It is employed to give an inverted V-shape pattern. Flatbed purl machines It has horizontal needle beds. These machines are occupied mainly in knitting simulated handknitted structures of a specialty type, such as basket purl, lace patterning and cable stitch.
Flat bed machine needle placement
The fabric produced in the circular knitting machine forms a tube with threads running continuously around the fabric. The circular machine starts to knit when the CAM systems on the needle beds move along the surface The needle bed on a circular knitting machine rotates clockwise. Latch and compound needles are used on circular knitting machines.
The majority of the machine's mechanisms are supported by the circular frame or body, which is shaped like a needle bed. The yarn supply system, often known as the creel, is a container that holds yarn packages. Given below are the main parts of a circular knitting machine and its function. Creel The yarn supply begins with the creel, which holds the cone. Each cone is placed on the cone holder. The number of cones used is determined on the creel capacity.
Feeder The yarn is fed into the feeder. The number of feeders is determined by the fabric's design. It is a device that supplies the required amount of yarn to the needle with proper tension. Sensor The sensor will automatically stop the machine if the is yarn breakage. Quality adjustment pulley Quality adjustment pulley controls the quality of knitted fabric by adjusting GSM and stitch length during the knitting process. To increase the fabric GSM the pulley is moved towards clockwise direction and to decrease the fabric GSM the pulley is moved towards the reverse direction
Cylinder Cylinder is the main parts of a knitting machine. The cylinder holds needle, sinker and cam. Cam The cam is the device that turns rotating motion of a needle into a specific reciprocating motion. Spreader After the fabric is produced, the knitted fabric is passed over a spreader mechanism through takeup roll and is wound into a roll. The function of the spreader is to distribute the take up tension uniformly
Automatic Needle Detector A device placed very closed the needles. It gives a signal if there is broken or damaged needle. Winding Roller This roller is located under the take down motion rollers. The function is to roll up knitted fabric.
4.4 Assign the operations of a warp knitting machine 4.4.1 Explain the basic principles of warp knitting 4.4.2 Detail the warp knitting machines
Warp knitting is a loop-forming procedure in which yarn is supplied parallel to the fabric selvedge into the knitting zone. For loop construction, each needle is fed by a different yarn. All of the yarns will be knitted simultaneously . Tricot and raschel are example of warp knitting machine.
Tricot Warp Knitting Machine features : • Knitting is done with fine filaments • Compound needle is used • Low fabric take down tension • Machine speed is high (up to 3500 course per minute) • Number of guide bars usually not more than four • Machine gauge up to 40 needles per inch • Machines are wider and comparatively simple structures are manufactured
Raschel machines uses latch needles together with a latch wire or blade. A set of take-down rollers pull the fabric down from the needles at an angle of 120 to 160 degrees, parallel to the needle bar. Warp beam is placed above the machine It uses up to 16 guide bars Different type of yarn can be used Machines are narrower and has lower speed
High fabric take down tension Sinkers hold down fabric only when the needle raises
4.5 Break down the differences between weft knitting and warp knitting 4.5.1 List the advantages of weft knitting 4.5.2 List the advantages of warp knitting 4.5.3 Differentiate between weft knitting and warp knitting
Weft knitting is the process of creating horizontal loops from a single strand of yarn. These loops can be woven into a flat or circular pattern. Warp knitting is a knitted fabric produced by machine with the yarns running in a lengthwise direction
Weft Knitting's Most Common Uses • Tailored garments such as dresses, suits, and jackets • Seamless hosiery • T-shirts, turtlenecks, and casual skirts • Fabrics with a high stretch and dimensional stability • Complicated patterns and highly textured fabrics
Producing lightweight fabrics, such as brassieres and sleepwear To make laundry bags, furniture, and stitchin fabrics. Inner sole linings of industrial safety and sports shoes are made from warp knits Ideal for use in the manufacturing of gloves, caps, and masks in the industrial sector Knitted structures that are three dimensional are made with this yarn It's used to make bio-textiles.
Warp Knitting Weft Knitting Loops are produced along fabric length (grows by columns, width increases). Loops are produced along fabric width (grows by rows, length increases). It is elastic in the length. It is elastic in the width. Yarn fed in the vertical direction. Yarn fed in the horizontal direction. Less elasticity. Higher elasticity. Each loop is made from a different yarn. A horizontal row of loops can be created using a single yarn. One strand is required for every needle. Any number of needles (usually 2- 3) can be utilized with a single yarn. Less shrinkage. More shrinkage. Any design is done easily All types of design is complex Suitable to produce coarse fabric Suitable to produce thin fabric