FUNDAMENTALS OF KNITTING MACHINES- BHARAT MACHINERY WORKS

What is knitting?

Out of total fabric production occurring in India, knitting forms more than 30% of the share. We define knitting as the process of making a piece of fabric by intermeshing the loops of yarn. The knitted fabrics that we make can be either in tubular or flat form. We can use the knitted fabrics for making apparels as well as other products such as sweaters, hosiery, underwear, stockings and socks.

Types of Knitting Machines:

We usually classify the knitting machines into two kinds, i.e. warp knitting machines and weft knitting machines. Warp knitting machines form loops in the vertical direction whereas weft knitting machines form loops in the horizontal direction. As compared to warp knitting, weft knitting is more open, more resilient and has more design possibilities. The type of stitch that we use in weft knitting affects both the properties as well as the appearance of the knitted fabric. Warp knitting offers more cover, less resilience, lighter weight and higher productivity.

Depending on the form of needle bed, type of fabric and type of needle used during the process of knitting, weft knitting machines can be further divided into two categories, i.e. circular knitting machines and flat knitting machines. In the circular knitting machines, we set the needles either parallel or radically in one or more circular beds whereas in flat knitting machines we use straight needle beds having independently operated needles usually of the latch type.

Circular And Flat Knitting Machines:

Circular knitting machines provide fast production speeds than that of flat knitting machines. Therefore, circular weft knitting machines offer more productivity as compared to the flat knitting machines. Most of the circular knitting machines contain the needles which are present in the grooves cut of the wall of a cylinder. The cylinder containing the needles usually has the diameter ranging from 1 cm i.e.0.4 inches to 1.5 metres, i.e. 5 feet. In some of the circular knitting machines, there are two sets of needles, present in the concentric cylinders so that they can provide the interlock function. During the process of the knitting, the butts of the needles move through the cam tracks. The needles slide up and down for picking up the yarn, forming a new loop, and casting off the previously formed loops. In the least complicated circular knitting machines, there is only one feeder to supply the yarn, and each needle picks up the yarn once during every revolution of the cylinder. 

                                          Whereas in the modern circular knitting machines there can be 100 feeders for supplying the yarn, and each needle has to pick up 100 threads per revolution. In circular knitting machines, we can use both latch as well as spring needles. Out of the two needles we most commonly use latch needles for circular knitting machines. We use modern circular knitting machines of plain or jersey type with 90–100 feeders in them to produce medium-weight fabric. Small bladelike units called as sinkers are present between every two needles to engage and hold the completed fabric. Sinkers prevent the fabric from riding up with the needles as they lift to form new stitches. We can also fix pattern wheels in the circular knitting machines to control the action of the needle to produce tuck and float stitches. Also, prefer to attach the Jacquard mechanism in the circular knitting machines for getting the better performance. Stop motions are also an essential feature necessary to stop the machine when a thread breaks. Yarn tension affects the uniformity of the fabric; therefore, it is vital to provide the circular knitting machine with the various tension controllers. By using positive feed method, we can feed precisely measured amounts of the yarn into the machine.

Circular rib knitting machines consist of a vertical cylinder. The vertical cylinder contains the slots of needles on the outer side and a horizontal bed in the form of a circular plate containing the needle slots that cut radially. Therefore, in circular rib knitting machines, there are two sets of needles arranged at right angles to each other. Circular knitting machines can produce seamless hosiery, knitted in the tubular form. Modern knitting machines like the Komet knitting machine uses the double-hooked needles present directly opposite to each other in the same plane to knit the leg and foot portions, the heel and the toe.

Circular knitting machines can knit underwear fabrics except to that of the fully fashioned underwear, leotards and tights which we knit by using cut, make, and trim operation. The best way of finishing the hosiery is by washing, drying, and a boarding process. During the finishing process, we place the hosiery over a thin metal or wooden form of appropriate shape and then press them between the two heated surfaces. While dealing with the nylon fibre, we make use of the pre-boarding process, in which we set the loops and the fabric in the pattern of appropriate shape before dyeing and finishing them. We then place the pattern of suitable shape containing the fabric in an autoclave or pass it through a high-temperature setting unit. When we treat the fabric by the pre-boarding process, then the fabric does not distort during dyeing.

We can also use circular knitting machines for making simulated furs. We intermesh the plain-stitch base fabric with the plush loops and then cut the loops to produce a pile. A more common method of forming the pile is by using a carded sliver. For creating the pile by using the technique of carded silver we take a plain-stitch fabric as the base and then intermesh it with the loose fibres from the silver. To determine the depth of the Pile, we measure the length of the fibres in the sliver.

The delicate knitting machines like Jacquard circular knitting machine incorporates in them electronic sinkers for giving better performance.

Flat knitting machines consist of a flat plate or needle bed or two beds at right angles to each other and each bed at a 45° angle to the horizontal. In flat knitting machines, the placement of the needle is on the flat plate or the needle bed. The upper edges of the plates which we call as throat allow the knitted fabric to pass downward through space between them. During the process of knitting, the cams attached to a carriage by a yarn guide pushes the needles up and down which then moves over the entire length of the machine. By using flat knitting machines, we can also alter the width of the fabric by increasing or decreasing the number of active needles. Flat knitting machines allow the production of shaped fabrics, which when we sew together produce fully fashioned garments. 

                                                      

                                           Though the flat bed knitting machines are suitable for hand operation when we have to use them for commercial purposes, then it’s always better to operate them by using power. By using flat knitting machines, we can get an unlimited variety as we have the freedom of selecting the colour and type of stitch. We always prefer to attach the automatic narrowing and widening devices in the cotton frame knitting machine so that we can knit fine, properly shaped fully fashioned goods like hosiery and sweaters. In flat knitting machines, we can change the machine cams after every course or even after every stitch; thus these machines offer more versatility in loop structure combinations as well as in patterning. By using flat knitting machines, we can easily knit one or both the beds. However, you should know that if you use electronic circular machines, then these provide us with the same capability as that of flat knitting machines.

We can further divide the flat knitting machines into four classes:

(i)    V-bed flat knitting machines having two inverted V-formed needle beds

(ii)    Purl machines having double ended needles

(iii)   Flat knitting machines that possess a single bed of needles- It includes most of the domestic models, and a few hand manipulated intarsia machines.

(iv)  Cotton patent machines--- these are single-bed machines having bearded needles arranged vertically. Bearded needles have an extended terminal hook or beard which can be bend to close the hook.

Parts Of Knitting Machines:

1. CAMS- cams are the devices that convert the rotary machine drive into suitable reciprocating action for the needles. The loops can be formed sequentially by the up and down motion of the needle butts moving through the cam system.

2. The needle which we mostly use in weft knitting is the latch needle. It consists of a latch, a needle hook, and a needle stem. The main benefit of the latch needle is that it controls the loop. The individual movement and control of the needle allow the complete formation of the loops.

3.  Another essential element in the knitting machine is the sinker. Sinkers perform the functions like loop formation, holding down, and knocking-over. However, in V-bed flat knitting machines with latch needles, the primary role of sinkers is to perform the holding-down function. Holding down sinkers provides us with tighter fabric structures having an improved appearance.

4.  Knitting machines also consist of brushes. The primary purpose of the brushes is to open the latches at the beginning of the procedure when the machine starts to knit and to avoid the closing of the latches.

5. The carriage pulls the yarn carrier or yarn feeder along the needle bed. It introduces and feeds the yarn required for knitting. The place of yarn carrier is usually over a dove-tail profiled rail.

6. Take down rollers helps in preventing the previous loop, which is present in the hook enclosure, from riding up with the needle ascension. It is a very crucial step in the process of loop formation because without the operation of the take down rollers the previous loop will not slide under the latches and new loops will not get formed.

Our company, Bharat Machinery Works, offers the best quality knitting machines:

Bharat Machinery Works is one of the leading manufacturer and supplier of Flat Knitting Machines and Circular Knitting Machines. Our machines are famous worldwide for their remarkable qualities like high durability, rust-resistant, consume less power, robust, eco-friendly, offers the best performance and functioning, time-saving. Our company keeps updating the machines with the latest advanced technologies to meet the ever increasing demands of the customers.

So, contact us for getting the best quality flat and circular knitting machines at affordable prices.