Circular Knitting Machine: Function, Principles, and Working Proces

In the realm of textile machinery, the circular knitting machine, a commonly chosen industrial textile device, holds a significant presence in manufacturing.The primary function of a circular knitting machine is to produce knitted fabric, utilized for various applications such as everyday undergarments, activewear, sweatshirts, T-shirts, and other semi-finished textile products. After production, the fabrics typically undergo dyeing and further processing before being transformed into clothing.

Principles of Operation:

The circular knitting machine operates based on the principle of power transmission through a series of mechanisms. The motor drives a small gear through a belt and pulley system, which, in turn, propels a large disc gear fixed with needle cylinders. The upper part of the frame is secured with the large disc gear, while the lower part rests on a fixed cam gear. As the large disc gear rotates, it synchronously rotates the entire take-down mechanism and needle cylinders. Simultaneously, the cam gear engaged with gear 8, after passing through a variable speed gearbox, drives the rotation of a transverse axis. Connected by a chain, the transverse axis drives the take-up roller to initiate the fabric-pulling process. The other side of the transverse axis, connected by a chain, propels the active pulley wheel, driving the coiling roller in synchronization. Through belt transmission from the active pulley wheel, the passive pulley wheel is driven, in turn powering the coiling roller for fabric winding.

Applications:

Utilizing needle selection mechanisms to deploy needles according to a predetermined program for the production of jacquard knitted fabrics.
Employing a brushing mechanism to feed loose fibers into the knitting needles, creating long-pile plush knitted fabrics.
Incorporating warp and weft lining devices to produce warp-knitted and weft-knitted fabrics.
Circular knitting machines come in over 350 varieties, and with the development of new chemical fiber types and post-processing techniques, characteristics such as fabric stiffness, wrinkle resistance, and durability have been improved. The application of finishing technologies like raising, shearing, brushing, embossing, and pleating has expanded the variety of knitted products.

Working Process of the Circular Knitting Machine:

Formation of Loops:

The yarn forms loops through vertical threading and horizontal connections, ultimately creating knitted fabric. Loop formation is the fundamental process of knitting.

Looping Stages:

Withdrawal of Loops: Move just-formed loops (termed "day loops") from the needle hook to the needle bar.
Yarn Insertion: Feed yarn onto the knitting needle.
Bending Yarn: Bend the yarn into the shape of loops, transferring newly inserted or recently bent yarn to the needle hook.
Closure: Seal the needle mouth.
Looping: Form a closed and predetermined-sized loop.
Drawing: Pull the newly formed loop away from the looping area.

Loop Connection:

Looping Together: Bring a new yarn or loop into contact with the day loop inside and outside the needle hook.
Loop Removal: Remove the day loop from the needle hook, placing it onto the new loop.
Loop Formation: Shape the yarn into a closed and specified-sized new loop.
Traction: Pull the new loop away from the looping area. This loop becomes the old loop in the next looping cycle.

The looping process can be categorized into knitting and braiding methods. In knitting method looping, the looping stages proceed in the aforementioned order. In braiding method looping, yarn bending starts with loop removal and occurs simultaneously with looping stages. In some knitting machines, individual knitting needles sequentially complete the looping process, while in others, multiple knitting needles perform the looping process simultaneously.

In summary, the circular knitting machine is a versatile and essential tool in textile manufacturing, playing a crucial role in the creation of various knitted fabrics with diverse applications. Understanding its functions and principles is key to optimizing its performance and expanding the range of knitted products.