Basic Elements of Circular Knitting Machines
  • Basic Elements of Circular Knitting Machines








    Circular knitting machine consists of the following knitting elements. 





    Circular knitting machine frame (chassis) is the part that carries all knitting elements on it and ensures that the machine remains as still and smooth as possible during operation. It is divided into two parts as lower and upper chassis. 




    The machine has engine, fabric pulling and winding mechanisms; ground connection. 


    upper frame 


    The cylinder is the part where the cover plates and auxiliary knitting elements are located. 




    The source of movement in circular knitting machines is the engine. The movement formed in the motor is transmitted from the main shaft to the yarn delivery device, the knitting unit where the plates are located, and the fabric pulling-winding parts by means of the gearbox and gears. In some machines, the lubrication, propeller and dust blowing mechanisms are operated by separate special motors. 




    In the circular knitting machine, including the needles on the cylinder, the parts around and performing the knitting process are the knitting machine elements. It consists of the following parts: 


    1-Knitting needles: 


    In single or double plate (cylinder or cylinder and cover) circular knitting machines, the knitting element that performs the knitting process lined up on the needle beds is the knitting needles. Working with slide needle and flexible tip needles is slower and more flexible, its use has decreased due to the instability of the tip. In single-plate machines, the needles arranged on the cylinder needle bed and moving up and down in the direction they take from the lock (steel) are cylinder needles. In double-plate machines, the needles that move back and forth in the direction taken from the locks on the cover needle bed, which is mounted in a way that the cylinder works regularly on the needle bed, are also called cap needles.

    Knitting needles take the movement from the steels in the lock mechanism (cam-core). The number of feet on the knitting needles has increased to give different movement to the needles from the same lock and to increase the patterning option. There are most 4-footed needles on the market.

    Knitting needles make the following movements in line with the movements they receive from the steels:


    A-Full rise movement for loop

    Half rise movement for B-Strap

    Straight (linear) pass motion for C-Jump


    In addition to these movements, the loop length and frequency are adjusted by adjusting the dive amount of the needle with the May gauge steel. 


    2-Needle bearings 


    Needle bed is the name given to the channels in which the needles that perform the knitting process are attached to the plates. Needle bearings rotate together with needles placed on circular plates. Needle bearings are made of wear-resistant, high-grade steel or steel alloys.

    The width of the needle beds directly affects the number of needles to be used in the machine and therefore the fineness of the machine. The distance between the needle channels, on the other hand, affects the machine division and thus the loop size. One of the most important factors affecting the surface appearance of the fabric to be produced is the quality of the needle beds. 


    3-Lock mechanisms (Steels) 


    In circular knitting machines, the part formed by the steel groups that drive the needles on the plates for movement is called lock mechanisms. The main task of the locking mechanisms is to provide the movements of the needles and to adjust the loop frequency. Using the loop setting steel, the loop length; It also determines the movement of the needles according to the pattern by using the hanger, jump and loop steel. There are a number of lock mechanisms suitable for machine fineness, diameter and number of systems, including cylinder only in single-plate circular knitting machine, cover and cylinder in double-plate circular knitting machine. In the same lock system, it is possible to make patterns by arranging different steels side by side and making different knitting movements with the needles in the same order. 




    In circular knitting machines, the knitting surface formed on the needle hooks must be pulled down. Since the fabric formed shrinks (pulls) a little, it is passed through a curved expander (knitted fabric tension pulley). In the winding mechanism, it is passed around the drafting rollers and wrapped in a flat form as a ball. In circular knitting machines, the fabric drafting mechanism rotates together with the knitting elements in accordance with the machine movement. The resulting fabric is passed through the drafting rollers in an amount suitable for the machine's operating speed and is pulled down and wrapped on the fabric roller. Two types of drafting systems, mechanical and electronic motorized, are used in circular knitting machines. Mechanical drafting takes its movement over the main engine. In this system, the shooting takes place at certain intervals in accordance with the working speed. The adjustment here is made according to the tension of the knitted fabric. A special motor is generally used in electronic shooting. In this system, a fixed draft is made in accordance with the fabric tension. As soon as the loop is formed, there is a downward pull.

    Since the fabric is knitted in the form of a tube in circular knitting machines, the winding process is at the bottom of the tube. In recent years, open width winding is also carried out in line with the demand and demand of the market. Before the knitted fabric comes to the drafting cylinder, it is cut with a knife and turned into an open width and wrapped in the winding cylinder in this way. 




    Control and safety elements in circular knitting machines are electronic and mechanical systems that detect errors on needles, threads or fabric and stop the machine. 


    1-Thread control elements 


    The yarn coming from the creel first passes through the scissors (knife) in the delivery device. Possible faulty knots on the yarn, thick – thin, neps, fly or waste yarns are checked by threading between two metal plates. In this way, faulty threads are prevented from going to the needles. Another control element on the furnior is the tension sensors that control the tension of the thread between the furnisor and the shuttles. In case the yarn falls below a certain tension, it stops the machine and prevents incorrect yarn delivery. These are the probes placed in the machine to warn of possible yarn breaks. It stops the machine in case of yarn breaks. 


    2-Needle control elements 


    Needle control elements are needle tongue openers and needle probe detectors. Needle tongue openers are placed on the machine at certain intervals and help to open the tongues of the needles in the machine. are destroyers. The needle probe stops the machine by turning on the warning lamp in case of errors caused by the needle, and shows the area where the error is. 


    3-Tissue control elements 


    Tissue control elements function during the knitting process and fabric winding. It is a system that warns by noticing possible fabric piling up or bursts on the fabric during the knitting process. 




    It is the name given to the main control panel of the circular knitting machine. In general, there are the following control elements on the control panel;


    1-Knitting row number information


    2-Indicator for determining the number of laps


    3-Stop, serial and step operation keys


    4-Machine working speed setting


    5-Propeller and furnisor circuit closing keys, etc.


    In addition to the machine control equipment, emergency stop button, serial and gradual start keys are placed around the machine in each machine. In the latest electronic and especially jacquard machines, there is also a pattern computer in addition to the control equipment.


    Posted by %PM, 11% 747% 2016 19%:%Apr in Knitting Read 4824 times

Basic Elements of Circular Knitting Machines