The circular knitting machine is mainly composed of a transmission mechanism, a yarn guiding mechanism, a loop forming mechanism, a control mechanism, a drafting mechanism and an auxiliary mechanism,yarn guiding mechanism, loop forming mechanism, control mechanism, pulling mechanism and auxiliary mechanisms (7, each mechanism cooperates with each other, thus realizing the knitting process such as receding, matting, closing, lapping, continuous loop, bending, de-looping and loop forming (8-9). The complexity of the process makes it more difficult to monitor the yarn transport state because of the varying yarn transport patterns that result from the diversity of fabrics. In the case of knitted underwear machines, for example, although it is difficult to identify the yarn transport characteristics of each path, the same parts have the same yarn transport characteristics when knitting each piece of fabric under the same pattern program, and the yarn jitter characteristics have good repeatability, so that faults such as yarn breakage can be determined by comparing the yarn jitter status of the same circular knitting parts of the fabric.
This paper investigates a self-learning external weft machine yarn status monitoring system, consisting of a system controller and a yarn status detection sensor, see Figure 1. The connection of the input and output
The knitting process can be synchronised with the main control system. The yarn status sensor processes the photoelectric signal by means of the infra-red light sensor principle and obtains the yarn movement characteristics in real time and compares them with the correct values. The system controller transmits the alarm information by changing the level signal of the output port, and the control system of the circular weft machine receives the alarm signal and controls the machine to stop. At the same time, the system controller can set the alarm sensitivity and fault tolerance of each yarn status sensor via the RS-485 bus.
The yarn is transported from the cylinder yarn on the yarn frame to the needle via the yarn status detection sensor. When the main control system of the circular weft machine executes the pattern program, the needle cylinder starts to rotate and, in conjunction with the others, the needle moves on the loop forming mechanism in a certain trajectory to complete the knitting. At the yarn condition detection sensor, signals reflecting the jittering characteristics of the yarn are collected.
Post time: May-22-2023