Quality Requirements for Knitting yarns in Circular Knitting Machine Production

Knitting yarn is subjected to complex mechanical effects such as bending, twisting and friction in circular knitting machine production. Therefore, in order to ensure the quality of knitting products, knitting yarns must have a series of strict quality requirements. These requirements are not only related to the performance of the yarn itself, but also directly affect the smooth progress of the knitting process and the quality of the final fabric.

Quality Requirements for Knitting Yarns

Strength and Elongation

The strength of a yarn is its ability to withstand tension and load. In circular knitting machine production, the yarn is subjected to constant tension, frequent mechanical manipulation and repeated action from the knitting needle, so it needs to be strong enough to avoid breaking. At the same time, the yarn also needs to have the appropriate elongation, so that it can be slightly extended when subjected to tension, to avoid breakage due to brittleness, so as to ensure the continuity and efficiency of knitting production.

Bendability

Circular knitting machine knitting process, the yarn needs to be constantly bent and wound between high-speed knitting needles. If the yarn is soft and flexible, it is easier to form a uniform coil, reducing friction between the needle and the yarn, thereby avoiding damage to the knitting machine components and breaking of the yarn itself. At the same time, good flexibility can also improve the texture of the knitted fabric, making it more soft and beautiful.

Twist and Torsional Stability

The twist of a yarn is an important index to measure its twisting degree. Too much twist will cause the yarn to become stiff and difficult to bend smoothly in the knitting process, which not only increases the operating burden of the knitting machine, but also easily causes the coil knot, affecting the appearance and structure of the knitted fabric. The yarn with too low twist is soft, but the strength is insufficient, and it is easy to pilling, which reduces the wear resistance of the knitted fabric. Therefore, when choosing knitting yarns, it is necessary to choose yarns with moderate twist for different circular machine processes and fabric characteristics to achieve the best knitting effect.

Hygroscopicity

Hygroscopicity of a knitted yarn refers to its ability to absorb moisture from the air. Yarns with good hygroscopic properties can maintain stable performance under different ambient humidity conditions. In circular knitting, the hygroscopic yarn can better regulate the yarn tension, avoid electrostatic problems caused by drying, and ensure the smooth running of the yarn in the machine. At the same time, the hygroscopic properties of the yarn can also improve the feel and comfort of the fabric, making the finished product more close-fitting and breathable.

Smoothness and Low Friction Coefficient

The smoothness and friction coefficient of yarn directly affect its running efficiency in knitting machine. Smooth yarns create lower friction with machine parts during knitting, reducing yarn breakage and machine wear caused by friction. If there are impurities such as grease and dust on the surface of the yarn, it will not only affect the smoothness of the yarn, but also lead to needle sticking, machine parts damage, and a decrease in production efficiency. In order to improve the smoothness of the knitted yarn and reduce the coefficient of friction, manufacturers can perform surface treatments on the yarn, such as adding antistatic agents and lubricants, and even using wax treatments to reduce the friction of the yarn during the knitting process.

Uniformity

Uniformity of yarn refers to the degree to which its thickness is consistent. In circular knitting, if the thickness of the yarn is uneven, it is easy to lead to the uneven density of the fabric surface, which affects the beauty and quality of the fabric. Uniform yarns ensure that a stable and consistent coil is formed during the weaving process, resulting in the production of high-quality knitted fabrics. Therefore, controlling the uniformity of yarn is the key to improve the quality of knitting products.

Hairiness

Hairiness refers to the degree of fiber removal from the surface of the yarn. Too much hair will not only rough the surface of the fabric, but also lead to needle blockage, machine stalling, and even yarn breakage. Therefore, for the yarn used in circular knitting, it is required that the hair rate is low and the yarn surface is smooth to ensure the smooth production and the quality of the finished product.

Stability of Yarn Structure

The structural stability of yarn mainly refers to the fact that when the yarn is subjected to mechanical forces, the arrangement of its internal fibers is not easy to deform or loose. The structurally stable yarn can maintain a consistent shape during the knitting process to avoid uneven coils or yarn breakage caused by fiber displacement, thereby improving the stability of the knitting process and the pass rate of the product.

Color Fastness

For dyed knitting yarns, color fastness is also an important quality indicator. In the process of circular knitting, the yarn will be in frequent contact with the knitting needle and subjected to certain friction, if the color fastness is poor, the color of the yarn will fade, not only affecting the appearance of the knitted fabric, but also may cause machine pollution. Therefore, dyed yarns need to have good color fastness to maintain the bright color and uniformity of the finished product.

Elasticity and Recovery of Yarn

The elasticity and recovery of knitting yarn refers to whether the yarn can quickly recover to its original length after being stretched by force. A yarn with good elasticity and recovery can effectively cushion the impact on the yarn during the knitting process, reduce the risk of yarn breakage, and also help to improve the elasticity and closeness of the knitted fabric, making the finished product more comfortable and durable.

Sum up

All in all, the quality requirements of knitting yarn directly affect the efficiency of circular machine production and the final quality of knitted fabric. Only by selecting yarns with high strength, good elongation, proper twist, excellent moisture absorption and smoothness, can we maintain a stable process in high-speed and continuous circular machine production, reduce yarn breakage, machine wear and other problems, and improve the consistency and beauty of the finished product.