Key points for the design of knitted fabrics in circular knitting machines

Key points for the design of large circular knitted woven fabrics: The design of large circular knitted woven fabrics should take into account the compatibility of raw materials, the accuracy of process parameters, the rationality of pattern structures, and the stability of finished product performance. At the same time, it should be combined with the requirements of terminal application scenarios to achieve a two-way optimization of design schemes and production efficiency. The core points can be divided into the following five dimensions: 1. Raw material selection: Matching the characteristics of the machine type with the functional raw materials of the fabric is the foundation of fabric quality. It is necessary to select the type of circular knitting machine (single-sided, double-sided, ribbing machine, etc.) and the purpose of the fabric in a targeted manner. 1. Fiber type selection: Pure cotton fiber is mainly skin-friendly and breathable, suitable for underwear and T-shirt fabrics; Polyester and nylon have high strength and good wear resistance, making them suitable for sportswear and home textile fabrics. Spandex has excellent elasticity and is often used in elastic knitted fabrics. Its content should be controlled (generally 3%-10%) to prevent yarn breakage or excessive elasticity of the fabric surface during weaving. 2. Yarn specification matching: Select the corresponding count of yarn based on the needle type of the circular knitting machine (such as 18G, 24G). For fine knitting machines, high-count yarns (such as 40S, 60S pure cotton yarns) are suitable, which can produce fine and thin fabrics. The coarse needle model is suitable for low-count yarns or plied yarns (such as 10S, 21S plied yarns), and is ideal for thick hoodie fabrics and loop fabrics. At the same time, attention should be paid to the twist of the yarn and the uniformity of the strip to reduce weaving breaks and fabric surface defects. 3. Raw material pretreatment: Yarns that are prone to pilling and static electricity need to undergo pre-shrinking and anti-static treatment. It is recommended that cotton blended yarns undergo singeing and mercerization treatment to enhance the smoothness and dyeing performance of the fabric surface. Ii. Pattern and Weave Structure Design: Balancing Aesthetics and wettability. The pattern and weave structure determine the appearance and wearing performance of the fabric. When designing, the loop formation rules and mechanical limitations of the circular knitting machine should be fully considered. 1. Basic fabric selection: The single-sided machine can be designed with plain weave, matte, mesh and other textures, suitable for light and thin fabrics. The double-sided machine can be designed with cotton, wool, ribbing, air layer and other structures. The fabric structure is tight and has good elasticity, making it suitable for thermal underwear and outerwear fabrics. The ribbing machine focuses on elastic ribbed fabric and needs to reasonably design the ribbing ratio (such as 1×1, 2×2 ribbing) to meet different elastic requirements. 2. Design principles for patterns: For complex patterns such as jacquard and inlaid patterns, the size of the pattern cycle should be controlled to avoid exceeding the capacity of the machine’s needle selector and prevent pattern confusion. For geometric patterns such as stripes and checks, the arrangement sequence of colored yarns and the yarn feeding ratio must be precisely calculated to ensure that the fabric patterns are symmetrical and without misalignment. 3. Special functional structure design: To meet the requirements of antibacterial, moisture absorption and sweat-wicking, fabrics with hollow structures and moisture-conducting groove structures can be designed. To meet the demand for wear resistance, the coil density of the fabric can be increased or a double-layer structure can be adopted. Iii. Process Parameter Setting: Precise control of the entire weaving process parameters is the key to connecting design and production. It is necessary to repeatedly adjust in combination with the characteristics of raw materials and fabric requirements. Core parameters include: 1. Yarn feeding tension control: Excessive tension can easily cause the coil to stretch and deform, and the fabric surface to be tight. If the tension is too small, the coil will become loose and the fabric surface will wrinkle. The tension of the yarn feeder needs to be adjusted according to the type of yarn and the model to ensure that the tension of each yarn path is uniform and consistent. 2. Matching vehicle speed with machine speed: Set a reasonable vehicle speed based on the strength of the raw materials and the complexity of the patterns. For complex patterns or fine and weak yarns, the vehicle speed should be reduced to decrease the breakage rate. Simple organization and strong yarn can appropriately increase the vehicle speed to enhance production capacity. 3. Adjustment of the gap between the settling plate and the syringe: If the gap is too large, it is prone to needle leakage and narrow path defects. If the gap is too small, it is easy to wear out the needle tongue and break the yarn. It is necessary to precisely adjust according to the thickness of the fabric and the fineness of the yarn to ensure the stability of the loop forming process. 4. Fabric weight control: The target weight can be achieved by adjusting the coil length, machine number, and yarn count. For instance, increasing the coil length can reduce the weight, while raising the machine number (with more stitches) can increase it. Dynamic optimization should be carried out in accordance with production requirements. Iv. Connection of Dyeing and Finishing Processes: Ensuring the Appearance and performance of finished products. Fabric design should take into account the compatibility of subsequent dyeing and finishing processes in advance to avoid quality issues after dyeing and finishing due to design flaws. 1. Color design compatibility: For light-colored fabrics, materials with high whiteness should be selected to avoid color differences after dyeing. For dark-colored fabrics, attention should be paid to the color fastness of the raw materials, and fibers with a high dye uptake rate should be selected. 2. Reserve shrinkage rate: Natural fiber fabrics are prone to shrinkage after dyeing and finishing. When designing, a reasonable shrinkage rate should be reserved (the shrinkage rate of pure cotton fabrics is generally 3%-5%) to ensure that the size of the finished product meets the customer’s requirements. 3. Functional finishing matching: If anti-wrinkle, waterproof and other functional finishing are required, during the design stage, fiber raw materials that are compatible with the corresponding finishing agents should be selected. For example, for waterproof finishing, formulas with an excessively high proportion of highly absorbent fibers should be avoided. V. Balance between Cost and Efficiency: The design plan to meet the demands of industrialized production should take into account both quality and economic benefits, and be suitable for large-scale production. 1. Simplify production processes: Under the premise of meeting functional requirements, give priority to choosing simple organizational structures to reduce the frequency of needle and yarn changes and lower production time costs. 2. Raw material cost control: Select raw materials with high cost performance based on market demand, such as using blended yarns instead of pure-spun yarns in non-core parts, or reducing raw material usage through organizational structure optimization. 3. Adapt to existing equipment: When designing, it is necessary to take into account the hardware conditions of the enterprise’s existing circular machine models, needle types, etc., to avoid increasing the renovation cost due to the design plan exceeding the equipment capacity.