Study on Different Parts of a Single Jersey Circular Knitting Machine

 

Study on Different Parts of a Single Jersey Circular Knitting Machine

A single jersey circular knitting machine is essential in the production of knit fabrics, especially single-layer fabrics used in t-shirts, sportswear, and casual clothing. This machine operates by knitting a single layer of fabric in a tubular form, using a series of needles arranged in a circular configuration. Each component in this knitting machine plays a crucial role in ensuring seamless operation, efficient fabric formation, and high-quality output. In this article, we will explore the key parts of a single jersey circular knitting machine, examining their functions and importance in the knitting process.

 

Overview of the Single Jersey Circular Knitting Machine

Single jersey circular knitting machines are widely used in the textile industry due to their simplicity, high productivity, and ability to create fabrics with excellent drape, flexibility, and comfort. These machines knit fabric using a single set of needles and can produce a wide variety of knit patterns, including plain jersey, rib, and interlock fabrics. The circular design allows continuous, high-speed production, which is ideal for bulk manufacturing.

 

Key Parts of a Single Jersey Circular Knitting Machine

1. Cylinder
• The cylinder is a critical component in circular knitting machines, designed to house the knitting needles. The cylinder rotates around a central axis, and as it turns, the needles knit the yarn into fabric. The diameter of the cylinder and the number of grooves (or slots) determine the machine’s gauge (needle density) and affect the fineness of the fabric produced.
2. Needles
• The single jersey machine typically uses latch needles, which have a hook and latch mechanism. As the cylinder rotates, these needles pull loops of yarn to form the knitted structure. The number of needles corresponds to the machine's gauge, impacting the fabric’s density and texture. Latch needles are chosen for their versatility and ability to create various knit stitches without requiring an external actuator.
3. Sinkers
• Positioned between the needles, sinkers are thin, metal plates that help control yarn tension and loop formation during knitting. The sinkers work by holding down the fabric, allowing the needles to form loops and preventing the fabric from riding up. The sinker movement ensures consistent loop size, contributing to uniform fabric texture.
4. Cam System
• The cam system in a single jersey machine guides the needle movement during knitting. The cams are strategically positioned around the cylinder, pushing the needles up and down in a controlled manner to produce stitches. The cam profiles determine the pattern of the fabric by controlling how the needles interact with the yarn. For single jersey fabrics, a simple cam system guides the latch needles in creating a plain-knit structure.
5. Yarn Feeder and Guide
• Yarn feeders and guides are responsible for delivering yarn from the yarn package to the needles. They ensure a steady flow of yarn with controlled tension, which is critical for uniform fabric formation. Multiple yarn feeders are used to increase the knitting speed and enable the machine to produce a larger fabric width in a single rotation.
6. Take-Down System
• The take-down system pulls the knitted fabric down and away from the needles, maintaining appropriate tension on the fabric as it forms. It typically includes rollers that gently draw the fabric, ensuring that the fabric does not accumulate near the knitting area and that loop size remains consistent. The take-down speed can be adjusted to control fabric density and weight.
7. Motor and Drive Mechanism
• The motor powers the machine’s rotational movement and speed. The drive mechanism, often a belt or gear system, transfers motor power to the cylinder and cams, allowing for precise control over the knitting process. The machine’s speed, measured in revolutions per minute (RPM), impacts productivity and the quality of the fabric. Higher RPMs enable faster production but require careful tension management.
8. Creel Stand
• The creel stand holds multiple yarn cones or spools, supplying yarn to the machine. Each yarn cone on the creel stand corresponds to a yarn feeder, and yarns from the creel are directed to the knitting area. The stand is designed to prevent yarn entanglement, breakage, or inconsistency in yarn tension, which are crucial for producing defect-free fabric.
9. Control Panel
• Modern single jersey circular knitting machines come equipped with an electronic control panel that allows operators to set parameters such as knitting speed, fabric tension, and stitch density. The control panel may also feature displays for monitoring production data, detecting faults, and adjusting settings for consistent quality.
10. Lubrication System
• The lubrication system is essential for maintaining the longevity and performance of the knitting machine. Continuous operation generates friction between moving parts, especially the needles, cylinder, and sinkers. A lubrication system, often automated, reduces wear and tear, ensuring smooth operation and extending the lifespan of machine components.
11. Fabric Spreader
• As the fabric exits the knitting area, it moves through a fabric spreader, which opens and flattens the tubular knit fabric to prevent wrinkles and distortions. The spreader is especially important in high-speed operations where fabric might otherwise curl or fold as it’s being drawn away.
12. Stop Motion Sensors
• To prevent faults and damage, single jersey machines are often equipped with stop motion sensors. These sensors detect yarn breaks, low yarn tension, or faults in the knitting process and automatically halt the machine, allowing operators to address the issue before production continues.

 

Functionality of the Single Jersey Circular Knitting Machine

In operation, a single jersey circular knitting machine functions as follows:

1. Yarn Feeding:
• Yarn from the creel stand is fed to the needles through the yarn guides, ensuring an uninterrupted supply of yarn with consistent tension.
2. Needle Operation:
• The cam system guides the latch needles in an up-and-down motion, creating loops by catching the yarn in the needle hooks and then closing the latches to form stitches. This cyclic motion continues as the cylinder rotates.
3. Loop Formation:
• As the needles move in synchronization with the sinkers, they form a series of interconnected loops that produce the knit fabric. The speed and precision of needle movement directly influence loop size and fabric density.
4. Fabric Take-Down:
• After the fabric is knitted, the take-down system draws the fabric downward, maintaining the proper tension for consistent loop formation.
5. Fabric Collection:
• The finished fabric is drawn off and wound onto a fabric roll, ready for further processing or finishing.

 

Importance of Each Part in the Knitting Process

Each part of a single jersey circular knitting machine plays a significant role in the machine’s functionality:

• Cylinder and Needles: Determine the stitch formation and quality.
• Cam System: Controls the loop formation and knitting pattern.
• Sinkers: Maintain fabric position and tension during knitting.
• Yarn Feeders: Ensure consistent yarn delivery, affecting fabric evenness.
• Take-Down System: Maintains appropriate tension on the knitted fabric, impacting loop size and uniformity.

 

Conclusion

Understanding the parts of a single jersey circular knitting machine and their functions is essential for textile production professionals. Each component works in harmony, influencing the fabric’s texture, quality, and production speed. Proper maintenance and adjustment of each part are critical to achieving high-quality fabrics and efficient production. By studying the detailed mechanisms and interrelations within a single jersey machine, textile engineers and operators can enhance fabric quality, improve machine longevity, and optimize overall productivity.