Automated Fabric Production via Mechanical Interlocking

Fundamental Principles of Weft Knitting Automation

Automated weft knitting relies on the synchronized movement of needles to form interlocked loops of yarn. These loops create a fabric structure distinct from woven fabrics, characterized by its stretch and drape. The process involves feeding yarn to needles, manipulating those needles to create loops, and then transferring those loops to form new loops in subsequent rows or courses.

Types of Knitting Machinery

Flatbed Machines

Flatbed machines utilize a flat needlebed, allowing for a wide range of stitch patterns and shaping possibilities. Needles are arranged in a line, and a carriage moves back and forth across the bed, selecting and actuating needles to create the fabric. These machines are often computer-controlled, providing precise pattern control and automation.

Circular Machines

Circular machines feature needles arranged in a circular configuration. The cylinder or dial rotates, causing the needles to move vertically and horizontally to form stitches. Circular machines are typically used for producing seamless tubes of fabric, such as hosiery or T-shirts. There are two main types: single jersey and double jersey machines, which differ in the number of needle sets and the fabric they produce.

Key Components and Their Functions

Needles

The core of the process. Latch needles, spring beard needles, and compound needles are common types, each with mechanisms for catching, holding, and releasing yarn loops. The selection and movement of needles determine the stitch pattern.

Yarn Feeders

Deliver yarn to the needles at a controlled rate. Multiple feeders can be used to create multi-colored fabrics or intricate stitch patterns.

Cams

Shaped tracks that control the vertical movement of the needles in cylinder or flatbed beds. Different cam designs create different stitch patterns.

Carriage (Flatbed Machines)

The moving component that houses the cams and other mechanisms for needle actuation. It traverses the needlebed, creating rows of stitches.

Take-Down Mechanism

Applies tension to the finished fabric, ensuring uniform stitch size and preventing distortion. Typically involves rollers or weighted bars.

Stitch Formation Process

The stitch formation cycle generally involves these steps: clearing (moving the old loop to the open needle), feeding (yarn being supplied to the open needle), closing (needle moves upward so the old loop can close around the new one), knocking over (the old loop is knocked off the needle), and drawing (new loop is pulled through old one.)

Patterning and Control Systems

Modern machinery commonly use computerized control systems. These systems allow for intricate pattern designs to be programmed and executed with precision, enabling the creation of complex knit structures. Software facilitates design input, simulation, and machine control.