The Science of Knitted Fabric Manufacturing: A Detailed Industrial Guide for Beginners

Knitted fabric manufacturing is a sophisticated mechanical process where yarn is converted into fabric through a series of intermeshing loops. Unlike weaving, which uses two sets of yarn (warp and weft), knitting relies on a single continuous yarn system to create elastic, breathable, and versatile textiles. For industry professionals and serious students, mastering the variables of the knitting cycle is essential for high-quality production.

1. Advanced Yarn Selection & Preparation

The performance of a knitted fabric begins with the technical parameters of the input yarn.

• Fiber Composition: While cotton is the standard, high-performance knits often use Combed Yarn to reduce hairiness and pilling. Synthetic blends like Polyester-Spandex are critical for "stretch and recovery" properties.

• Yarn Count & Twist: In knitting, the Twist Multiplier (TM) must be carefully balanced. Too much twist leads to "spirality" (where the garment twists after washing), while too little twist results in weak fabric with poor durability.

• Waxing: For high-speed circular knitting, yarn must be treated with paraffin wax to reduce friction as it passes through the needles.

2. Types of Knitting Technologies

Modern manufacturing is divided into two primary categories, each defined by the direction of the loop formation.

Weft Knitting (Circular & Flat)

Weft knitting is the most common method for apparel.

• Circular Knitting: Used for seamless tubes, T-shirt fabrics (Single Jersey), and Rib fabrics. These machines can have over 90 feeders, allowing for incredible production speeds.

• Flat Bed Knitting: Essential for sweaters, collars, and "Fully Fashioned" garments. Modern CNC flat machines can knit complex 3D shapes directly.

Warp Knitting (Tricot & Raschel)

Warp knitting is faster than weft knitting and produces fabrics that are "run-proof."

• Tricot: Commonly used for lingerie and sportswear.

• Raschel: Used for technical textiles like automotive upholstery, cargo nets, and intricate lace.

3. The 4 Stages of the Knitting Cycle

Every stitch formed on a machine follows these four precise mechanical movements:

1. Running-Up: The needle moves up to allow the previous loop to drop below the latch.

2. Clearing: The old loop is cleared from the needle hook.

3. Feeding: The new yarn is placed into the needle hook.

4. Knock-Over: The needle pulls the new yarn through the old loop, forming a new stitch.

4. Technical Finishing & Quality Parameters

The "Greige" fabric coming off a knitting machine is not yet ready for use. It must undergo rigorous finishing:

Process	Purpose	Impact on Quality
Heat Setting	Stabilizes synthetic fibers	Prevents shrinkage and curling
Compacting	Controls the "Residual Shrinkage"	Ensures the garment fits after washing
Enzyme Wash	Removes surface fuzz (Pilling)	Increases softness and "hand feel"

5. Common Knitting Defects and Solutions

To achieve "A-Grade" fabric, quality control must monitor for these specific industrial issues:

• Holes/Drop Stitches: Usually caused by weak yarn or incorrect needle tension.

• Oil Stains: Caused by excessive lubrication of the sinkers and needles.

• Spirality: A common defect in Single Jersey where the vertical columns of stitches (wales) lean to one side. This is corrected during the Stenter process or by using S/Z twist balanced yarns.

Conclusion

Knitted fabric manufacturing is a balance of mechanical precision and material science. By understanding the intricacies of needle cycles, yarn twist, and finishing stability, manufacturers can produce textiles that meet the rigorous demands of the modern global market.