- Weft Knits: These include plain, rib, purl, pattern, and double knits.
- Warp Knits: These include tricot, raschel, and milanese.
In knitting, the wale refers to a column of loops running lengthwise, corresponding to the warp in woven fabric. A course refers to a crosswise row of loops, corresponding to the filling in woven fabric.
Characteristics of Knitting
Knitting is a method of constructing fabric by interlocking a series of loops using one or more yarns. Compared with woven fabrics, which are rigid and stable, knit fabrics are more flexible and can conform more easily to changes in shape. This flexibility is due to the intermeshed loops, which allow knitted fabrics to stretch and fit the form. Knitted fabrics also tend to maintain a smoother appearance and provide better mobility, making them ideal for activewear and sports apparel.
Knitting systems are classified into two main categories: weft knitting and warp knitting.
Weft Knitting
Weft knitting involves forming loops in a horizontal manner, where adjacent needles knit one row of loops at a time from the same yarn. There are two primary types of weft knitting machines:
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Circular Knitting Machines
- These machines create fabric in a spiral configuration around a cylinder, producing a continuous tube of fabric.
- The fabric width is determined by the number of needles on the machine.
- Each revolution of the machine completes one course for each yarn fed into it.
- Common applications include producing seamless garments, socks, and t-shirts.
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Flat Bed Machines
- In flat bed machines, needles are arranged in a straight line on a flat plate, called the bed.
- These machines may have one or two beds of needles (opposite each other), which allow for the production of more complex patterns.
- Commonly used to produce sweaters, trims, scarves, and other flat fabrics.
- A course is the horizontal row of loops formed by adjacent needles in the same knitting cycle. The course count is measured as the number of courses per linear unit (in inches or centimeters). For example, a 1-inch by 1-inch area with 5 horizontal loops would have 5 courses per inch.
- A wale is the vertical column of loops formed by the same needle in successive knitting cycles. The wale count is similarly measured per linear unit.
Weft knitting is known for its elasticity, making it ideal for garments that require stretch, such as hosiery and activewear.
Warp Knitting
Warp knitting, in contrast to weft knitting, involves forming loops in a vertical direction. Each loop is created from a separate lengthwise yarn. In warp knitting machines, all needles knit simultaneously across the width of the machine.
Warp Knitting Process
- Yarns are wound onto a beam from yarn packages arranged in a creel. These warp yarns must be parallel to one another for the knitting process.
- Each yarn typically requires its own needle. For example, a machine with 1,000 needles requires a minimum of 1,000 warp yarns.
- More elaborate fabrics can be created by providing more than one yarn for each needle.
Types of Warp Knitting Machines
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Tricot Machines
- These machines produce lightweight, smooth, and fine fabrics.
- Commonly used for lingerie, activewear, and linings.
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Raschel Machines
- These machines are versatile and capable of producing intricate designs.
- Often used for lace, nets, and more robust fabrics like upholstery and outerwear.
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Crochet Machines
- Used for decorative and ornamental fabrics.
- Applications include craft textiles, trims, and artistic fabrications.
Comparison of Weft and Warp Knitting
| Feature | Weft Knitting | Warp Knitting |
|---|---|---|
| Loop Direction | Horizontal | Vertical |
| Flexibility | Highly elastic, ideal for stretch garments | Stable, less elastic, suitable for technical uses |
| Machines Used | Circular and flat bed | Tricot, raschel, and crochet |
| Applications | Apparel (t-shirts, sweaters, activewear) | Technical textiles, lace, lingerie, upholstery |
| Yarn Requirement | Single yarn for rows | Individual yarns for each needle |
Conclusion
Knitting, as a versatile fabric construction method, plays a pivotal role in textile production due to its unique ability to create flexible, stretchable, and comfortable fabrics. The two primary systems—weft knitting and warp knitting—each offer distinct advantages and applications. Weft knitting, known for its elasticity and simplicity, is ideal for everyday garments like t-shirts, sweaters, and activewear. In contrast, warp knitting provides stability and durability, making it suitable for technical textiles, lingerie, and decorative fabrics.
By understanding the underlying mechanisms of knitting, including the concepts of wales and courses, and the machinery involved, manufacturers can tailor fabrics to meet the specific needs of industries ranging from fashion to automotive and sportswear. As advancements in technology continue to refine knitting techniques, this time-honored method remains an essential cornerstone in the ever-evolving textile industry.
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