Monday, April 19, 2010

What Types of Machines are used to Produce Sweaters?

Most of the sweaters sold in the retail stores are produced on machines. In most cases, industrial flatbed knitting machines are used. There are two types of flatbed knitting machines, hand loom and computerized. Both have their advantages and disadvantages depending on the type of sweaters being produced.

Hand Loom Flatbed Knitting Machine
Hand loom flatbed knitting machine is a smaller and less costly type of machine that does not run automatically. Instead, it is manually operated to produce sweater panels. The operator follows the knitting instructions given, adjusts the cam, and knits each row accordingly. It is more labor intensive than a computerized machine but still more efficient than hand knitting or hand crochet.

• Cost saving on yarns: The wastage is very low when using a hand loom machine. This is because a broken yarn or a hole could be detected immediately by the operator and fixed on the spot, eliminating the percentage of non-usable panels knitted. If the cost of material is very high (such as cashmere), using hand loom machines for production may be cheaper.
• Cost saving on machine: Hand loom machine is much cheaper than a computerized machine. Although the labor cost may be more to operate a hand loom machine, it is still cheaper to breakeven if production is done in low labor cost countries such as China and India. Many smaller factories tend to choose hand loom machines because they are able to start operating with lower capital expenditure.

• Limited knitting capabilities: hand loom machine offers less variety on the type of stitches and knitting techniques. To create complicated patterns, needles have to be moved around frequently and it could become too time consuming or sometimes even impossible to do.
• Quality consistency: each machine is operated by a different person. Even though there are ways to control the quality, the variance of hand loom machine quality is still higher.

Hand Loom Flatbed Knitting Machine

Computerized Flatbed Knitting Machine
A computerized flat bed knitting machine is programmed to run automatically. To set up, a technician studies the sweater design and specifications, and then translates them into a computer program. The computerized machine is able to read the program and knit the sweater panels according to the design.
Note that unless it’s a special knit & wear/whole garment machine, panels are knitted then linked together with another specialized linking machine. We will discuss fully fashion and linking in a later blog post. Hand loom machines also require the same linking process to complete a garment.

• Variety of stitches & finishes: computerized machine offers more stitch and finish varieties. A complicated jacquard pattern can only be done on computerized machines
• Quality consistency: machine can control the tension and pattern more consistently. Since all machines run on the same program, there is less variance in terms of quality.
• Efficiency: only one operator is required to run 6-7 machines. The operator’s main function is to watch over the panels knitted in case of defect and to ensure the machines do not run out of yarns. In a case of defect, the operator stops the machine, makes adjustments, and re-starts the machine. No intensive manual labor necessary.

• Cost of machine: the cost of a brand new computerized machine is around US $40,000-$60,000, which is significantly more than the cost of hand loom machine. However, it is much more efficient and productive once the cost of the machine is recouped.
• Wastage of yarns: the yarn wastage percentage is slightly higher because the machine cannot fix the mistake or defect on its own. The defect panels are either thrown away or they require manual labor to fix.

A Stoll Computerized Flatbed Knitting Machine. Major manufacturers in this category are Stoll and Shima Seiki.

Overall, computerized machine offers better production quality and variety. For the most part, the cost of production evens out so customers usually do not have a preference on which type of machines used. As the labor cost increases, computerized knitting machines will become more prevalent.