There are many classification methods of sewing machines, and the more common ones are by stitches and uses. The stitches of sewing machines can be classified into two types: lock stitch and chain stitch. The lockstitch, the most common, consists of two stitches that are interwoven like twisted rope, with the interweaving point in the middle of the sewing material. From the cross-section of the stitches, the two stitches are like two locks locking each other, so they are called lock stitches. This stitch is used in sewing materials such as cotton, wool fabric or leather with a small shrinkage rate. The front and back have the same shape, like a dotted line. The stitches are densely distributed, and the fastness of sewing is generally higher than that of manual sewing.
Chain stitches are formed by self-connecting or interconnecting loops of sutures, commonly used are single-thread chain, double-thread chain and three-thread overlock stitches. The feature of this stitch is that the stitches are elastic and can expand and contract with the sewing material without breaking the stitches. It is suitable for garments made of elastic fabrics or products and clothing blanks that are easy to be loose when overlocked.
In addition, sewing machines can be divided into household, industrial, and service industry machines according to their uses, and can also be divided into hand sewing machines, pedal sewing machines, and electric sewing machines according to their driving forms.
