Classification of sewing machines a lot, generally distinguished by stitch and use. Sewing machine stitching can be summarized as the lock stitch and chain stitch two categories. Lock stitch is most common, it is formed by two stitches, intertwine like a laid up, its interweaving in the middle of sewing material. From a cross-section of the stitches, two stitches as well as two locks lock, called the lock stitch. This stitch used in the shrinkage of cotton, wool or leather material, positive and negative shape, like a dotted line. Distribution density stitch, sewing of stretch more than hand sewing. Chain stitch is the suture loops connected or interconnected, commonly used are single chain, double chain and wire stitching. This stitch is elastic stitch, scale along with the material without break thread, applicable to lines of elastic fabric clothes or sewing easy to loose products and the slab. In addition, the sewing machine in accordance with the use can be divided into household, industrial and service industry machine, according to the drive type can also be divided into hand-cranked sewing machines, foot sewing machines, electric sewing machine.