There are many ways to classify sewing machines, and the more common one is to distinguish them by stitches and uses. The stitches of the sewing machine can be classified into two types: lock stitch and chain stitch. The lock stitch is the most common. It consists of two sutures, which are interwoven with each other like a twisted rope. The interlacing point is in the middle of the sewing material. From the cross-section of the stitches, the two stitches are like two locks locked to each other, so they are called lock stitches. This stitch is used for sewing materials such as cotton, wool fabric or leather with low shrinkage. The front and back sides 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 stitch is formed by self-connection or interconnection of suture loops. Commonly used are single-thread chain, double-thread chain and three-thread overlock stitch. This kind of stitch is characterized by its elasticity, and can stretch with the sewing material without breaking the stitch. It is suitable for clothes made of elastic fabrics or products and garment blanks that are easy to be sewn.
In addition, sewing machines can be divided into household, industrial, and service industries according to their uses, and can also be divided into hand-operated sewing machines, pedal sewing machines, and electric sewing machines according to the driving mode.
(1) After the work is finished, insert the needle into the needle hole plate, raise the presser foot, and cover the machine head with a machine cover to prevent intrusion of dust.
(2) When starting to work, first check the main parts, how light and heavy it is when you step on it, whether there is a special sound, whether the needle is normal, etc. If any abnormality is found, it should be overhauled in time.
(3) After the machine has been used for a long period of time, a major repair should be carried out. If parts with larger wear are found, replace them with new ones.