① The fabric is irregular

In the process of using sewing machine to sew fabric, sometimes the movement speed of fabric is uneven and the stitch time is short. The movement of clothing materials depends on the cooperation of feeding teeth and presser foot. Therefore, when the above irregular movement of clothing materials occurs, it can be concluded that the teeth and presser foot are in fault or the pressure is not adjusted properly. For example, the presser foot pressure is too small. If the cloth is not pressed tightly, it will cause irregular walking. At this time, just turn down the adjusting screw to compress the fabric. If the presser foot is too high to hold the clothing material, it will also cause the clothing material to move around at will or not at all. When adjusting, first lift the presser foot wrench, loosen the guide frame screw, and then move the presser foot rod from top to bottom, so that the distance between the presser foot and the needle plate is adjusted to a height of 7-8 mm. Then tighten the screw immediately before driving.

Another reason is that the teeth screw is loose, which causes the teeth to shake left and right during operation, so that the clothing material can not move forward regularly. The processing method is to remove the needle plate. Screw the two teeth together. After tightening, install the needle plate. Check whether there is friction between the two sides of the tooth and the edge of the needle plate groove. If there is friction, it will cause noise and machine weight. At this time, only remove the needle plate, loosen the tooth screw, adjust the tooth position to the middle of the needle plate groove, and then install the needle plate after tightening the tooth screw.

② The material doesn't move forward

The movement of clothing materials depends on teeth. When the material doesn't move at all, you have to look for problems on your teeth. If the teeth are too low, the fabric cannot move forward. When adjusting, first pull up the head of the machine, loosen the screw of the tooth lifting crank, and then gently lift the tooth rack with a screw driver to make the feeding tooth face upward. 8-1 mm above the needle plate. It's the standard size of tooth height. As long as it is adjusted to this position, the material can move normally. Finally, tighten the screw. When screwing, pull up the head of the machine.

③ The material goes back and forth

When sewing the fabric, it often appears that the fabric moves back and forth, that is, one step forward and one step backward. The reason is that the feeding teeth are too high. The plane of the teeth exposed to the needle plate is too high. The teeth are always exposed to the outside of the needle plate and move back and forth, causing the fabric to move back and forth. When adjusting, loosen the teeth lifting crank screw, press the teeth down gently with a screwdriver to reduce the feeding teeth to the standard height, that is, the teeth are 0.8-1 mm above the needle plate, and then tighten the crank screw.

④ The material retreats

In the sewing work, sometimes the material does not move forward, but moves towards the operator, that is, the material moves backward. The reason for this failure is that the angle between the crank of the upper shaft and the eccentric screw of the cam is not right. Therefore, the teeth can move forward rhythmically. It is entirely by the movement of the feeding cam. Because the cam itself is eccentric. Therefore, the fork moves forward and backward, and the fork drives the cloth feeding shaft and the tooth rack, which makes the teeth move back and forth. It can be seen that the eccentric position of the cam is very important.

The standard angle between the upper shaft crank and the cam screw. As long as the angle between the cam screw and the upper axle crank is adjusted to 260-300, the fabric will not retreat.

When adjusting, pull down the back cover of the machine head to see the feeding cam. Insert the screw driver into the housing to loosen the screw of the feeding cam, then turn the screw to the position of 260-300 with the upper shaft, and then tighten the cam screw.