Check first if such a problem arises.
Problems with sewing machine settings: Check that the sewing machine is set up correctly. Whether the stitches of the sewing machine are too small or too large, whether the thread tension is too tight or too loose, etc.
Loose thread: Check whether the bottom line and upper line are loose, if the bottom line is too loose, it will cause the thread to move when sewing the fabric, or produce a large number of bottom threads piled up on the cloth surface below.
Here's how to get started:
1. First of all, use a slotted screwdriver to unscrew the 2 screws that fix the needle plate.
Press the lower left (or right) corner of the needle board and the needle board will be warped and the needle board can be removed.
Here you can directly see the tightened adjustment screws of the bottom line. In order to prevent the screws from slipping off due to vibration, there will be paint sealing.
2. Before adjusting, first install the bottom line, pull the wire out to feel the tightness, and remember the feeling of pulling the wire on your hand.
3. Find a small screwdriver to adjust the screws: turning in the clockwise direction is tightening, and turning in the counterclockwise direction is to relax the attention while tightening the screws and pulling the wire outward, so that the change in tightness can be felt in the hand. The bottom line is piled up.
It should be noted that some wearing parts of the sewing machine should be replaced regularly, so that the problems when sewing will be greatly reduced.