What are the maintenance and adjustment standards for the sewing machine

In the daily use of the sewing machine, some problems may occur due to factors such as loose screws, displacement of parts, wear and collision, which can cause blockage on the sutures. Common rheumatic diseases include floating lines, jumping lines, non circular spaces, broken lines, and ripple marks. Please adjust according to the following methods:
1、 Floating line - the seam on the garment is too loose and floats on the surface
1. Tighten the wire clamp nut
2. Tighten the thread tension spring.
2、 Jump stitch - discontinuity in seam and seam on the garment
1. Fine tune the adjustment screws on the lifting joint, so that the bottom surface of the circular triangular tip lightly touches the large needle to make way for the flat surface
2. Adjust the bias screw on the swing head of the large needle so that it is close to the bottom of the V-shaped groove when entering the hanging needle.
3. Adjust the needle holder so that the needle touches the bearing, but not too tightly.
4. Adjust the relative orientation of the two groove camshafts slightly, so that the large needle penetrates through the middle or slightly above the center of the coil on the forming triangle. The circular triangle should be positioned in the middle of the plane where the large needle gives way when hooking.
3、 Broken line
1. Moderately loosen the wire clamp nut or use only a single wire clamp.
2. Loosen the thread tension spring.
3. Adjust the pain screw on the needle arm so that the large needle does not rub against the clothes hanging needle.
4. Adjust the nut on the rocker arm connecting rod to align the large needle with the center of the V-shaped groove of the clothes hanging needle.
5. Slightly adjust (rotate) the orientation of the small cam to ensure that the sewing needle tip stays in sync with the V-shaped groove of the hanging needle.
4、 Space not in a circle - sewing cannot be completed when there is a gap between the garment pieces
1. Fine tune the upper adjustment screw of the lifting joint or the biased screw on the large needle swing head to ensure the correct orientation of the circular triangle and the large needle.
2. Adjust the orientation of the bending plate, ensuring that the bottom edge of the square hole is flush with the center of the hanging needle, and that the large needle passes through the center of the square hole.
3. Fine tune the relative orientation of the left and right sides of the slot cam to allow the large needle to penetrate from the middle or slightly above the vertical direction of the circular triangle. When forming a triangular hook line, it should be located in the middle direction of the plane where the large needle gives way.
5、 Wave shaped stitching - unclear stitching on the garment or drifting up and down
1. The same row (column) of clothing pieces should be inserted into the hanging needle.
2. Carefully adjust the clothes hanging needle to ensure that it is evenly spaced and of uniform height.
3. Replace the deformed large needle (note that the tail of the newly replaced large needle should protrude about 1.5mm from the end face of the needle seat, ensuring that the large needle enters the V-shaped groove near the bottom of the hanging needle when pointed)