Five-thread overlock sewing machine stitch skip stitch adjustment for knitted materials(1)

Knitted fabrics are processed, and the fabrics are very soft. When sewing with a five-thread overlock sewing machine, the phenomenon of "stitch skipping" and "thread jamming" of the machine is often encountered.

The 6 key points in this failure are analyzed, hoping that its handling method can solve problems for readers.

In garment manufacturing enterprises, general four-thread overlock sewing machines process knitted fabrics, and five-thread overlock sewing machines process woven fabrics. However, with the development of the times, the technical requirements of garment production have also changed. It is required to use a five-thread overlock machine to process knitted fabrics, and the fabrics are very soft, and the phenomenon of "stitch skipping" and "thread jamming" of the machine is often encountered during sewing operations.

◆Key point 1: The distance between the chain stitch looper and the Five-thread overlock sewing machine needle

Under normal circumstances, the distance between the five-thread chain stitch looper and the machine needle is between 1.6 mm and 1.8 mm. However, when processing knitted fabrics, because the fabric is very soft, the fabric will run up and down with the needle, and it is not easy to start loops. , especially prone to skip stitches. Therefore, when we process knitted fabrics, we need to adjust the distance between the five-thread chain stitch looper and the needle of the overlock sewing machine to 2.0 mm to 2.2 mm. If the distance is too large, the machine will not form a chain line when the machine is empty. ; If the distance is too small, stitches will skip, so the distance between the chain stitch looper and the machine needle must be adjusted properly.

◆Key point 2: The forward and backward motion of the chain stitch looper

When making knitted fabrics, the forward and backward movement of the looper is too large. When the needle is lowered, it will not be inserted into the five-thread loop and stitches will be skipped. Therefore, we should adjust the front and rear positions of the chain stitch looper in place, that is, the looper hook The gap between the needle and the needle when threading is 0.01 mm. After the needle returns, it is inserted into the back of the looper. The gap between the needle and the looper should be small.

When adjusting, we can open the cover next to the presser foot lifter rod, and we can see that there is a screw in the middle. Loosen the screw with an inner hexagonal screwdriver, and move up the connecting rod that adjusts the front and rear movement of the chain stitch looper, so that the chain The forward and backward movement of the looper with the type stitch becomes smaller, and then the screw can be tightened.

◆Key point 3: Gap between chain stitch looper and machine needle

The normal gap between the five-thread chain stitch looper and the five-thread overlock sewing machine needle is between 0.05 mm and 0.1 mm, but when making knitted fabrics, the needle thread loop is not easy to form, so we need to separate the chain stitch looper and the machine needle. The plane gap is adjusted to 0. If the gap is adjusted to 0, it is easy to cause the needle to break when making thicker joints. At this time, we should adjust the needle guard, that is, turn the tip of the chain stitch looper to the center of the needle, so that the plane gap between it and the needle is 0, at this time, the gap between the guard needle and the machine needle tip is also 0.