Type 781 keyhole machine will often appear on line from the beginning.

The reason for the failure of the keyhole is that the bottom and surface lines are not properly twisted on the fabric before the surface scissors are opened. This failure is not caused by a certain part of the problem. It needs to be checked and adjusted from several aspects.

(1) check whether the loose wire steel can be loosed 5 to 7mm when the machine is shut down. Its function is to loose the surface line after the keyhole is finished. When carrying out the next keyhole, it will provide enough surface line to the rotary shuttle with the take-up rod to prevent the surface line from coming out of the scissors.

(2) when the face line scissors cut the face line and clip the thread head, you can use the hand to pull the following line. If you easily pull the face line out of the face line scissors, it shows that the clamping force of the face line scissors is loose.

Adjustment method: can be

The clipping board on the surface scissors is unloaded, slightly bent and reinstalled so that the thread scissors do clip the thread.

At the same time, it is necessary to check that the face line scissors should keep the amount of 0.5mm when the scissors are completely closed and the maximum limit.

(3) check whether the needle is bent, whether the thread is threaded and whether the quality of the surface is poor, because if there is a needle jumping before the scissors are opened, then when the scissors are opened, the surface line will emerge from the pinhole.

Adjustment method: correctly adjust the matching time between the needle and the shuttle, and the opening time of the surface thread scissors, so that the scissors of the face line slowly extend when the initial seam is between fifth and 7 needles.

(4) inspection

If the length of the bottom line is insufficient, if the bottom line length is not enough, then the bottom line and the face line can not be properly twisted, so that the surface line can be pulled out from the pinhole. The standard length of the bottom line is to expose the spindle sleeve spring 36mm. If the length is not enough, the angle of the bottom line can be adjusted to make the line size larger.

The above points are for reference only. In actual work, equipment needs to be analyzed and judged before being adjusted.