What Are the General Faults of Direct Drive Compound Feed Sewing Machine?

- Mar 18, 2020-

Direct drive compound feed sewing machine is a kind of multipurpose lockstitch sewing machine. Its biggest feature is that it adopts large hook hook thread and is equipped with upper and lower comprehensive feeding mechanism and presser foot alternate lifting mechanism. Because of its strong seam thickness, good seam performance, and stable back seam stitching, it is widely used in leather, canvas and other medium-thick products.


Adjustment for general faults:

(1) Needle position.

When the needle is lowered to the lowest point, the center of the needle hole should be at the same position as the inner surface of the rotary hook. If the sewing material is thick, the center of the needle hole can be appropriately lowered by about 0.5 mm.


(2) Synchronization of needle and rotary hook.

Standard synchronization relationship: the needle moves down to the lowest position and then rises to 2.5 mm. At this time, the hook tip should be consistent with the center line of the needle, and the hook tip should be higher than the needle thread hole at this position. The upper edge is about 1.2 to 1.5 mm. In addition, the clearance between the bottom of the needle notch and the hook tip should be between 0 and 0.05 mm.

compound feed sewing machine

(3) Feed teeth position

① The standard position is to adjust the feed amount to the maximum. When the front end of the feed teeth is close to the front side of the throat plate slot, the plane gap between the front end of the feed teeth and the front side of the throat plate slot is 1.5 mm.

② When the feed teeth moves to the highest point, it should be 0.8 ~ 1.2 mm higher than the plane of the needle plate. When sewing thicker materials, it can be appropriately raised by about 1.5 mm. The feed teeth is generally in a horizontal position. When the sewing conditions need to be tilted, it should be adjustment.


(4) Feeding synchronization

The standard position is that when the feed cloth moves to be flush with the plane of the throat plate, the needle tip of the machine should also be flush with the surface of the throat plate. If the sewing material is thin, the needle tip can be slightly lower than the plane of the needle plate by about 0.5 mm.


(5) Adjustment of feeding mechanism

Under normal circumstances, the upper feeding of The direct drive compound feed sewing machine should be synchronized with the lower feeding, but special situations are often encountered in actual sewing. It should be appropriately adjusted according to the different friction coefficients of various sewing materials and the sewing process requirements. Adjust the center distance between the foot slider and the swing foot shaft. Increasing the center distance increases the amount of the upper feed; decreasing the center distance decreases the amount of the upper feed. In addition, in actual operation, the upper feeding time can be adjusted to be slightly slower than the lower feeding time according to special requirements.


(6) Adjustment of presser foot cross lifting mechanism

When sewing medium-heavy materials, the lifting amount of the swinging presser foot is within 5.5 mm, and the lifting amount of the small presser foot is about 3.5 mm. Under the condition that other mechanisms are unchanged, the sum of the lifting amount of the two presser feet is a fixed value, but the total lifting amount of the swinging presser foot and the small presser foot can also be changed. The eccentric link rod screw be adjusted and the presser foot lifting shaft. The center distance is sufficient. The smaller the center distance is, the more the lifting amount of the swing foot and the small presser foot increases; otherwise, the lifting amount decreases.


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