The straightness and smoothness of the luggage zipper, the zipper is in a natural sag, no waves or bends. The zipper manufacturer introduced that the zipper teeth of the injection zipper should be bright, with no dents in the middle of the front, no missing teeth, and the metal zipper teeth are neatly arranged, without skew, without broken tooth chains, and the teeth have good bite. The color of the metal zipper is uniform, bright and smooth, and there is no color difference.
The glued position of the zipper tape is symmetrical, without skew, and the glued place is rotated 180 degrees for 10 times. The coating of the electroplating slider is bright, without peeling and scratches caused by foreign matter, and the thickness of the coating is not less than 3UM. The painted surface of the plastic spray slider is bright, the coating is uniform and firm, and there are no bubbles. Pull the slider to move back and forth, the slider slides smoothly and flexibly, without jumping or blocking feeling. When the slider is activated up and down at the socket, special attention should be paid to the obstruction.
Pull the two zipper tapes apart at an angle of about 60, with a moderate pulling speed. If the slider does not slide, it means that the slider is self-locking, otherwise it means that there is no self-locking or the self-locking strength is insufficient. Lift the pull tab perpendicular to the plane of the slider and the cover is secure. Resin zipper pulls come in many shapes. No matter what kind of slider, you must feel whether the slider can be pulled freely, whether it can’t be pulled up or not closed.