Continuing from the previous article, we will continue to introduce the methods for determining the strength of zippers. The following methods can be used to test the quality of zippers for different purposes, and the results of these tests can be used to determine the quality of zippers.

6.Zipper Slider Self-Lock With Intensive Force 

The slider is locked at the middle of a zipper chain and separated the teeth on both sides,then pulled outwards in oppsite directions.

To measure the locking strength and tooth resistance strength within the slider.

7.Jack Shift With Intensive Force 

Separate the two teeth chain tapes and place one end of the box retainer in the upper clamp, while the other end is clamped in the lower clamp.

8.Zipper Slider Combine With Intensive Force 

Install the slider body in the lower clamp and clamp the pull tab in the upper clamp.

Measure the strength of the slider when strengthen force to the both pull tab and the bottom of the body of a assembled slider.

9.Bottom Stop With Intensive Force 

Pull down the slider to the bottom stop and then pull both sides of the chain outward in the opposite directions.

Bottom stop holding strength and the resistance strength of the teeth inside the slider are measured.

10.Bending Pull With Intensive Force 

Fold a section of zipper in half and install it vertically in the upper and lower clamps.Aligning the chain teeth and the jaw part of the clamp tightly. Leave 0.5-1mm on the folded end face. The measured value is the bending strength.