Zipper and Slider Testing Technique
There are various methods to evaluate Zipper & Slider quality. The procedures in various quality standards worldwide are more or less similar and are documented well under ASTM, ISO, BIS, JIS, DIN, ISI and other well known International Standards.
Zipper & Slider strengths are checked as a routine inspection, For this the method laid out in
JIS-S3015 is used. The same standard is used by the YKK also, the world's leading Zipper manufacturer.
The basic strength can be determined based on the following inspection methods, from which all round strength appropriate for respective uses can be judged.
TENSILE TESTING METHODS
Crosswise Zipper Strength
To determine the Zipper Strength the Zipper Chain in closed position is clamped in-between specially designed Jaws of 25 mm width and pulled at a fixed speed at 90 degree angle to the chain interlocked direction.
The resistance is measured in Kgf till failure.
Top Stop Holding Strength
The lower part of an interlocked Zipper is clamped and the Slider is pulled right up to the top stop. Holding strength is measured by pulling the Slider against the Top Stop in the Tensile Testing machine.
Bottom Stop Holding Strength
A slider is pulled down till the end so that it touches the bottom stop and then the top single chains are opened to the right and left sides and are clamped in the Tensile tester. Bottom stop holding strength and resistance of the Zipper teeth inside the Slider are measured.
Box Holding Strength
The open part is fixed to the tensile tester clamps.The clamps cover only on the area where the reinforcement tape exists as shown in the figure and the tensile strength is measured till failure.
Slider Lock Strength
A slider is locked around the middle of a zipper chain and top single chains are opened to the right and left sides. Locking strength of the Slider to the Zipper and resistance of the teeth inside the slider are measured.
Tensile Strength of the Slider
The Body to Puller Strength is measured by this test. The complete slider is mounted on a special jig and load is applied to the Puller while keeping the Body fixed at 90 degrees. The resistance of the slider is measured till failure and is recorded in Kgf.
Tensile Tester velocity used in the above tests varies between 100~300 mm / min and the standard Clamp width used is 25mm.