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Things To Know About Zippers

Posted on by hungthinh
Zipper 4 1

A. How to Evaluate Zipper Quality

  • Tape (Band): The fabric should be evenly dyed, with no stains or defects. When touched, it feels smooth and soft, with a subtle wave-like appearance both vertically and horizontally.
  • Teeth: The surface of the teeth should be smooth, allowing the slider to move effortlessly without producing noise.
  • Slider (Brace): The slider should glide smoothly, remain secure, and not detach during use.
  • Seam (Hem): The seam must be firmly attached to the tape, with no risk of tearing or detachment. The separating pin and retainer can be designed with square bolts for added flexibility.
  • Top Stop: On metal and nylon zippers, the top stop should align perfectly with the first tooth, with a gap no greater than 1mm. It must be sturdy and visually appealing.
  • Bottom Stop (End Stop): The bottom stop should be firmly fastened to the teeth or tape and maintain a neat, durable appearance.

B. Tips for Choosing the Right Zipper

Each zipper is designed for specific applications. When purchasing, it’s important to specify the following to the manufacturer:

  1. 1
    Intended Use: Whether the zipper will be used on leather trunks, footwear, jackets, raincoats, tents, jeans that require heavy washing, or leather products with high acidity.
  2. 2
    Material Requirements: Ensure the zipper is free from harmful substances such as AZO dyes or nickel, and meets special standards such as passing a needle detector if required.

C. Zipper Length Tolerance

Due to machine speed and manufacturing precision, a slight tolerance in zipper length is inevitable. The longer the zipper, the larger the acceptable tolerance.

MH Zipper Tolerance Chart:

Size

Specification (mm)

Tolerance



3#

≤315


>315–630


>630–1000


>1000


±3


±5


±6


±（L×1%)




4#


≤315


±4



5#


﹥315~630


±6




7# 





8# 





10# 



>630–1000


>1000



≤315



>315–630


>630–1000


>1000



±7


±（L×1%)



±5



±7


±9


±（L×1%)



Japanese Standard (NEW Century Fair):

Zipper Length(cm)

Allowable Tolerance





Below 30


±5mm





30-below60


±10mm





60-below100


±15mm





Above100


±3%




Types of Zippers

  • Closed-End Zipper (non-separable)
  • Open-End Zipper (separable)
  • Two-Way Open-End Zipper (separable)
  • Two-Way Closed-End Zipper – O Tape
  • Two-Way Closed-End Zipper – X Tape

How to Measure Zipper Length

  • Closed-End Zipper: From the top of the slider to the bottom stop.
  • Open-End Zipper: From the top of the slider to the end of the open part.
  • Two-Way Open-End Zipper: From the top of the slider to the bottom of the supplementary tape.
  • Double-Slider Zipper (Head-to-Head): From the top of one slider to the bottom stop of the other slider.
  • Double-Slider Zipper (Bottom-to-Bottom): From the top of one slider to the bottom stop of the other slider.
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