ASTM D3657-03 (R2021) pdf free download.Standard Specification for Zipper Dimensions.
1 .1 This specification establishes standard dimensions for zippers of all materials for specified size designation; for equivalency, in inch-pound and metric units, of zipper length and length tolerances, of tape width and width tolerances, and of tape end lengths.
1 .2 The values stated in either SI units or inch-pound units are to he regarded separately as standard. The values stated in each system are not necessarily exact equivalents: therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
3.1.1 For definitions of zipper terms used in this standard, refer to Terminology D2050. For definitions of other textile terminology used in this standard refer to Terminology D123.
4. Sampling
4.1 Sample the lot and select the number of specimens as directed in Test Methods D2060.
5. Dimensions and Perniissible Variations
5.1 Zippers shall conform to the dimensions listed in Tables
5.2 Tables 2 and 3 include tolerances which represent trade practice and arc in common use. The tolerances are not uniform between sizes because of differing requirements of the zippers based on their normal end-use.
5.3 Table 2, within a size, has uniform plus tolerances. Minus tolerances increase nonuniformly with increasing length because that is accepted trade practice based on the requirements of the end products in which the zippers are installed.
5.3.1 Because zipper chain is composed of a series of elements with a prescribed pitch and each element must remain complete to function, it is impossible to manufacture a zipper deliberately to an exact stated length. Therefore a shipment of zippers of a stated length will not likely average the stated length. Both the lot average length and the length of individual zippers should fall within the tolerances in Table 2.
5.4 Table 4 shows the metric conversion for standard inch-pound unit tape end lengths. Tape end length tolerances arc not shown due to widely varying end-use requirements and inherent zipper manufacturing dimension variations. Tolerances to be observed should be agreed upon between purchaser and supplier.
6. Test Methods
6.1 Size—Determine the zipper size as directed in the mouth width procedure of Test Methods D2060.
6.2 Zipper Length—Determine the zipper length as directed in the length of completely assembled zipper procedure of Test Methods D2060.
6.3 Tape Width—Determine the zipper tape width as directed in the tape width procedure of Test Methods D2060.ASTM D3657 pdf download.