ASTM D3883-04(R2020) pdf free download

ASTM D3883-04(R2020) pdf free download.Standard Test Method for Yarn Crimp and Yarn Take-up in Woven Fabrics
1. Scope
1.1 This test method covers the determination of the rela- tionship between the length of a piece of fabric and the length of the yarn in the fabric by measurement of the yarn crimp and yarn take-up. 1.2 This test method applies to woven fabrics. 1.3 The values stated in either SI or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in parentheses. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Summary of Test Method
4.1 Bench marks are placed on a length of a yarn as it lies in a woven fabric. The distance between the bench marks is measured. The yarn is removed from the fabric, straightened by applying suitable tension, and the distance between the bench marks is remeasured. Yarn crimp is the change in length expressed as a percent and based on the in-fabric distance. Yarn take-up is the change in length expressed as a percent and based on the out-of-fabric distance.
5. Significance and Use
5.1 The relationship ofthe length ofa piece offabric and the length of yarn in the fabric can be determined accurately only be measuring the length of yarn entering the loom and the length of fabric made from that particular length of yarn. In most cases, however, the determination must of necessity be made on a woven fabric by measuring the length of yarn removed from a measured length of fabric, thus introducing certain variations that will influence the accuracy of the test. Yarn removed from the woven fabric contains undulations or waves that have been introduced by the weaving process. Heat, moisture, and mechanical shrinkage on subsequent finishing operations may accentuate these undulations, and in all probability, increase the force to pull them out and straighten the yarn. In order to accurately measure the length of the yarn after the removal of the crimp, these undulations must be pulled out without elongating the yarn. In some cases, the minimum force necessary to straighten the yarn will cause a certain amount of the elongation to take place, thus increasing the length of the yarn. Also, stresses imposed upon the yarn during the weaving process may have been sufficient to stretch the yarn beyond its elastic limit, again increasing its length. It is recognized that determination made by measuring length of yarn removed from a measured length of fabric may tend to give crimp values that are somewhat higher than the crimp in the yarn as it lay in the fabric. In the case of fabrics made from yarns that exhibit differential shrinkage, or yarns of widely different count, or yarns woven at different tensions, the crimp of each type of yarn in the fabric must be determined and reported separately. 5.2 This test method can be used for acceptance testing of commercial shipments but comparisons should be made with caution because information on estimates of between- laboratory precision is limited as noted in 13.1.