ASTM D3937-01

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D3937–01
Standard Test Method for
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Crimp Frequency of manufactured Staple Fibers
This standard is issued under the fixed designation D 3937; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 crimp, n—in a textile strand, the undulations, wavi-
ness, or succession of bends, curls, or waves in the strand
1.1 This test method covers the determination of the crimp
induced either naturally, mechanically, or chemically.
frequency of manufactured staple fibers. This test method is
3.1.1.1 Discussion—Crimp has many characteristics,
applicable to all crimped provided the crimp can be viewed
among which are its amplitude, frequency, index, and type. In
two-dimensionally as a sine-wave configuration.
this test method, crimp is characterized by a change in the
1.1.1 It should be recognized that yarn manufacturing pro-
directional rotation of a line tangent to the fiber as the point of
cesses or treatments to manufactured yarns can influence or
tangent progresses along the fiber. Two changes in rotation
modify crimp in fiber. Hence, the value for crimp of fibers
constitute one unit of crimp.
taken from spun yarns may be different than that of the same
3.1.2 crimp frequency, n—in manufactured staple fibers,the
fiber prior to the manufacturing or treatment processes.
number of crimps or waves per unit length of extended or
1.2 Three options are provided for preparation of the speci-
straightened fiber.
mens. Option One (preferred) uses single fibers for the speci-
3.1.3 crimp index, n—an indirect measure of the amplitude
menswithalowmagnificationavailable,OptionTwo(optional
of crimp.
for staple or tow samples) uses fiber chips as the specimens,
3.1.3.1 Discussion—Crimp index is calculated as the differ-
and Option Three uses projected images of single fibers.
ence in the distance between two points on the fiber as it lies
1.3 The values stated in SI units are to be regarded as the
in an unstretched condition in one plane and the distance
standard. The inch-pound units in parentheses are for informa-
between the same two points when the fiber is straightened
tion only.
under a specified tension expressed as a percentage of the
1.4 This standard does not purport to address all of the
unstretched distance. To improve reproducibility, the un-
safety concerns, if any, associated with its use. It is the
stretcheddistancemaybemeasuredunderaspecified,verylow
responsibility of the user of this standard to establish appro-
tension to align the fiber in one plane.
priate safety and health practices and determine the applica-
3.1.4 fiber chip, n—in manufactured textiles, staple fibers
bility of regulatory limitations prior to use.
that are massed together as a unit and that maintain a single
2. Referenced Documents geometry or alignment.
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3.1.5 For definitions of other textile terms used in this test
2.1 ASTM Standards:
method, refer to Terminology D 123.
D 123 Terminology Relating to Textiles
D 1776 Practice for Conditioning and Testing Textiles
4. Summary of Test Method
D 2258 Practice for Sampling Yarn for Testing
4.1 For Option One, a fiber specimen of manufactured
D 3333 Practice for Sampling manufactured Staple Fibers,
staple is placed on a short pile or plush surface. The crimps
Sliver, or Tow for Testing
along the entire length of the specimen is counted. After the
3. Terminology
specimen is counted, the fiber is straightened without defor-
mation and its uncrimped length measured. Crimp frequency is
3.1 Definitions:
reported as the number of crimps per unit of extended length.
4.2 For Option Two, the number of crimps is counted in
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This test method is under the jurisdiction ofASTM Committee D13 onTextiles
fiber chip specimens. The specimen length is measured on
and is the direct responsibility of Subcommittee D13.58 on Yarn and Fiber Test
fibers taken from each of the chips.
Methods.
4.3 For Option Three, the fiber specimen is mounted be-
Current edition approved Sept. 10, 2001. Published December 2001. Originally
tween microscope slides. The image of the specimen is
published as D 3937 – 80. Last previous edition D 3937 – 94.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
projected and its crimp is counted. The extended length of the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
specimen is measured as in Option One.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
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