ASTM D3882-99(2006)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D3882–99 (Reapproved 2006)
Standard Test Method for
Bow and Skew in Woven and Knitted Fabrics
This standard is issued under the fixed designation D 3882; 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 the selvages and form one or more arcs across the width of the
fabric. (See alsodouble bow .)
1.1 This test method covers the determination of bow and
3.1.2 double bow, n—two fabric bows, arcing in the same
skew of filling yarns in woven fabrics and the courses in
direction, as in a flattened M or W depending on the viewing
knitted fabrics.
angle. (See alsodouble bow .) (Compare double reverse bow.)
1.2 This test method can also be used to measure the bow
3.1.2.1 Discussion—In tubular knits, there may be differen-
and skew of printed geometric designs such as plaids.
tial bowing between the top and bottom of the tube.
1.3 The values stated in either SI units or inch-pound units
3.1.3 double hooked bow, n—one hooked bow at each side
are to be regarded separately as the standard. Within the text,
of the fabric that arc in opposite directions. (See alsohooked
the inch-pound units are shown in parentheses. The values
bow .)
stated in each system may not be exact equivalents; therefore,
3.1.4 double reverse bow, n—two fabric bows arcing in
each system shall be used independently of the other. Combin-
opposite directions. (See also bowdouble bow.) (Compare .)
ingvaluesfromthetwosystemsmayresultinnonconformance
3.1.5 hooked bow, n—a fabric condition in which the filling
with this test method.
yarns or knitted courses are in the proper position for most of
1.4 This standard does not purport to address all of the
the fabric width but are pulled out of alignment at one side of
safety concerns, if any, associated with its use. It is the
the fabric. (See also double hooked bow.)
responsibility of the user of this standard to establish appro-
3.1.6 knitted fabric, n—astructureproducedbyinterlooping
priate safety and health practices and determine the applica-
one or more ends of yarn or comparable materials.
bility of regulatory limitations prior to use.
3.1.7 skew, n—a fabric condition resulting when filling
2. Referenced Documents yarns or knitted courses are angularly displaced from a line
perpendicular to the edge or side of the fabric.
2.1 ASTM Standards:
3.1.7.1 Discussion—Knitted courses or filling yarns usually
D 123 Terminology Relating to Textiles
appear as straight line at right angles to the edge or side of the
D 1776 Practice for Conditioning and Testing Textiles
fabric.Whentubularknittedfabricisfinished,differentialskew
D 2904 Practice for Interlaboratory Testing of a Textile Test
may occur on the top and bottom part of the tube.
Method that Produces Normally Distributed Data
3.1.8 standard atmosphere for testing textiles,
D 2906 Practice for Statements on Precision and Bias for
n—laboratoryconditionsfortestingfibers,yarns,andfabricsin
Textiles
which air temperature and relative humidity are maintained at
D 3990 Terminology Relating to Fabric Defects
specific levels with established tolerances.
3. Terminology
3.1.8.1 Discussion—Textile materials are used in a number
ofspecificend-useapplicationsthatfrequentlyrequiredifferent
3.1 Definitions:
testing temperatures and relative humidities. Specific condi-
3.1.1 bow, n—afabricconditionresultingwhenfillingyarns
tioning and testing of textiles for end-product requirements can
or knitting courses are displaced from a line perpendicular to
be carried out using Table 1 in Practice D 1776.
3.1.9 For definitions of fabric defect terms, refer to Termi-
nology D 3990. For definitions of other textile terms used in
This test method is under the jurisdiction ofASTM Committee D13 onTextiles
this test method, refer to Terminology D 123.
and is the direct responsibility of Subcommittee D13.60 on Fabrics, Specific.
Current edition approved Jan. 1, 2006. Published February 2006. Originally
4. Summary of Test Method
approved in 1980. Last previous edition approved in 1999 as D 3882 – 99.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.1 Bow—A straightedge is placed across the fabric be-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
tween two points at which a marked filling yarn, knitting
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. course, designated printed line, or designated design meets the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3882–99 (2006)
TABLE 1 Critical Differences, 95% Probability Level, for Bow
products. In some cases, a specified amount of skew is needed,
and Skew for the Conditions Noted
for example, to prevent trouser leg twisting. Matching plaids
A
Property Number of Critical Differences for the Conditions Noted ,%
from distorted patterns may create serious problems for the
Observations in
Repeatability Reproducibility
garment manufacturer or home sewer. Wavy or sharp breaks in
Each Average
the bow line are more detrimental to the appearance of small
(Within- (Between-
(Single-Operator)
Laboratory) Laboratory)
parts of a garment (such as collars, pockets, and so forth) than
Precision
Precision Precision
a gradual slope from a straight line.
Bow 1 0.80 0.80 0.80
3 0.46 0.46 0.46
6. Apparatus
6 0.33 0.33 0.33
12 0.23 0.23 0.23 6.1 Measuring Stick or Steel Tape, graduated in 1-mm
24 0.16 0.16 0.16 1
( ⁄16-in.) divisions and longer than the width of the fabric that
is to be measured.
Skew 1 2.99 2.99 3.18
3 1.73 1.73 2.04
6.2 Rigid Straightedge, longer than the width of the fabric
6 1.22 1.22 1.63
that is to be measured.
12 0.86 0.86 1.38
6.3 Flat Surface, of sufficient length to unroll or unfold the
24 0.61 0.61 1.24
fabric (see 6.4).
A
The critical differences for Table 1 were calculated using t = 1.960, which is
6.4 Fabric Inspection Table (Optional), to unroll and roll
based on infinite degrees of freedom.
fabric rolls or unfold and fold fabric bolts with sufficient
lighting that provides transmitted light from underneath the
two selvages or edges. The greatest distance between the
fabric to make the defect more clearly visible.
straightedge and the marked filling line, knitting course,
7. Sampling and Test Specimens
designated printed line, or designated design is measured
parallel to the selvage.
7.1 Primary Sampling Unit—Consider rolls or bolts of
4.2 Skew—The straight-line distortion of a marked filling
fabric or fabric components of fabricated systems to be the
yarn, knitting course, designated printed line, or designated
primary sampling unit, as applicable.
design is measured from its normal perpendicular to the
7.2 Laboratory Sampling Unit—As a laboratory sampling
selvage or edge.
unit take the entire roll or bolt after removing a first 1-mm
(1-yd)length.Forfabriccomponentsoffabricatedsystems,use
5. Significance and Use
the entire system.
5.1 This test method is considered satisfactory for accep-
7.3 Test Specimens—As test specimens, select 3 test areas
tance testing of commercial shipments.
from each laboratory sampling unit. Exclude the first and last
5.1.1 If there are differences of practical significance be-
fifth of the roll or bolt or piece length. Select test areas at
tween reported test results for two laboratories (or more),
random but no closer to one another than one fifth of the roll
comparative tests should be performed to determine if there is
or bolt or piece length.
a statistical bias between them, using competent statistical
8. Conditioning
assistance. As a minimum, the test samples to be used are as
homogeneous as possible, are drawn from the material from 8.1 Conditionthetestspecimenstomoistureequilibriumfor
which the disparate test results were obtained, and are ran-
testing in the standard atmosphere for testing textiles in
domlyassignedinequalnumberstoeachlaboratoryfortesting. accordance with Practice D 1776 or, if applicable, in the
Other fabrics with established test values may be used for this specified atmosphere in which the testing is to be performed.
purpose. The test results from the two laboratories should be 8.1.1 When full rolls or bolts of fabric cannot be properly
compared using a statistical test for unpaired data, at a conditioned in a reasonable time with available facilities,
probability level chosen prior to the testing series. If a bias is
perform the test without conditioning and report the actual
found, either its cause must be found and corrected, or future condition prevailing at the time of the test. Such results may
test results must be adjusted in consideration of the known
not correspond with the results obtained when testing condi-
bias. tioned specimens at the standard atmosphere for testing tex-
5.2 Individual rolls are normally accepted or rejected on the
tiles.
basis of the maximum amount of bow or skew in a specific roll
9. Procedure
of fabric. The average bow or skew in a roll or lot or the range
of bow or skew in a roll may be determined but are not 9.1 Test the test specimens in the standard atmosphere for
normally used in the trade for acceptance or rejection. testing textiles in accordance with Section 8.
5.3 Bow or skew can be induced during fabric manufactur- 9.2 Handle the test specimens carefully to avoid altering the
ing, dyeing, tentering, finishing, or other operations where a natural state of the material.
potential exists for uneven distribution of tensions across the 9.3 Lay the fabric on a smooth, horizontal surface without
fabric width. Bow and skew are more visually displeasing in tension in any direction or use the optional fabric inspection
colored, patterned fabrics such as plaids and horizontal stripe
...