ASTM D3882-08(2020)
(Test Method)Standard Test Method for Bow and Skew in Woven and Knitted Fabrics
Standard Test Method for Bow and Skew in Woven and Knitted Fabrics
SIGNIFICANCE AND USE
5.1 This test method is considered satisfactory for acceptance testing of commercial shipments.
5.1.1 If there are differences of practical significance between reported test results for two laboratories (or more), comparative tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, the test samples to be used are as homogeneous as possible, are drawn from the material from which the disparate test results were obtained, and are randomly assigned in equal numbers to each laboratory for testing. Other fabrics with established test values may be used for this purpose. The test results from the two laboratories should be compared using a statistical test for unpaired data, at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results must be adjusted in consideration of the known bias.
5.2 Individual rolls are normally accepted or rejected on the basis of the maximum amount of bow or skew in a specific roll 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 normally used in the trade for acceptance or rejection.
5.3 Bow or skew can be induced during fabric manufacturing, dyeing, tentering, finishing, or other operations where a potential exists for uneven distribution of tensions across the fabric width. Bow and skew are more visually displeasing in colored, patterned fabrics such as plaids and horizontal stripes rather than in solid colors because the contrast makes the distortion more prominent. These defects may cause sewing problems in such fabrics and draping problems in finished products. In some cases, a specified amount of skew is needed, for example, to prevent twisting of pant legs made of twill fabric. Matching plaids from distorted patterns may create serious problems for the garment manufacturer or home sewer. Wavy ...
SCOPE
1.1 This test method covers the determination of bow and skew of filling yarns in woven fabrics and the courses in knitted fabrics.
1.2 This test method can also be used to measure the bow and skew of printed geometric designs.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3882 − 08 (Reapproved 2020)
Standard Test Method for
Bow and Skew in Woven and Knitted Fabrics
This standard is issued under the fixed designation D3882; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope D2906 Practice for Statements on Precision and Bias for
Textiles (Withdrawn 2008)
1.1 This test method covers the determination of bow and
D3990 Terminology Relating to Fabric Defects
skew of filling yarns in woven fabrics and the courses in
knitted fabrics.
3. Terminology
1.2 This test method can also be used to measure the bow
3.1 For all terminology related to Fabric Defects see Termi-
and skew of printed geometric designs.
nology D3990.
1.3 The values stated in either SI units or inch-pound units
3.2 The following terms are relevant to this standard: bow,
are to be regarded separately as standard. The values stated in
double bow, double hooked bow, double reverse bow, hooked
each system may not be exact equivalents; therefore, each
bow, knitted fabric, skew, standard atmosphere for testing
system shall be used independently of the other. Combining
textiles.
values from the two systems may result in non-conformance
with the standard.
3.3 For definitions of all other textile terms seeTerminology
D123.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4.1 Bow—Astraightedgeisplacedacrossthefabricbetween
mine the applicability of regulatory limitations prior to use.
two points at which a marked filling yarn, knitting course,
1.5 This international standard was developed in accor-
designated printed line, or designated design meets the two
dance with internationally recognized principles on standard-
selvages or edges. The greatest distance between the straight-
ization established in the Decision on Principles for the
edge and the marked filling line, knitting course, designated
Development of International Standards, Guides and Recom-
printed line, or designated design is measured parallel to the
mendations issued by the World Trade Organization Technical
selvage.
Barriers to Trade (TBT) Committee.
4.2 Skew—The straight-line distortion of a marked filling
yarn, knitting course, designated printed line, or designated
2. Referenced Documents
design is measured from its normal perpendicular to the
2.1 ASTM Standards:
selvage or edge.
D123 Terminology Relating to Textiles
D1776 Practice for Conditioning and Testing Textiles
5. Significance and Use
D2904 Practice for Interlaboratory Testing of a Textile Test
5.1 This test method is considered satisfactory for accep-
Method that Produces Normally Distributed Data (With-
tance testing of commercial shipments.
drawn 2008)
5.1.1 If there are differences of practical significance be-
tween reported test results for two laboratories (or more),
comparative tests should be performed to determine if there is
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
a statistical bias between them, using competent statistical
and is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,
Specific.
assistance. As a minimum, the test samples to be used are as
Current edition approved July 1, 2020. Published August 2020. Originally
homogeneous as possible, are drawn from the material from
ε1
approved in 1980. Last previous edition approved in 2016 as D3882 – 08(2016) .
which the disparate test results were obtained, and are ran-
DOI: 10.1520/D3882-08R20.
domlyassignedinequalnumberstoeachlaboratoryfortesting.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Other fabrics with established test values may be used for this
Standards volume information, refer to the standard’s Document Summary page on
purpose. The test results from the two laboratories should be
the ASTM website.
compared using a statistical test for unpaired data, at a
The last approved version of this historical standard is referenced on
www.astm.org. probability level chosen prior to the testing series. If a bias is
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3882 − 08 (2020)
found, either its cause must be found and corrected, or future 7.3.1 Optical test specimens—Select 3 test areas from each
test results must be adjusted in consideration of the known sampling unit. Exclude the first and last 10 m (11 yd) of a roll
bias. and test random areas within the roll.
7.3.1.1 Cut pieces that are at least 400 mm (16 in.) in width
5.2 Individual rolls are normally accepted or rejected on the
can be measured for bow and skew.
basis of the maximum amount of bow or skew in a specific roll
of fabric. The average bow or skew in a roll or lot or the range
8. Conditioning
of bow or skew in a roll may be determined but are not
8.1 Conditionthetestspecimenstomoistureequilibriumfor
normally used in the trade for acceptance or rejection.
testing in the standard atmosphere for testing textiles in
5.3 Bow or skew can be induced during fabric
accordance with Practice D1776 or, if applicable, in the
manufacturing, dyeing, tentering, finishing, or other operations
specified atmosphere in which the testing is to be performed.
where a potential exists for uneven distribution of tensions
8.1.1 When full rolls or bolts of fabric cannot be properly
across the fabric width. Bow and skew are more visually
conditioned in a reasonable time with available facilities,
displeasing in colored, patterned fabrics such as plaids and
perform the test without conditioning and report the actual
horizontal stripes rather than in solid colors because the
condition prevailing at the time of the test. Such results may
contrast makes the distortion more prominent. These defects
not correspond with the results obtained when testing condi-
may cause sewing problems in such fabrics and draping
tioned specimens at the standard atmosphere for testing tex-
problems in finished products. In some cases, a specified
tiles.
amount of skew is needed, for example, to prevent twisting of
9. Procedure
pant legs made of twill fabric. Matching plaids from distorted
patterns may create serious problems for the garment manu- 9.1 Test the test specimens in the standard atmosphere for
facturer or home sewer. Wavy or sharp breaks in the bow line testing textiles in accordance with Section 8.
are more detrimental to the appearance of small parts of a
9.2 Handle the test specimens carefully to avoid altering the
garment (such as collars, pockets, and so forth) than a gradual
natural state of the material.
slope from a straight line.
9.3 Lay the fabric on a smooth, horizontal surface without
5.3.1 Automotive interior textiles used for seat bolsters,
tension in any direction or use the optional fabric inspection
cushions, headrests and door panels may be susceptible to bow
table.
and skew, especially when visually patterned fabrics are joined
or mated to a straight edge surface. 9.4 Bow:
9.4.1 Measure the bow in three places spaced as widely as
possible along the length of the fabric or along a minimum of
6. Apparatus
1 m (1 yd). If possible, make no measurement closer to the
6.1 Measuring Stick or Steel Tape, graduated in 1-mm
ends of the roll or piece of fabric than1m(1 yd).
( ⁄16-in.) divisions and longer than the width of the fabric that
9.4.2 Follow a distinctive color yarn or pattern line across
is to be measured.
the width of the fabric. Trace one filling yarn, knitting course,
6.2 Rigid Straightedge or t-square, longer than the width of
or printed line across the full width of the fabric using a soft
the fabric that is to be measured.
pencil or suitable marker.
9.4.3 Place a rigid straightedge across the fabric connecting
6.3 Flat Surface, of sufficient length to unroll or unfold the
the points at which the distinctive color yarn or pattern line, or
fabric (see 6.4).
marked yarn meets the two selvages or edges.
6.4 Fabric Inspection Table (Optional), to unroll and roll
9.4.4 Measure the distance along the straightedge between
fabric rolls or unfold and fold fabric bolts with sufficient 1
the two selvages or edges to the nearest 1 mm ( ⁄16 in.) and
lighting that provides transmitted light from underneath the
record as the baseline distance (BL).
fabric to make the defect more clearly visible.
9.4.4.1 Forcertainenduseswhereseveralnarrowpanelsare
sewn in a garment, it will be necessary to measure the bow
7. Sampling and Test Specimens
across a narrower distance than the total width of the fabric, for
example, a width of 38 cm (15 in.).This distance is used as the
7.1 Primary Sampling Unit—Consider rolls or bolts of
fabric width when calculating the bow.
fabric or fabric components of fabricated systems to be the
9.4.4.2 For automotive or other applications where narrow
primary sampling unit, as applicable.
panels or cut pieces are used, it will be necessary to measure
7.2 Laboratory Sampling Unit—As a laboratory sampling
bowacrossanarrowerdistancethanacrossthefullwidthofthe
unit take the entire roll or bolt after removing a first 1-mm
fabric, for example, a width of 400 mm (16 in.). Use this
(1-yd)length.Forfabriccomponentsoffabricatedsystems,use
distance as the fabric width when calculating bow.
the entire system.
9.4.5 Measure the greatest distance parallel to the selvages
7.3 Test Specimens—As test specimens, select 3 test areas oredgesbetweenthestraightedgeandthedistinctivecoloryarn
from each laboratory sampling unit. Exclude the first and last orpatternline,ormarkedyarntothenearest1mm( ⁄16in.)and
fifth of the roll or bolt or piece length. Select test areas at record as the bow distance (D) including the type. (See Fig. 1).
random but no closer to
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