ASTM D3882-08(2012)e1
(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
This test method is considered satisfactory for acceptance testing of commercial shipments.
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.
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.
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 or sharp breaks in t...
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
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Designation: D3882 − 08(Reapproved 2012)
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.
ε NOTE—The language in 9.5.2 and 9.5.5 was corrected editorially to match Fig. 2 in July 2012.
1. Scope 3. Terminology
3.1 For all terminology related to Fabric Defects see Termi-
1.1 This test method covers the determination of bow and
nology D3990.
skew of filling yarns in woven fabrics and the courses in
knitted fabrics.
3.2 The following terms are relevant to this standard: bow,
double bow, double hooked bow, double reverse bow, hooked
1.2 This test method can also be used to measure the bow
bow, knitted fabric, skew, standard atmosphere for testing
and skew of printed geometric designs.
textiles.
1.3 The values stated in either SI units or inch-pound units
3.3 For definitions of all other textile terms seeTerminology
are to be regarded separately as standard. The values stated in
D123.
each system may not be exact equivalents; therefore, each
system shall be used independently of the other. Combining
4. Summary of Test Method
values from the two systems may result in non-conformance
4.1 Bow—Astraightedgeisplacedacrossthefabricbetween
with the standard.
two points at which a marked filling yarn, knitting course,
1.4 This standard does not purport to address all of the
designated printed line, or designated design meets the two
safety concerns, if any, associated with its use. It is the
selvages or edges. The greatest distance between the straight-
responsibility of the user of this standard to establish appro-
edge and the marked filling line, knitting course, designated
priate safety and health practices and determine the applica-
printed line, or designated design is measured parallel to the
bility of regulatory limitations prior to use.
selvage.
4.2 Skew—The straight-line distortion of a marked filling
2. Referenced Documents
yarn, knitting course, designated printed line, or designated
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
Method that Produces Normally Distributed Data (With- 5.1 This test method is considered satisfactory for accep-
drawn 2008) tance testing of commercial shipments.
D2906 Practice for Statements on Precision and Bias for 5.1.1 If there are differences of practical significance be-
Textiles (Withdrawn 2008) tween reported test results for two laboratories (or more),
comparative tests should be performed to determine if there is
D3990 Terminology Relating to Fabric Defects
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
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
which the disparate test results were obtained, and are ran-
and is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,
Specific.
domlyassignedinequalnumberstoeachlaboratoryfortesting.
Current edition approved July 1, 2012. Published August 2012. Originally
Other fabrics with established test values may be used for this
ε1
approved in 1980. Last previous edition approved in 2008 as D3882 – 08 . DOI:
purpose. The test results from the two laboratories should be
10.1520/D3882-08R12E01.
compared using a statistical test for unpaired data, at a
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
probability level chosen prior to the testing series. If a bias is
Standards volume information, refer to the standard’s Document Summary page on
found, either its cause must be found and corrected, or future
the ASTM website.
test results must be adjusted in consideration of the known
The last approved version of this historical standard is referenced on
www.astm.org. bias.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D3882 − 08 (2012)
5.2 Individual rolls are normally accepted or rejected on the 8. Conditioning
basis of the maximum amount of bow or skew in a specific roll
8.1 Conditionthetestspecimenstomoistureequilibriumfor
of fabric. The average bow or skew in a roll or lot or the range
testing in the standard atmosphere for testing textiles in
of bow or skew in a roll may be determined but are not
accordance with Practice D1776 or, if applicable, in the
normally used in the trade for acceptance or rejection.
specified atmosphere in which the testing is to be performed.
5.3 Bow or skew can be induced during fabric
8.1.1 When full rolls or bolts of fabric cannot be properly
manufacturing, dyeing, tentering, finishing, or other operations
conditioned in a reasonable time with available facilities,
where a potential exists for uneven distribution of tensions
perform the test without conditioning and report the actual
across the fabric width. Bow and skew are more visually
condition prevailing at the time of the test. Such results may
displeasing in colored, patterned fabrics such as plaids and
not correspond with the results obtained when testing condi-
horizontal stripes rather than in solid colors because the
tioned specimens at the standard atmosphere for testing tex-
contrast makes the distortion more prominent. These defects
tiles.
may cause sewing problems in such fabrics and draping
problems in finished products. In some cases, a specified
9. Procedure
amount of skew is needed, for example, to prevent twisting of
9.1 Test the test specimens in the standard atmosphere for
pant legs made of twill fabric. Matching plaids from distorted
testing textiles in accordance with Section 8.
patterns may create serious problems for the garment manu-
facturer or home sewer. Wavy or sharp breaks in the bow line
9.2 Handle the test specimens carefully to avoid altering the
are more detrimental to the appearance of small parts of a natural state of the material.
garment (such as collars, pockets, and so forth) than a gradual
9.3 Lay the fabric on a smooth, horizontal surface without
slope from a straight line.
tension in any direction or use the optional fabric inspection
5.3.1 Automotive interior textiles used for seat bolsters,
table.
cushions, headrests and door panels may be susceptible to bow
9.4 Bow:
and skew, especially when visually patterned fabrics are joined
9.4.1 Measure the bow in three places spaced as widely as
or mated to a straight edge surface.
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,
or printed line across the full width of the fabric using a soft
6.2 Rigid Straightedge or t-square, longer than the width of
pencil or suitable marker.
the fabric that is to be measured.
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
7.1 Primary Sampling Unit—Consider rolls or bolts of
example, a width of 38 cm (15 in.).This distance is used as the
fabric or fabric components of fabricated systems to be the
fabric width when calculating the bow.
primary sampling unit, as applicable.
9.4.4.2 For automotive or other applications where narrow
7.2 Laboratory Sampling Unit—As a laboratory sampling
panels or cut pieces are used, it will be necessary to measure
unit take the entire roll or bolt after removing a first 1-mm
bowacrossanarrowerdistancethanacrossthefullwidthofthe
(1-yd)length.Forfabriccomponentsoffabricatedsystems,use
fabric, for example, a width of 400 mm (16 in.). Use this
the entire system.
distance as the fabric width when calculating bow.
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 one another than one fifth of the roll
or bolt or piece length. 9.4.5.1 If double bow is evident, measure and record both
7.3.1 Optical test specimens—Select 3 test areas from each distances.
sampling unit. Exclude the first and last 10 m (11 yd) of a roll
NOTE 1—Fig. 1 represents typical examples of bows in a fabric that do
and test random areas within the roll.
not have any skew. Many variations in the shape or deepest portion of
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