1、Designation: D 3882 08Standard Test Method forBow and Skew in Woven and Knitted Fabrics1This standard is issued under the fixed designation D 3882; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of bow andskew of filling yarns in woven fabrics and the courses inknitted fabrics.1.2 This test me
3、thod can also be used to measure the bowand skew of printed geometric designs.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the
4、other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practi
5、ces and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 1776 Practice for Conditioning and Testing TextilesD 2904 Practice for Interlaboratory Testing of a Textile TestMethod that Produces Normally
6、 Distributed DataD 2906 Practice for Statements on Precision and Bias forTextiles3D 3990 Terminology Relating to Fabric Defects3. Terminology3.1 Definitions: (For all terminology related to Fabric De-fects see D3990.)3.1.1 The following terms are relevant to this standard:3.1.2 bow, na fabric condit
7、ion resulting when filling yarnsor knitting courses are displaced from a line perpendicular tothe selvages and form one or more arcs across the width of thefabric. (See alsodouble bow .)3.1.2.1 Discussionbow and bias is a synonym for bowand skew.3.1.3 double bow, ntwo fabric bows, arcing in the same
8、direction, as in a flattened M or W depending on the viewingangle. (See alsodouble bow .) (Compare double reverse bow.)3.1.3.1 DiscussionIn tubular knits, there may be differen-tial bowing between the top and bottom of the tube.3.1.4 double hooked bow, none hooked bow at each sideof the fabric that
9、arc in opposite directions. (See alsohookedbow .)3.1.5 double reverse bow, ntwo fabric bows arcing inopposite directions. (See also double bow.)3.1.6 hooked bow, na fabric condition in which the fillingyarns or knitted courses are in the proper position for most ofthe fabric width but are pulled out
10、 of alignment at one side ofthe fabric. (See also double hooked bow.)3.1.7 knitted fabric, na structure produced by interloopingone or more ends of yarn or comparable materials.3.1.8 skew, na fabric condition resulting when fillingyarns or knitted courses are angularly displaced from a lineperpendic
11、ular to the edge or side of the fabric.3.1.8.1 DiscussionKnitted courses or filling yarns usuallyappear as straight line at right angles to the edge or side of thefabric. When tubular knitted fabric is finished, differential skewmay occur on the top and bottom part of the tube.3.1.8.2 Discussionbow
12、and bias is a synonym for bowand skew.3.1.9 standard atmosphere for testing textiles,nlaboratory conditions for testing fibers, yarns, and fabrics inwhich air temperature and relative humidity are maintained atspecific levels with established tolerances.3.1.9.1 DiscussionTextile materials are used i
13、n a numberof specific end-use applications that frequently require differenttesting temperatures and relative humidities. Specific condi-tioning and testing of textiles for end-product requirements canbe carried out using Table 1 in Practice D 1776.1This test method is under the jurisdiction of ASTM
14、 Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,Specific.Current edition approved July 1, 2008. Published August 2008. Originallyapproved in 1980. Last previous edition approved in 2006 as D 3882 99 (2006).2For referenced ASTM standards, visit
15、 the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, P
16、A 19428-2959, United States.3.1.10 For definitions of fabric defect terms, refer to Termi-nology D 3990. For all other terminology related to textiles,see Terminology D 123.4. Summary of Test Method4.1 BowA straightedge is placed across the fabric be-tween two points at which a marked filling yarn,
17、knittingcourse, designated printed line, or designated design meets thetwo selvages or edges. The greatest distance between thestraightedge and the marked filling line, knitting course,designated printed line, or designated design is measuredparallel to the selvage.4.2 SkewThe straight-line distorti
18、on of a marked fillingyarn, knitting course, designated printed line, or designateddesign is measured from its normal perpendicular to theselvage or edge.5. Significance and Use5.1 This test method is considered satisfactory for accep-tance testing of commercial shipments.5.1.1 If there are differen
19、ces of practical significance be-tween reported test results for two laboratories (or more),comparative tests should be performed to determine if there isa statistical bias between them, using competent statisticalassistance. As a minimum, the test samples to be used are ashomogeneous as possible, a
20、re drawn from the material fromwhich the disparate test results were obtained, and are ran-domly assigned in equal numbers to each laboratory for testing.Other fabrics with established test values may be used for thispurpose. The test results from the two laboratories should becompared using a stati
21、stical test for unpaired data, at aprobability level chosen prior to the testing series. If a bias isfound, either its cause must be found and corrected, or futuretest results must be adjusted in consideration of the knownbias.5.2 Individual rolls are normally accepted or rejected on thebasis of the
22、 maximum amount of bow or skew in a specific rollof fabric. The average bow or skew in a roll or lot or the rangeof bow or skew in a roll may be determined but are notnormally used in the trade for acceptance or rejection.5.3 Bow or skew can be induced during fabric manufactur-ing, dyeing, tentering
23、, finishing, or other operations where apotential exists for uneven distribution of tensions across thefabric width. Bow and skew are more visually displeasing incolored, patterned fabrics such as plaids and horizontal stripesrather than in solid colors because the contrast makes thedistortion more
24、prominent. These defects may cause sewingproblems in such fabrics and draping problems in finishedproducts. In some cases, a specified amount of skew is needed,for example, to prevent twisting of pant legs made of twillfabric. Matching plaids from distorted patterns may createserious problems for th
25、e garment manufacturer or home sewer.Wavy or sharp breaks in the bow line are more detrimental tothe appearance of small parts of a garment (such as collars,pockets, and so forth) than a gradual slope from a straight line.5.3.1 Automotive interior textiles used for seat bolsters,cushions, headrests
26、and door panels may be susceptible to bowand skew, especially when visually patterned fabrics are joinedor mated to a straight edge surface.6. Apparatus6.1 Measuring Stick or Steel Tape, graduated in 1-mm(116-in.) divisions and longer than the width of the fabric thatis to be measured.6.2 Rigid Stra
27、ightedge or t-square, longer than the width ofthe fabric that is to be measured.6.3 Flat Surface, of sufficient length to unroll or unfold thefabric (see 6.4).6.4 Fabric Inspection Table (Optional), to unroll and rollfabric rolls or unfold and fold fabric bolts with sufficientlighting that provides
28、transmitted light from underneath thefabric to make the defect more clearly visible.7. Sampling and Test Specimens7.1 Primary Sampling UnitConsider rolls or bolts offabric or fabric components of fabricated systems to be theprimary sampling unit, as applicable.7.2 Laboratory Sampling UnitAs a labora
29、tory samplingunit take the entire roll or bolt after removing a first 1-mm(1-yd) length. For fabric components of fabricated systems, usethe entire system.7.3 Test SpecimensAs test specimens, select 3 test areasfrom each laboratory sampling unit. Exclude the first and lastfifth of the roll or bolt o
30、r piece length. Select test areas atrandom but no closer to one another than one fifth of the rollor bolt or piece length.7.3.1 Optical test specimensSelect 3 test areas from eachsampling unit. Exclude the first and last 10 m (11 yd) of a rolland test random areas within the roll.7.3.1.1 Cut pieces
31、that are at least 400 mm (16 in.) in widthcan be measured for bow and skew.8. Conditioning8.1 Condition the test specimens to moisture equilibrium fortesting in the standard atmosphere for testing textiles inaccordance with Practice D 1776 or, if applicable, in thespecified atmosphere in which the t
32、esting is to be performed.8.1.1 When full rolls or bolts of fabric cannot be properlyconditioned in a reasonable time with available facilities,TABLE 1 Critical Differences, 95 % Probability Level, for Bowand Skew for the Conditions NotedProperty Number ofObservations inEach AverageCritical Differen
33、ces for the Conditions NotedA,%Repeatability Reproducibility(Single-Operator)Precision(Within-Laboratory)Precision(Between-Laboratory)PrecisionBow 1 0.80 0.80 0.803 0.46 0.46 0.466 0.33 0.33 0.3312 0.23 0.23 0.2324 0.16 0.16 0.16Skew 1 2.99 2.99 3.183 1.73 1.73 2.046 1.22 1.22 1.6312 0.86 0.86 1.382
34、4 0.61 0.61 1.24AThe critical differences for Table 1 were calculated using t = 1.960, which isbased on infinite degrees of freedom.D3882082perform the test without conditioning and report the actualcondition prevailing at the time of the test. Such results maynot correspond with the results obtaine
35、d when testing condi-tioned specimens at the standard atmosphere for testing tex-tiles.9. Procedure9.1 Test the test specimens in the standard atmosphere fortesting textiles in accordance with Section 8.9.2 Handle the test specimens carefully to avoid altering thenatural state of the material.9.3 La
36、y the fabric on a smooth, horizontal surface withouttension in any direction or use the optional fabric inspectiontable.9.4 Bow:9.4.1 Measure the bow in three places spaced as widely aspossible along the length of the fabric or along a minimum of1 m (1 yd). If possible, make no measurement closer to
37、 theends of the roll or piece of fabric than1m(1yd).9.4.2 Follow a distinctive color yarn or pattern line acrossthe width of the fabric. Trace one filling yarn, knitting course,or printed line across the full width of the fabric using a softpencil or suitable marker.9.4.3 Place a rigid straightedge
38、across the fabric connectingthe points at which the distinctive color yarn or pattern line, ormarked yarn meets the two selvages or edges.9.4.4 Measure the distance along the straightedge betweenthe two selvages or edges to the nearest 1 mm (116 in.) andrecord as the baseline distance (BL).9.4.4.1 F
39、or certain end uses where several narrow panels aresewn in a garment, it will be necessary to measure the bowacross a narrower distance than the total width of the fabric, forexample, a width of 38 cm (15 in.). This distance is used as thefabric width when calculating the bow.9.4.4.2 For automotive
40、or other applications where narrowpanels or cut pieces are used, it will be necessary to measurebow across a narrower distance than across the full width of thefabric, for example, a width of 400 mm (16 in.). Use thisdistance as the fabric width when calculating bow.9.4.5 Measure the greatest distan
41、ce parallel to the selvagesor edges between the straightedge and the distinctive color yarnor pattern line, or marked yarn to the nearest 1 mm (116 in.) andrecord as the bow distance (D) including the type. (See Fig. 1).9.4.5.1 If double bow is evident, measure and record bothdistances.NOTE 1Fig. 1
42、represents typical examples of bows in a fabric that donot have any skew. Many variations in the shape or deepest portion of thearc can occur in actual fabrics. No provision is made to measure bow inthe presence of skew.9.4.5.2 When measuring narrow panels, for example, 400mm (16 in.), measure the b
43、ow across the width from left toright in 400 mm (16 in.) increments. For example, measure fullwidth units, 400 mm (16 in.). On the right side align with theright selvage and measure a 400 mm (16 in.) section. Thesemeasurements may overlap with some of the previouslymeasured sections.9.5 Skew:9.5.1 M
44、easure the skew in three places spaced as widely aspossible along the length of the fabric or along a minimum of1 m (1 yd). If possible, make no measurement closer to theends of the roll or piece of fabric than 1 m.9.5.2 Follow a distinctive color yarn or pattern line acrossthe width of the fabric.
45、Trace one filling yarn, knitting course,or printed line across the full width of the fabric using a softpencil or suitable marker (LineAC if right-hand skew, LineADif left-hand skew).9.5.3 Place a rigid straight edge or t-square across the fabricwidth perpendicular to the selvage or edge such that i
46、tcoincides with the lower point on the fabric at which thedistinctive color yarn or pattern line, or marked yarn meets oneof the selvages or edges (Line BC).9.5.4 Measure the distance along the straightedge ort-square between the two selvages or edges (Line BC) to thenearest 1 mm (116 in.) and recor
47、d as the fabric width (W). (SeeFig. 2.)9.5.4.1 For automotive or other applications where narrowpanels or cut pieces are used, it will be necessary to measureskew across a narrower distance than across the full width offabric, for example, a width of 400 mm (16 in.). Use thisdistance as the fabric w
48、idth when calculating skew.9.5.5 Measure the distance parallel to the selvages or edgesbetween the straightedge and the distinctive color yarn orpattern line, or marked yarn to the nearest 1 mm (116 in.) (LineAD, or BD) and record including the skew direction, right-hand“ Z,” left hand “S,” and whet
49、her evident on the face orback of the fabric. (See Fig. 2.)NOTE 2Fig. 2 represents a schematic drawing of typical skew;variations may occur in actual fabric. Examination of Fig. 2 will show thatthe skew in a fabric will be consistently categorized as left-hand (orright-hand) regardless whether the fabric is being fed from the top orbottom roll of the viewing frame or whether the direction of skew ismeasured from the right or left selvage or side, provided either the face orback of the fabric is being viewed.10. Calculation10.1 Bow, Individual MeasurementsCa
