1、Designation: D3882 08 (Reapproved 2016)Standard Test Method forBow and Skew in Woven and Knitted Fabrics1This standard is issued under the fixed designation D3882; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number 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.
3、1.2 This test method 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 indep
4、endently of the 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 a
5、nd health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD2904 Practice for Interlaboratory Testing of a Textile TestMethod that Prod
6、uces Normally Distributed Data (With-drawn 2008)3D2906 Practice for Statements on Precision and Bias forTextiles (Withdrawn 2008)3D3990 Terminology Relating to Fabric Defects3. Terminology3.1 For all terminology related to Fabric Defects see Termi-nology D3990.3.2 The following terms are relevant to
7、 this standard: bow,double bow, double hooked bow, double reverse bow, hookedbow, knitted fabric, skew, standard atmosphere for testingtextiles.3.3 For definitions of all other textile terms see TerminologyD123.4. Summary of Test Method4.1 BowAstraightedge is placed across the fabric betweentwo poin
8、ts at which a marked filling yarn, knitting course,designated printed line, or designated design meets the twoselvages or edges. The greatest distance between the straight-edge and the marked filling line, knitting course, designatedprinted line, or designated design is measured parallel to theselva
9、ge.4.2 SkewThe straight-line distortion 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
10、shipments.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 isa statistical bias between them, using competent statisticalassistance. As a minimum, the test samples to be
11、used are ashomogeneous as possible, are 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 laborat
12、ories should becompared using a statistical 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 ac
13、cepted or rejected on thebasis of the 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.1This test method is under the jurisdicti
14、on of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,Specific.Current edition approved July 1, 2016. Published July 2016. Originally approvedin 1980. Last previous edition approved in 2012 as D3882 08(2012)1. DOI:10.1520/D3882-08R16.2For
15、referenced ASTM standards, visit 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.3The last approved version of this historical standard is referenc
16、ed onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 Bow or skew can be induced during fabricmanufacturing, dyeing, tentering, finishing, or other operationswhere a potential exists for uneven distribution of tensions
17、across the fabric width. Bow and skew are more visuallydispleasing in colored, patterned fabrics such as plaids andhorizontal stripes rather than in solid colors because thecontrast makes the distortion more prominent. These defectsmay cause sewing problems in such fabrics and drapingproblems in fin
18、ished products. In some cases, a specifiedamount of skew is needed, for example, to prevent twisting ofpant legs made of twill fabric. Matching plaids from distortedpatterns may create serious problems for the garment manu-facturer or home sewer. Wavy or sharp breaks in the bow lineare more detrimen
19、tal to the appearance of small parts of agarment (such as collars, pockets, and so forth) than a gradualslope from a straight line.5.3.1 Automotive interior textiles used for seat bolsters,cushions, headrests and door panels may be susceptible to bowand skew, especially when visually patterned fabri
20、cs 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 Straightedge or t-square, longer than the width ofthe fabric that is to be measured.6.3 Flat Su
21、rface, 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 transmitted light from underneath thefabric to make the defect more clearly visible.7. Samp
22、ling 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 laboratory samplingunit take the entire roll or bolt after removing a first 1-mm(1-yd) length. Fo
23、r 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 or piece length. Select test areas atrandom but no closer to one another than one fifth of t
24、he 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 that are at least 400 mm (16 in.) in widthcan be measured for bow and skew.8. Conditioning8
25、.1 Condition the test specimens to moisture equilibrium fortesting in the standard atmosphere for testing textiles inaccordance with Practice D1776 or, if applicable, in thespecified atmosphere in which the testing is to be performed.8.1.1 When full rolls or bolts of fabric cannot be properlyconditi
26、oned in a reasonable time with available facilities,perform the test without conditioning and report the actualcondition prevailing at the time of the test. Such results maynot correspond with the results obtained when testing condi-tioned specimens at the standard atmosphere for testing tex-tiles.9
27、. 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 Lay the fabric on a smooth, horizontal surface withouttension in any direction or use the
28、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 theends of the roll or piece of fabric than1m(1yd).9.4.2 Follow a distinctive color yar
29、n 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 across the fabric connectingthe points at which the distinctive color yarn or pattern li
30、ne, 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 For certain end uses where several narrow panels aresewn in a garment, it will be necessa
31、ry 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 or other applications where narrowpanels or cut pieces are used, it will be necessary to
32、 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 distance parallel to the selvagesor edges between the straightedge and the distinctive color y
33、arnor 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 represents typical examples of bows in a fabric that donot have any skew. Many variation
34、s 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 bow across the width from left toright in 400 mm (16 in.) increments. For example, measur
35、e fullwidth units, 400 mm (16 in.). On the right side align with theD3882 08 (2016)2right selvage and measure a 400 mm (16 in.) section. Thesemeasurements may overlap with some of the previouslymeasured sections.9.5 Skew:9.5.1 Measure the skew in three places spaced as widely aspossible along the le
36、ngth 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. Trace one filling yarn, knitting course,or printed line across the full
37、width of the fabric using a softpencil or suitable marker (LineAC if right-hand skew, Line DCif 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 itcoincides with the lower point on the fabric at which thedistinctive c
38、olor 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 record as the fabric width (W). (SeeFig. 2.)9.5.4.1 For automotive or other
39、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 width when calculating skew.9.5.5 Measure the distance parallel to the s
40、elvages or edgesbetween the straightedge and the distinctive color yarn orpattern line, or marked yarn to the nearest 1 mm (116 in.) (LineAB, or BD) and record including the skew direction, right-hand“ Z,” left hand “S,” and whether evident on the face orback of the fabric. (See Fig. 2.)NOTE 2Fig. 2
41、 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 (orFIG. 1 Typical Bow ConditionsFIG. 2 Typical Skew ConditionsD3882 08 (2016)3right-hand) regardless whether t
42、he 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 MeasurementsCalculate the maxi-mum bow of indiv
43、idual specimens to the nearest 0.1 % ornearest 0.5 mm using Eq 1.Bow, % 5 100D/BL! (1)or Bow, mm in! 5 Dwhere:D = maximum bow distance, mm (in.), (from 9.4.5), andBL = baseline distance, mm (in.), (from 9.4.4).10.1.1 If double bow is present, calculate the larger of thetwo bows.10.2 Skew, Individual
44、 MeasurementsCalculate the skewof individual specimens to the nearest 0.1 % or 0.5 mm usingEq 2 or Eq 3, as applicable.Skew, %, right 2 hand 5 100AB!/BC (2)Skew, %, left 2 hand 5 100BD!/BC (3)or Skew, mm in! 5 AB or BDwhere:AB = skew distance, right hand, mm (in.), (from 9.5.5),BD = skew distance, l
45、eft hand, mm (in.), (from 9.5.5), andBC = width of fabric, mm (in.), (from 9.5.4).11. Report11.1 Report that the skew or bow were determined asdirected in Test Method D3882. Describe the material orproduct sampled and the method of sampling used.11.2 Report the following information for each laborat
46、orysampling unit:11.2.1 Bow:11.2.1.1 Individual bow in units of measurement or percent,11.2.1.2 Maximum bow in units of measurement or percent,11.2.1.3 Fabric width, and11.2.1.4 Type of bow observed, for example, double bow,double reverse bow, double hooked bow, hooked bow, or othervariation.11.2.2
47、Skew:11.2.2.1 Individual skew in units of measurements andpercent,11.2.2.2 Maximum skew in units of measurements andpercent,11.2.2.3 Fabric width,11.2.2.4 Direction of skew, right-hand “Z,” left-hand “S”,and11.2.2.5 Side of fabric where skew was observed, face orback.11.3 The actual temperature, in
48、degrees C (F) and relativehumidity (%) conditions prevailing at the time of the test.11.3.1 Report the pretest conditioning environment, tem-perature in degrees C (F) and relative humidity (%).12. Precision and Bias12.1 SummaryIn comparing two averages of three deter-minations when using the procedu
49、res in this test method, thedifferences should not exceed the single-operator precisionvalues shown in Table 1 for the respective number of tests in 95out of 100 cases when all the observations are taken by thesame well-trained operator using the same piece of equipmentand specimens randomly drawn from the sample of material.Larger differences are likely to occur under all other circum-stances.12.2 Interlaboratory Test Data4An interlaboratory testwas run in 1981 in which randomly drawn specimens of threematerials were tested in each of three laboratories
