1、Designation: D3882 081Standard 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 revision. A number
2、in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTESection 3 was updated editorially in September 2011 in accordance with the Committee D13 Terminology policy.1. Scope1.1 This test method covers the d
3、etermination of bow andskew of filling yarns in woven fabrics and the courses inknitted fabrics.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 val
4、ues stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently 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
5、its use. It is theresponsibility of the user of this standard to establish appro-priate safety and 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
6、and Testing TextilesD2904 Practice for Interlaboratory Testing of a Textile TestMethod that Produces Normally Distributed DataD2906 Practice for Statements on Precision and Bias forTextiles3D3990 Terminology Relating to Fabric Defects3. Terminology3.1 For all terminology related to Fabric Defects se
7、e Termi-nology D3990.3.2 The following terms are relevant to 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
8、BowA straightedge is placed across the fabric be-tween two points at which a marked filling yarn, 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 printe
9、d line, or designated design is measuredparallel to the selvage.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 c
10、onsidered satisfactory for accep-tance testing of commercial 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
11、 statisticalassistance. As a minimum, the test samples to be 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 b
12、e used for thispurpose. The test results from the two laboratories 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 consid
13、eration of the knownbias.5.2 Individual rolls are normally accepted 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 acce
14、ptance or rejection.1This test method is under the jurisdiction of ASTM 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 app
15、roved in 2006 as D3882 99 (2006).DOI: 10.1520/D3882-08.2For 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.3Withd
16、rawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 Bow or skew can be induced during fabric manufactur-ing, dyeing, tentering, finishing, or ot
17、her 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 prominent. These d
18、efects 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 the garment manufact
19、urer 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 and door panels ma
20、y 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 Straightedge or t-squa
21、re, 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 transmitted light
22、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 laboratory samplingunit
23、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 or piece length. Se
24、lect 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 that are at least
25、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 D1776 or, if applicable, in thespecified atmosphere in which the testing is to be per
26、formed.8.1.1 When full rolls or bolts of fabric cannot be properlyconditioned 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
27、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 Lay the fabric on
28、 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 theends of the
29、 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 across the fabr
30、ic 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 For certain end
31、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 or other applic
32、ations 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 distance parallel to
33、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 represents typi
34、cal 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 bow across the w
35、idth 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:D3882 08129.5.1 Measur
36、e 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. Trace
37、 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 itcoin
38、cides 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 record as
39、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 width
40、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 whether e
41、vident 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
42、 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 individual spe
43、cimens to the nearest 0.1 % ornearest 0.5 mm using Eq 1.Bow, % 5 100D/BL! (1)FIG. 1 Typical Bow ConditionsFIG. 2 Typical Skew ConditionsD3882 0813or Bow, mm in! 5 D (1)where: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 pr
44、esent, calculate the larger of thetwo bows.10.2 Skew, Individual MeasurementsCalculate the skewof individual specimens to the nearest 0.1 % or 0.5 mm usingEq 2 or Eq 3, as applicable.Skew, %, right2hand 5 100AB!/BC (2)Skew, %, left2hand 5 100BD!/BC (3)or Skew, mm in! 5 AB or BD (3)where:AB = skew di
45、stance, right hand, mm (in.), (from 9.5.5),BD = skew distance, left 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 samp
46、ling used.11.2 Report the following information for each laboratorysampling 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 rever
47、se bow, double hooked bow, hooked bow, or othervariation.11.2.2 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
48、 skew was observed, face orback.11.3 The actual temperature, in 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 compar
49、ing two averages of three deter-minations when using the procedures 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 s
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