ASTM_D_3882_-_08_2012e1.pdf

Designation:D388208(Reapproved 2012)1Standard 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 in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEThe language in 9.5.2 and 9.5.5 was corrected editorially to match Fig.2 in July 2012.1.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 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 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 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 and Testing TextilesD2904 Practice for Interlaboratory Testing of a Textile TestMethod that Produces Normally Distributed Data(With-drawn 2008)3D2906 Practice for Statements on Precision and Bias forTextiles(Withdrawn 2008)3D3990 Terminology Relating to Fabric Defects3.Terminology3.1 For all terminology related to Fabric Defects see Termi-nology D3990.3.2 The following terms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 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 points 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 theselvage.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 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 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 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 consideration of the knownbias.1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,Specific.Current edition approved July 1,2012.Published August 2012.Originallyapproved in 1980.Last previous edition approved in 2008 as D3882 081.DOI:10.1520/D3882-08R12E01.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 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 acceptance or rejection.5.3 Boworskewcanbeinducedduringfabricmanufacturing,dyeing,tentering,finishing,or other operationswhere a potential exists for uneven distribution of tensionsacross 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 t