1、BRITISH STANDARDBS EN 14970:2006Textiles Knitted fabrics Determination of stitch length and yarn linear density in weft knitted fabricsThe European Standard EN 14970:2006 has the status of a British StandardICS 59.080.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44
2、g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 14970:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 15 February 2006 BSI 15 February 2006ISBN 0 580 47691 XNat
3、ional forewordThis British Standard is the official English language version of EN 14970:2006. The UK participation in its preparation was entrusted to Technical Committee TCI/24, Textiles Physical testing, which has the responsibility to: A list of organizations represented on this committee can be
4、 obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facili
5、ty of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.
6、aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis d
7、ocument comprises a front cover, an inside front cover, the EN title page, pages 2 to 13 and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCH
8、E NORMEN 14970January 2006ICS 59.080.30English VersionTextiles - Knitted fabrics - Determination of stitch length andyarn linear density in weft knitted fabricsTextiles - toffes mailles - Dtermination de la longueurde fil absorbe et de la masse linique du fil dans lestricots mailles cueilliesTextili
9、en - Maschenwaren - Bestimmung der Maschenlngeund der lngenbezogenen Garnfeinheit bei GestrickenThis European Standard was approved by CEN on 9 December 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the
10、status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A
11、 version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Est
12、onia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISC
13、HES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14970:2006: EEN 14970:2006 (E) 2 Contents page Foreword 3 Introduction4 1 Scope .5 2 Normative referenc
14、es .5 3 Terms and definitions.5 4 Apparatus 6 5 Conditioning and testing atmosphere.6 6 Method A: Stitch length6 7 Method B: Linear density .8 8 Test report .8 Annex A (informative) Example of exploitation of the test method “barr analysis“9 Annex B (informative) Example of measurement on typical kn
15、itted fabrics11 Annex C (informative) Statistical evaluation of the precision.12 Bibliography.13 EN 14970:2006 (E) 3 Foreword This European Standard (EN 14970:2006) has been prepared by Technical Committee CEN/TC 248 “Textiles and textile products”, the secretariat of which is held by BSI. This Euro
16、pean Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 2006, and conflicting national standards shall be withdrawn at the latest by July 2006. According to the CEN/CENELEC Internal Regulations, the national
17、standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portuga
18、l, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14970:2006 (E) 4 Introduction The stitch length and yarn linear density, as defined and determined within this European Standard is part of the characterisation of a knitted fabrics structure. EN 14970:2006 (E) 5 1 Sco
19、pe This European Standard specifies test methods for the determination of stitch length and yarn linear density of a weft knitted fabric. They can be applied to warp knitted fabrics, if it is possible to de-knit the fabric. The measurements will be applied to yarns from each knitting machine feeder
20、and/or different patterning courses. The results can be used for the analysis of fabric fault, e.g. barr analysis. 2 Normative references The following referenced documents are indispensable for the application of this European Standard. For dated references, only the edition cited applies. For unda
21、ted references, the latest edition of the referenced document (including any amendments) applies. EN ISO 139, Textiles Standard atmospheres for conditioning and testing (ISO 139:2005) 3 Terms and definitions For the purposes of this European Standard, the following terms and definitions apply. 3.1 w
22、eft-knitted fabrics generic name applied to knitted fabrics in which the stitches made by each weft thread are formed substantially across the width of the fabric NOTE Weft-knitted fabrics are characterised by the fact that each weft thread is fed at right angles to the direction in which the fabric
23、 is produced. 3.2 warp-knitted fabrics generic name applied to knitted fabrics in which the stitches made from each warp thread are formed substantially along the length of the fabric NOTE Warp knitted fabrics are characterised by the fact that each warp thread is fed more or less in line with the d
24、irection in which the fabric is produced. 3.3 stitch loop basic unit of most knitted fabrics consisting of a loop meshed at its base with a previously formed loop 3.4 stitch length length of yarn knitted into one stitch in a weft-knitted or in a warp-knitted fabric 3.5 linear density mass per unit l
25、ength of linear textile materials 3.6 course row of stitches across the width of a weft-knitted or of a warp-knitted fabric EN 14970:2006 (E) 6 3.7 wale column of stitches along the length of a weft-knitted or of a warp-knitted fabric 3.8 rack length 480 courses of warp knitted fabric 3.9 barr strip
26、iness (weft knitting) fault in weft-knitted fabric (usually knitted on multi-feeder machine) appearing as light or dark course-wise stripe(s). In warp-knitted fabric the same fault may occur in the vertical direction 4 Apparatus 4.1 Length measurement apparatus The apparatus for the length measureme
27、nt of the yarn shall contain the following: clamps for firmly securing the yarn ends; the means of application of tension to the yarn being measured by the moving of one of the clamps; a graduated measuring scale having 1 mm division positioned such that the length of yarn secured within the clamps
28、is included in the total length measurement. 4.2 Balance, accurate to 1 mg or better. 5 Conditioning and testing atmosphere The standard temperate atmosphere for preconditioning, conditioning and testing textiles as specified in EN ISO 139 shall be used. 6 Method A: Stitch length 6.1 Principle A len
29、gth of yarn taken from the fabric sample over a defined number of stitch loops is measured under an appropriate tension. Stitch length is determined by calculation, dividing the length measured by the number of stitch loops. 6.2 Test specimens The test specimen shall be large enough to enable a mini
30、mum length of yarn of 250 mm to be taken from the shortest course. A minimum of 10 yarns from each course type shall be taken for the length measurement determination of stitch length. During removal and during the measurement of yarns, avoid loss of twist. NOTE Where a widthways pattern is included
31、 in the fabric, this should be the distance over which the number of stitch loops is counted. EN 14970:2006 (E) 7 6.3 Procedure Identify the courses. If the structure is complex, describe the structure or the pattern according to EN ISO 8388. Clarify the de-knitting direction of the sample. Cut alon
32、g one wale of a sample, count the required number of stitch loops as described in Annex B starting from this cut then cut along the wale at the required distance. Record the number of stitch loops counted. Remove the first yarn from the prepared fabric specimen and secure in the clamps of the measur
33、ing device, carefully preventing loss of twist. Slide the moving clamp so as to apply the required tension as given in Table 1. Measure and record in millimetres the length of yarn. Table 1 Application of tension Yarn type Tension to be applied Fibre staple yarn (excluding bare elastane) 0,5 cN/tex
34、0,1 cN/tex Filament yarn (excluding bare elastane) 2,0 cN/tex 0,5 cN/tex NOTE Bare elastane yarns are measured untensioned. If knitting crimp still remains in the yarn at this tension, increase the tension as necessary to remove this knitting crimp, and achieve a straightened state. This revised ten
35、sion shall be included within the final report. Remove subsequent lengths of yarn and measure in the same manner as for the first, achieving a total of 10 measurements. If different course/ feeder types exist within the fabric sample, this procedure should be carried out on each type. For the analys
36、is of fabric faults, refer to the example in Annex B. 6.4 Calculation and expression of results Record the individual values measured for each course/feeder type and calculate the mean of the individual results for each. Calculate the stitch length per one stitch, expressed in millimetres, for each
37、course type as follows: BAC = where A is the mean yarn length (mm); B is the number of stitch loops; C is the stitch length (mm). Express the result per one stitch. Other expressions of results may be used, for example: - yarn length for 100 stitches; EN 14970:2006 (E) 8 - yarn length over a specifi
38、ed pattern repeated. 7 Method B: Linear density 7.1 Principle A defined length of yarn is removed from the knitted fabric using the method described in 6.3. The mass is determined and the linear density is calculated. 7.2 Test specimen Use the same test specimens as described in 6.2 or if necessary
39、use a larger number of specimens so that a minimum of 10 m length in total is obtained. 7.3 Procedure Determine the straightened length of each of the removed yarns by applying the appropriate tension according to Table 1 and continue removing yarn to give a minimum total length of 10 m for every co
40、urse. Combine length of yarn from each course/feeder type, weigh accurately on the balance and record the mass in grams. 7.4 Calculation and expression of results Calculate from the individual lengths measured, the total length of yarn for each course. From this and the total mass of the yarns, dete
41、rmine the linear density using the Tex System or other system as agreed between parties. 8 Test report The test report shall contain the following information: a) reference to this European Standard, i.e. EN 14970; b) method used; c) reference of the sample; d) apparatus used if required; e) measure
42、ment tension used and if additional tension is used, this should be stated; f) statement if more than one course/feeder type is included within the fabric; g) repeat number for each course/feeder type; h) mean stitch length values for each course; i) number of stitch loops from which the yarn has be
43、en taken, or width ways pattern repeat if appropriate; j) for the method B, mean value of the linear density; k) individual values if required; l) any deviations from this European Standard which may have affected the results. EN 14970:2006 (E) 9 Annex A (informative) Example of exploitation of the
44、test method “barr analysis“ A.1 Principle The variation of stitch length/ linear density is a good indication of the knitting regularity and may be a cause of barriness. The stitch length and/or linear density should be determined for all the feeders of the knit. A.2 Test specimen Use the same test
45、specimen as described in 6.2 for stitch length and 7.2 for linear density. NOTE In the case of a defect analysis it may not be necessary to measure stitch length/ linear density for each feeder. As agreed between the two parties, the measurement may concern only the defect area, including a few yarn
46、s before and after the defect. A.3 Procedure Use the same measurement method as described in 6.3 for stitch length and 7.3 for linear density. NOTE 1 If individual yarn linear density measurement is required for the analysis of barr, the appropriate balance of fine weight measurement will be require
47、d e.g. torsion balance. NOTE 2 If the yarns have been removed from a warp knit fabric, using the length measured and the number of stitches counted, the rack length (480 courses) should be calculated for each end. A.4 Calculation and expression of results Report the individual value and calculate th
48、e median or any other expression of results if required for a statistic analysis. If the knitted fabric has different course type, the results should be reported separately for each course type. Individual yarn length measurements and linear density determinations should be reproduced in charts and
49、graphs for easier thread analysis within a fabric (see Figure A.1). EN 14970:2006 (E) 10 Values Number of extracted yarns 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Yarn length measurement (cm) 30,2 30,2 30,1 30,3 30,2 27,5 30,3 30,3 30,0 30,1 30,0 30,5 30,2 30,5 30,5 30,4 30,5 30,5 30,6 30,8 30,5Number of extracted yarns 22 23 24 25 26 27 28 29 30 31 32 Median Median +3% Median -3% Median +5% Median -5%Yarn length measurement (cm) 26,5 30,8 30,8 30,7 30,5 30,6 30,8 30,5 30,8 30,8 30,5 30,30 31,21 29,39 31,82 28,79 Graph 33,032,031,029,
