ASTM D2255 D2255M-2009(2013)e1 Standard Test Method for Grading Spun Yarns for Appearance《短纤纱外观分级的标准试验方法》.pdf

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1、Designation: D2255/D2255M 09 (Reapproved 2013)1Standard Test Method forGrading Spun Yarns for Appearance1This standard is issued under the fixed designation D2255/D2255M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of

2、last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEReferences to the adjuncts in 7.1 and 7.2 were updated editorially in December 2015.INTRODUCTIONCotton yarn appearance standa

3、rds were first adopted in 1938 and revised in 1964, with Series IIIbeing revised again in 1975. The 1964 boards had different yarn sizes for the four-grade exhibits oneach board. The 1975 Series III board used the same yarn number for each grade.The appearance grade of yarn is based on the composite

4、 evaluation of several factors, such asunevenness, fuzziness, and neppiness. The differences in the yarn numbers in the 1964 standards alongwith the differences in other factors distort the comparison between grades and makes grading moredifficult.To overcome this shortcoming, in 1975 the Series III

5、 board was revised using the same size yarnfor all four grades. After evaluating the improvements, it was decided to revise all of the series usinga mid-range yarn number for each grade in the series, and narrow the range in the most active series.This was accomplished by adding a new board, Series

6、VI.Anear mid-range yarn number was selectedto represent equal steps between adjacent grades for all the factors considered in yarn appearancegrading. These yarns were produced with current commercial manufacturing equipment and practices.Finally, to obtain better yarn definition and better reproduci

7、bility from set to set, it was decided touse offset photo printing.Shortly after these new boards were published in 1979, it became apparent that in the Series II-79Board the A and B grades were not clearly defined and appeared to be switched. This was correctedin the 1987 Series II Board.In 1987 a

8、world wide survey was conducted on how the Yarn Appearance Boards were being used.From responses it became apparent that the boards are being used for grading yarns other than 100 %cotton combed or carded yarns. Respondents were using the boards to grade yarn blends, ring spunyarns, open-end spun ya

9、rns and other spinning systems. The boards are used both for process qualitycontrol and customer acceptance.In view of the above findings, it was decided to revise the method to include grading of all singlespun yarns.1. Scope1.1 This test method covers the grading of singles spunyarns for appearanc

10、e.1.2 This test method does not apply to plied yarns.1.3 The values stated in either inch-pound or SI units are tobe regarded separately as the standard. The values stated ineach system are not exact equivalents, therefore, each systemmust be used independently of the other. Combining valuesfrom the

11、 two systems may result in non-conformance with thestandard.1.4 This standard does not purport to address the safetyconcerns associated with its use. It is the responsibility of theuser of this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory

12、 limita-tions prior to use.21This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved July 1, 2013. Published September 2013. Originallyapproved in 1964. Last previous edition appr

13、oved in 2009 as D2255 09. DOI:10.1520/D2255_D2255M-09R13E01.2The requirements for the appearance of cotton yarns are covered in TolerancesD2645, Roller-Drafted Yarns.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Referenced Docume

14、nts2.1 ASTM Standards:3D123 Terminology Relating to TextilesD2258 Practice for Sampling Yarn for TestingD2645 Tolerances for Yarns Spun on the Cotton or WorstedSystemsD3888 Terminology for Yarn Spinning SystemsD3990 Terminology Relating to Fabric DefectsD4849 Terminology Related to Yarns and Fibers2

15、.2 ASTM Adjuncts:4Spun Yarn Appearance Standards (6 Boards with Photos)3. Terminology3.1 For definitions of textile terms used in this method:bunch, cover, fuzz, nep, slub, thick place, thin place, and yarnappearance, refer to Terminology D4849. For other textileterms used in this test method, refer

16、 to Terminology D123,Terminology D3888, and Terminology D3990.4. Description of Yarn Grades4.1 Grade A YarnGrade A yarn may have no large nepswhich are over three times the normal diameter of the yarn andvery few small ones. Grade A yarn must have good uniformityfrom 25 mm to 25 mm (inch to inch), a

17、nd good cover withoutexcessive fuzziness. No foreign matter may be present inGrade A yarn.4.2 Grade B YarnGrade B Yarn may have no large neps,but may have a few small ones. Grade B yarn may have nomore than three small pieces of foreign matter per board orspecimen providing they do not form slubs. G

18、rade B yarn maybe slightly more irregular and may have slightly more fuzz thana Grade A yarn.4.3 Grade C YarnGrade C yarn may have more neps, andlarger ones as well as more fuzziness and a greater amount offoreign matter than Grade B yarn. The contrast between thethick and thin places and the normal

19、 diameter of the yarn maybe greater than in Grade B yarn resulting in an over-all rougherappearance.4.4 Grade D YarnGrade D yarn may have some slubs thatare more than three times the average diameter of the yarn.Grade D yarn may have more neps, neps of a larger size, morethick and thin places, more

20、fuzz and more foreign matter thanGrade C yarn. When slubs or large neps are present, Grade Dyarn may have fewer neps than Grade C yarn. Grade D yarnmay have an over-all rougher appearance than Grade C yarn.4.5 Yarn Below Grade DYarn below Grade D may havemore defects and an overall rougher appearanc

21、e than Grade Dyarn.NOTE 1The permitted number of defects for any grade should alwaysbe determined by comparison with the official “ASTM Spun YarnAppearance Standards” photographs.5. Summary of Test Method5.1 Yarn specimens, wound on black boards, are comparedwith photographs of specimens representin

22、g the appearancegrades. The grade is based on fuzziness, neppiness,unevenness, and visible foreign matter.6. Significance and Use6.1 This method is considered satisfactory for acceptancegrading of commercial shipments because it has been usedextensively in the trade for this purpose.6.1.1 If there a

23、re 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, use the samples for such a com-parative tests tha

24、t are as homogeneous as possible, drawn fromthe same lot of material as the samples that resulted in disparateresults during initial testing and randomly assigned in equalnumbers to each laboratory. The test results from the labora-tories involved should be compared using a statistical test forunpai

25、red data, a probability level chosen prior to the testingseries. If a bias is found, either its cause must be found andcorrected, or future test results for that material must beadjusted in consideration of the known bias.6.2 The appearance of a woven or knitted fabric depends toa large extent on th

26、e smoothness, cleanliness, and generalappearance of the yarns from which the fabric is manufactured.Instruments are available for the measurement of unevennessand for counting neps and other imperfections in yarn, but thevalues obtained from such tests are not easily integrated into anover-all expre

27、ssion for actual fabric appearance. Yarn appear-ance grading affords additional information which the manu-facturer of woven or knitted goods may, through experience,correlate with the appearance to be expected in fabrics madefrom the yarns.7. Apparatus7.1 Spun Yarn Appearance Standards4A series of

28、photo-graphic standards representing Grades A, B, C, and D in sixranges of yarn numbers. Grade A is the highest and the othersare progressively lower. The range of yarn numbers to begraded by each series is listed in Table 1. The standards are3For referenced ASTM standards, visit the ASTM website, w

29、ww.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.4Available from the ASTM International Headquarters. Request adjunct No. asfollows:ADJD225501 (Series 1-79) ADJD225504

30、 (Series 4-79)ADJD225502 (Series 2-79) ADJD225505 (Series 5-79)ADJD225503 (Series 3-79) ADJD225506 (Series 6-79)ADJD2255ALLTABLE 1 Requirements for Preparations of SpecimensSeriesRange of Yarn NumbersCountAWrapsBSingle Cot-ton CountTex per in. per cm1 1 to 12 590 to 50 8 20 82 12 to24 50to25 18 22 9

31、3 24 to36 25to16 30 26 104 36 to50 16to12 42 32 135 50 to 75 12 to 8 60 38 156 75 to 135 8 to 4 100 48 19AActual single yarn count used on boards.BThe specified number of wraps is subject to a tolerance of 10 %.D2255/D2255M 09 (2013)12illustrated in Fig. 1. See also ADJD2255ALL.7.2 Yarn Grading Cabi

32、net5A cabinet with storage spacefor the appearance standards, a shelf or rack on which onepanel of standards and the specimen to be graded can bedisplayed, and lights mounted on brackets to illuminate thespecimen and standards at the proper angle. A picture of theyarn appearance grading cabinet bein

33、g used by a grader isshown in Fig. 2. See ADJD2255.57.2.1 The lights on the cabinet shall consist of two unitsfocused on the standard when in the grading position from alocation about 300 mm (12 in.) in front with one unit slightlyabove and one unit slightly below the standards. Each unit shallbe eq

34、uipped with two 150-W daylight incandescent bulbsmounted in a reflector which extends across the cabinet toprovide uniform light intensity over the standard.7.3 Yarn BoardsRectangles of heavy cardboard,wallboard, or light plywood, at least 140 by 250 mm (5.5 by9.5 in.) in size, finished completely i

35、n dull black. To fit theusual type of winder, there should be a rounded 20-mm(0.80-in.) notch at the center of one of the long edges toaccommodate the screw of the revolving clamp. In one of theshort edges there should be knife cuts or small notches to holdthe ends of the yarn. One of these should b

36、e placed approxi-mately 10 mm (0.40 in.) from the straight side of the board andthe other about 20 mm (0.80 in.) from the notched side.7.4 Yarn Board WinderA small machine to rotate a yarnboard end-over-end, and fitted with a traversing guide toadvance the yarn across the board as it is wound. The m

37、achineshall be capable of spacing the yarn evenly as required in Table1 with a tolerance of 610 %.7.4.1 All parts of the tension device on the winder whichcomes in contact with the yarn shall be made of a smoothmaterial, such as porcelain or metal, to prevent disturbance ofthe fibers in the yarn.8.

38、Adjustment of Yarn Board Winder8.1 Set the traversing mechanism of the winder for therequired spacing, wind a trial board, and count the wraps in awidth of at least 25 mm (1 in.). If the number of wraps does notconform to the tolerances specified in Table 1, adjust to thecorrect spacing (Note 2). On

39、 the most generally used type ofmachine, this adjustment may be made by changing thediameter of the friction wheel or by filing a new notch in theshaft on which the friction wheel slides.NOTE 2The spacing is critical in its influence on the appearance of thespecimen. Closer spacing places a greater

40、length of yarn on the board andhence, a larger number of imperfections per unit of area. Wider spacinghas the opposite effect.9. Sampling, Selection, and Number of Specimens9.1 Take the lot sample as specified in the applicablematerial specification or as directed in Practice D2258.9.2 For the labor

41、atory sample, take five packages (cones,spools, bobbins, etc.) at random from each case of the lotsample.9.3 Prepare one specimen from each package in the labora-tory sample.10. Conditioning10.1 Specimens need be neither preconditioned nor condi-tioned.5Prints of detailed drawings of a suitable cabi

42、net are available from ASTMInternational Headquarters. Request Adjunct No. ADJD2255.FIG. 1 ASTM Spun Yarn Appearance StandardsD2255/D2255M 09 (2013)1311. Preparation of Specimens11.1 Mount a yarn board in the revolving clamp of thewinder and set the traversing mechanism to give the spacingspecified

43、in Table 1 for the nominal yarn number.11.2 If comparing two or more lots which differ slightly inyarn number and fall in different series (example: 35s and 37s),wind them to the same spacing and compare with the sameseries of standards. In any case, compare only yarns thenumbers of which are not mo

44、re than 10 % above the upperlimit nor more than 10 % below the lower limit of the series ofstandards by which they are graded.11.3 Mount the package to unwind freely, lead the yarnthrough the tension device and traversing pigtail guide, andsecure the end in a notch or knife-cut near the left hand si

45、de ofthe board. When unwinding yarn over the end of the package,wind the board at 50 to 100 rpm using just sufficient tension tospace the yarn evenly on the board. If the package must beunwound from the side, wind at a low enough speed to avoidjerking, breaking, or tangling the yarn.11.4 Wind until

46、the last wrap is within approximately 20mm (0.8 in.) of the right-hand side and secure the end of theyarn near the right-hand corner.12. Procedure12.1 Place the appropriate series of Spun Yarn AppearanceStandards in the grading position on the shelf or support in theyarn grading cabinet. Set one spe

47、cimen at a time in front of thepanel of standards and move it from side to side for comparisonwith the different standards from about1m(1yd).12.2 Thick places, bunches, or slubs are considered theworst defects in yarn because in practically all cases they willcause end breakage in later processing.

48、Yarn with bunches orslubs will not be assigned Grade A or Grade B.12.3 When any one defect or combination of them isexcessive for a grade, assign the next lower grade to thespecimen.12.4 Assign to the specimen the grade designated for thephotograph which it is equal to or better than without beingeq

49、ual to the next higher grade. Consider the information inSection 4 in making the assignment.Also, grade the back of thespecimen in a similar manner. Record the grade of the poorerside as the grade of the specimen if the two sides are as muchas one grade different.12.5 Each specimen shall be graded independently by threeexperienced yarn graders, and the grade reported shall be thatassigned by all three graders when they are in agreement, or bytwo in agreement, provided the third grader does not differ bymore than one grade from the grade assigned by the other two.