1、Designation: D1155 10Standard Test Method forRoundness of Glass Spheres1This standard is issued under the fixed designation D1155; 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 i
2、ndicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method2covers the determination of thepercent of true spheres in glass spheres used for retroreflectivemarking purposes and industrial uses.1.2 This
3、 test method includes two procedures as follows:1.2.1 Procedure A, in which the selected specimen is splitinto two size ranges or groups prior to separation into truespheres and irregular particles, and1.2.2 Procedure B, in which the selected specimen is splitinto five size ranges or groups prior to
4、 separation.1.2.3 In determining compliance with specification require-ments, either Procedure A or Procedure B may be used. Wheretests indicate failure to meet the specified percent of truespheres and irregular particles, the referee test shall be made inaccordance with Procedure B.1.3 The values s
5、tated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.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
6、 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E11 Specification for Woven Wire Test Sieve Cloth and TestSievesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducti
7、ng an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Other Document:ASTM MNL32 Manual on Test Sieving Methods3. Summary of Test Method3.1 The glass particles are mechanically separated into truespheres and irregular particles by controlled vibration on aglass plate fixed at a pr
8、edetermined slope.4. Significance and Use4.1 The roundness of glass spheres is one measurable aspectrelating to their performance as a retroreflective media. Thefunction of this test method is to measure the percent of truespheres as related to compliance with applicable specifications.NOTE 1This me
9、thod has been used in other industrial areas outsidethe intended scope of this test method.5. Apparatus (Fig. 1)5.1 Electrical Feeder-Vibrator, upon which is mounted asmooth glass panel, 152.4 mm (6 in.) wide and 381 mm (15 in.)long.5.2 Hinged Base, supporting the vibrator and panel in sucha manner
10、that the angle of slope of the glass panel with thehorizontal may be varied and fixed in any predeterminedposition.5.3 VibratorMeans of varying the amplitude or strengthof the vibrations transmitted to the glass panel, at a fixedfrequency of 60 impulses per second.5.4 Feeding Device or Pan (Optional
11、), affixed to the glasspanel in such a manner that the selected sample of glass maybe evenly dropped at a uniform rate upon the glass panel, fromvarious heights above the panel and at various points on theslope.5.5 Collecting Pans or Containers, at either end of thesloping panel, in which to collect
12、 the spheres and irregularparticles.5.6 Digital Level, approximately 30 to 60 cm (12 to 24 in.)in length (not shown).1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.44 on T
13、raffic Coatings.Current edition approved July 1, 2010. Published September 2010. Originallyapproved in 1951. Last previous edition approved in 2003 as D1155 03. DOI:10.1520/D1155-10.2For information on the development of this test method, reference may be madeto the paper by Keeley, A. E., “Roundnes
14、s Testing of Glass Spheres,” ASTMBulletin, No. 174, May 1951, p. 72.3For 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 w
15、ebsite.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Selection of Specimen6.1 Select a specimen of approximately 10 to 50 g of theglass spheres to be tested for roundness in one of the followingways:6.1.1 By mechanically splitti
16、ng a bag or other container ofglass spheres, selected at random from the shipment to betested, or6.1.2 By grain or seed-rod selection from the container.6.1.3 The final sample for testing must be obtained using theappropriate sample splitters or reducers. Arrive as near aspossible to the desired sam
17、ple quantity for testing by onlyusing this equipment.6.1.4 When there is a need to obtain the highest degree ofaccuracy possible the operator should use a sample size that isclosest to the 50 g size limit. In cases where there are disputesbetween the results obtained by two or more testing parties t
18、hemaximum sample size should be used in order to settle thedispute.7. Procedure A7.1 Sieve the selected specimen through a 300-m (No. 50)sieve (Note 2). Run the spheres retained on the sieve as onegroup, and run the spheres passing the sieve as a second group.NOTE 2Detailed requirements for ASTM sie
19、ves are given in Speci-fication E11. The purchaser or specifying agency may require alternativesieve sizes to be used in lieu of the above reference sizes.7.2 Level the glass panel; then set the angle of the roun-dometer plate to the 300-m (50 U.S. Sieve) setting of 2.3degrees (from the table in Fig
20、. 2) using a digital level. Affix thefeed hopper to the side of the panel at the upper one-third pointof the slope, so that the spheres may be dropped in a uniform monolayer onto the glass panel from a height of approximatelyFIG. 1 Apparatus for Roundness Test of Glass SpheresU.S. Mesh Decimal Angle
21、20 1.030 1.140 1.550 2.360 2.770 3.180 3.6100 3.9FIG. 2 Angle Chart for Setting the Roundometer Inclination with aDigital LevelD1155 10213 mm (12 in.).Alternatively, the material may be manually fedby slowly pouring from a height of 13 mm (12 in.) to a pointin the center of the plate one-third down
22、from the uphill end.7.3 Place the size group to be tested in the feed pan unlessmanual feeding is being used, and start the vibrator. Set thevibrator amplitude control at such a position that irregularparticles on the upper half of the panel will move slowly up theslope, while the true spheres roll
23、down. Feed slowly, at such arate that no “bunching up” or flooding of spheres on the paneloccurs.7.4 When the glass panel is well covered with spheres, stopfeeding until separation of true spheres has occurred. Stop thevibrator and, after all true spheres have rolled down the slopeinto the sphere pa
24、n, brush or scrape all particles remaining onthe panel into the upper pan containing the irregular particles.For purpose of test, all particles not rolling freely down theslope are considered as irregular.7.5 Repeat the procedure described in 7.3 and 7.4 until theselected size group has been complet
25、ely separated, removingthe true spheres and irregular particles from the collecting pansinto appropriate containers.7.6 Using the true spheres collected in the primary separa-tion, repeat the procedure described in 7.3 and 7.4. Next, feedusing the irregular particles collected in the primary separat
26、ion,and again repeat the procedure described in 7.3 and 7.4.Examine the separated spheres and irregular particles under a20-diameter magnifying glass and repeat the reruns untilsatisfactory separation is obtained.7.7 Determine the total weights of the true spheres and ofthe irregular particles obtai
27、ned by the above separations, andrecord.7.8 Using the second size group obtained in accordancewith 7.1, repeat the procedure described in 7.2-7.7 setting theangle of the roundometer plate to the 100 U. S. Sieve setting of3.9 degrees (from the table in Fig. 2) using a digital level.7.9 From the total
28、 weight of true spheres obtained from bothsize groups, calculate the percent of true spheres in the totalspecimen, using as 100 % the total weight of true spheres plusirregular particles collected in the testthereby eliminatingfrom the calculation any loss of spheres that may have occurredduring han
29、dling and testing.8. Procedure B8.1 Divide the specimen into five size ranges or groups, asfollows:Passing Sieve Retained on Sieve600-m (No. 30) 425-m425-m (No. 40) 300-m300-m (No. 50) 212-m212-m (No. 70) .TABLE 1 Percent True Spheres (Rounds)RepeatabilityStandardDeviationReproducibilityStandardDevi
30、ationRepeatabilityLimitReproducibilityLimitSieve Size % True SpheresAverageASample Size(g)s x srsRrR30 23.187 1.600 1.342 2.076 2.162 5.813 6.05340 45.669 10.667 2.719 2.130 3.228 5.963 9.03750 72.202 14.655 1.553 .982 1.748 2.751 4.89470 84.669 7.283 1.758 1.528 2.156 4.280 6.037Pan 80.355 2.437 6.
31、771 2.919 7.178 8.174 20.099AAverage of laboratories calculated averages.Note: The average sample size used to conduct this testing was 36.642 grams.D1155 103NOTE 3The purchaser or specifying agency may require alternativesieve sizes to be used in lieu of the above reference sizes in thedeterminatio
32、n of roundness.8.2 Level the glass panel; then set the angle of the roun-dometer plate to the value indicated in Table 1 for the sievefraction being tested. For example, the sieve fraction passingthe 600 m Sieve (No. 30) and retained on the 425 m Sieve(No. 40), the 425 m (No. 40) Sieve setting shoul
33、d be used (1.5degrees).Affix the feed hopper over the center line of the panel,at the upper one-third point of the slope, with the feed endup-slope and approximately 13 mm (12 in.) from the glasspanel. Alternatively, the material may be manually fed byslowly pouring from a height of 13 mm (12 in.) t
34、o a point in thecenter of the plate one-third down from the uphill end.8.3 Place the size group to be tested in the feed pan, unlessmanual feeding is being used, and start the vibrator. Set thevibrator amplitude control at such a position that irregularparticles on the upper half of the panel will m
35、ove slowly up theslope, while the true spheres roll down. Feed slowly, at such arate that no “bunching up” or flooding of spheres on the paneloccurs.8.4 When the glass panel is well covered with spheres, stopfeeding until separation of true spheres has occurred. Stop thevibrator and, after all true
36、spheres have rolled down the slopeinto the sphere pan, brush or scrape all particles remaining onthe panel into the upper pan containing the irregular particles.For purposes of this test, all particles not rolling freely downthe slope are considered as irregular.8.5 Repeat the procedure described in
37、 8.3 and 8.4 until theselected size group has been completely separated, removingthe true spheres and irregular particles from the collecting pansinto appropriate containers.8.6 Using the true spheres collected in the primary separa-tion, repeat the procedure described in 8.3 and 8.4. Next, feedusin
38、g the irregular particles collected in the primary separationand again repeat the procedure described in 8.3 and 8.4.Examine the separated spheres and irregular particles under a20-diameter magnifying glass and repeat the reruns untilsatisfactory separation is obtained.8.7 The procedure described in
39、 8.3, 8.4, and 8.5 comprisesthe primary separation and that in 8.6 is one complete rerun.Make a primary separation for each of the five size groupslisted in 8.1 and then make the appropriate number of rerunsfor each size group, as follows:Spheres Retained on Sieve Reruns425-m (No. 40) 4300-m (No. 50
40、) 4212-m (No. 70) 5Spheres Passing Sieve212-m (No. 70) 5NOTE 4In lieu of performing the mandated number of reruns, whenapplicable the operator can evaluate the repeatability of two reruns withthe information provided in Section 10 to determine the precision of theresults.8.8 From the total weight of
41、 true spheres obtained fromseparations from all five size groups, calculate the percent oftrue spheres in the total specimen, using as 100 % the totalweight of true spheres plus irregular particles collected in thecomplete testthereby eliminating from the calculation anyloss of spheres that may have
42、 occurred during handling andtesting.9. Report9.1 Report the following information:9.1.1 The weight percent of true spheres in the total speci-men and9.1.2 Whether Procedure A or Procedure B was used.10. Precision and Bias410.1 The precision of this test method is based on aninterlaboratory study of
43、 Test Method D1155, Test Method forRoundness of Glass Spheres, conducted in 2008. Five labora-tories participated in this study. Each of the labs reportedtriplicate test results for a single material. Every “test result”reported represents an individual determination. Except for theuse of data from
44、only five laboratories and a single material,Practice E691 was followed for the design and analysis of thedata; the details are given in the appropriate Research Report.10.1.1 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more t
45、han the “r” value for that material, “r”istheinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.10.1.2 Reproducibility Limit (R)Two test results shall bejudged not eq
46、uivalent if they differ by more than the “R” valuefor that material; “R” is the interval representing the critical4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1153.D1155 104difference between two test results for the same
47、 material,obtained by different operators using different equipment indifferent laboratories.10.1.2.1 Reproducibility limits are listed in Table 1.10.1.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.10.1.4 Any judgment in accordance with sta
48、tement 10.1.2would normally have an approximate 95 % probability ofbeing correct, however the precision statistics obtained in thisILS must not be treated as exact mathematical quantities whichare applicable to all circumstances and uses. The limitednumber of laboratories reporting results guarantee
49、s that therewill be times when differences greater than predicted by theILS results will arise, sometimes with considerably greater orsmaller frequency than the 95 % probability limit would imply.The reproducibility limit should be considered as a generalguide, and the associated probability of 95 % as only a roughindicator of what can be expected.10.2 BiasAt the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on bias is being made.10.3 The precision statement w
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