1、Designation: D1155 10 (Reapproved 2015)Standard 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 numbe
2、r in parentheses indicates 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 indust
3、rial uses.1.2 This 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
4、or groups prior to separation.1.2.3 In determining compliance with specificationrequirements, either Procedure A or Procedure B may be used.Where tests indicate failure to meet the specified percent oftrue spheres and irregular particles, the referee test shall bemade in accordance with Procedure B.
5、1.3 The values stated 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 app
6、ro-priate safety 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 Pract
7、ice for Conducting 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 pla
8、te fixed at a predetermined 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 specificatio
9、ns.NOTE 1This method 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
10、in sucha manner 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 strength ofthe vibrations transmitted to the glass panel, at a fixedfrequency of 60 impulses per second.5.4 Feeding Device
11、or Pan (Optional), 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
12、which to collect 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 ofSubcommi
13、ttee D01.44 on Traffic Coatings.Current edition approved June 1, 2015. Published June 2015. Originallyapproved in 1951. Last previous edition approved in 2010 as D1155 10. DOI:10.1520/D1155-10R15.2For information on the development of this test method, reference may be madeto the paper by Keeley, A.
14、 E., “Roundness 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 pag
15、e onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. 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 mechani
16、cally splitting 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 th
17、e desired sample 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 test
18、ing parties themaximum 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
19、 for ASTM sieves 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 roundo-meter plate to the 300-m (50 U.S. Sieve) setting of 2.3degrees (from the
20、 table in Fig. 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 uniformmonolayer onto the glass panel from a height of approximately 13 mm (12 in.).Alternatively, the material may be manually fed
21、FIG. 1 Apparatus for Roundness Test of Glass SpheresU.S. Mesh Decimal Angle20 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 10 (2015)2by slowly pouring from a height of 13 mm (12 in.) to a pointin the center of the p
22、late one-third down 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 th
23、e true spheres roll 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 slo
24、peinto the sphere pan, 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 gr
25、oup has been completely separated, removingthe true spheres and irregular particles from the collecting pansinto appropriate containers.7.6 Using the true spheres collected in the primaryseparation, repeat the procedure described in 7.3 and 7.4. Next,feed using the irregular particles collected in t
26、he primaryseparation, and again repeat the procedure described in 7.3 and7.4. Examine the separated spheres and irregular particlesunder a 20-diameter magnifying glass and repeat the rerunsuntil satisfactory separation is obtained.7.7 Determine the total weights of the true spheres and ofthe irregul
27、ar particles obtained 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.
28、7.9 From the total 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
29、occurredduring handling 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) .NOTE 3The purchaser or specifying agency may require alternativesieve sizes
30、to be used in lieu of the above reference sizes in thedetermination of roundness.8.2 Level the glass panel; then set the angle of the roundo-meter 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
31、on the 425 m Sieve(No. 40), the 425 m (No. 40) Sieve setting should 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
32、be manually fed byslowly pouring from a height of 13 mm (12 in.) to 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 posi
33、tion that irregularparticles on the upper half of the panel will move 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 o
34、f true spheres has occurred. Stop thevibrator and, after all true 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
35、 are considered as irregular.8.5 Repeat the procedure described in 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 primaryseparatio
36、n, repeat the procedure described in 8.3 and 8.4. Next,feed using the irregular particles collected in the primaryseparation and again repeat the procedure described in 8.3 and8.4. Examine the separated spheres and irregular particlesunder a 20-diameter magnifying glass and repeat the rerunsuntil sa
37、tisfactory separation is obtained.TABLE 1 Percent True Spheres (Rounds)RepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitSieve Size % True SpheresAverageASample Size(g)sx srsRrR30 23.187 1.600 1.342 2.076 2.162 5.813 6.05340 45.669 10.667 2.719 2.130
38、 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 6.771 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 10 (2015)38.7 The
39、procedure described in 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 (
40、No. 40) 4300-m (No. 50) 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 Fr
41、om the total weight of 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
42、 spheres that may have 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 anin
43、terlaboratory study of 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 fo
44、r theuse of data from 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 i
45、f theydiffer by more than 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
46、 shall bejudged not equivalent if they differ by more than the “R” valuefor that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.10.1.2.1 Reproducibilit
47、y 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 statement 10.1.2would normally have an approximate 95 % probability ofbeing correct, however the precision statistics o
48、btained in thisILS must not be treated as exact mathematical quantities whichare applicable to all circumstances and uses. The limitednumber of laboratories reporting results guarantees that therewill be times when differences greater than predicted by theILS results will arise, sometimes with consi
49、derably 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 was determined through sta-tistical examination of 75 results, from five laboratories, on asingle material.11. Keywo
