1、Designation: D 1155 03Standard Test Method forRoundness of Glass Spheres1This standard is issued under the fixed designation D 1155; 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
2、 indicates the year of last reapproval. Asuperscript epsilon (e) 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 T
3、his 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
4、 to 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 value
5、s 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 appro-priate saf
6、ety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:E 11 Specification for Wire Cloth and Sieves for TestingPurposes33. Summary of Test Method3.1 The glass particles are mechanically separated into truespheres and
7、 irregular particles by controlled vibration on aglass plate fixed at a predetermined slope.4. Significance and Use4.1 The roundness of glass spheres is one measureableaspect relating to their performance as a retroreflective media.The function of this test method is to measure the percent oftrue sp
8、heres as related to compliance with applicable specifi-cations.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
9、in.)long.5.2 Hinged Base, supporting the vibrator and panel 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 strengthof the vibrations transmitted to the glass panel, at a
10、fixedfrequency of 60 impulses per second.5.4 Feeding Device or Pan, affixed to the glass panel in sucha manner that the selected sample of glass may be evenlydropped at a uniform rate upon the glass panel, from variousheights above the panel and at various points on the slope.5.5 Collecting Pans or
11、Containers, at either end of thesloping panel, in which to collect the spheres and irregularparticles.6. Selection of Specimen6.1 Select a 50-g specimen of the glass spheres to be testedfor roundness in one of the following ways:6.1.1 By mechanically splitting a bag or other container ofglass sphere
12、s, selected at random from the shipment to betested, or6.1.2 By grain or seed-rod selection from the container.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 gr
13、oup.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 Traffic Coatings.Current edition approved May 10, 2003. Published June 2003. Originallyapproved in 1951. Withdrawn
14、 December 2002 and reinstated as D 1155 03.2For information on the development of this test method, reference may be madeto the paper by Keeley, A. E., “Roundness Testing of Glass Spheres,” ASTMBulletin, No. 174, May, 1951, p. 72.3Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM Internationa
15、l, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NOTE 2Detailed requirements for ASTM sieves are given in Speci-fication E 11.7.2 Level the glass panel; then raise one end from thehorizontal by the distance in inches indicated on the calibrationcurve in Fig. 2 f
16、or the average diameter of spheres in the group.Affix the feed hopper to the side of the panel at the upperone-third point of the slope, so that the spheres may be droppedin a uniform monolayer onto the glass panel from a height ofapproximately 13 mm (12 in.).7.3 Place the size group to be tested in
17、 the feed pan, andstart the vibrator. Set the vibrator amplitude control at such aposition that irregular particles on the upper half of the panelwill move slowly up the slope, while the true spheres rolldown. Feed slowly, at such a rate that no “bunching up” orflooding of spheres on the panel occur
18、s.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 pan, brush or scrape all particles remaining onthe panel into the upper pan containing the irregu
19、lar 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 completely separated, removingthe true spheres and irregular particles from the collecting pansinto ap
20、propriate containers.7.6 Fill the feed pan with the true spheres collected in theprimary separation, and repeat the procedure described in 7.3and 7.4. Next, fill the feed pan with the irregular particlescollected in the primary separation, and again repeat theprocedure described in 7.3 and 7.4. Exam
21、ine the separatedspheres and irregular particles under a 20-diameter magnifyingglass and repeat the reruns until satisfactory separation isobtained.7.7 Determine the total weights of the true spheres and ofthe irregular particles obtained by the above separations, andrecord.7.8 Using the second size
22、 group obtained in accordancewith 7.1, repeat the procedure described in 7.2-7.7.7.9 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 t
23、he testthereby eliminatingFIG. 1 Apparatus for Roundness Test of Glass SpheresFIG. 2 Calibration Curve for Roundness TesterD1155032from the calculation any loss of spheres that may have occurredduring handling and testing.8. Procedure B8.1 Divide the specimen into five size ranges or groups, asfollo
24、ws:Passing Sieve Retained on Sieve600-m (No. 30) 425-m425-m (No. 40) 300-m300-m (No. 50) 212-m212-m (No. 70) .8.2 Level the glass panel; then raise one end from thehorizontal by the distance in inches indicated on the calibrationcurve in Fig. 2 for the minimum diameter of spheres in thegroup. Affix
25、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 10 mm (38 in.) from the glasspanel.8.3 Place the size group to be tested in the feed pan, andstart the vibrator. Set the vibrator amplitude control at such apositi
26、on that irregular particles on the upper half of the panelwill move slowly up the slope, while the true spheres rolldown. Feed slowly, at such a rate that no “bunching up” orflooding of spheres on the panel occurs.8.4 When the glass panel is well covered with spheres, stopfeeding until separation of
27、 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
28、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 Fill the feed pan with the true spheres collected in thep
29、rimary separation, and repeat the procedure described in 8.3and 8.4. Next, fill the feed pan with the irregular particlescollected in the primary separation and again repeat theprocedure described in 8.3 and 8.4. Examine the separatedspheres and irregular particles under a 20-diameter magnifyingglas
30、s and repeat the reruns until satisfactory separation isobtained.8.7 The 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 reru
31、nsfor each size group, as follows:Spheres Retained on Sieve Reruns425-m (No. 40) 4300-m (No. 50) 4212-m (No. 70) 5Spheres Passing Sieve212-m (No. 70) 58.8 From the total weight of true spheres obtained fromseparations from all five size groups, calculate the percent oftrue spheres in the total speci
32、men, 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 occurred during handling andtesting.9. Report9.1 Report the following information:9.1.1 The weight percent of true spher
33、es in the total speci-men and9.1.2 Whether Procedure A or Procedure B was used.10. Precision and Bias10.1 A round-robin study is currently underway in order togenerate a precision statement.11. Keywords11.1 roundness; glass spheresASTM International takes no position respecting the validity of any p
34、atent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revisi
35、on at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your co
36、mments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrigh
37、ted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D1155033
