ASTM C1651-2011(2018) Standard Test Method for Measurement of Roll Wave Optical Distortion in Heat-Treated Flat Glass.pdf

1、Designation: C1651 11 (Reapproved 2018)Standard Test Method forMeasurement of Roll Wave Optical Distortion in Heat-Treated Flat Glass1This standard is issued under the fixed designation C1651; the number immediately following the designation indicates the year oforiginal adoption or, in the case of

2、revision, the year of last revision. A number 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 method is applicable to the determination ofthe peak-to-valley depth and peak-to-peak

3、distances of theout-of-plane deformation referred to as roll wave which occursin flat, heat-treated architectural glass substrates processed in aheat processing continuous or oscillating conveyance oven.1.2 This test method does not address other flatness issueslike edge kink, ream, pocket distortio

4、n, bow, or other distor-tions outside of roll wave as defined in this test method.1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4

5、 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.

6、5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to T

7、rade (TBT) Committee.2. Referenced Documents2.1 Reference to these documents shall be the latest issueunless otherwise specified by the authority applying this testmethod.2.2 ASTM Standards:2C162 Terminology of Glass and Glass ProductsC1036 Specification for Flat GlassC1048 Specification for Heat-St

8、rengthened and Fully Tem-pered Flat Glass3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 peak-to-valley depth of roll wavecharacteristicdepth, W, of roll wave as illustrated in Fig. 1.3.1.2 peak-to-peak wavelength of roll wavecharacteristiclength, L, of roll wave shown as a si

9、ne-wave representing thedeformed surface section as illustrated in Fig. 1.3.1.3 roll waveA repetitive wave-like departure fromflatness in glass that results from heat treating the glass in ahorizontal roller hearth furnace. Roll wave excludes edgeeffects such as edge kink and distortion influenced b

10、y assemblyor installation.3.1.4 roll wave optical distortionvisual distortion, D, thatresults from roll wave and expressed as lens power as in Eq 1.3.1.5 valley-to-valley wavelength of roll wavecharacteristic length, L, of roll wave shown as a sine-waverepresenting the deformed surface section as il

11、lustrated in Fig.1.4. Summary of Test Method4.1 This test consists of moving an instrument across theglass surface in a direction parallel to the direction that theglass substrate traveled during heat processing. The instrumentwill primarily measure the out-of-plane deformation of theglass surface w

12、hich is characteristic of the glass and known as“roll wave”. The peak-to-valley depths of the roll waves, W,and the peak-to-peak distances, L, are measured. (See Fig. 1.)4.1.1 Other out-of-plane deformations of the glass surfacemay also be present which do not have the same peak andvalley wave chara

13、cter of the roll wave, but which also result inthe appearance of optical distortion in the glass.4.1.2 The optical distortion due to the out-of-plane defor-mation of the surface is measured as an optical power, similarto the optical power of a cylindrical mirror or lens.4.1.3 For those deformations

14、that do have a wave character,the distortion can be calculated using the following formula.From the measured roll wave depth, W and the measured1This test method is under the jurisdiction of ASTM Committee C14 on Glassand Glass Products and is the direct responsibility of Subcommittee C14.11 onOptic

15、al Properties.Current edition approved Aug. 1, 2018. Published August 2018. Originallyapproved in 2008. Last previous edition approved in 2011 as C1651 11. DOI:10.1520/C1651-11R18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org

16、. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with interna

17、tionally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1peak-to-peak or valley to valley wavelength of the

18、 roll wave, L,the optical roll wave distortion D is:D 5 42W/L2(1)where W and L are in metres and D is in diopters. Thedimensions of diopters (dpt) is m-1. The more usual unit ofoptical distortion is millidiopters which are obtained by mul-tiplying the value in diopters by 1000.4.2 Appendix X1 and re

19、ferences show the relationshipbetween W, L, the measured radius of curvature R and theoptical distortion of a reflecting surface, D.5. Significance and Use5.1 This test method is a procedure for determining thepeak-to-valley depth and the wavelength of roll wave in flatglass and then calculating the

20、 optical distortion resulting fromthat roll wave. Peak-to-valley measurements provide a meansof monitoring the roll wave distortion in a heat processed glassproduct.5.2 Measured peak-to-valley depth provides informationrequired by some specifiers of heat-treated glass products.5.3 Roll wave is inher

21、ent in flat glass which has been heattreated in a furnace in which rollers are used to convey theglass.5.4 Consult Specifications C1036 and C1048 for additionalglass characteristics and quality information.6. Apparatus6.1 Optical distortion in flat glass can be characterized bydetermining the out-of

22、-plane deformation of the glass by use ofan instrument to measure the peak-to-valley depth of thedeformations. Two such instruments are the so-called “FlatBottom” Gauge and the “Three Point Contact” Gauge. (Asstated in 10.1 a Round Robin Interlaboratory Study (ILS) willbe carried out to establish, a

23、mong other things, the comparativeprecision and bias of measurement made with the “FlatBottom” Gauge and the “Three Point Contact” Gauge.)6.2 The “Flat Bottom” Gauge consists of a flat plate whichis a minimum of 12 in. (305 mm) long. (The flat plate shall beequal to or greater in length than the cir

24、cumference of thefurnace roller and less than twice the circumference of theroller.) It shall be no less than 2 in. (50.8 mm) wide, with asmooth, low-coefficient of friction surface and have a depthmeasuring gauge equipped with a dial indicator, digitalmicrometre, or linear variable differential tra

25、nsformer (LVDT)with a protruding ball-end spring loaded plunger. Thisindicator, micrometre, or LVDT is used to measure the out-of-plane depth, W, of valleys and is located at the center of the bar.Such a gauge is shown in Fig. 2.6.3 The “Three Point Contact” Gauge has three contactpoints, one at eac

26、h end of the gauge and equally spaced froma center contact point at which position the depth of the rollwave is measured. The distance between the outboard contactFIG. 1 Representative Roll Wave Showing “W” and “L”FIG. 2 “Flat Bottom” Roll Wave Gauge with Dial IndicatorC1651 11 (2018)2points of the

27、“Three Point Contact” Gauge must be adjustableto permit setting the outside contact points apart by a distanceequal to the wavelength, L, of the roll wave. The center contactpoint is a depth measuring gauge which can be either a dialindicator, a digital micrometre, or a spring loaded LVDTplunger. Su

28、ch a gauge is shown in Fig. 3 and Fig. 4.NOTE 1The wavelength of the roll wave is often, but not always equalto the circumference of the conveyor rolls in the tempering furnace.NOTE 2Surface distortions apart from roll wave are likely presentand should not be considered when calculating the average

29、wavelength(Lave)in8.1. These invalid wavelengths include: (1) any peak-to-peak orvalley-to-valley distance that is not within 61 in. (625.4 mm) of rollcircumference (if known), or (2) any peak or valley measurement thatdoes not repeat at equal intervals.NOTE 3If the measured roll wave wavelength is

30、not within 61 in.(625.4 mm) of roll circumference, or when the circumference of thefurnace roll is not known, the Flat Bottom Gauge should be used tomeasure roll wave since its use does not depend on knowing the averagewavelength of the roll wave.6.4 These instruments can be manually conveyed across

31、 theglass or fitted with a trolley system for pulling it across theglass and plotting depth, W, versus position as described in theliterature. (1, 2, 3)36.5 The glass to be measured shall be placed on a flatsupporting surface with any edge/end kink facing upward. Thedirection of the edge/end kink ma

32、y be determined by usingvisual or optical inspection techniques (such as the reflection ofa Zebra board) or production documentation, or both. Thesupporting surface should have dimensions equal to or exceed-ing the dimensions the specimen to be tested. The departurefrom flatness of the supporting su

33、rface shall be less than thedepth of the out-of-plane roll wave deformations if the mea-surement is to be accurate. The table or surface must be free ofdebris and any other surface condition that might affect thereading.6.6 This test method is appropriate principally for in-plantor laboratory measur

34、ement of roll wave distortion. The testmethod can be adapted to on-site measurements of roll waveonly after removal of the glass from its frame and supportingit in accordance with 6.5. This would automatically excludeinsulating glass units and laminated glass lites from measure-ment under this test

35、method.7. Procedure7.1 Place the clean test lite on a flat supporting surface inaccordance with 6.5.7.1.1 Prior to using the roll wave gauge for measurement,place it on a rigid flat surface, such as a granite plate, or on apiece of annealed float glass which is greater than or equal to38 in. (10 mm)

36、 in thickness and which is larger than the gauge.The depth of measuring plunger must be depressed by someamount when the gauge is resting on the flat surface.Adjust thegauge meter to read zero, following the gauge manufacturersinstructions.7.1.2 Determine the direction of the roll waves using visual

37、or optical inspection (such as the reflection of a Zebra board)or production documentation, or both. Place a measuring tapeon the glass surface perpendicular to the roll waves. Themeasuring tape shall extend from leading or trailing edge andextend the entire length of the substrate where the roll wa

38、vepeaks and valleys will be determined.7.2 Procedure A: Measuring with a Flat Bottom Gauge:7.2.1 Place the gauge on the surface of the glass as shown inFig. 2 at the approximate centerline of the glass dimensionperpendicular to the roll wave and near one end of the expectedscan. To eliminate the inf

39、luence of the end-effects on thecomputation of Optical Distortion, the first peak or valley usedfor computation of optical distortion shall be no less than 12 in.(305 mm), or one wavelength, whichever is larger, from theedge of the glass.3The boldface numbers in parentheses refer to a list of refere

40、nces at the end ofthis standard.FIG. 3 “Three-Point Contact” Gauge on ValleyC1651 11 (2018)37.2.2 Without pressing down on the gauge, push or pull italong the centerline, parallel to the measuring tape and observethe depth measuring gauge oscillating between peaks andvalleys.7.2.3 Determine the read

41、ing of the depth measuring gauge,pior vi, at each peak and valley as you push or pull the gaugealong the centerline. These readings along with the locations ofthe peaks P1,P2,P3, ,Pnand valleys V1,V2,V3, ,Vmcanbe marked on the glass using a washable marking pen. Transferthese numbers to a table simi

42、lar to Table 1.7.2.4 While the above specifies only a single traverse of theglass, it is obvious that several traverses will better representthe distortion over the face of the glass. It is common practice,for instance, to make three to five traverses across the glass inorder to better represent the

43、 distortion of the entire glasssurface.7.2.5 Calculate the distortion, D, using section 8.2.7.3 Procedure B: Measuring with a “Three Point Contact”Gauge:7.3.1 The procedure previously described for using the flatbottom type roll wave gauge generally applies to the “ThreePoint Contact” Gauge. However

44、, the test method differs asfollows:7.3.2 Whenever the wavelength, L, is not known from priortest results, make a preliminary run, following steps describedin 7.2.1 and 7.2.2. Then use 8.1 to establish the averagewavelength, L. If necessary, change the contact points of thegauge so that the distance

45、 between the end contact points isequal to L, and the contact points are equidistant from the dialor indicator in the center of the gauge.7.3.3 Check that the dial or digital gauge still reads zero ona flat surface as stated in 7.1.1. When the end contact points arelocated at peaks and the plunger i

46、s located in the valley, thegauge will indicate the peak-to-valley depth. With end contactpoint located at the bottom of a valley, the plunger is forcedupward, and will show peak-to-valley with the opposite sign.(See Fig. 3 and Fig. 4.)7.3.4 Follow the same procedure for obtaining data asdescribed i

47、n 7.2.2 and 7.2.3 and which is shown in Fig. 3 andFig. 4.7.3.5 Calculate the distortion using section 8.2.8. Calculation8.1 Calculating the Average Wavelength of the Roll Wave:8.1.1 Required only for use of the “Three Point Contact”Gauge.8.1.2 In the example given in Table 1, the distance betweenPea

48、k 1 and Peak 4 (three waves) is 25.0 in. (635 mm) and thedistance between Valley 1 and Valley 3 (two waves) is 16.8 in.(425 mm).8.1.3 With the distance to the first peak equal to P1,tothesecond peak equal to P2, and to the nth peak equal to Pn; andthe distance to the first valley equal to V1, to the

49、 second valleyequal to V2and to the mthvalley equal to Vm, the followingyields the average wavelength of the roll wave:Lave5 Pn2 P1!/n 2 1!1Vm2 V1!/m 2 1!#/2 (2)where n is the number of peaks and m is the number ofvalleys. In the example shown in Table 1, n =4,andm =3sothatLave5 25.0/3116.8/2!/2 5 8.4 in. (3)orLave5 635/31425/2!/2 5 213 mm (4)FIG. 4 “Three Point Contact” Gauge on PeakTABLE 1 Example of Data Table for Roll Wave Measurementsfrom a “Flat Bottom” GaugePeak1Valley1Peak2Valley2Peak3Valley3Peak4Distance Pior Vito Peak or Valley ininches (mm)12.0(305)1