1、Designation: C1651 11Standard 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 revision, the year
2、 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 distances of theou
3、t-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 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathem
4、aticalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This test method does not address other flatness issueslike edge kink, ream, pocket distortion, bow, or other distor-tions outside of roll wave as defined in this test method.1.4 This standard doe
5、s 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 Reference
6、 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-Treated Flat GlassKind HS,Kind FT Coated and Uncoated Glass
7、3. 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 sine-wave representing thedeformed surface
8、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 by assemblyor installation.3.1.4 roll wave
9、 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 illustrated in Fig.1.4. Summary of Test Met
10、hod4.1 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 which is characteristic of the glass and k
11、nown 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 character of the roll wave, but which also res
12、ult 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 that do have a wave character,the distort
13、ion can be calculated using the following formula.From the measured roll wave depth, W and the measuredpeak-to-peak or valley to valley wavelength of the roll wave, L,the optical roll wave distortion D is:D 5 4p2W/L2(1)1This test method is under the jurisdiction of ASTM Committee C14 on Glassand Gla
14、ss Products and is the direct responsibility of Subcommittee C14.11 onOptical Properties.Current edition approved Oct. 1, 2011. Published October 2011. Originallyapproved in 2008. Last previous edition approved in 2008 as C165109. DOI:10.1520/C1651-11.2For referenced ASTM standards, visit the ASTM w
15、ebsite, 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 website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United S
16、tates.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 1 000.4.2 Appendix X1 and references show the relationshipbetween W, L, the measured r
17、adius 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 optical distortion resulting fromthat roll wave. Peak-to-
18、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 inherent in flat glass which has been heattreated in a furnace
19、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-plane deformation of the glass by use ofan instrument to
20、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, among other things, the comparativeprecision and bias of me
21、asurement 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 circumference of thefurnace roller and less than twice the ci
22、rcumference 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, digital mi-crometre, or linear variable differential transformer (LVDT)with a protruding ball-end spring loaded p
23、lunger. This indica-tor, micrometre, or LVDT is used to measure the out-of-planedepth, W, of valleys and is located at the center of the bar. Sucha gauge is shown in Fig. 2.6.3 The “Three Point Contact” Gauge has three contactpoints, one at each end of the gauge and equally spaced froma center conta
24、ct point at which position the depth of the rollwave is measured. The distance between the outboard contactpoints of the “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
25、 is a depth measuring gauge which can be either a dialindicator, a digital micrometre, or a spring loaded LVDTplunger. Such 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.NO
26、TE 2Surface distortions apart from roll wave are likely present andFIG. 1 Representative Roll Wave Showing “W” and “L”FIG. 2 “Flat Bottom” Roll Wave Gauge with Dial IndicatorC1651 112should not be considered when calculating the average wavelength (Lave)in 8.1. These invalid wavelengths include: (1)
27、 any peak-to-peak orvalley-to-valley distance that is not within 6 1 inch (6 25.4 millimetres)of roll circumference (if known), or (2) any peak or valley measurementthat does not repeat at equal intervals.NOTE 3If the measured roll wave wavelength is not within 6 1 inch(6 25.4 millimetres) of roll c
28、ircumference, or when the circumference ofthe furnace 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 theglass or fitted with a trolley sy
29、stem 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 may be determined by usingvisual or opti
30、cal 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 surface shall be less than thedepth of t
31、he 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 measurement of roll wave distortion. The tes
32、tmethod 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 exclude3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.FIG. 3 “Three-Point Contact
33、 Gauge on ValleyFIG. 4 “Three Point Contact” Gauge on PeakC1651 113insulating glass units and laminated glass lites from measure-ment under this test 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 meas
34、urement,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) 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
35、 surface.Adjust thegauge meter to read zero, following the gauge manufacturersinstructions.7.1.2 Determine the direction of the roll waves using visualor optical inspection (such as the reflection of a Zebra board)or production documentation, or both. Place a measuring tapeon the glass surface perpe
36、ndicular to the roll waves. Themeasuring tape shall extend from leading or trailing edge andextend the entire length of the substrate where the roll wavepeaks 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
37、 inFig. 2 at the approximate centerline of the glass dimensionperpendicular to the roll wave and near one end of the expectedscan. To eliminate the influence of the end-effects on thecomputation of Optical Distortion, the first peak or valley usedfor computation of optical distortion shall be no les
38、s than 12 in.(305 mm), or one wavelength, whichever is larger, from theedge of the glass.7.2.2 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 reading
39、 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,.Vmcan bemarked on the glass using a washable marking pen. Transferthese numbers to a table similar to
40、 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 disto
41、rtion 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, the
42、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 betwe
43、en 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 is loca
44、ted 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 in 7.2.
45、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 betweenPeak 1 an
46、d 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 secon
47、d valleyequal to V2 and to the mth valley equal to Vm, the followingyields the average wavelength of the roll wave:Lave5 Pn2 P1! / n21! 1 Vm2 V1! / m21!# / 2 (2)where n is the number of peaks and m is the number ofvalleys. In the example shown in Table 1, n = 4 and m =3sothatLave5 25.0/3 1 16.8/2!/2
48、 5 8.4 in. (3)orLave5 635/3 1 425/2!/2 5 213 mm (4)8.2 Calculating the Optical Distortion:8.2.1 The Optical Distortion can be calculated at each peakand valley except for the first and last peak or valley for whichthere is no “previous” or “next” peak or valley, respectively.The distortion values, D
49、pior Dviobtained for peaks and valleyswill only be accurate if the gauge is evenly supported on theglass. If the gauge is not fully supported at a peak or valley, aDpior Dvivalue should not be calculated for that point and novalue should be reported.TABLE 1 Example of Data Table for Roll Wave Measurementsfrom a “Flat Bottom” GaugePeak1Valley1Peak2Valley2Peak3Valley3Peak4Distance Pior Vito Peak or Valley ininches (mm)12.0(305)16.5(419)20.4(517)24.4(616)29.0(736)33.3(844)37.0(940)Depth Reading pior viof Peak or Valleyin inches (mm)0(0)0.0015(0.038)0(0)0.0033(0.084
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