1、Designation: C 1651 08Standard Test Method forMeasurement of Roll Wave Optical Distortion in Heat-Treated Flat Glass1This standard is issued under the fixed designation C 1651; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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 the
3、out-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 math
4、ematicalconversions 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 d
5、oes 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 Referen
6、ce to these documents shall be the latest issueunless otherwise specified by the authority applying this testmethod.2.2 ASTM Standards:2C 162 Terminology of Glass and Glass ProductsC 1036 Specification for Flat GlassC 1048 Specification for Heat-Treated Flat GlassKindHS, Kind FT Coated and Uncoated
7、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 sine-wave representing thedeformed sur
8、face 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
9、 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 illustrated in Fig.1.4. Summary of Tes
10、t 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 which is characteristic of the glass
11、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 character of the roll wave, but which als
12、o 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 that do have a wave character,the di
13、stortion 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)where W and L are in metres and D is in diopters. Thedimensions of diopters
14、(dpt) is m-1. The more usual unit ofoptical distortion is millidiopters which are obtained by mul-tiplying the value in diopters by 1 000.1This test method is under the jurisdiction of ASTM Committee C14 on Glassand Glass Products and is the direct responsibility of Subcommittee C14.11 onOptical Pro
15、perties.Current edition approved Sept. 1, 2008. Published February 2009.2For 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 AS
16、TM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 Appendix X1 and references show the relationshipbetween W, L, the measured radius of curvature R and theoptical distortion of a reflecting surface, D.5. Significance and
17、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-valley measurements provide a meansof monitoring the roll wave distortion in a heat processed
18、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 in which rollers are used to convey theglass.5.4 Consult Specifications C 1036 and C 1048 for
19、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 measure the peak-to-valley depth of thedeformations. Two such instruments are the so-called
20、“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 measurement made with the “FlatBottom” Gauge and the “Three Point Contact” Gauge.)6.2 The 9Fla
21、t Bottom9 Gauge consists of a flat plate which isa 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 circumference of theroller) It shall be no less than 2 in. (50.8 mm) wide, with asmooth, low-c
22、oefficient of friction surface and have a depthmeasuring gauge equipped with a dial indicator, digital mi-crometer, or linear variable differential transformer (LVDT)with a protruding ball-end spring loaded plunger. This indica-tor, micrometer, or LVDT is used to measure the out-of-planedepth, W, of
23、 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 contact point at which position the depth of the rollwave is measured. The distance between the o
24、utboard 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 as specified in Note1. The center contact point is a depth measuring gauge whichcan be either a dial indicator, a di
25、gital micrometer, or a springloaded LVDT plunger. 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.NOTE 2If the measured peak-to-peak distance of a measured rollwave is no
26、t within 6 1 in. (6 25.4 mm) of roll circumference, distortionsother than roll wave are likely present and this test method does not apply.FIG. 1 Representative Roll Wave Showing “W” and “L”FIG. 2 “Flat Bottom” Roll Wave Gauge with Dial IndicatorC16510826.4 These instruments can be manually conveyed
27、 across 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 which has dimensions equal to or exceedingthe dimensions the specime
28、n to be tested. The departure fromflatness of the supporting surface shall be less than the depth ofthe out-of-plane roll wave deformations if the measurement isto be accurate. The table or surface must be free of debris andany other surface condition that might affect the reading.6.6 This test meth
29、od is appropriate principally for in-plantor laboratory measurement 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 unit
30、s 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 measurement,place it on a rigid flat surface, such as a granite plate, or on apiece of anneal
31、ed 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 surface.Adjust thegauge metre to read zero, following the gauge manufacturersinstruction
32、s.7.1.2 Determine the direction of the roll waves using visualinspection or production documentation, or both. Place ameasuring tape on the glass surface perpendicular to the roll3The 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 PeakC1651083waves. The measuring tape shall extend for the leading ortrailing edge and extend the entire length of the substrate wherethe roll wave peaks and valleys will be determined.7.2 Procedure A: Measuring with a Flat Bottom Gauge:7.2.1 Pl
34、ace the gauge on the surface of the glass as shownin Fig. 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
35、 computation of optical distortion shall be no less 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 be
36、tween peaks andvalleys.7.2.3 Determine the reading of the depth measuring gauge,Wi, at each peak and valley as you push or pull the gauge alongthe centerline. These readings along with the locations of thepeaks P1,P2,P3,Pnand valleys V1,V2,V3,.Vmcan bemarked on the glass using a washable marking pen
37、. Transferthese numbers to a table similar to Table 1. (Note that the Peakreadings Wiwill not be zero for a “Three Point Contact”Gauge).7.2.4 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
38、 the flatbottom type roll wave gauge generally applies to the “ThreePoint Contact” Gauge. However, 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 t
39、he averagewavelength, L. If necessary, change the contact points of thegauge so that the distance 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 f
40、lat surface as stated in 7.1.1. When the end contact points arelocated at peaks and the plunger is 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 oppos
41、ite sign.(See Fig. 3 and Fig. 4.)7.3.4 Follow the same procedure for obtaining data asdescribed in 7.2.2 7.2.3 and which is shown in Fig. 3 and Fig.4. When filling the data table, use only positive signs on all Pand V readings.7.3.5 Calculate the distortion using section 8.2.8. Calculation8.1 Calcul
42、ating 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 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.
43、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 second valleyequal to V2 and to the mth valley equal to Vm, the followingyields the average wavelength of the roll wave:Lave5 Pn2
44、 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 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 b
45、e calculated at each peakand valley when using the “Three Point Contact” gauge, exceptfor the last peak or valley for which there is no “next” peak orvalley. For the “Flat Bottom” Gauge only the peak to valleydepth values, Wi, obtained in the valleys are meaningful sincethe readings at the peaks wil
46、l all be about zero (for bowed orwarped glass, for example, the values may not be exactly zero).8.2.2 For both the “Three Point Contact” Gauge and the“Flat Bottom Gauge” the optical distortion values, Di(inDiopters), for the depths of the valleys, Wi, obtained fromTable 1 and shown in Table 2 are ar
47、rived at using the followingformulae (as mentioned in 8.2.1, calculation is not possible atthe last data point:Di5 4p2Wi/Vi11 Vi#2for Viand Wiin meters (5)TABLE 1 Example of Data Table for Roll Wave Measurementsfrom a “Flat Bottom” GaugePeak1Valley1Peak2Valley2Peak3Valley3Peak4Distance Pior Vi,to Pe
48、ak or Valley ininches (mm)9.0(229)13.5(343)17.4(441)21.4(540)26.0(660)30.3(768)34.0(864)Depth Reading Wiin inches (mm)0(0)0.0015(0.038)0(0)0.0033(0.084)0(0)0.0022(0.056)0(0)TABLE 2 Example of Data Table for Reporting Optical DistortionUsing a “Flat Bottom” GaugePeak1Valley1Peak2Valley2Peak3Valley3Pe
49、ak4Distance Pior Vi,to Peak or Valleyin inches (mm)9.0(229)13.5(343)17.4(441)21.4(540)26.0(660)30.3(768)34.0(864)Depth ReadingWiininches (mm)0(0)0.0015(0.038)0(0)0.0033(0.084)0(0)0.0022(0.056)0(0)Calculated Distortion,Di,inmillidiopters (mdpt)NA 35 NA 74 NA 57 NAC1651084orDi5 4p2/25.4! 3106# Wi /Vi11 Vi#2for Viand Wiin in. (6)orDi5 4p2x 106# Wi/Vi11 Vi#2for Viand Wiin millimeters (7)8.2.3 For the “Three Point Contact” Gauge only, the distor-tion can also be calculated at the peaks (still excluding the lastdata points if it is a peak), by the following si
