1、Designation: F205 94 (Reapproved 2010)1Standard Test Method forMeasuring Diameter of Fine Wire by Weighing1This standard is issued under the fixed designation F205; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last r
2、evision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1NOTEThis standard was converted to solely SI units editorially in December 2010.1. Scope1.1 This test method covers the measurement of the
3、averagediameter of fine wire by weighing a known length; it appliesparticularly to sizes up to 0.13 mm used in electron devices andlamps.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to a
4、ddress 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 ASTM Standards:2F180 Test M
5、ethod for Density of Fine Wire and RibbonWire for Electronic Devices3. Apparatus3.1 The apparatus shall consist of a suitable torsion or otherdirect-reading balance capable of reading to 0.002 mg or 0.1 %of the weight to be weighed (whichever is larger), with anaccuracy of 0.004 mg or 0.2 % (whichev
6、er is larger). The rangeof the balance (or the size of the specimen) shall be such thatthe reading will lie within the upper half of the scale.4. Test Specimens4.1 Test specimens shall be selected at least 1 m from theend of a spool or sufficiently far from the end to be free fromkinks or other dama
7、ge resulting in lack of straightness of thecut length.4.2 The wire shall be drawn from the spool under a loweven tension so that no elongation of the wire takes place.4.3 Each test specimen shall be cut to a length of 200 6 0.1mm. To prevent stretching, care shall be taken so that thetension is just
8、 sufficient to eliminate the sag and curl. Anydisagreement concerning the amount of tension to be used incutting shall be resolved between the manufacturer and thepurchaser.4.4 The test specimen shall be folded upon itself severaltimes and twisted to make a compact bundle with loopconsisting of a si
9、ngle strand for hanging it on the balancebeam. In the case of multiple specimens, all specimens shall betwisted together and hung by a loop consisting of a singlestrand. The specimen shall be handled as little as possible. Theoperators hands shall be clean and dry.5. Number of Specimens5.1 Weigh a s
10、ingle specimen if its weight lies within theupper half of the scale of the instrument. When the weight isless than half of the scale of the instrument, weigh a sufficientnumber of specimens, 200 mm in length, simultaneously sothat the total weight will register in the upper half of the scale,prefera
11、bly as close to the limit of the balance as possible. Usethe lowest range instrument compatible with the weight of the200-mm weight specimen to reduce the number of 200-mmlengths that must be weighed together.6. Repetition of Weighing6.1 If the corrected weight of a single specimen lies within60.5 %
12、 of either the minimum or the maximum limit specifiedfor the wire weight, cut and weigh two more specimens of wirein a similar manner. When two or more lengths of wire havebeen weighed simultaneously to produce a reading in the upperhalf of the scale because of the small size of the wire, cut andwei
13、gh two more sets of specimens in a similar manner.7. Calibration and Checking of the Balance7.1 Check the balance regularly in accordance with therecommendations of the manufacturer.7.2 If a variety of weights are to be determined, calibrate thebalance at five major points on the scale and at zero b
14、ydetermining the weights of calibrated check weights. If any1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.03 on MetallicMaterials.Current edition approved Dec. 1, 2010. Published January 2011. Originallyapproved i
15、n 1945 as B205 45 T. Last previous edition approved in 2005 as F205 94(2005). DOI: 10.1520/F0205-94R10.2For 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
16、 Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.point is in error by more than 1 %, remove the balance fromservice and repair it.Apply corrections determined by checkingto the apparent readin
17、gs to obtain corrected weights. Obtaincorrections applied to apparent weights by interpolation be-tween the closest calibrated points, one above and one belowthe reading.7.3 If the amount of work to be weighed at one point on thescale justifies it, the balance may be calibrated with a standardweight
18、 (or combination of weights) deviating by not more than10 % from that of the weight to be determined. In this case,adjust the balance so that the balance reads the known weightof the check weight correctly when it is in balance, therebyreducing the correction to zero.7.4 Calibrate the balance, at ze
19、ro under no load, or atpositive values when loaded to check weights, by using theaverage of three consecutive readings, taken under conditionsspecified in 7.2 or 7.3, whichever is applicable.8. Calibration with Standard Weights8.1 Check weights are subject to change of mass due towear from handling
20、and use, and from chemical action result-ing from exposure. Depending on use, but not less than twicea year, compare the calibrated check weights with the primaryweights, calibrated by the National Institute of Standards andTechnology, and apply the necessary corrections.8.2 The primary standard che
21、ck weights shall be NISTClass M, or equivalent, for weight determinations of 2.00 mgor less, and Class S, or equivalent, for weight determinationsover 2.00 mg.9. Procedure9.1 Handle and use the balance as recommended by themanufacturer. Direct particular attention to requirements forcareful handling
22、, protection from vibration and atmosphericdust, errors induced by temperature changes, and the necessityfor avoiding paralax in reading.10. Calculation10.1 Calculate the average diameter of the wire from thefollowing equation (see Appendix X1):D 5 3.1413/=D! 3 =W,where:D = average diameter of wire,
23、 mils (mils 3 0.0254 = mm),D = density of wire, g/cm3(see Note 1),W = weight of wire, mg/200 mm,Also, letK 5 3.1413/=D,thenD 5 K =W see Note2!.NOTE 1The density of wire for alloys not found in Table 1 may bedetermined at or near the finished size and the finished condition inaccordance with Test Met
24、hod F180.NOTE 2Values for density and the constant K for several alloys aregiven in Table 1.11. Interpretation of Results11.1 If a single specimen or a single set of specimens isweighed, and its corrected weight, or average weight whenmultiple specimens are used, is found to lie between the point0.5
25、 % above the minimum limit and 0.5 % below the maximumlimit, the wire shall be considered to meet the specified limits.11.2 If the corrected wire weight is under 0.5 % below theminimum limit or over 0.5 % above the maximum limit, thewire is considered not to meet the specified limits.11.3 If the cor
26、rected weight of a single specimen, or theaverage weight when multiple specimens are used, lies withinthe range of 6 0.5 % of the maximum or 60.5 % of theminimum limit, exactly three specimens or three sets ofspecimens shall be weighed, and the average corrected valuecompared with the maximum and mi
27、nimum limits. If theaverage of the three readings lies between the maximum limitand the minimum limit, the weight of the wire is considered tolie within these limits.NOTE 3The following is an example of the evaluation of results. If aspecified weight of 8.00 mg/200 mm and a specified tolerance of 63
28、%(60.24, mg/200 mm) is assumed, the range determined by these specifi-cations must be 7.76 to 8.24 mg/200 mm. The working zones for weighingwill be:Minimum limit:+ 0.5 %, 7.76 + 0.04 = 7.80 mg/200 mm0.5 %, 7.76 0.04 = 7.72 mg/200 mmMaximum limit:0.5 %, 8.24 0.04 = 8.20 mg/200 mm+ 0.5 %, 8.24 + 0.04
29、= 8.28 mg/200 mmThe corrected weight of a single cut length of wire found to lie between7.80 and 8.20 mg/200 mm will suffice to accept the wire. The correctedweight on a single cut length of wire found to be less than 7.72 mg/200mm or more than 8.28 mg/200 mm will suffice to reject the wire as outsi
30、dethe specified limits.If the corrected weight of a single cut length is found to be betweeneither 7.72 and 7.80 mg/200 mm, or 8.20 and 8.28 mg/200 mm, two morepieces shall be cut, weighed, and averaged with the first weight. If theaverage of the three weights lies between 7.76 and 8.24 mg/200 mm,in
31、clusive, the wire is considered to meet the specified range; if outsidethese limits, it is considered not to meet it.12. Dimensions, Mass, and Permissible Variations12.1 Permissible variations from the specified weight shallbe designated by maximum and minimum weights, or as aplus-and-minus percenta
32、ge tolerance to be applied to thenormal weight.TABLE 1 Density and Constant K for Diameter CalculationsAlloyDensity,Ag/cm3ConstantKAluminum + 1 % magnesium 2.7 1.912Aluminum + 1 % silicon 2.7 1.912Gold 19.32 0.71585 % nickel, 15 % chromium 8.47 1.07958 % nickel, 20 % molybdenum, 20 %iron, 2 % mangan
33、ese8.78 1.06095 % nickel, 5 % manganese 8.74 1.063Permanickel 8.77 1.061Monel 8.81 1.058Molybdenum 10.14 0.986Tantalum 16.59 0.771Tungsten 19.17 0.717AThe density values in this table have been determined by ASTM Test MethodF180.F205 94 (2010)1213. Report13.1 The report shall consist of the number o
34、f readings, andthe average corrected weight of the wire to three significantfigures in milligrams per 200 mm, except that for sizes under1.00 mg/200 mm only two significant figures shall be reported.The value reported shall be the weight of the outside end of thespool unless it shall have been agree
35、d otherwise between themanufacturer and the purchaser.14. Precision and Bias14.1 PrecisionThe precision of this test method has notbeen formally evaluated using an interlaboratory testing pro-gram. However, it is possible to evaluate the standard deviationof the wire diameter, s(D), for a given expe
36、rimental setup,using the following equation which is based on propagation oferrors:sD! 5 =$dD /dD!2s2D! 5 dD /dW!2s2W! 1 dD/dL!2s2L!%.where each of the partial derivative terms are obtained fromappropriate differentiation of the definition of specimen wirediameter, D, shown in 10.1 and L is the wire
37、 length.14.2 BiasProper measurement technique for all the vari-ables shown in the equation which defines s(D)in14.1 shouldeliminate bias from this test method.15. Keywords15.1 electronic devices; fine wire; wire bondingAPPENDIX(Nonmandatory Information)X1. DERIVATION OF DIAMETER CALCULATION EQUATION
38、X1.1 The diameter calculation equation in Section 12 wasderived as follows:Wire weight 5 x2sectional area 3 length3 density, orW 5 p D2/4! 3 L 3D,where:W = wire weight,D = wire diameter,L = wire length, andD = wire density.Rearranging,D25 4W/p LDorD 5 = 4W/p LD51.1284 = W/LD.LetW 8 5 W/L,thenD 5 1.1
39、284 =W 8/D.Correcting for unit:W 8 = weight in mg/200 mm (or mg/20 cm),D = density in gm/cm3(or 1000 mg/cm3), andD = diameter in mils (where 1 mil = 0.00254 cm),thenD 5 1.1284W 8 mg/20 cm!D1000 mg/cm3!/0.00254 cmmil,orD 5 1.1284 = W 8/D!cm2/20000! /0.00254 cm,orD 5 1.1284 cm/141.42! = W 8/D /0.00254
40、 cm,orD 5 3.1413 =W 8/D.Other useful equations:W 8 5 0.10134 D D2, andD59.868 W/D2!.F205 94 (2010)13ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that dete
41、rmination 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 revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or
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43、t 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 copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints
44、(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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).F205 94 (2010)14
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