1、Designation: D6205 12Standard Practice forCalibration of the James Static Coefficient of FrictionMachine1This standard is issued under the fixed designation D6205; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. 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 practice covers the testing of the James Machinefor repeatability of static coefficient of friction, relative to astanda
3、rd reference interface consisting of the working surfacesof Borco2board and standard leather shoe sole material, or acontrol polish film and standard leather shoe material. Thepractice provides basis data on the stability of the JamesMachine to ensure accurate static coefficient of friction deter-mi
4、nations over time and repeated use and for determining if theJames Machine is mechanically calibrated and properlyaligned.1.2 This practice is written specifically for James Machineswith manual or motorized test table transport. Variations of thispractice for the calibration of versions of James Mac
5、hineswhich are semi-automated are obvious. Calibration practicessuggested by the manufacturer of semi-automatic James Ma-chines should be followed in preference to this practice.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespons
6、ibility 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:3D2047 Test Method for Static Coefficient of Friction ofPolish-Coated Flooring Surfaces as Meas
7、ured by theJames MachineD2825 Terminology Relating to Polishes and Related Mate-rialsD4103 Practice for Preparation of Substrate Surfaces forCoefficient of Friction TestingE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE178 Practice for Dealing With
8、 Outlying Observations2.2 Federal Specification:KK-L-165C Leather, Cattlehide, Vegetable Tanned andChrome Tanned, Impregnated, and Soles43. Terminology3.1 Definitions:For general definitions, see Test MethodD2047 and Terminology D2825.3.2 Definitions of Terms Specific to This Standard:3.2.1 Borco, n
9、special 5-ply vinyl drawing board cover.3.2.2 Borco/standard leather reference interface,nworking interface consisting of the white side of the Borcomaterial, mounted as described in this practice, and thestandard leather shoe sole material, mounted on a precisionshoe pad as described in Section 7 o
10、f Test Method D2047.3.2.3 control polish, na reference polish of known or wellestablished Static Coefficient of Friction, as determined byrepeated determinations using Test Method D2047 over a longperiod of time and preferably by determinations on multipleJames Machines.3.2.4 control polish/standard
11、 leather reference interface,nworking interface consisting of a dried film of controlpolish, applied according to the procedures of Practice D4103on standard vinyl composition tile, and the standard leathersole material, mounted on a precision shoe pad as described inSection 7 of Test Method D2047.3
12、.2.5 standard test sequence, nseries of not less than eightconsecutive Static Coefficient of Friction (SCOF) determina-tions made on the Borco/standard leather interface or controlpolish/standard leather interface in accordance with this prac-tice. The arithmetic average and standard deviation of on
13、e1This practice is under the jurisdiction of ASTM Committee D21 on Polishesand is the direct responsibility of Subcommittee D21.06 on Slip Resistance.Current edition approved Oct. 1, 2012. Published October 2012. Originallyapproved in 1998. Last previous edition approved in 2006 as D6205- 06. DOI:10
14、.1520/D6205-12.2Borco is a registered trademark for a Danish product imported into the UnitedStates by Sierra Group, a division of Wallace Leisure Products, Inc. Available fromPapyro-Tex A/S, DK-2730, Herlev, Denmark; distributed in North America throughdrafting and office supply stores under the tr
15、ade names “Borco,” “Vyco,” and“Altex” board covers.3For 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 ASTM website.4Available
16、 from Standardization Documents Order Desk, Bldg 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Atten: NPODS.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1standard test sequence is the Static Coefficient of Friction(SCOF
17、) of the interface.4. Summary of Practice4.1 The performance of the James Machine, in the standardconfiguration for the determination of Static Coefficient ofFriction (SCOF), is tested relative to a standard workinginterface consisting of the surface of white Borco material incontact with a standard
18、 leather shoe pad, or a control polishfilm in contact with a standard leather shoe pad. The staticcoefficient of friction values generated provide a basis toestablish the repeatability of the mechanical configuration ofthe James Machine and determine whether the machine re-mains within the calibrati
19、on limits.5. Significance and Use5.1 This practice is used to calibrate the James Machine fordetermination of static coefficient of friction of polish surfacesin accordance with Test Method D2047. Over considerabletime and repeated use the James Machine may tend tomechanical misalignment, giving sel
20、f-evident, anomalousreadings. The periodic accumulation and comparison of datagenerated by this practice provides an indication of when themachine is no longer within the calibration limits and can nolonger be expected to provide accurate and reliable data.5.2 Semi-automated James machines may perfo
21、rm an inter-nal calibration/alignment test. These automated tests should beroutinely run per the manufacturers recommendation. If therepeatability tests of this practice indicate that the machine isout of calibration, the manufacturer should be contacted andtheir suggestions followed. Unqualified di
22、sassembly,modification, or adjustment may void the instrument warrantyof semi-automated James Machines.6. Interferences (Troubleshooting)6.1 Deviations in calibration data and anomalies in machineaccuracy and repeatability are due to the following interfer-ences:6.1.1 Contamination of the Test Surfa
23、cesThese are mostcommonly due to fingerprints or other soils on the workingleather surface or the working surface of the Borco board, orthe presence of residual materials on the Borco board from useof an improper cleaning solution. Generally, contamination ofthe working surfaces will result in low r
24、eadings.6.1.2 Irregular Test Table TransportThis problem is mostcommon on James Machines that derive test table transportfrom manual cranking, which may not be smooth and uniform,but it may also be caused by localized wear or grit and dirt inthe drive mechanism or on the transport guides of the test
25、 table.Test table movement that is not smooth and uniform willprovide low readings.6.1.3 Improper Rate of Test Table TransportEven whenuniform, the use of an improper rate of test table transport willresult in changes in the readings. This is most often seen inmanually cranked test table transports,
26、 where the rate of travelis difficult to judge subjectively without training and practice.Many motor driven test tables have an electrical motor speedcontrol to adjust the rate of table travel, and this can beinadvertently changed. Too rapid a rate of travel will result inhigh readings, and too slow
27、 a rate of travel will result in lowreadings.6.1.4 Wear or BindingWear or binding at the followingbearing surfaces will result in deviations from calibration andloss of machine repeatability: upper strut pivot, upper strut ballbearings, back plate, strut rack and pinion gear assembly, lowerstrut piv
28、ot, and shoe pad cups for lower strut pivots. Theseproblems are most often the result of the normal, repeated useof the James Machine, but they can also be caused by heavyimpacts, improper use, improper or inadequate periodic clean-ing and lubrication, or inadequate protection of the machinefrom dir
29、t. Wear resulting in excessive play in the bearingsurfaces will cause lower readings. Sporadic binding of thebearing surfaces and pivot points will result in loss of machinerepeatability. Consistent binding of the bearing or pivot sur-faces can result in high readings.6.1.5 Test Table not FlatTest t
30、ables are warped out offlatness by heavy impacts onto the table, storage of heavy itemson the edges of the test table, or storage of the James Machinewith the weight and strut in the upright position resting on thetest table. Test table flatness may be assessed visually or by useof a machinists dial
31、 gage attached to the strut rack gear and incontact with the traversing test table. Lack of adequate testtable flatness will result in poor repeatability of data as afunction of the test specimen (tile) placement on the table.6.1.6 Test Table not LevelThis is often due to the entireJames machine not
32、 being level. Otherwise, this problem isusually caused by wear of the table transport guides, an impacton the table, or improper use of the test table for storage. A testtable which is not level will result in abnormal readings. Thedeviation from accurate readings will depend on the magnitudeand dir
33、ection of the deviation of the test table from level. Aftermany adjustments are made to level the Test Table, use themachinists square to ensure that the plane of strut motion isperpendicular to the Test Table.6.1.7 Excess Play or Movement in the Strut Rack GearThis results from wear in the strut ra
34、ck and pinion gearassembly, loss of lubricant, or use of an improper lubricant inthe gear box. Care must be taken that there is enough freedomin the movement of the strut rack gear so that the verticalmotion of the strut rack gear is not impeded. Excess play in anydirection perpendicular to the vert
35、ical motion of the strut rackgear will result in low readings.6.1.8 Test Table Travel is not in the Plane of Strut MotionThis is usually caused by excessive movement in the strut rackgear assembly so that the plane of strut motion is rotated (see6.1.7), binding or excessive movement in at least one
36、of theupper strut pivots (see 6.1.4), or wear of the test table transportguides (see 6.1.6). This problem results in low readings, sincethe slipping motion of the shoe pad on the test surface iscompounded by a skewing action (greater lateral forces areapplied at the interface than are recorded by th
37、e linear tabledisplacement shown on the chart).6.1.9 Chart Board (or Chart) is not in a Plane Parallel tothe Plane of the Strut MotionThis problem is usually due toa heavy impact on the chart board, but it can also be due to theuse of a pad of charts (rather than an individual sheet) attachedD6205 1
38、22to the chart board. The magnitude and sign of deviations inreadings that result from this problem depend on the magnitudeand direction of the deviation of the chart board from a parallelconfiguration with respect to the plane of strut motion.6.1.10 Warped, or “Out of True” Back Plate, Chart Board,
39、Strut Arm, or Strut Rack GearThough this problem can bethe result of heavy impact, it is most commonly the result ofnot maintaining the James Machine in a controlled temperatureenvironment. The James Machine is a complex assembly ofparts that are rigidly held in alignment by bead welds or bolts.Sinc
40、e many of the parts are constructed of different metals,temperature changes (and the different coefficients of thermalexpansion) will result in very large forces being applied to thejoints or to the components themselves. This can result in adistortion or warping of the parts, particularly those whi
41、ch arelarge or have at least one long dimension.7. Apparatus7.1 James Machine5,6See Fig. 1.7.2 Standard Reference Leather6,7Leather sole materialconforming to Federal Specification KK-L-165C (Type 1,Class 6).7.3 Leather/Shoe Pad AssemblyReference leathermounted on the machined shoe pad.7.4 Borco Boa
42、rd2drafting and drawing board workingsurface cover.7.5 Reference Surface6,8Aluminum plate, 30.48 by 30.48by 0.3175 cm (12 by 12 by 0.125 in.), which has beenmachined flat, to which 30.48 by 30.48 cm (12 by 12 in.) Borcoboard has been mounted, white side up.7.6 Chart.6,97.7 Cleaner SolutionAlcohol an
43、d water-based cleaner thatdoes not leave a non-volatile residue, such as householdwindow glass cleaner, or equivalent.7.8 Cleaning ClothClean, lint-free, absorbent cloth orwhite paper towel.7.9 Shoe Pad StopMetal block, approximately 15 cm (6in.) wide and long enough to fit between the James Machine
44、test table retaining bar and the leading edge of the metal shoepad when the strut is in the full upright position and the testtable is in the start position. The shoe pad stop end shall beconstructed so that it contacts only the machined shoe pad andnot the leading edge of the leather. See Fig. 2. T
45、he shoe padstop prevents slippage of the shoe pad during movement of thetest table during calibration of the James Machine.7.10 Spring Clips or Drafting Tape.7.11 Machinists Square.8. Test Surface8.1 For James Machine calibration the test surface assemblywill consist of the working interface between
46、 the standardreference leather, mounted on the shoe pad, and the mountedBorco board reference surface, or between the mounted stan-dard reference leather and the control polish applied andequilibrated on a Vinyl Composition Tile as described in TestMethod D2047 and Practice D4103.8.2 The test surfac
47、es shall not be altered, adulterated, orcontaminated in any matter, except for the cleaning procedurewhich begins each test sequence. When not in use, thereference surface and leather/shoe pad assembly shall be storedin individual, sealed, dust-proof plastic bags, and protectedfrom impacts, contamin
48、ation, and scratches. A single tile of thecontrol polish shall be freshly prepared per Test Method D2047and Practice D4103 for each test sequence. Cleaning solution isnot to be used with the control polish.9. Procedure9.1 Preliminary:9.1.1 Remove the reference surface from its protectiveplastic bag.
49、9.1.2 Clean the bottom aluminum surface and the Borcosurface with cleaning solution and a clean, lint-free cloth orsoft paper towel. Wipe dry and set the clean reference surfaceaside in a dust-free environment to thoroughly dry (do not heat)for a minimum of 30 min before using it in the test procedure.Do not touch the cleaned reference surface or allow it tocontact other objects. If the reference surface is a controlpolish, prepare and handle it in accordance with PracticeD4103 and Test Method D2047.9.1.3 Mount a chart on the chart board with the spring clip
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