1、Designation: D 6205 06Standard Practice forCalibration of the James Static Coefficient of FrictionMachine1This standard is issued under the fixed designation D 6205; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 asta
3、ndard 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
4、-minations 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
5、Machineswhich 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 theresp
6、onsibility 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:3D 2047 Test Method for Static Coefficient of Friction ofPolish-Coated Flooring Surfaces as
7、Measured by theJames MachineD 2825 Terminology Relating to Polishes and Related Ma-terialsD 4103 Practice for Preparation of Substrate Surfaces forCoefficient of Friction TestingE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 178 Practice for Deali
8、ng With 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 MethodD 2047 and Terminology D 2825.3.2 Definitions of Terms Specific to This Standard:3.2.
9、1 Borco, nspecial 5-ply vinyl drawing board cover.3.2.2 control polish, na reference polish of known or wellestablished Static Coefficient of Friction, as determined byrepeated determinations using Test Method D 2047 over a longperiod of time and preferably by determinations on multipleJames Machine
10、s.3.2.3 reference surface, Borco standard leather system,nworking interface of the set consisting of the white side ofthe Borco material, mounted as described in this practice, andthe standard leather shoe sole material, mounted on a precisionshoe pad as described in this practice.3.2.4 standard tes
11、t 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 onestandard test se
12、quence is the Static Coefficient of Friction(SCOF) 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
13、of white Borco material incontact with a standard 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 of1This practice is under the juri
14、sdiction of ASTM Committee D21 on Polishesand is the direct responsibility of Subcommittee D21.06 on Slip Resistance.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1998. Last previous edition approved in 1998 as D 6205-98.2Borco is a registered trademark for a Dani
15、sh 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 trade names “Borco,” “Vyco,” and“Altex” board covers.3For re
16、ferenced 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 from Standardization Documents Order Desk, Bldg 4 Section
17、 D, 700Robbins Ave., Philadelphia, PA 19111-5094, Atten: NPODS.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the James Machine and determine whether the machine re-mains within the calibration limits.5. Significance and Use5.1 This
18、 practice is used to calibrate the James Machine fordetermination of static coefficient of friction of polish surfacesin accordance with Test Method D 2047. Over considerabletime and repeated use the James Machine may tend tomechanical misalignment, giving self-evident, anomalousreadings. The period
19、ic 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 perform an inter-nal calibration/alignment te
20、st. 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 andhis suggestions followed. Unqualified disassembly, modifica-tion, or adjustment ma
21、y void the instrument warranty.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 SurfacesThese are mostcommonly due to fingerprints or other soils on the work
22、ingleather 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 readings.6.1.2 Irregular Test Table TransportThis problem is mostcommon o
23、n 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 table.Test table movement that is not smooth and uniform willprovide lo
24、w 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, where the rate of travelis difficult to judge subjectively without trai
25、ning and practice.Many motor driven test tables have an electrical motor speedcontrol which adjusts the rate of table travel, and this can beinadvertently moved out of adjustment. Too rapid a rate oftravel will result in high readings, and too slow a rate of travelwill result in low readings.6.1.4 W
26、ear 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 pivot, and shoe pad cups for lower strut pivots. Thesep
27、roblems are most often the result of the normal, repeated useof the James Machine, but they can also be caused by heavyimpacts, improper use, improper periodic cleaning and lubri-cation, or inadequate protection of the machine from dirt. Wearresulting in excessive play in the bearing surfaces will c
28、auselower readings. Sporadic binding of the bearing surfaces andpivot points will result in loss of machine repeatability.Consistent binding of the bearing or pivot surfaces can result inhigh readings.6.1.5 Test Table not FlatTest tables are warped out offlatness by heavy impacts onto the table, sto
29、rage 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 gage attached to the strut rack gear and incontact with the travers
30、ing 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 problem is usually causedby wear of the table transport guides, but it may also resultfrom an impact on the tab
31、le or improper use of the test table forstorage. A test table which is not level will result in abnormalreadings. The deviation from accurate readings will depend onthe magnitude and direction of the deviation of the test tablefrom level.6.1.7 Excess Play or Movement in the Strut Rack GearThis resul
32、ts from wear in the strut rack 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 anydirecti
33、on perpendicular to the vertical motion of the strut rackgear will result in low readings.6.1.8 Test Table Travel and the Plane of Strut Motion arenot ParallelThis is usually caused by excessive movement inthe strut rack gear assembly so that the plane of strut motion isrotated (see 6.1.7), binding
34、or excessive movement in at leastone of the upper strut pivots (see 6.1.4), or wear of the testtable transport guides (see 6.1.6). This problem results in lowreadings, since the slipping motion of the shoe pad on the testsurface is compounded by a skewing action (greater lateralforces are applied at
35、 the interface than are recorded by thelinear table displacement 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 tha
36、n an individual sheet) attachedto 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 T
37、rue” Back Plate, Chart Board,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 alignmen
38、t by bead welds or bolts.Since 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
39、parts, particularly those which arelarge or have at least one long dimension.D62050627. 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 o
40、n the machined shoe pad.7.4 Borco Board2drafting 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 Ch
41、art.6,97.7 Cleaner SolutionAlcohol and water-based cleanerthat does 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 en
42、ough to fit between the James Machinetest 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 leadi
43、ng edge of the leather. See Fig. 2. The 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 con
44、sist of the working interface between 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 D 2047
45、and Practice D 4103.8.2 The test surfaces 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 ba
46、gs, and protectedfrom impacts, contamination, and scratches. A single tile of thecontrol polish shall be prepared per Test Method D 2047 andPractice D 4103 for each test sequence.9. Procedure9.1 Preliminary:9.1.1 Remove the reference surface from its protectiveplastic bag.9.1.2 Clean the bottom alum
47、inum 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
48、 reference surface or allow it tocontact other objects.9.1.3 Remove the leather/shoe pad assembly from its pro-tective plastic bag. Do not touch the leather surface.9.1.4 Mount a chart on the chart board with the spring clip.Load the pen holder with a fine tipped ballpoint pen or HB leadpencil that
49、has been sharpened to a non-fragile point.9.1.5 Visually and physically inspect all the bearing pointsfor wear, binding, excessive play, soil, and proper lubrication.9.1.6 Test the table transport for smooth operation and even,uniform motion. If the test table transport mechanism is motordriven, test and adjust the rate of table transport to be 152.4cm/min (60.0 in./min or 1.0 in./s).9.1.7 Place the leather/shoe pad assembly on a clean,lint-free cloth or paper towel on the test table, block the weightand strut in the upright position, and engage the lower strutp
