1、Designation: D 7255 06e1Standard Test Method forAbrasion Resistance of Leather (Rotary Platform, Double-Head Method)1This standard is issued under the fixed designation D 7255; 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 (e) indicates an editorial change since the last revision or reapproval.e1NOTEIn Note 2, the reference to H-19 was editorially corrected to H-18 in September 2006.1. Scope1.1 This test method cov
3、ers the determination of the abra-sion resistance of leather using the rotary platform, double-head tester (RPDH).1.2 This standard does 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 s
4、afety and health practices and to determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1517 Terminology Relating to LeatherD 1610 Practice for Conditioning Leather and LeatherProducts for TestingD 2240 Test Method for Rubber PropertyDurometer
5、HardnessD 2813 Practice for Sampling Leather for Physical andChemical Tests3. Terminology3.1 Definitions:3.1.1 abrasera wear testing instrument, also referred to asa rotary platform, double head (RPDH) tester or abrader.3.1.2 abrasionthe wearing away of any part of a materialby rubbing against anoth
6、er surface.3.1.3 abrasion cyclein abrasion testing, one or moremovements of the abradant across a material surface, or thematerial surface across the abradant, that permits a return to itsstarting position. In the case of the rotary platform test method,it consists of one complete rotation of the sp
7、ecimen.3.1.4 resurfacethe preparation of an abrasive wheel on aresurfacing disk or diamond tool wheel refacer, prior to use intesting.3.2 For definitions of other leather terms used in this testmethod, refer to Terminology D 1517.4. Summary of Test Method4.1 Aspecimen is abraded using rotary rubbing
8、 action undercontrolled conditions of pressure and abrasive action. The testspecimen, mounted on a turntable platform, turns on a verticalaxis, against the sliding rotation of two abrading wheels. Oneabrading wheel rubs the specimen outward toward the periph-ery and the other, inward toward the cent
9、er. The resultingabrasion marks form a pattern of crossed arcs over an area ofapproximately 30 cm2. Resistance to abrasion is evaluated byvisual inspection of the specimen or change in weight, asdescribed in Section 14.5. Significance and Use5.1 The resistance of leather to abrasion, as measured on
10、atesting machine in the laboratory, is generally only one ofseveral factors contributing to wear performance or durabilityas experienced in the actual use of the material. While“abrasion resistance” (often stated in terms of the number ofabrasion cycles) and “durability” (defined as the ability towi
11、thstand deterioration or wear out in use, including the effectsof abrasion) are frequently related, the relationship varies withdifferent end uses and different factors may be necessary in anycalculation of predicted durability from specific abrasion data.This test method provides a comparative rank
12、ing of materialperformance, which can be used as an indication of relativeend-use performance.5.2 The resistance of leather to abrasion may be affected byfactors including test conditions, type of abradant, pressurebetween the specimen and abradant, mounting or tension of thespecimen, and type, kind
13、, or amount of finishing materials.5.3 Abrasion tests utilizing the rotary platform, double-headtester may be subject to variation due to changes in theabradant during specific tests. Depending on abradant type andtest specimen, the wheel surface may change (that is, becomeclogged) due to the pick u
14、p of finishing or other materials fromtest specimens and must be cleaned at regularly definedintervals.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.07 on Physical Properties.Current edition approved April 1, 2006. Pu
15、blished April 2006.2For 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 ASTM website.1Copyright ASTM International, 100 Barr Ha
16、rbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 The measurement of the relative amount of abrasionmay also be affected by the method of evaluation and may beinfluenced by the judgment of the operator.6. Apparatus6.1 Rotary Platform, Double-Head (RPDH) Tester,3con-sisting
17、 of the elements described in 6.1.1-6.1.5 (see Fig. 1).6.1.1 A turntable platform, which is removable, parts pro-vided with the turntable include the S19 rubber pad, clampplate and nut, and clamping ring to secure the specimen to theturntable. The turntable is motor driven and mounted so as toproduc
18、e a circular surface travel of an essentially flat specimenin the plane of its surface,6.1.2 A motor capable of rotating the turntable platform at aspeed of either 72 6 2 r/min for 110 V/60 Hz or 60 6 2 r/minfor 230 V/50 Hz,6.1.3 A pair of pivoted arms to which the abrasive wheelsand accessory weigh
19、ts or counterweights are attached,NOTE 1Without auxiliary weights or counter weights applied, eacharm will apply a load against the specimen of 250 6 1 g (exclusive of themass of the wheel itself).6.1.4 A vacuum suction system and vacuum pickup nozzleto remove debris and abrasive particles from the
20、specimensurface during testing. The height of the vacuum pickup nozzleshall be adjustable, and will have two openings with oneopening positioned between the two wheels and over the wearpath and the other placed diametrically opposite. The distancebetween the axes of the two openings shall be 76.0 6
21、1.0 mm,and6.1.5 A counter to record the number of cycles (revolutions)made by the turntable platform.6.2 Abrasive Wheels,4which are attached to the free end ofthe pivoted arms, and are able to rotate freely about horizontalspindles.6.2.1 Their internal faces shall be 52.4 6 1.0 mm apart andthe hypot
22、hetical line through the two spindles shall be 19.05 60.3 mm away from the central axis of the turntable (see Fig. 2).When resting on the specimen, the wheels will have aperipheral engagement with the surface of the specimen, thedirection of travel of the periphery of the wheels and of thespecimen a
23、t the contacting portions being at acute angles, andthe angles of travel of one wheel periphery being opposite tothat of the other. Motion of the abrasive wheels, in oppositedirections, is provided by rotation of the specimen and theassociated friction there from.6.2.2 The wheels shall be 12.7 6 0.3
24、 mm thick and have anexternal diameter of 51.9 6 0.5 mm when new, and in no caseless than 44.4 mm. The abrasive wheels are either resilient orvitrified based, with both types of wheels consisting of hardparticles embedded in a binder material and manufactured indifferent grades of abrasive quality.N
25、OTE 2The H-18 wheels typically produce a harsher abrasion thanthe CS-17 wheels, which produce a harsher abrasion than the CS-10wheels.3Available from Tabert Industries, 455 Bryant Street, North Tonawanda, NY14120.4The sole source of supply of the apparatus known to the committee at this timeis Taber
26、 Industries, 455 Bryant Street, North Tonawanda, NY 14120. If you areaware of alternative suppliers, please provide this information to ASTM Interna-tional Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee,1which you may attend.FIG. 1 R
27、otary Platform, Double-Head TesterD725506e126.2.3 Prior to testing, ensure the expiration date has notpassed for resilient wheels. Follow the manufacturers recom-mended practice for breaking in new or resurfacing previouslyused wheel sets (see Section 10).NOTE 3The hardness of the resilient wheels c
28、an be checked with TestMethod D 2240. An acceptable hardness for CS-10 and CS-17 wheels is81 6 5 units on Shore Durometer A-2 Scale.6.3 Accessory Loads, which can be attached to the pivotedabrader arms to increase the load against the specimen to 500or 1000 g per wheel (exclusive of the mass of the
29、wheel itself).Counterweight attachments of 125 or 175 g are available toreduce the load against the specimen, and can be used with orwithout the accessory load.6.4 Auxiliary Apparatus:6.4.1 Resurfacing disc3(S-11), is used for resurfacing ofresilient wheels.6.4.2 Asoft bristle brush, to remove loose
30、 particles from thesurface of the specimen after testing.6.4.3 Wheel refacer,3for resurfacing vitrified wheels orcorrecting out of round wheels.6.4.4 Specimen mounting cards (for example, Part S-36-1),3a 108 mm round mounting card with a 6.35 mm center hole andone side coated with pressure-sensitive
31、 adhesive used formounting specimens. Use of the mounting card is not requiredwhen using a clamping ring. If using a weight loss method ofevaluation and a mounting card, the mounting cards should beconditioned in the standard testing environment before use (seeSection 12).7. Sampling7.1 Take a lot s
32、ample as described in Practice D 2813,orasagreed upon by the interested parties. Because leather is anatural product, the physical properties may vary depending onlocation on the hide, side or skin from which the test sample istaken. Random sampling of specimens from a predefinedlocation and orienta
33、tion minimizes test bias and variability.8. Number and Preparation of Test Specimens8.1 If the number of specimens to be tested is not specifiedby agreement between the interested parties, test three speci-mens.8.2 Cut a circular specimen approximately 100 to 110 mmin diameter, with a 6.35 mm diamet
34、er hole in the center of thespecimen. A sample cutter or die may be used for this purpose.8.3 Clean the back of the specimen with a soft bristle brushto remove any loose debris. Mount specimen to a roundspecimen-mounting card (such as S-36-1), ensuring that thespecimen is free of folds, creases, or
35、wrinkles. Avoid gettingoil, water, grease, and so forth, on the specimen when handling.FIG. 2 Diagrammatic Arrangement of ApparatusD725506e138.3.1 Alternatively, a sample of 130 6 5 mm diameter maybe used, with or without a mounting card, and secured to theturntable with a clamp ring.8.4 If the leat
36、her has a pattern such as embossment, ensurethat the specimen is a representative sampling of the pattern.9. Preparation of Apparatus9.1 LoadA load of 1000 g per wheel should be used,unless otherwise agreed upon by the interested parties.9.2 Vacuum Pickup NozzleThe height of the vacuumpickup nozzle
37、should be set 7 6 1 mm above the specimensurface, unless otherwise agreed upon by the interested parties.9.3 Vacuum SuctionThe vacuum suction force should beadjusted to lift the abraded particles, but not lift the specimen.When the suction nozzles are in position, the air pressure in thesuction devi
38、ce shall be within the range stated in 11.1.5.Asetting of 75 - 100 has been found to be sufficient and shouldbe used, unless otherwise agreed upon by the interested parties.NOTE 4Vacuum suction force may be influenced by the condition ofthe collection bag, which must be emptied or replaced on a regu
39、lar basis.Any connection or seal leaks will also influence suction force.9.4 Selection of Wheel TypeThe CS-10 wheel should beused, unless otherwise agreed upon by the interested parties.10. Standardization of Abrading Wheels10.1 Preparation of resilient abrading wheelsTo ensurethat the abrading func
40、tion of the wheels is maintained at aconstant level, prepare the resilient wheels following 10.1.1-10.1.410.1.1 Mount the selected resilient wheels on their respec-tive flange holders, taking care not to handle them by theirabrasive surfaces. Adjust the load on each wheel to 1000 g orthe load agreed
41、 upon between the interested parties.10.1.2 Mount the resurfacing disc (S-11) on the turntableand affix using the clamp plate and nut, and clamp ring. Lowerthe abrading heads carefully until the wheels rest on theresurfacing disc. Place the vacuum pick-up nozzle in positionand adjust it to a distanc
42、e of 7 6 1 mm above the surface of thedisc.10.1.3 Set the counter to zero and adjust the vacuumsuction force to 100.10.1.4 If the vacuum system does not turn on automaticallyat the start of the test, start the vacuum suction and then theturntable. Resurface the wheels by running them for theappropri
43、ate number of cycles against the resurfacing disc asshown in Table 1. Each resurfacing disc is good for one 25 or50 cycle resurfacing operation, after which it must be dis-carded. Do not touch the surface of the wheels after they areresurfaced.NOTE 5New Set of Wheels (break-in procedure)The composit
44、ion ofresilient wheels can make them subject to slight changes of form. Beforeplacing in service a new set of resilient wheels they must be subjected totwo (2) resurfacings of 50 cycles to ensure perfect contact of the abradingfaces with the specimen surface. The resurfacing disc is used only once(m
45、aximum of 50 cycles), therefore this initial resurfacing of new wheelswill require two (2) resurfacing discs.NOTE 6Starting a Test with Previously Used WheelsBefore testinga specimen with previously used wheels, resurface 25 to 50 cycles on anew resurfacing disc. When the previous test was short in
46、duration(1,000 cycles), resurfacing of 25 cycles is sufficient. When the previoustest was 1,000 cycles or more, a resurfacing of 50 cycles is recommended.Wheels that have not been used for an extended period of time mayrequire a break-in resurfacing like a new set of wheels.NOTE 7Resurfacing During
47、TestingTo maintain consistency andavoid clogging of wheel faces, the wheels should be resurfaced after every1000 cycles of use. During the course of a test which requires more than1000 cycles, remove the specimen after every 1000 cycles (or as agreed byinterested parties) and resurface the wheels fo
48、r 25 to 50 cycles with a newresurfacing disc. The sample should be carefully replaced after resurfacingof the wheels.10.2 Preparation of Vitrified Abrading WheelsVitrifiedwheels do not require refacing unless the abrading surfacebecomes clogged, chipped or out of round. A wheel refacershould be used
49、 to correct any of these conditions.11. Calibration11.1 Verify calibration of the rotary platform, double headtester as directed by the equipment manufacturer (see Appen-dix X1).11.1.1 Wheel PositionThe wheels should be spacedequally on both sides from the wheel-mounting flange to thecenter of the specimen holder (see 6.2.1). The distance from theinside of the wheel-mounting flange to the center of thespecimen holder is 38.8 6 0.5 mm.11.1.2 Wheel BearingsThe RPDH tester wheel bearingsinstalled in the free end of the pivoting arms to support thewheels should
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