1、Designation: D 7142 05Standard Test Method forHolding Strength of Prong-Ring Attached Snap Fasteners1This standard is issued under the fixed designation D 7142; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. 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 test method covers the determination of the holdingstrength of a prong-ring to the socket or stud of a snap fastenerusing
3、a tensile testing machine (Option 1) or a manual teststand and force-measuring gage (Option 2).1.2 This test method is applicable to prong-ring type snapfasteners in garments or to be attached to fabrics intended foruse in apparel (see Annex A1).1.3 The values stated in either SI units or inch-pound
4、 unitsare to be regarded separately as standard. Within the text, theinch-pound units are shown in parentheses. The values statedin each system are not exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformanc
5、ewith the specification.1.4 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 safety and health practices and determine the applica-bility of regulatory limitations prio
6、r to use.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD 123 Terminology Relating to TextilesD 1776 Practice for Conditioning Textiles for Testing2.2 Federal Document:16 CFR Parts 1500.48-1500.53 and 1501.4 EngineeringTest Manual for Childrens
7、Toys33. Terminology3.1 Definitions:3.1.1 force, na physical influence exerted by one body onanother which produces acceleration of bodies that are free tomove and deformation of bodies that are not free to move.3.1.2 holding strength, nin snap fasteners, the force re-quired to separate the prong-rin
8、g from its attached mating part(socket or stud).3.1.2.1 DiscussionIn this test method, a diametric force isapplied which simulates the diametric biting or pinching of achild; however, in practice, the disengaging force used tounsnap a snap fastener is usually applied at the edge of thefastener.3.1.3
9、 prong-ring type fastener, ngeneric name for snapfasteners which use a multi-pronged ring to penetrate throughfabric to mechanically set a matching socket on one side of aclosure and to set a matching stud on the facing closureallowing the outer and inner closure facings to be snappedtogether. (See
10、Fig. 1.)3.1.4 socket, nin snap fasteners, the female functionalpart of the fastener which engages with the stud part of thefastener to form the closure of two parts of the item on whichthe fastener is used. (See Fig. 1.)3.1.4.1 DiscussionProng-ring attached socket or studsnap fasteners are designed
11、to be mechanically attached togarments or other items through the deformation interaction ofthe prong-ring with the socket or stud. Other forms of snapfasteners exist which may be attached to the foundation of thegarment or other item by means of sewn threads or adhesivebonding.3.1.5 strength, nthe
12、property of a material that resistsdeformation induced by external forces.3.1.5.1 DiscussionIn this standard, the deformation is theseparation of the prong-ring from the socket or stud of a snapfastener.3.1.6 stud, nin snap fasteners, the male functional part ofa snap fastener which engages with, or
13、 snaps into, the mouth ofthe socket to form a closure of two parts of the item, or garmenton which the fastener is used. (See Fig. 1.)3.1.6.1 DiscussionSee discussion for socket.3.1.7 For definitions of other textile terms used in thisstandard, refer to Terminology D 123.4. Summary of Test Method4.1
14、 Option 1A specimen, consisting of a fastener socketor stud attached to fabric by a prong-ring, is mounted in aspecial test fixture on a tensile testing machine. A force isapplied diametrically until the prong-ring separates from thesocket or stud, or the fabric is torn. The force at separation is1T
15、his test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.54 on Subassemblies.Current edition approved July 1, 2005. Published August 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custom
16、er Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Federal Register, Vol 44, No. 117, June 1979, ConsumerProduct Commission, 16 CFR Parts 1500 and 1501.1Copyright ASTM International, 100
17、Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.reported as the holding strength. If the fabric tears, the force atfabric failure is recorded and the data is reported and it isconsidered as a different category and is reported separate fromthe holding strength of the
18、fasteners.4.2 Option 2A specimen, consisting of a fastener socketor stud attached to fabric by a prong-ring, is mounted in aspecial test fixture on a manual pull test stand which is fittedwith a portable force gage. A force is applied until theprong-ring separates from the socket or stud, or the fab
19、ric istorn. The force at separation is reported as the holding strength.If the fabric tears, the force at fabric failure is recorded and thedata is reported and it is considered as a different category andis reported separate from the holding strength of the fasteners.5. Significance and Use5.1 Both
20、 test methods are considered satisfactory for accep-tance testing of commercial shipments of garments withprong-ring type snap fasteners.5.1.1 In case of dispute arising from differences in reportedtest results when using this test method for acceptance ofcommercial shipment, the purchaser and the s
21、upplier shouldconduct comparative tests to determine if there is a statisticalbias between their laboratories. Competent statistical assis-tance is recommended for the investigation of bias. As aminimum, the two parties should take a group of test speci-mens that are as homogeneous as possible and t
22、hat are from alot of material of the type in question. The test specimensshould then be randomly assigned in equal numbers to eachlaboratory for testing. The average results from the twolaboratories should be compared using appropriate statisticalanalysis and an acceptable probability level chosen b
23、y theparties before testing is begun. If a bias is found, either thecause must be determined and corrected, or the purchaser andsupplier must agree to interpret future test results with consid-eration to the known bias.5.2 Comparison of results from test equipment operating ondifferent principles is
24、 not recommended. In cases of conflictbetween the test results achieved with manual test equipment(Option 2) and motorized CRE (constant rate of extension)tensile testing machine (Option 1), the results from the motor-ized equipment shall take precedence.5.3 This test method may be used to determine
25、 the compat-ibility of prong-ring type snap fasteners and fabrics for use inapparel. In which case, the fasteners are attached to the fabricin the manner in which they will be used and the combinedunits tested. See Annex A1.6. Apparatus6.1 For Option 1:6.1.1 Tensile Testing Machine, CRE type, meetin
26、g Specifi-cation D76. (See Figs. 2 and 3.)6.1.2 Upper Snap Fixture Attachment 4, Fig. 4, designed todiametrically attach to the socket or stud of the snap fastenerwhich is attached to the fabric specimen or garment beingtested.6.1.3 Lower Snap Fixture Attachment 4, Fig. 4, designed tosecure the fabr
27、ic and thereby the socket or stud attached to it ina horizontal plane.6.2 For Option 2:6.2.1 Force Measuring Gage 5, modified with an attachmentto be fastened on to the upper arm of a test stand with the uppertest fixture suspended from it. (See Fig. 3.)6.2.2 Upper Snap Fixture Attachment 4, Fig. 4,
28、 designed todiametrically attach to the socket or stud of the snap fastenerwhich is attached to the fabric specimen or garment beingtested.6.2.3 Lower Snap Fixture Attachment 4, Fig. 4, designed tosecure the fabric and thereby the socket or stud attached to it ina horizontal plane.6.2.4 Test Stand,
29、see Fig. 5.7. Sampling7.1 Lot Sample:7.1.1 For acceptance testing, randomly select the number ofshipping cartons or other containers of garments as directed inan applicable material specification, contract or other agree-ment between the purchaser and the supplier. Consider thecartons or containers
30、to be the primary sampling units.FIG. 1 Prong-ring Attached Fastener PartsD7142052NOTE 1An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween shipping units, between sampling units within a shipping unit andbetween spec
31、imens to provide a sampling with a meaningful producersrisk, consumers risk, acceptable quality level and limiting quality level.7.2 Laboratory Sample:7.2.1 For acceptance testing, take 1 garment from each lotsampling unit provided that it has ten snap fasteners. If thegarment contains fewer than te
32、n snap fasteners, take a numberof garments from each laboratory sampling unit to obtain theten snap fasteners. If garment has snaps attached to multiplelocations; i.e. collar, shoulder, placket, front, crotch, leg cuff,and the like, take appropriate number of garments that willprovide ten snaps per
33、location.7.3 Test Specimens:7.3.1 Test ten specimens from each garment. A test speci-men consists of the assembled prong-ring, fabric and a socketor a stud. The locations of the specimens must allow for secureclamping in the fixtures. Specimens need not be cut from thegarment provided that the garme
34、nt does not interfere with thetest.8. Preparation of Apparatus8.1 For Option 1:8.1.1 Preparation:8.1.1.1 Set up and verify the tensile testing machineaccording to the manufacturers instructions and 8.1.1.2-8.1.1.4.8.1.1.2 Attach the upper and lower snap fixtures to thetesting machine and check the a
35、lignment. (See Figs. 2 and 3.)8.1.1.3 Select a force range for separation to occur between10 and 90 % of full scale force.8.1.1.4 Set the loading rate for 300 6 10 mm/min (12.0 60.5 in./min).8.1.2 Total Operating System:8.1.2.1 Verify the operating system (loading, extension,clamping, and recording
36、or data collecting) by testing standardspecimens of snap fasteners and fabrics for holding strength asdirected in Section 10.8.1.2.2 Maintain a record of the data.8.2 For Option 2:8.2.1 Preparation:8.2.1.1 Setup the manual test stand and verify the forcereading of the force gage according to the man
37、ufacturersinstructions and 8.2.1.2-8.2.1.4.8.2.1.2 Attach the upper fixture to the force gage and thelower fixture to the table of the manual testing stand and checktheir alignment. (See Fig. 5.)8.2.1.3 Select and adjust the control switches of the forcegage.FIG. 2 CRE-Type Tensile Testing Machine s
38、etup With TestFixtures For Option 1.FIG. 3 Closeup of CRE-Type Tensile Testing Machine FixtureSetup.D71420538.2.1.4 Adjust the distance between the upper and lower testfixture to allow clearance for the setup of the test specimen.8.2.2 Total Operating System:8.2.2.1 Verify the operating system (load
39、ing, extension,clamping, and recording or data collecting) by testing setupspecimens of snap fasteners and fabrics for holding strength asdirected in Section 10 and Annex A1.3.8.2.2.2 Maintain a record of the data.9. Conditioning9.1 Condition the specimens by bringing them from the dryside to approx
40、imate moisture equilibrium for testing in thestandard atmosphere for testing textiles as directed in PracticeD 1776.10. Procedure10.1 Option 1:10.1.1 Position prong-ring of the specimen in the lowersnap clamping fixture and ensure that it is flat and centered inthe fixture. Tighten the clamping fixt
41、ure on the specimen.10.1.2 Position the upper clamping fixture for the jaws to fitover the perimeter edge of the socket or stud of the specimen.Turn the adjustment screw until the jaws make contact with thefastener. Do not include any loose fabric in the jaws. Be carefulthat the upper fixture does n
42、ot affect the structural integrity ofthe fastener when tightening the fixture onto the fastener.10.1.3 Initiate the test by applying force to the machine untilthe prong-ring disengages from the fastener or the fabric tears.FIG. 4 Upper and Lower Snap Clamping FixturesD714205410.1.4 Record the force
43、to disengage the prong-ring fromthe fastener as the holding force to the nearest 0.1 N (0.5 lbf).If the fabric tears before the fastener and prong-ring disengage,record the specimen as failing. The value of the fabricspecimen failure is recorded separate from the recording of thevalues of the fasten
44、er holding strength.10.2 Option 2:10.2.1 Position prong-ring of the specimen in the lowersnap clamping fixture and ensure that it is flat and centered inthe fixture. Tighten the clamping fixture on the specimen withthe socket or stud facing up.10.2.2 Position the upper clamping fixture for the jaws
45、to fitover the perimeter edge of the socket or stud of the specimen.Turn the adjustment screw until the jaws make contact with thefastener. Do not include any loose fabric in the jaws. Be carefulthat the upper fixture does not affect the structural integrity ofthe fastener.10.2.3 Apply a force of 3
46、pounds per second until thefastener disengages from its prong-ring or the fabric tears. Orapply specified tensile force and hold for specified time asagreed upon by purchaser and seller of snap and10.2.4 Record the force to separate the prong-ring from thesocket or stud fastener part as the holding
47、strength to thenearest 0.1 N (0.5 lbf). If the fabric tears before the prong ringseparates from the socket or stud, record the specimen asfailing. The value of the fabric specimen failure is recordedseparate from the recording of the values of the fastenerholding strength.11. Report11.1 State that t
48、he specimens were tested as directed in TestMethod D XXXX. Describe the material or product sampledand the method of sampling used. Include in the material orproduct description the size of prong-ring snap fastener, theFIG. 5 Manual Testing ApparatusD7142055type of fabric, the style of the garment a
49、nd the location of thefastener on the garment (collar, shoulder, placket, front, crotch,leg cuff, and the like).11.2 Report the following information:11.2.1 The individual values of force to separate the fastenerfrom the fabric, and the average holding strength for eachlaboratory sampling unit and for the lot.11.2.2 The number of specimens that failed (fabric tears)along with their individual values.12. Precision and Bias12.1 Precision4An interlaboratory test was conducted in2003.12.2 The value for holding strength of prong-ring to socketor stud of snap fasteners i
