1、 ENGINEERING MATERIAL SPECIFICATIONMaterial Name Specification NumberDate Action Changes1996 06 17 Activated M. TraceWP 3948-a Page 1 of 3 THERMAL CONDUCTOR, GRAPHITE LOADED SILICONE RUBBER WSS-M99G171-A1. SCOPEThe mate rial defined by this specification is a thermally conductive padconsisti ng of g
2、raphite imbedded in a polymer matrix and silicone rubber.This mat erial is used as a thermal conductor where electrical insulationis not required.2. APPLICATIONThis s pecification was released originally for material used as a thermalconducto r between the high power switching transistors and the he
3、at sinkin th e traction inverter module for the electric vehicle. The pad is torep lace thermal grease which contaminates the electronic components andcauses assembly problems.3. REQUIREMENTSAll te sts are conducted without adhesive coated material unless otherwisespecified on the engineering drawin
4、g.3.1 QUALITY SYSTEM REQUIREMENTSMaterial suppliers and part producers must conform to Quality SystemRequirements, QS-9000. Material specification r equirements are to beused fo r initial qualification of materials. A Control Plan forong oing production verification is required. This plan must berev
5、iewed and approved b y the relevant Ford Materials activity and/orFor d Supplier Technical Assistance (STA) prior to production partssubmission. Appropriate statistical tools must be used to analyzepr ocess/product data and assure consistent processing of thematerials.Part producers using this mater
6、ial in their products, must use Fordapproved materials and must conform to a process control plan whichhas been approved by STA and/or the relevant Materials Activity.3.2 INFRARED SPECTROPHOTOMETRY AND/OR THERMAL ANALYSISFord Motor Company, at its option, may conduct infrared and/ortherma l analysis
7、 of material/parts supplied to this specification.The IR spectra and thermograms established for i nitial approval shallconst itute the reference standard and shall be kept on file at thedesignated material laboratory. All samples sha ll produce IR spectraand thermograms that correspond to the refer
8、ence standard when testedunder the same conditions.ENGINEERING MATERIAL SPECIFICATIONWSS-M99G171-AWP 3948-b Page 2 of 3 3.3 CONDITIONING AND TEST CONDITIONSAll test values indicated herein are based on ma terial conditioned ina control led atmosphere of 23 +/- 2 C and 50 +/- 5 % relativehumidity for
9、 not less than 24 h prior to testing and tested under thesame conditions unless otherwise specified.3.4 VOLUME RESISTIVITY, ohm-cm, min 5.0(ASTM D 257)3.5 APPARENT THERMAL CONDUCTIVITY, W/m-K, min 2.2(ASTM D 5470)3.6 TENSILE STRENGTH, N/mm2, min(ASTM D 412)Warp 24.0Fill 24.03.7 ELONGATION, %, min 1.
10、0(ASTM D 412)3.8 BREAKING STRENGTH, N/mm, min(ASTM D 1458)Warp 2.7Fill 2.93.9 HARDNESS, Shore A 72 - 86(ASTM D 2240)3.10 ADDITIONAL REQUIREMENTSSpecific requirements for material and/or manufa ctured parts shall bespecified on the Engineering drawing, Engineerin g parts specificationand/or performan
11、ce specification. All critical areas with respect tothese properties shall be clearly designated on the engineeringdrawing.3.9 SUPPLIERS RESPONSIBILITYAll materials supplied to this specification must be equivalent inal l characteristics to the material upon which approval wasoriginally granted.Pri
12、or to making any change in the properties, composition,constr uction, color, processing or labeling of the materialorig inally approved under this specification, whether or not suchchange s affect the materials ability to meet the specificationrequir ements, the Supplier shall notify Purchasing, Tox
13、icology andthe affected Materials Engineering activity of the proposed changesand obtain the written approval of the Materials Engineeringactivity. Test data, t est samples and a new code identification areto be submitted with the request.ENGINEERING MATERIAL SPECIFICATIONWSS-M99G171-AWP 3948-b Page
14、 3 of 3 Substance restrictions imposed by law, regulations or Ford, apply tothe materials addressed by this document. The restrictions aredefined in Engineering Materials Specification WSS-M99P9999-A1.4. APPROVAL OF MATERIALSMat erials defined by this specification must have prior approval by theres
15、p onsible Materials Engineering activity. Suppliers desiring approvalof thei r materials shall first obtain an expression of interest from theaffec ted Purchasing, Design and Materials Engineering activity. Uponrequest, the Supplier shall submit to the affected Materials Engineeringactivity a comple
16、ted copy of their laboratory test reports, signed by aqualified and authorized representative of the test faci lity, demonstratingful l compliance with all the requirements of this specification (testresults, not nominal values), the material designation a nd code number, andtes t specimens for Ford
17、 evaluation. Fords engineering approval of amateri al will be based on its performance to this specification and on anassessment of suitability for intended processes and/or applications. Uponapprov al, the material will be added to the Engineering Material ApprovedSource List.5. GENERAL INFORMATION
18、The information given below is provided for clarification and assistancein meeting the requirements of this specification.5.1 THERMAL RESISTANCEThe t hermal performance of a thermal conductor prepared from thegraph ite imbedded polymer matrix and silicone rubber sheet stockspecified herein can be de
19、termined using various test methods called“thermal resistance“ or “thermal impedance“ tests. These tests takeinto account variations in the thermal conductiv ity of the conductingand insulating materials caused by the adhesive and its filler,componen t surface finish, and clamping forces. For modeli
20、ngpurposes, this data may be more appropriate than thermal conductivitywhich is a property of the bulk material. Thermal impedance andtherma l interfacial impedance can be obtained from the apparentther mal conductivity measurements from paragraph 3.5 using testmethod ASTM D 5470.5.2 THICKNESS*, nominal, mm 0.127(ASTM D 374)*Thickn ess originally approved. Other thicknesses may be used asspecified on the engineering drawing.
