1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW14711 Determination of the Specific Volume Resistance of Elastomers, Plastics and Adhesives Copyright 2012 General Motors Company All Rights Reserved December 2012 Originating Department: North American Engineering Standards Page 1 of 5 1 Scope Note
2、: Nothing in this standard supercedes applicable laws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Purpose. Not applicable. 1.2 Foreword. If light metals (such as aluminum, magnesium) or zinc-plated body pa
3、nels come into contact with precious metals or solid bodies conducting electrons (e.g., graphite), this may lead, in the presence of electrolytes, to the preferential corrosion of the light metals. To avoid this contact corrosion, elastomers, plastics and adhesives shall have a sufficiently high ins
4、ulation resistance. The same applies if such materials are in contact with painted light metal surfaces as the insulating paint layer may not offer sufficient protection against contact corrosion, because of faults or damages in the part. The insulation resistance depends both on the specific volume
5、 resistance and on the specific surface resistance of the test piece. The determination of the specific volume resistance is performed to check the uniformity of the insulating material. The specific volume resistance is considerably affected by temperature and moisture. 1.3 Applicability. Not appli
6、cable. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. IEC 60093 2.2 GM Standards/Specifications. GMW3221 3 Resources 3.1 Facilities. Not applicable. 3.2 Equipment. 3.2.1 Test Equipment. 3.2.1.1 Clamping equipmen
7、t with two electrodes of each 10 mm 0.1 mm 10 mm 0.1 mm, gold plated to ensure good electrical contact. 3.2.1.2 Pressure gauge to apply a pressure force of 0.2 N/cm2 0.02 N/cm2. 3.2.1.3 Multi-meter with suitable connectors in accordance to IEC 60093. Copyright General Motors Company Provided by IHS
8、under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14711 Copyright 2012 General Motors Company All Rights Reserved December 2012 Page 2 of 5 3.3 Test Vehicle/Test Piece. 3.3.1 Test Material
9、. 3.3.1.1 Shape and Size. Unless otherwise specified, the following test pieces shall be used: 3.3.1.1.1 Test pieces from test panels shall be 120 mm 120 mm 2 mm 0.1 mm. 3.3.1.1.2 Test pieces from finished parts are strip-shaped test pieces with parallel sides, length and width of each 11 mm minimum
10、 and a thickness of 2 mm 0.1 mm. If the required thickness of 2 mm cannot be reached from the finished part, coplanar test pieces of a smaller thickness shall be prepared. To calculate the specific volume resistance, the thickness and the width (if less than 11 mm) of the test pieces shall be measur
11、ed to an accuracy of 0.1 mm. Note: Do not mark the test pieces in the measuring area. 3.3.1.2 Number of Test Pieces. For initial sample approval and arbitration purposes, at least five (5) test pieces cut from at least two components shall be tested, for routine quality control purposes at least fiv
12、e (5) test pieces shall be tested. 3.4 Test Time. Not applicable. 3.5 Test Required Information. Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. 4.1.1 Test Sample Preparation The surface of the test pieces shall be cleaned with ethanol before conditioning. Before m
13、easurement, the test pieces shall be conditioned for 48 h minimum to GMW3221 Code A. 4.2 Conditions. 4.2.1 Environmental Conditions. Not applicable. 4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been agreed upon. Such requirements shall be specified on component
14、 drawings, test certificates, reports, etc. 4.3 Instructions. 4.3.1 Test Procedure The test pieces are positioned between two (2) electrodes of 10 mm 0.1 mm 10 mm 0.1 mm and, to avoid air inclusions, a pressure force of 0.2 N/cm2 0.02 N/cm2 is applied. The specific volume resistance shall be measure
15、d in an atmosphere to GMW3221 Code A or within 10 minutes of being removed from this atmosphere. (Test pieces may be transported in a conditioned desiccator.) The volume resistance is measured according to IEC 60093. The preferred test voltage is 100 V (volts). If the test voltage differs this fact
16、shall be stated along with the actual value of the voltage. 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. Not applicable. 5.3 Test Documentation. 5.3.1 Evaluation and Rating. The specific volume resistance in ohms centimeter (cm) shall be calculated per 5.3.1.1, and 5.3.1.2
17、. 5.3.1.1 Test pieces with 11 mm minimum edge length in both directions: Rx daxR Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14711 Co
18、pyright 2012 General Motors Company All Rights Reserved December 2012 Page 3 of 5 Where: Rx = Specific Volume Resistance in ohms centimeter (cm) R = Volume resistance, measured in ohms () a = Length of measuring electrode in centimeters (cm) d = Test piece thickness in centimeters (cm) 5.3.1.2 Test
19、pieces with width less than 11 mm: d baRRx Where: Rx = Specific Volume Resistance in ohms centimeter (cm) R = Volume resistance, measured in ohms () a = Length of measuring electrode in centimeters (cm) b = Width of test piece in centimeters (cm) d = Test piece thickness in centimeters (cm) 5.3.2 Re
20、port. 5.3.2.1 The specific volume resistance shall be expressed as the range of the values determined, in ohms centimeter (cm). The values shall be expressed in scientific notation to two significant figures. 5.3.2.2 With reference to this test procedure, the results shall be represented in a test r
21、eport. The report shall include the following: Complete identification of the specimen. Conditioning of the test specimen. Test conditions. Specific volume resistance values, in ohms centimeter (cm). Test voltage applied. Any deviations to the test method. 6 Safety This standard may involve hazardou
22、s materials, operations, and equipment. This standard does not propose to address all the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prio
23、r to use. 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. cm Centimeter IEC International Electrotechnical Commission V Volts Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitte
24、d without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14711 Copyright 2012 General Motors Company All Rights Reserved December 2012 Page 4 of 5 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW14711 Example: Specific Volume R
25、esistance to GMW14711 106 ohms centimeter (cm) minimum 9 Release and Revisions This standard was originated in October 2005. It was first approved by the Rubber Technical Development Group in December 2006. It was first published in February 2007. Issue Publication Date Description (Organization) 1
26、FEB 2007 Initial publication. 2 DEC 2012 5 Year Revision. Revised Section 3. Added Appendix A. (Elastomers Global Subsystem Leadership Team) Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license
27、 from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14711 Copyright 2012 General Motors Company All Rights Reserved December 2012 Page 5 of 5 Appendix A Figure A1: Equipment for Clamping and Measuring Device Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
