1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW15680 Bowed Panel Test Method, Low Angle Stress Copyright 2013 General Motors Company All Rights Reserved June 2013 Page 1 of 6 1 Scope Note: Nothing in this standard supercedes applicable laws and regulations. Note: In the event of conflict between
2、 the English and domestic language, the English language shall take precedence. 1.1 Purpose. This standard describes a test procedure to determine the dynamic shear strength of double sided acrylic foam tape used for bonding moldings, claddings, wheel flares, etc., to approved current exterior autom
3、otive paint systems. 1.2 Foreword. Not applicable. 1.3 Applicability. All vehicles. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. None 2.2 GM Standards/Specifications. GMW14665 3 Resources 3.1 Facilities. Not a
4、pplicable. 3.1.1 Calibration. The test facilities and equipment shall be in good working order and shall have a valid calibration label. 3.1.2 Alternatives. Alternative test facilities and equipment may also be used. However, all measuring variables as specified in this standard shall be determined
5、correctly with respect to their physical definition. 3.2 Equipment. 3.2.1 Panels with dimensions of 305 mm x 51 mm and no thicker than 1.65 mm. Panels shall be prepared from cold rolled steel (CRS) panels, painted on one side with the current exterior paint system, and from chromic acid etched anodi
6、zed aluminum. Each test sample will require one painted substrate and one anodized aluminum substrate. 3.2.2 Chromic acid etched anodized aluminum bar (per GMW14665 Type DET), 12.7 mm x 228.6 mm and 1.27 mm thick, fabricated from 24ST3 AA2024-T3 aluminum. 3.2.3 Mechanical roller 6.8 kg (15 lb) weigh
7、t. 3.2.4 Bowed test fixture. See Appendix A. 3.2.5 Aluminum bar centering guide. 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 GMW15680 Co
8、pyright 2013 General Motors Company All Rights Reserved June 2013 Page 2 of 6 3.3 Test Vehicle/Test Piece. Tape to be tested 12.7 mm width. 3.4 Test Time. Calendar time: 2 to 5 days Test hours: 1 to 72 hours Coordination hours: Not applicable hours 3.5 Test Required Information. Not applicable. 3.6
9、Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. 4.1.1 All samples are to be conditioned at 23 C 2 C before and during testing unless otherwise specified. 4.1.2 Clean the test substrates with a 1:1 mixture of isopropyl alcohol and distilled water. Wipe and dry thoroughly with a clean c
10、loth or tissue. 4.1.3 Apply tape non-liner side to anodized aluminum test bar. 4.1.4 Roll one time with a 6.8 kg (15 lb) roller. 4.1.5 Slide panel into the aluminum strap centering guide. This is used for alignment only. See Figure A1. 4.1.6 Place aluminum strap in center of paint panel using the ce
11、ntering guide. Start at one end of the opening and guide the aluminum strap into place so that it lays flat against the guide. 4.1.7 Remove guide and roll down with a 6.8 kg (15 lb) roller, down and back. (Two (2) passes.) 4.1.8 Mark the paint panel on both sides at the end edge of the aluminum stra
12、p with a fine line marker. This line will be a reference point for measuring the length of the peel. See Figure A2. 4.1.9 Condition the specimen for 24 h at 23 C 2 C or as requested in the specification. 4.2 Conditions. 4.2.1 Environmental Conditions. All samples are to be conditioned at 23 C 2 C be
13、fore and during testing unless otherwise specified. 4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been agreed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 4.3 Instructions. 4.3.1 Remove the side of the fixtur
14、e with the red screws. Starting at the stop pen bend the panel and slide it under the lip of the remaining side. Make sure that it is firmly in place. Replace the side and start screwing it down tightly. Do both ends then the middle to hold the sample in place. Place the fixture in the rack provided
15、 and condition accordingly. See Figure A3. 4.3.2 How to Take Measurements. 4.3.2.1 Measurements should be taken before the test begins and after 1 h, 2 h, 4 h, 8 h, 24 h, 48 h and 72 h increments. All measurements should be recorded in a spread sheet. See Figure A4. 4.3.2.2 Height is measured by det
16、ermining the distance from the paint panel where the marks were placed to the bottom of the end of each aluminum strap. Using a metric (millimeter) ruler, place the ruler flat against the panel at each end of the bar on the mark referenced in 4.1.8, and measure the distance to the bottom of the alum
17、inum bar. Record this measurement. See Figure A5. 4.3.2.3 Peel length is measured from the end of each bar to the location where lifting of the tape from the paint panel begins. If no lifting occurs, record zero (0). If lifting occurs, slide the ruler into the gap and measure the distance from the b
18、eginning of the peel to the mark signifying the end of the aluminum bar. Any lifting is measured and marked. Cohesive failure (foam split) of the tape core is not measured or considered a failure. If cohesive failure has occurred, measure the distance from the onset of foam split to the mark signify
19、ing the end of the aluminum bar. See Figure A6. 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 GMW15680 Copyright 2013 General Motors Compa
20、ny All Rights Reserved June 2013 Page 3 of 6 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. Not applicable. 5.3 Test Documentation. Report test conditions, material (tape) identification, height and length at the specified times; failure mode, and any observations. 6 Safety
21、This standard may involve hazardous 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 applicabil
22、ity of regulatory limitations prior to use. 7 Notes 7.1 Glossary. Foam Split: Cohesive failure of the tape core. 7.2 Acronyms, Abbreviations, and Symbols. CRS Cold rolled steel DET Decorative, Exterior, Transparent 8 Coding System This standard shall be referenced in other documents, drawings, etc.,
23、 as follows: Test to GMW15680 9 Release and Revisions This standard was originated in September 2007. It was first approved by the Trim Adhesives Team in June 2008. It was first published in June 2008. Issue Publication Date Description (Organization) 1 JUN 2008 Initial publication. 2 JUN 2013 Refre
24、sh. (Adhesives 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 from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15680 Copyright 2013 General Motors Comp
25、any All Rights Reserved June 2013 Page 4 of 6 Appendix A Figure A1: Alignment Fixture This fixture is used to align the aluminum bar correctly on the panel. Figure A2: Panel Marking Shows where to mark the panel. Mark both ends of the panel to have a reference point for measurements taken later. Fig
26、ure A3: Bowed Panel Fixture Initial Setup What the Bowed Panel Fixture should look like after initial setup. 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 ENGIN
27、EERING STANDARDS GMW15680 Copyright 2013 General Motors Company All Rights Reserved June 2013 Page 5 of 6 Figure A4: Tested Sample Ready for Measurements Measurements should be taken at each end. Figure A5: Measuring Height The height measurement taken from the reference point to bottom of aluminum
28、bar. 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 GMW15680 Copyright 2013 General Motors Company All Rights Reserved June 2013 Page 6 of 6 Figure A6: Measuring Peel Length Take measurement from reference point to start of peel front (any lifting means failure). Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
