1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW16687 Shrinkage of Heat-Bonding Sheet-Form Materials Copyright 2011 General Motors Company All Rights Reserved October 2011 Originating Department: North American Engineering Standards Page 1 of 3 1 Scope Note: Nothing in this standard supercedes ap
2、plicable laws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Purpose. This procedure describes a method for determining the shrinkage of materials during baking. 1.2 Foreword. Not applicable. 1.3 Applicabilit
3、y. This test procedure applies to sheet-form materials which are applied to the body on the paint shop sealer line and baked through the Primer Oven (traditional paint shops) or through the Sealer Oven (compressed process paint shops). Typical materials include floor pan vibration dampers and floor
4、pan plug sealers. The shrinkage measured is that in the plane of the material only; thickness changes are not evaluated. The results obtained are for unrestrained shrinkage of the material and are not representative of values experienced in actual use when the material bonds to a restraining surface
5、. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. None 2.2 GM Standards/Specifications. None 2.3 Additional References. None 3 Resources 3.1 Facilities. Not applicable. 3.2 Equipment. 3.2.1 Oven. Forced-air, circ
6、ulating-type oven, capable of maintaining a set temperature within 3 C. 3.2.2 Measuring Scale. Measuring scale with 1 mm increments. 3.3 Test Piece. All dimensions are as specified below, unless otherwise specified or agreed upon by the GM approving engineer. 3.3.1 Test Material. Samples of the mate
7、rial to be evaluated, sufficient to make three (3) pieces, each 100 x 100 mm. 3.3.2 Release Agent. Use one of the following: Talcum powder or release paper. 3.3.3 Metal Panel. Electrocoated (ELPO) sheet metal panel large enough to fit three (3) test samples. 3.4 Test Time. Calendar time: 1 day Test
8、hours: 2 hours Coordination hours: 1 hour Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16687 Copyright 2011 General Motors Company All Rights Reserved October 2011 Page 2 of 3 3.5 Test Required Information. No
9、t applicable. 3.6 Personnel/Skills. Trained lab technician or test engineer. 4 Procedure 4.1 Preparation. Cut three (3) samples, each 100 x 100 mm. Two (2) edges must be parallel to machine direction, and this orientation must be marked on each sample. 4.2 Conditions. 4.2.1 Environmental Conditions.
10、 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 drawings, test certificates, reports, etc. 4.3 Instructions. 4.3.1 Dust the ELPO panel liberally with talcum powder. Apply enough t
11、alcum powder so that the test samples remain totally unbonded from the ELPO panel through the bake process. Alternately apply release paper. 4.3.2 Place the test samples on the dusted panel and bake according to the material specification. If no bake is specified, use the appropriate maximum bake as
12、 specified in Table 1. Table 1: Bake Conditions Note 1 Paint Shop Type For Materials That Bake in This Oven Use This Maximum Bake Traditional Paint Shops Primer Surfacer Oven Low Bake 90 minutes at 158 C Primer Surfacer Oven High Bake 60 minutes at 180 C Primer Surfacer Oven Powder Bake 60 minutes a
13、t 190 C Compressed Process Paint Shops Sealer Oven 20 minutes at 163 C Note 1: All bakes are specified as times at metal temperature. 4.3.3 Allow to cool. Check that the samples are totally unbonded from the panel. If any bonding exists, repeat the baking process using new samples and a heavier dust
14、ing of talcum powder or a different release paper. 4.3.4 Measure the X (machine direction) and the Y dimensions of the baked samples. Make the measurements at the center of the sample. Sum the three measurements in each direction: X and Y 5 Data 5.1 Calculations. Calculate the shrinkage in each (X a
15、nd Y) direction: % X Shrinkage = (300 X) / 300) x 100% % Y Shrinkage = (300 Y) / 300) x 100% 5.2 Interpretation of Results. Not applicable. 5.3 Test Documentation. Report the percent (%) shrinkage in the X (machine direction) and Y directions. 6 Safety This standard may involve hazardous materials,
16、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 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING ST
17、ANDARDS GMW16687 Copyright 2011 General Motors Company All Rights Reserved October 2011 Page 3 of 3 establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 7 Notes 7.1 Glossary. Machine Direction: The direction of the material paralle
18、l to the direction of extrusion. 7.2 Acronyms, Abbreviations, and Symbols. ELPO Electrodeposition or Electrocoat 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW16687 9 Release and Revisions This standard was originated in September 2011. It was first approved by the Paint Acoustic Damper Team in October 2011. It was first published in October 2011. Issue Publication Date Description (Organization) 1 OCT 2011 Initial publication. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
