1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW4750 Color Read-Through of Automotive Fabrics Copyright 2011 General Motors Company All Rights Reserved September 2011 Originating Department: North American Engineering Standards Page 1 of 2 1 Scope Note: Nothing in this standard supercedes applica
2、ble 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 test standard is used to assess the ability to see through automotive textile materials. 1.2 Foreword. Not applicable. 1.3 Applicability.
3、This procedure applies to automotive fabrics. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ISO 105/A02 2.2 GM Standards/Specifications. GMW3221 3 Resources 3.1 Facilities. Not applicable. 3.2 Equipment. 3.2.1
4、Color Machine. Spectrophotometer capable of CIELAB measurements with a 10 degree standard observer, a D65 or C standard illuminate, and an orifice size between 10 and 30 mm. The acceptable machine geometries are 45 degree/normal 45/0, normal/45 degree 0/45, diffused/normal d/0, or normal/diffused 0/
5、d. If a diffuse geometry instrument is used, the specular component of reflectance shall be excluded from the measurement. The angle between the sample normal and the illuminating beam in 0/d geometry, and the angle between the sample normal and the viewing beam in d/0 geometry, shall not exceed 10
6、degrees. Note: Normally, the larger the orifices size the better. However, in cases where the test specimen has a large pattern, select an orifice size which allows the taking of readings over all colors of the pattern. 3.2.2 Cutting dies or shears for preparation of test specimens. 3.2.3 Apparatus
7、for conditioning to the appropriate requirements as described in GMW3221 - Code A, unless otherwise specified in the relevant materials specification. 3.3 Test Vehicle/Test Piece. 3.3.1 Black and White Standard Backings. The white standard backing, when measured using the equipment specified in 3.2.
8、1 with the specular component excluded, shall have an L value greater than 90 where L = Luminosity. The black standard backing, when measured in the same way, shall have an L value of less than 20. The size of these standard backings must be larger than the orifice being used. 3.4 Test Time. Calenda
9、r time: 2 days Test hours: 1 hour Coordination hours: 0 hour 3.5 Test Required Information. Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. 4.1.1 At least one test specimen, 100 5 x 100 5 mm shall be prepared. Note: Specimen size is not critical providing measureme
10、nt can be properly taken. 4.1.2 Unless otherwise specified in the relevant material specification, conditioning shall be performed according to GMW3221 - Code A. 4.2 Conditions. 4.2.1 Environmental Conditions. 4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been a
11、greed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 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 ENGINEERI
12、NG STANDARDS GMW4750 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 2 of 2 4.3 Instructions. 4.3.1 Place the show surface of the test specimen over the orifice. 4.3.2 Place the white standard backing over the test orifice and on top of the test specimen and read the L
13、value. Note: Be sure that there is no space between the test specimen and the standard backing when measuring. 4.3.3 Without moving the test specimen, place the black standard backing over the orifice and read the L value again. Note: Be sure that there is no space between the test specimen and the
14、standard backing when measuring. 4.3.4 Repeat the above procedure as many times as necessary to achieve an accurate representation of the materials pattern. 4.3.5 Visually compare the fabric over each of the standards (black standard and white standard) to the ISO international Standard gray scale I
15、SO 105/A02. 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. Visually compare the fabric over each of the standards (black standard and white standard) to the ISO International Standard gray scale ISO 105/A02. The minimum acceptable value is 4.5. 5.3 Test Documentation. 5.3.1
16、Report the largest difference (dL) found as a result of the difference in the measurements obtained in 4.3.2, 4.3.3, and 4.3.4. If there is a pattern in the fabric, describe the area tested which yielded that result. 5.3.2 Report the most equivalent ISO Gray scale value as observed in 4.3.5. 5.3.3 D
17、eviations. Deviations from the conditions of this standard shall have been agreed upon between supplier and vehicle manufacturer. All deviations shall be specified on the component drawings, material specifications, etc, and shall be indicated on test certificates, reports, etc. 6 Safety This standa
18、rd 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 applicability of regu
19、latory limitations prior to use. 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. CIELAB Color Space Coordinates dL Largest Difference ISO International Organization for Standardization L Luminosity TDG Textile Development Group 8 Coding System This standard shall be r
20、eferenced in other documents, drawings, etc., as follows: Test to GMW4750 9 Release and Revisions This standard was originated in August 2000. It was first approved by the Global Textile Development Group (TDG) in January 2001. It was first published in April 2001. Issue Publication Date Description
21、 (Organization) 1 APR 2001 Initial publication. 2 SEP 2005 This test method was updated in May 2005 and was approved during the Global Textile Development Group Conference at GMNA in May 2005. 3 SEP 2011 Five year refresh. (Textile 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-,-,-
