1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW16745 Water Jet Tests Copyright 2012 General Motors Company All Rights Reserved March 2012 Originating Department: North American Engineering Standards Page 1 of 4 1 Scope This standard describes the test method to test the ability of exterior graph
2、ics (decals) or painted plastics to withstand high pressure wand car wash spray. The procedure can also be applied to other materials such as paint, ornamentation, etc. Unless indicated otherwise, use Method A. Note: Nothing in this standard supercedes applicable laws and regulations. Note: In the e
3、vent of conflict between the English and domestic language, the English language shall take precedence. 1.1 Purpose. The purpose of this test is to evaluate the adhesion of graphics or paint to the substrate after exposure to high pressure water spray, such as those used at a car wash. 1.2 Foreword.
4、 Not applicable. 1.3 Applicability. This test applies to exterior components such as painted plastic components and exterior graphics. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. None 2.2 GM Standards/Specifi
5、cations. None 2.3 Additional References. None. 3 Resources 3.1 Facilities. Not applicable. 3.2 Equipment. 3.2.1 Test Apparatus. 3.2.1.1 Car wash unit of such design and construction as to maintain a minimum pressure (at gun tip) of 8247 kPa (1200 psi) for a minimum period of 5 s, with gun tip fan an
6、gle of 15 and/or 25. 3.2.1.2 Rack or fixture that will support a test panel at a 75 mm to 200 mm distance from tip and film edge, and at a 45 to 90 angle of film to water spray. Distance and angle should be adjustable. 3.2.1.3 Cutting jig that facilitates making 90 cuts into the film with a razor bl
7、ade. 3.3 Test Vehicle/Test Piece. Not applicable. 3.4 Test Time. Not applicable. 3.5 Test Required Information. Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. Not applicable. 4.2 Conditions. 4.2.1 Environmental Conditions. Copyright General Motors Company Provided
8、 by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16745 Copyright 2012 General Motors Company All Rights Reserved March 2012 Page 2 of 4 4.2.2 Test Conditions. Deviations from the
9、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 Test Procedure. 4.3.1.1 Method A - for External Graphics. 4.3.1.1.1 Clean a 51 mm x 305 mm painted test panel with VM and P
10、Naphtha or 50/50 water-isopropyl alcohol. 4.3.1.1.2 Apply a 25 mm x 203 mm decal using a 2 kg roller; two passes, once in each direction at a rate of 305 mm per minute. 4.3.1.1.3 Cut the decal with a razor blade in a series of cuts on a 45 angle spaced 12.7 mm apart. The cutting process is repeated
11、with 45 angle cuts made in the opposite direction so that finished cuts form 12.7 mm squares and triangles (Figure 1). The cuts must be made straight down into the film (90 angle). A cutting jig will facilitate this cutting process. Figure 1: Method A 4.3.1.2 Method B - for Painted Plastics. 4.3.1.2
12、.1 Clean a 51 mm x 102 mm (or larger) painted test panel or part with VM and P Naphtha or 50/50 water - isopropyl alcohol. 4.3.1.2.2 Cut two intersecting sets of 21 vertical and 6 horizontal parallel cuts through the coating to the substrate. Parallel cuts are to have 3 mm spacing, intersection angl
13、es of 90, and are to be at 90to the specimen edge. See Figure 2. Figure 2: Method B 4.3.1.3 Methods A and B. 4.3.1.3.1 Unless otherwise specified, painted samples shall be subjected to the testing after a minimum aging period of 72 h following the baking or drying cycle. A shorter aging period may b
14、e used, provided it is recognized that this represents a more severe condition of test and that results obtained at different aging times under 72 h are not a good basis for comparing the relative performance characteristics of paint finishes. 4.3.1.3.2 Condition panel for 20 minutes at room tempera
15、ture or as required. S c r i b e P a tt e r nCopyright 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 GMW16745 Copyright 2012 General Motors Company
16、All Rights Reserved March 2012 Page 3 of 4 4.3.1.3.3 Test run parameters shown in Table 1. Table 1:Test Parameters Method A Method B Pressure (at nozzle outlet) 8500 kPa 340 kPa (1232 psi 50 psi) 8274 kPa 340 kPa (1200 psi 50 psi) Fan Angle 15 25 Water Temperature Room Temperature Room Temperature N
17、ozzle to Specimen Distance 200 mm 75 mm Angle of Impingement 45 90 Specimen Scribe Pattern Figure 1 Figure 2 Temperature of Test Specimen Room Temperature (RT) Room Temperature (RT) Duration of Impingement 5 s 5 s Nozzle Oscillation None None Performance Measurement Rating mm2 paint removed 5 Data 5
18、.1 Calculations. Not applicable. 5.2 Interpretation of Results. Not applicable. 5.3 Test Documentation. 5.3.1 Evaluation and Rating. 5.3.1.1 Evaluation of Test Specimens. 5.3.1.1.1 Method A - for Exterior Graphics. After the test is run on duplicate film samples, each affected square or triangle is
19、assigned a value of 1, 2, or 3: 1 = Small area if adhesion loss is 3 mm or less 2 = Any amount of adhesion loss more than 3 mm but short of complete removal of square triangle 3 = Complete removal of square or triangle The numerical ratings given each effected area are totaled for each film strip an
20、d divided by ten. That number is the rating. 5.3.1.1.2 Method B - for Painted Plastics. After the test is run in triplicate, total area (mm2) of paint removed both inside and outside of the scribed area. Each scribed square is 9 mm2. 5.4 Report. 5.4.1 Method A for Exterior Graphics. The report shall
21、 include the following: 5.4.1.1 Rating. 5.4.1.2 Applied panel conditioning. 5.4.1.3 Film construction. 5.4.1.4 Water temperature. 5.4.1.5 Decal supplier. 5.4.1.6 Paint system. 5.4.2 Method B - for Painted Parts. Copyright General Motors Company Provided by IHS under license with General Motors Compa
22、nyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16745 Copyright 2012 General Motors Company All Rights Reserved March 2012 Page 4 of 4 5.4.2.1 For each of the three samples, report area (square millimeters) of paint removed.
23、Also, report average area of paint removed for the three samples (square millimeters). 5.4.2.2 Substrate supplier and designation. 5.4.2.3 Paint System supplier and designation. 5.4.2.4 Any substrate deformation. 5.4.3 Control. A control should be always run unless otherwise specified. 6 Safety This
24、 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 applicability
25、of regulatory limitations prior to use. 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. RT Room Temperature VM and P Varnish Makers and Painters 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW16745 9 Releas
26、e and Revisions This standard was originated in December 2011. It was first approved by the Finishes & Coatings Global Subsystem Leadership Team in March 2012. It was first published in March 2012. Issue Publication Date Description (Organization) 1 MAR 2012 Initial publication. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
