1、WORLDWIDEENGINEERINGSTANDARDSTest Procedure GMW14829Tape Adhesion Test for Paint Finishes Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Originating Department: North American Engineering Standards Page 1 of 91 ScopeNote: Nothing in this standard supercedes applicable laws and
2、 regulations.Note: In the event of conflict between the English and domestic language, the English language shall takeprecedence.1.1 Purpose. This standard specifies the test method to be used to evaluate the adhesion properties ofpainted metal, plastic and sealer before and after environmental test
3、ing. This standard describes thecrosshatch and the “X” cut tape adhesion test using the cutting tools or cutting guide. All paint systems mustmeet the adhesion requirements when the appropriate method is used. Unless otherwise specified, the dry filmthickness will determine which guide or tool is re
4、quired. If either method is not usable due to size and/or shapeconstraints (typically found in small parts) the application of this test will be at the discretion of the responsibleengineer.1.2 Foreword. Not applicable.1.3 Applicability. Evaluation of the adhesion properties of painted metal, plasti
5、c and sealer before and afterenvironmental testing.2 ReferencesNote: Only the latest approved standards are applicable unless otherwise specified.2.1 External Standards/Specifications.ASTM D3330M ASTM D3759MASTM D3652M2.2 GM Standards/Specifications.None3 Resources3.1 Facilities. Not applicable.3.2
6、Equipment.3.2.1 Pressure Sensitive Adhesion Tape. It is extremely important that the tape adhesively bonds to steelaccording to ASTM D3330M with a minimum 180 degree peel strength value of 760 N/m. Weaker adhesiveswill reduce the severity of the test results. The tape backing should exhibit low elon
7、gation. The variousparameters of the recommended tape are described in 3.2.1.1 thru 3.2.1.4.3.2.1.1 Nominal Dimensions.x Width, 20 mm minimumx Thickness, total ASTM D3652M, 0.14 mm3.2.1.2 Properties.x Peel strength, steel ASTM D3330M, 760 N/m minimumx Elongation ASTM D3759M, 5% maximum3.2.1.3 Shelf
8、Life.x Twelve (12) months maximum.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 GMW14829 Copyright 2012 General Motors Company All Rights
9、ReservedOctober 2012 Page 2 of 93.2.1.4 Recommended Products.x 3M8981x 3M898x Or equivalent3.2.2 Sharp razor knife, retractable carbide cutter by Reider (Swiss) Rico Marker, cutting tool by Gardco orBYK Gardner crosscut tester.3.2.3 Cutting guide at 1 mm, 2 mm and 3 mm.3.2.4 Rubber eraser or equival
10、ent instrument for applying tape.3.2.5 Stiff pencil brush.3.3 Test Vehicle/Test Piece.3.3.1 Test Material. The test pieces wherever possible shall be the finished part. If size, shape, etc., of thefinished part is impracticable, tests shall be conducted on specially prepared coated test panels.3.4 T
11、est Time. Not applicable.3.5 Test Required Information. Not applicable.3.6 Personnel/Skills. Not applicable.4 Procedure4.1 Preparation. The adhesion of organic coatings as determined by this test method shall be defined as thetendency of the coating to become detached in the vicinity of scribed line
12、s. Method A will be scribed in theshape of a lattice pattern and Method B will be scribed in an “X” pattern. Both methods require cutting throughthe coating, before and after exposure to defined environmental conditions. Use sharp blades, as dull bladestend to cause chatter and can result in lower r
13、atings.4.2 Conditions. Parts in the as received conditions should be clean and dry before conducting the test. Oil,wax or any residue in the painted surface shall be removed with soap and water or any other cleaner. Dry thesamples by blotting with an absorbent paper or cloth.4.2.1 Environmental Cond
14、itions.4.2.1.1 When specified, the coated test specimens shall be subjected to an environmental test, such as waterimmersion, humidity or salt spray test, etc., before conducting the tape adhesion test. In this case, conduct theenvironmental test as required and dry samples by blotting with an absor
15、bent paper or cloth.4.2.1.2 Select a representative area or an area suspected of having poor film adhesion on the paint surface tobe tested. Do not select sagged, solvent popped or obviously defective areas, as these defects should berated separately.4.2.1.3 The recovery time after exposure to envir
16、onmental cycle tests and before tape adhesion tests shall be1 h unless otherwise specified.4.2.1.4 Multiple tape adhesion tests may be required (minimum of three) depending on approval requirementsand space permitting. Larger parts will require more space. Geometric configuration and processingchara
17、cteristics should be considered.4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been agreed upon. Suchrequirements shall be specified on component drawings, test certificates, reports, etc.4.3 Instructions.4.3.1 Test Procedure, Method A.4.3.1.1 The crosshatch/cutt
18、ing tool should be inspected prior to use and replaced if any damage is observed.The crosshatch/cutting tool should be replaced if any inconsistencies in the scribe installation are observed.4.3.1.2 Make a crosshatch cut with a sharp cutting tool or guide as shown in Figure A1. The number of linesan
19、d spacing between the lines shall depend upon the coating film thickness as shown in Table A1. Make allcuts approximately 20 mm long. Cut through the film in one steady motion using just sufficient pressure on thecutting tool to have the cutting edge reach the substrate. When making successive singl
20、e cuts with the aid of aguide, place the guide on the uncut area and cut through the film to the substrate. Make similar type andnumber of cuts perpendicular and centered on the original cuts.Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo r
21、eproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14829 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 3 of 94.3.1.3 After making the required cuts, brush the film lightly with a soft bristle brush or tissue to remove a
22、nydetached flakes or ribbons of coating.4.3.1.4 Dispense or cut a strip of tape approximately 75 mm long being careful not to allow the adhesive sideto come in contact with anything before the test application. Place the center of the tape over the grid so thatthe tape covers the crosshatch diagonal
23、ly.4.3.1.5 Press the tape down firmly on the surface with sufficient rubs of the eraser to remove air bubbles andto insure good contact between the tape and paint surface.4.3.1.6 After 5 s to 10 s, grasp the tail end of the tape between thumb and forefinger and pull upward with arapid jerking motion
24、 perpendicular to the paint film.4.3.1.7 Rate the adhesion performance as shown in Figure A2, and description of performance using the keyin Table A2. Paint adhesion should be reviewed on both the part and the tape.4.3.2 Test Procedure, Method B.4.3.2.1 The scribe/cutting tool should be inspected pr
25、ior to use and replaced if any damage is observed. Thescribe/cutting tool should be replaced if any inconsistencies in the scribe installation are observed.4.3.2.2 With a sharp pointed razor knife, cut an “X” consisting of two bisecting lines each approximately 75 mmlong, through the paint film to t
26、he substrate as shown in Figure A3. If the area to be tested on the paintedsample is less than the standard tape test area, then the application of this test will be at the discretion of theresponsible engineer. If utilized, report the percentage area remaining on the surface as shown in Figure A4.W
27、hen cutting, hold knife perpendicular to the surface and avoid any side motion. For relatively soft substrates,such as plastics and sealers, avoid cutting so deeply that the substrate is displaced.4.3.2.3 After making the required cuts, brush the film lightly with a soft bristle brush or tissue to r
28、emove anydetached flakes or ribbons of coating.4.3.2.4 Dispense or cut a strip of tape approximately 125 mm to 150 mm long being careful not to allow theadhesive side to come in contact with anything before the test application.4.3.2.5 Cover the “X” with tape so that the tape is centered over the in
29、tersection and extends for at least38 mm on both sides of the intersection in the direction of approximately the 25 degree angles. The remaining50 mm to 75 mm of tape provides a loose tail on one end to grasp when removing tape.4.3.2.6 Press the tape down firmly on the surface with sufficient rubs o
30、f the eraser to remove air bubbles andto insure good contact between the tape and paint surface.4.3.2.7 After 5 s to 10 s, grasp the tail end of the tape between thumb and forefinger and pull upward with arapid jerking motion perpendicular to the paint film.4.3.2.8 Estimate the percentage area of pa
31、int not removed by the tape test area of 20 mm x 75 mm(1500 mm2) as shown in Figure A5. Paint adhesion should be reviewed on both the part and the tape.5 Data5.1 Calculations. Not applicable.5.2 Interpretation of Results. Not applicable.5.3 Test Documentation.5.3.1 Report: Method A. Record the tape
32、adhesion rating as shown in Figure A2.5.3.1.1 Record the failure mode indicating where the failure occurred, that is, within substrate, between firstcoat and substrate, between first and second coat, etc.5.3.1.2 Submit both painted sample and tape for review. Tape should be submitted on an overhead
33、(acetatefilm). The tape should never be placed back on the sample.5.3.2 Report: Method B. Record the tape adhesion rating as the percentage of area of paint remaining asshown in Figure A5, and the type of removal as shown in Figure A6.5.3.2.1 Record the failure mode indicating where the failure occu
34、rred, that is, within substrate, between firstcoat and substrate, between first and second coat, etc.5.3.2.2 Submit both painted sample and tape for review. Tape should be submitted on an overhead (acetatefilm). The tape should never be placed back on the sample.Copyright General Motors Company Prov
35、ided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14829 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 4 of 96 SafetyThis standard may involve hazar
36、dous materials, operations, and equipment. This standard does not propose toaddress all the safety problems associated with its use. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and determine the applicability of regulatory limitations pri
37、orto use.7 Notes7.1 Glossary. Not applicable.7.2 Acronyms, Abbreviations, and Symbols. Not applicable.8 Coding SystemThis standard shall be referenced in other documents, drawings, etc., as follows:Test to GMW148299 Release and RevisionsThis standard was originated in November 2005. It was first app
38、roved by Paint in September 2006. It was firstpublished in October 2006.Issue Publication Date Description (Organization)1 OCT 2006 Initial publication.2 JAN 2011 Removed regional standard references and made minimal changes tocontent. (Global Paint and Polymers Center).3 OCT 2012 Added a new 4.3.1.
39、1 and 4.3.2.1 and renumbered existing paragraphs(obtained email approval from Global Paint and Polymers Center forchanges and to publish and approve document through GlobalCorrosion GSSLT). (Corrosion GSSLT)Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot
40、 for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14829 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 5 of 9Appendix AFigure A1: Crosshatch Test (Method A)Table A1: Cutter Spacing for Test Method AFilm T
41、hickness(microns)Spacing(millimeters)Number of Cuts(In each direction) 60 1 660 to 200 2 6 200 3 6Copyright 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 STAN
42、DARDS GMW14829 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 6 of 9Figure A2: Adhesion Performance for Test Method A (Crosshatch)Table A2: Rating Scale Key for Test Method A (Crosshatch)Surface of crosscutarea from whichflaking has occurredRating(classification)None0 1 2
43、 3 4Greaterthan65%5Rating Description0 The edges of the cuts are completely smooth; none of the squares of the lattice isdetached.1 Detachment of small flakes of the coating at the intersections of the cuts.Across cut area of 5% maximum is affected.2 The coating has flaked along the edges and/or at
44、the intersections of the cuts.Across cut area of 5% minimum but 15% maximum.3The coating has flaked along the edges of the cuts partly or wholly in large ribbons,and/or it has flaked partly or wholly on different parts of the squares.Across cut area of 15% minimum but 35% maximum is affected.4The co
45、ating has flaked along the degrees of the cuts in large ribbons and/or somesquares have detached partly or wholly.Across cut area of 35% minimum but 65% maximum is affected.5 A crosscut area of 65% is affectedCopyright General Motors Company Provided by IHS under license with General Motors CompanyN
46、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14829 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 7 of 9Figure A3: X-Cut Test (Method B)Figure A4: X-Cut Test Small Area (Method B)Copyright General
47、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 GMW14829 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 8 of 9Figure A5: Adhesion
48、Performance for Test Method B (X-Cut)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 GMW14829 Copyright 2012 General Motors Company All Righ
49、ts ReservedOctober 2012 Page 9 of 9A - Paint removed along knife cut evenlyB - Paint removed in the “V” section of the knife cutC - Paint removed in a “Patch not Touching” knife cutD - Paint Removed in a “Patch Touching” knife cutFigure A6: Type of RemovalCopyright General Motors Company Provided by IHS under license with General Motors CompanyN
