1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW16554 2K Urethane Monocoat for Chrome-Plate Copyright 2011 General Motors Company All Rights Reserved August 2011 Originating Department: North American Engineering Standards Page 1 of 4 1 Scope This specification covers the requirements of
2、a two-component (2K) urethane monocoat used on chrome plate, exterior vehicle applications. These requirements cover part performance and general process methods for ensuring long-term integrity of the coating system. 1.1 Material Description. The paint is a 2K urethane monocoat used over chrome-pla
3、ted, exterior vehicle applications. This specification is in reference to 2K urethane monocoat paints that are pigmented. It does not pertain to paints where the intent is to clearcoat or tint. These paints are designed specifically for obtaining excellent adhesion and weatherability to chrome-plate
4、d surfaces. All qualified paint systems used for this application shall meet GMW3005 generic topcoat performance requirements. In addition, supplemental test requirements listed in Table A1 are required. Paint systems that meet these requirements can utilize a primer or be single-coat applications.
5、This specification does not apply to paint systems designed to be applied over resist coats. Although these paints can be applied over resist coats, 9984255 covers resist and topcoat applications specifically. Any paint in contact with chrome shall meet the requirements of this specification. This a
6、lso applies to parts with a combination of resist coating and paint on chrome. 1.1.1 Although primarily intended for use on chrome-plated plastics, this 2K urethane monocoat paint may be qualified for use on other substrates, such as metal. The final surface must be chromium-plated. 1.1.2 These coat
7、ings are part of a total painted product system and must meet the requirements set forth in this specification and those shown on engineering drawings. Approved Paint on Parts Specification (APOPS) GMW14797 is required. APOPS requirements are specific to any given combination of plastic substrates,
8、chrome finish, physical plating line and physical painting line. APOPS submissions shall also include supplemental testing listed in Table A1. 1.2 Symbols. Not applicable. 1.3 Typical Applications. Typical applications are grille black-out areas and emblems. Paint on chrome is generally used for cos
9、t savings when compared to resist and topcoat. In other cases, a two-part component construction may be used with one piece being chrome-plated and the other molded in color or painted part. Less masking, multiple components, and more than one pass of paint can be avoided with paint over chrome. Som
10、e durability may require compromise. For example, resist and topcoat painting will provide better hiding of small metal chips of the chrome below the paint surface. Trace appearances of chrome through the paint can occur if the part is impacted by stones or other objects. The use of paint on chrome
11、compared to resist and topcoat should be evaluated prior to design release. 1.4 Remarks. Not applicable. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. SAE J2527 2.2 GM Standards/Specifications. 9984255 GMW14729
12、 GM9531P GMW14797 GMW3005 GMW15572 GMW3059 GMW15581 GMW3221 GMW15777 GMW14668 GMW15919 GMW14700 GMW16193 2.3 Additional References. TMC003 Material Safety Data Sheet guidance documents 3 Requirements Monocoats shall meet the following requirements for engineering approval. 3.1 Sample Conditioning. A
13、ll samples are to be conditioned prior to each requirement test as specified in GMW3221, Code D. All samples shall be painted in the timeframe consistent with this specification after chrome-plating. Sample painting Copyright General Motors Company Provided by IHS under license with General Motors C
14、ompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16554 Copyright 2011 General Motors Company All Rights Reserved August 2011 Page 2 of 4 should be in a manner consistent with the chrome-plating process being used. 3.2 Requ
15、irements on Delivery. 3.2.1 Test Samples. Test samples shall be plaques or parts injection molded from plating grade GM-approved plastics. For example, Acrylonitrile Butadiene Styrene (ABS) per GMW15572 (ABS T5 or T6), or plating grade Acrylonitrile Butadiene Styrene and Polycarbonate (ABS+PC) per G
16、MW15581 (ABS+PC T7). Parts or plaques are plated accordingly to meet the performance requirements of GMW14668 and GMW16193. 3.2.2 Surface Preparation. Adhesion to chrome is a particularly difficult surface to adhere to. Paints can be formulated specifically to adhere to chrome. The surface of the ch
17、rome must be free of any dirt, oil, or other foreign matter prior to painting. Chrome-plated parts are also subject to oxidation. If oxidation occurs, the paint adhesion can be adversely affected. No significant oxidation of the chrome-plated part can be tolerated prior to painting, since this can a
18、ffect adhesion. Painting on chrome is intended to be treated as a concurrent process to chrome-plating, with required timeframes between chrome-plating and painting. Any deviations to these requirements must be approved by Materials Engineering and meet the requirements of this specification. Additi
19、onally, any pretreatment processes used to prepare chrome for painting must be approved by Materials Engineering. Chrome-plating process conditions must be maintained in a manner consistent with obtaining required paint adhesion. Any loss of adhesion to the chrome surface will be considered a violat
20、ion to the requirements of this specification. 3.2.3 Application. Reduce and apply uniformly to achieve normally recommended dry film thickness. Report percent solids and actual dry film thickness. A minimum film thickness of 30 to 40 m is required to reduce chrome appearance due to stone impact. Hi
21、gh-gloss paints should not be considered acceptable to this application unless proof can be demonstrated through performance tests required to this specification. High-gloss paints pose considerable higher risk of paint adhesion loss than low-gloss paints. 3.2.4 Bake. Bake the monocoat using normal
22、monocoat supplier-recommended time and temperature. Record and report surface temperature during baking. Bake oven mapping and charts are required per GMW14797. 3.2.5 Appearance. Must meet the requirements of GMW15777 for Zone A. 3.2.6 GMW16193 plated area appearance requirements shall be met. 3.3 P
23、erformance Requirements. Must meet the requirements of GMW3005 for Class 2, Type C. Minimum film thickness shall be 38 m (1.5 mil). Contact Material Engineering prior to beginning GMW14797 or GMW3005 test planning. 3.3.1 Additional Paint Test Requirements. In addition to paint test requirements outl
24、ined in GMW3005 and GMW14797, special chrome adhesion tests are listed in Table A1. 4 Manufacturing Process 4.1 Painting on chrome requires high standards of process control to the manufacturing process. Adverse changes in chrome surface conditions due to the plating process, chemistry changes, plan
25、t environment, and duration of time between chrome and paint need to be avoided. Any change to the chrome-plating process must be evaluated for its effects on the painting process. 4.2 Paint on chrome is intended to be a concurrent operation to minimize timeframes associated with oxidation of the ch
26、rome and plant environmental effects on adhesion. Parts will be painted within two (2) hours of chrome-plating. The chrome-plating source is required to be the painting source as well for process and manufacturing control. Any deviations to the time requirements for painting on chrome must be approv
27、ed by Materials Engineering. Adherence to GMW14797 APOPS requirements is needed in the desired timeframe after chrome-plating. Chrome parts that exceed this required timeframe, if not painted, are to be considered scrap. Prior to painting, no attempts at posttreatment for the purpose of extending th
28、e allowed timeframe are allowed unless approved by Materials Engineering. 4.3 Masking operations for painting on chrome should be designed in such a fashion as to avoid overspray and unsightly unfinished edge to paint. Refer to engineering drawings for specific mask line requirements. 4.4 Paint line
29、 locations should be specified by the appropriate part drawings. Step or channel features must be incorporated into the part design for acceptable masking operations. Clean and crisp paint lines should be obtainable from the part design and masking operations. 4.5 Cleanliness is required of the chro
30、me surface prior to painting. The surface shall be free of any oil, dirt, minerals, salts, or other foreign substances. Greater control of the plating line cleaning and rinsing is required. Mild acid rinse Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot
31、for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16554 Copyright 2011 General Motors Company All Rights Reserved August 2011 Page 3 of 4 steps can also be employed prior to final rinse stages. 4.6 Crack or micropore density must be
32、maintained as consistent with good chrome-to-paint adhesion. 4.7 Excessive exposure to air, heat, or moisture prior to painting is to be avoided. Parts are required to be completely dry prior to painting. 5 Rules and Regulations 5.1 Legal Regulations. All materials must satisfy applicable laws, rule
33、s, regulations and recommendations valid in the country of usage. 5.2 Language. In the event of conflict between the English and domestic language, the English language shall take precedence. 5.3 Inspection and Rejection. Samples of components or materials released to a GM material specification sha
34、ll be tested for conformity with the requirements of this material specification and approved by the responsible Engineering department prior to commencement of delivery of bulk supplies. A new approval must be received for any changes, e.g., properties, manufacturing process, location of manufactur
35、e, etc. If not otherwise agreed, all testing and documentation normally required for initial release must be completed. It is the responsibility of the supplier to inform the customer in a timely manner, without solicitation, and to include documentation of all modifications of materials and/or proc
36、esses and to apply for a new release. If not otherwise agreed, all release tests shall be repeated and documented by the supplier prior to commencement of delivery of non-conforming bulk supplies. In individual cases, a shorter test can be agreed to between the responsible Engineering department and
37、 the supplier. 5.4 Initial Source Approval. No shipments shall be made by any supplier until representative initial production samples have been approved by the appropriate Materials Engineering department(s) as meeting the requirements of this specification. 5.5 Material Safety Data Sheets/Safety D
38、ata Sheets (MSDS/SDS). For new product submissions, or when a change in chemical composition of an existing product has occurred, a complete copy of the Material Safety Data Sheet/Safety Data Sheet must be submitted in compliance with the Globally Harmonized System of Classification and Labeling of
39、Chemicals (GHS) requirements or other country-specific MSDS/SDS requirements. In addition, product MSDS/SDS submissions must be in compliance with specific country General Motors TMC003 Material Safety Data Sheet/Safety Data Sheet guidance documents where available. 5.6 All materials supplied to thi
40、s standard must comply with the requirements of GMW3059, Restricted and Reportable Substances for Parts. 6 Approved Sources Engineering qualifications of an approved source are required for this standard. Only sources listed in the GM Materials File GM Supply Power under this standard number have be
41、en qualified by Engineering as meeting the requirements of this standard. Sources must meet qualifications to GMW14797 APOPS using paint systems approved to this specification and GMW3005. 7 Notes 7.1 Glossary. Not applicable 7.2 Acronyms, Abbreviations, and Symbols. 2K Two-component ABS Acrylonitri
42、le Butadiene Styrene ABS+PC Acrylonitrile Butadiene Styrene and Polycarbonate APOPS Approved Paint on Parts Specification CTS Component Technical Specification GHS Globally Harmonized System of Classification and Labeling of Chemicals MSDS Material Safety Data Sheet SDS Safety Data Sheet UV Ultravio
43、let VTS Vehicle Technical Specification 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Material per GMW16554 9 Release and Revisions This standard was originated in March 2011. It was first approved by the Finishes and Coatings GSSLT in July 2011. I
44、t was first published in August 2011. Issue Publication Date Description (Organization) 1 AUG 2011 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-,-,-GM WORL
45、DWIDE ENGINEERING STANDARDS GMW16554 Copyright 2011 General Motors Company All Rights Reserved August 2011 Page 4 of 4 Appendix A Table A1: Supplemental Test Requirements Supplemental Test Requirement Test Specification Requirement Thermal Shock GMW15919 No paint removal Water Jet GM9531P, Method B
46、Maximum paint removal 60 mm2 Oven age 168 h at 83 C + Chip Resistance GMW14700 (Method A or B) Minimum rating of 7 Weathering + 96 h Humidity + Tape Adhesion SAE J2527-A Extended ultraviolent (UV) filters, 2500 kJ/m2 exposure to exterior Xenon arc weatherometer No change. Equal to original untested
47、sample. GMW14729 No blistering, discoloration or adhesion loss GMW14829 Maximum rating of 1 Weathering + Chip Resistance SAE J2527-A Extended UV filters, 2500 kJ/m2 exposure to exterior Xenon arc weatherometer No change. Equal to original untested sample. GMW14700 (Method A or B) Minimum rating of 6
48、 Weathering + Thermal Shock SAE J2527-A Extended UV filters, 2500 kJ/m2 exposure to exterior Xenon arc weatherometer No change. Equal to original untested sample. GMW15919 No paint removal Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
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