1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW14885 Painted Aluminum Road Wheels - Paint Performance Requirements Copyright 2012 General Motors Company All Rights Reserved August 2012 Originating Department: North American Engineering Standards Page 1 of 9 1 Scope 1.1 Material Descripti
2、on. This specification defines the performance requirements for pre-treatment, paint materials, and processing required to paint/coat aluminum road wheels. In some cases, this specification might be applied for aluminum wheel trim. Coating/Paint durability requirements are also included. Note: For c
3、hrome aluminum wheels and wheel trim, refer to GMW15774. For chrome plated plastic wheel trim (including claddings) refer to GMW14668. 1.2 Symbols. Not applicable. 1.3 Typical Applications. Painted aluminum road wheels and wheel trim. 1.3.1 Classification/Wheel Types. Type A. Wheels with any clear p
4、aint(s) over bright metal sections of the disc outer and/or rim flange, for example, bright polished wheels and machined-faced wheels. Type B. Fully color painted wheels without any areas of clear paint(s) over bright metal on the disc outer and/or rim flange. 1.4 Remarks. This specification applies
5、 to all surfaces that are designated on the engineering part drawing to meet these requirements. Painted parts must meet these requirements prior to going into the field and must also satisfy GMs and its customers expectations for appearance and cosmetic durability. All deviations from this specific
6、ation must be agreed upon by GM and must be documented on the part drawing. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ISO/IEC 17025 ISO 4892-2 SAE J2633 ISO 4892-1 SAE J1976 SAE J2635 2.2 GM Standards/Speci
7、fications. GMW3059 GMW14334 GMW14704 GMW15287 GMW3286 GMW14458 GMW14729 GMW15774 GMW14124 GMW14668 GMW14829 GMW15919 GMW14333 GMW14700 GMW15282 2.3 Additional References. GM Drawing Number 9591083 GM Research Report CES-176 TMC003 Material Safety Data Sheet guidance documents (available at ). 3 Requ
8、irements 3.1 Resources. 3.1.1 Calibration. The equipment used at the test facilities shall be in good working order and shall have a valid calibration label. 3.1.2 Alternatives. Alternative test facilities and equipment may also be used and must be maintained by MATSPC approved suppliers to support
9、continuous improvement, Production Part Approval Process (PPAP), and troubleshooting. 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 GMW148
10、85 Copyright 2012 General Motors Company All Rights Reserved August 2012 Page 2 of 9 3.1.3 Facilities. All Tier 1 suppliers shall have ISO/IEC 17025 accreditation for their test facility for General Motors to accept data. Proficiency data shall be kept current and made available at the request of th
11、e GM Materials Engineer. 3.1.4 Equipment. All equipment and test procedures utilized to supply data to this specification shall be documented on the Scope of Accreditation for the facility. 3.1.5 Test Vehicle/Test Piece. Test pieces, wherever possible, shall be the finished part. If size, shape, etc
12、., of the finished part is impracticable, tests shall be conducted on specially prepared coated test panels, as agreed upon by the appropriate GM Materials Engineer. 3.1.6 Test Time. There shall be no deviations from the minimum test times documented in this specification unless it is agreed upon by
13、 the GM Materials Engineer. Suppliers are encouraged to run parts in test to the point of nonconformance to understand ultimate performance. 3.1.7 Test Required Information. These test requirements are intended for routine acceptance and control of production painted parts using materials and proces
14、ses previously found to be satisfactory. These test requirements do not represent the complete testing necessary for engineering approval. 3.2 Conditions. Parts should be tested at the earliest 72 h after final bake unless otherwise specified in a reference specification. A shorter aging time may be
15、 used, provided it is recognized that it represents a more severe condition of test. Laboratory conditions, such as humidity and temperature, should be recorded to help understand any test anomalies. 3.3 Data. Proficiency data should be included in the test reporting format if it is required by the
16、customer, e.g., filiform testing. 3.4 Safety. This procedure may involve hazardous materials, operations, and equipment. This method does not propose to address all the safety problems associated with its use. It is the responsibility of the user of the method to establish appropriate safety and hea
17、lth practices and determine the applicability of regulatory limitations prior to use. 3.5 Documentation. Samples of components or material released to this specification shall be tested for conformity with the requirements of this specification and approved by the responsible GM department prior to
18、the start of delivery of production-level components or materials. Any change to the component or material, e.g., design, function, properties, manufacturing process and/or location of manufacture, requires a new release of the product. It is the sole responsibility of the supplier to provide the cu
19、stomer, unsolicited, with documentation of any change or modification to the product/process, and to apply for a new release. The entire verification test shall be repeated and documented by the supplier prior to start of delivery of a modified or changed product. In some cases, a shorter test can b
20、e agreed to between the responsible GM department and the supplier. Deviations from the requirements of the test procedures shall have been agreed upon. Such requirements shall be specified on component drawings. 4 Manufacturing Process 4.1 Appearance. Appearance must meet GM Drawing Number 9591083.
21、 Overspray must not interfere with retention of adhesive balance weights. Appearance of the clear and color must compare favorably to the approved engineering standards. For matching caps/trim and wheel counterparts, each supplier is responsible for utilizing production parts from their own process
22、and from the other suppliers process as an ongoing quality control procedure to ensure color/texture match. The frequencies shall be included in the control plans. GM shall be consulted to review discrepancies. 4.1.1 Production Part Approval Process (PPAP). Color/appearance submissions shall be prod
23、uced with production processing equipment and materials, and the processing parameters shall be documented at the time of color/appearance approval. All deviations from production intent shall be identified at the time of color/appearance approval. 4.2 Pre-treatment. Clean and pre-treat using the ap
24、propriate procedure. All products must meet GMW3059, and final coatings shall be Chrome VI-free. The selection of the pre-treatment system is left to the discretion of the wheel/trim supplier, providing all requirements of this specification are met, including Section 6. Pre-treatment materials shal
25、l be used in accordance with the suppliers recommendations for processing (e.g., bake or flash times and temperature, minimum thickness and bath monitoring). Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitte
26、d without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14885 Copyright 2012 General Motors Company All Rights Reserved August 2012 Page 3 of 9 Note: Production pre-treatment processes that use more than one chemical supplier are unacceptable. De-ionized (DI) water chemical companies ar
27、e excluded from this requirement. Pre-treatment coatings for bright metallic surfaces must be uniformly water clear and not change the color or appearance of the aluminum. There should be no evidence of a loose or powdery surface following coating application. There should be no visible stains or di
28、scoloration on the part subsequent to the final pre-treatment stages. Parts should not be touched or handled in any way following pre-treatment and prior to painting unless clean cotton gloves are used. Each pre-treatment system is required to contain a deoxidization process. 4.3 Organic Coating Req
29、uirements. The selection of powder, or powder and liquid clear paint systems for this application, is left to the discretion of the wheel/trim supplier, providing all requirements of this specification are met, including Section 6. Coating materials shall be used in accordance with the suppliers rec
30、ommendations for processing (e.g., bake or flash times and temperature, minimum thickness and bath monitoring). Accent color coatings, inks, etc., must be compatible with the primer and clear topcoat materials used on the part. They shall have no detrimental effects that might alter the appearance o
31、r durability of the part assembly. All pigments used in paints, inks, etc., must meet paragraph 4.4.12. Edge film thickness data should be submitted with the validation (PPAP) data and incorporated into the control of the processing. The location of the measurement area will be determined by GM Supp
32、lier Quality or Materials Engineering. 4.3.1 Type A Requirements. Apply (acrylic) powder or (acrylic) liquid clear coatings to areas specified on the part drawing. All color paints, inks, etc., shall be coated with a clear topcoat in order to meet the cosmetic durability requirements. Wheels and tri
33、m that are machined, polished, etc., after paint material has been applied must be reprocessed through the pre-treatment steps prior to any subsequent clearcoat application. Apply clear topcoat(s) to areas specified on the part drawing. Dry film thickness for an acrylic powder or liquid, is to be 40
34、 m minimum. Acrylic powder is required for the clear topcoat. An alternate coating system with an acrylic liquid clearcoat over polyester powder clearcoat may be used with GM Engineering approval. The dry film thickness of the liquid acrylic clearcoat and the powder polyester clearcoat shall be a mi
35、nimum of 80 m. 4.3.2 Type B Requirements. Type B wheels shall have a minimum total dry film thickness of 100 m. Wheels must be coated with powder or liquid primer, liquid or powder color paint, and acrylic liquid or acrylic powder clear topcoat paints. Apply clear topcoat(s) to areas specified on th
36、e part drawing. Dry film thickness for an acrylic powder or liquid is to be 40 m minimum. An alternate coating system with an acrylic liquid clearcoat over polyester powder clearcoat may be used with GM Engineering approval. The dry film thickness of the liquid acrylic clearcoat shall be 20 m minimu
37、m on a minimum dry film thickness of 40 m of polyester clearcoat. Note: For bright metal wheel trim which uses a reheat/reflow of the coating where there has been deformation of the substrate, a polyester topcoat is acceptable. For trim parts that are located in the center of the wheel and are not i
38、n the car wash tire/wheel brush area, the clear topcoat paint minimum thickness requirements may be excepted if the parts are validated at the minimum production thickness. The film build on the trim blank must be at least 40 m minimum. Trim parts shall be tested after all forming and subsequent hea
39、ting processes are performed. Film build mapping and edge film thickness data of the finished product shall be submitted with the validation (PPAP) data. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted wi
40、thout license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14885 Copyright 2012 General Motors Company All Rights Reserved August 2012 Page 4 of 9 Table 1: Minimum Dry Film Thickness by Zone Zone Note 1 Type A (Polished or Machine Finished Note 2) TYPE B (Fully Painted) Total Thickness Zones A
41、 and B 40 m 100 m Zone C 40 m Zone D 40 m Note 1: See GM Drawing Number 9591083 for description of Zones A, B, C, and D. Note 2: The minimum dry film thickness of the fully painted portions a machine-finished wheel shall meet the dry film thickness requirements for Type B. 4.4 Finished Part Durabili
42、ty Requirements. The durability requirements pertain to finished parts after all painting, heating, and forming operations. All combinations of coatings (paints, inks, etc.) as they appear on the finished parts are required to meet these requirements. When submitting for part approval, the supplier
43、shall identify that the cosmetic surfaces with the least corrosion protection were validated to meet these requirements. 4.4.1 Tape Adhesion Test. Crosshatch test according to GMW14829 prior to and after humidity exposure for 120 h per GMW14729 with a minimum of 99% paint adhesion or rating 0. There
44、 shall be no evidence of blistering or other appearance changes at end of humidity exposure. 4.4.2 High-Humidity Exposure. Expose painted parts per GMW14729. There shall be no evidence of blistering or other appearance changes at end of humidity exposure after 240 h. 4.4.3 Salt Spray Fog Test. Parts
45、 must pass a salt spray and adhesion test when evaluated at 1000 h exposure. Painted parts must pass GMW3286 (1000 h) with no more than 1 mm of creepback (see GMW15282) from edges and scribes and no other loss of adhesion after evaluation. All coated surfaces must be scribed per GMW15282. Evaluate p
46、er GMW15282. There shall be no evidence of blistering or other appearance changes at the end of the 1000 h. 4.4.4 Copper-Accelerated Acetic Acid Salt Spray (CASS) Test. An optional salt spray testing method is acceptable to expedite approvals if it is specified in the validation agreement. Painted p
47、arts must pass 168 h of CASS test exposure per GMW14458 with no more than 3 mm of creepback (see GMW15282) from edges and scribes and no other loss of adhesion after evaluation. All coated surfaces must be scribed and evaluated per GMW15282. There shall be no surface corrosion or coating degradation
48、, excluding the scribes and cut edges. 4.4.5 Filiform Resistance. Parts must meet a filiform resistance requirement of no more than 4 mm maximum length of any filament from the scribe line when tested per SAE J2635, for a period of 672 h in humidity. Furthermore, there shall be no filament growth on
49、 the non-scribed test surfaces at the end of the test because this is an indication of insufficient coating coverage at that site (excluding sample prepared cut edges). GMW15287 is an alternate procedure that could be used to meet this requirement if agreed upon by GM Materials Engineering. Proficiency data is required for filiform resistance testing. 4.4.6 Stone Impact Resistance. Parts must pass the stone impact resistance test per GMW14700. Requireme
