GMNA-9984047-1995.pdf
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1、m 9006377 0000439 587 I GENERAL MOTORS ENGINEERING STANDARDS I Materials and Processes - Paint I ACRYLIC POWDER TOPCOAT FOR PARTS 9984047 1 SCOPE. This specification describes the requirements for an acrylic powder topcoat to be used on exterior compo- nent parts. 2 REFERENCED STANDARDS. GMlOOOM GM4
2、494M ASTM D1186 GM4348M GM4495M ASTM D1895 GM4350M GM4496M ASTM D345 1 GM4367M GM962OM GM4493M ASTM D153 3 REQUIREMENTS. Materials approved to this specifi- cation must meet all the minimum requirements of GM4367M, Class 3. Only exceptions or requirements specific to this type of material are noted
3、herein. Once qualified to these require- ments, routine testing of parts is covered by GM4350M. 3.1 RESTRICTED AND REPORTABLE CHEMICALS (GMlOOOM). By 1997 start of salesable vehicles, all materi- als supplied to this specification must comply with the requirements listed in GMlOOOM, “Restricted and
4、Reportable Chemicals.” 3.2 MATERIAL. 3.2.1 The paint shall be in powder form. 3.2.2 The powder chemistry must be at least 65% acrylic. 3.3 FILM THICKNESS (ASTM D1186). All durability and appearance requirements must be met within a minimum range of 51 to 102 urn (2 to 4 mils). Film build not to exce
5、ed 102 p (4 mils) including in line repairs. Individual colors may have narrower ranges for optimum appearance. Individual colors may also have higher film builds than the technology minimum due to hiding or ultraviolet opacity. 3.4 BAKE. The target bake for these powders is 20 minutes metal tempera
6、ture 157 to 204 C (315 to 400F). Supplier shall provide bake time and temperature charts showing the bake processing window wherein all performance require- ments are met. A bake chart that has been signed by NAO Paint Engineering is the only acceptable document that will be allowed in either an ass
7、embly plant or Tier 1 or Tier 2 supplier to General Motors. 3.5 SUBMISSION INFORMATION REQUIREMENTS (GM4493M). Chart 1 of this specification must be completed prior to approval of the product. 3.5.1 Particle Size. Significant differences in particle size may effect the handling and appearance of pow
8、der coatings. Supplier shall identify particle size and distribution per ASTM D3451, Section 8.4. Electronic Counting Analysis is the preferred methodology. 3.5.2 Volatile Content. Although powders are nominally 100% solids at room temperature, some volatiles may emanate during the baking process. M
9、ass percent solids and volatile content shall be determined using ASTM D3451, Section 13. 3.5.3 Density and Specific Gravity. Apparent density and its bulk factor shall be determined in accordance with ASTM D1895. For specific gravity determinations use ASTM D153 or with modifications described in A
10、STM D3451, Section 18. 3.5.4 Gel Time. The mean gel time of the product shall be determined in accordance with ASTM D3451, Section 14. 3.5.5 Quality Control. The supplier must provide a listing of quality control policies and procedures for both raw and fin- ished materials. 3.6 PANEL PREPARATION PR
11、OCEDURE (GM4494M). This specification states the panels that must be prepared to qualify a product. Panels to be prepared are designated by top- coat Type . The types primarily used for approval to this specification are lypes B, C, and F depending on the intended product. 3.7 COMPATIBILITY TESTING
12、(GM4495M). Specific areas of Section 6 of this specification will be performed depending on the intended product. 3.8 PROCESSABILITY TESTING (GM4496M). Pertinent sections of this specification must be performed. 3.8.1 Appearance. The material must meet or exceed corpo- rate specifications for gloss,
13、 DOI, orange peel, and uniformity as designated in GM4348M. 3.8.2 Appearance Matrix. Production representative electro- static powder guns shall be used. Report fluidizing air pressure, electrostatic voltage, feed and conveyance (or equiv- alent) air pressures, and powder flow in oz(lb)/min. 3.8.3 F
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