GMW17572

Description / Abstract: This specification covers the requirements for initial coating approval, for coatings to be used for a metalized finish that is protected within an exterior lighting application. The metalized finish is created using Physical Vapor Deposition (PVD); i.e., vacuum evaporation, sputter deposition, arc vapor deposition, etc. The coating system may consist of all or a select combination of the following: basecoat, metallic layer, protective topcoat and tinted top coat.

Material Description. Coating technology shall be documented with each approval.

Symbols. Not applicable.

Applicability. Typical applications are exterior lighting reflectors, bezels and decorative components which are protected within an assembly.

Remarks. This specification covers the requirements for initial coating approval, for coatings used for a protected metalized finish system typically used on exterior lighting applications. The coating(s) must meet the requirements set forth in this specification to be considered for production.

Initial coating approval per this specification is system specific; i.e., substrate, pretreatment, basecoat, metallic layer and protective top coat or tinted top coat. The following describes system approval guidance for each type of coating.

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  Basecoat lacquers requires coating approval per substrate family.
• Metallic layer has no material approval, application approved through the Approved Paint on Plastics Systems (APOPS) and/or Production Part Approval Process (PPAP) testing only.

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  Protective top coat (secondary lacquer operation) or in-chamber protective coat (Hexamethyldisiloxane (HMDSO) is plasma polymerized subsequent to the deposition in the same vacuum chamber to provide a thin (on average 20 nm) corrosion protective layer) requires an initial coating approval on a single substrate.

• Tinted top coat approval is required for each colored tint on a single substrate and metallization process.

Any additional substrates and/or system combinations shall be validated through APOPS using coatings approved to this specification. APOPS is intended as detailed review and approval of a new combination of GM approved substrate, GM approved paint or coating and production process for a specific molder/painter/application. This is accomplished by the GM Materials Engineer with the GM supplier. The APOPS approval documentation is required with the component/assembly PPAP package.

This specification shall be used in conjunction with the APOPS approval, a section of Materials Specification File (MATSPC) which lists approved substrate, cleaning, priming and topcoat combinations as defined in 1.4.1.

This 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 of regulatory limitations prior to use.