System and method for plastic overmolding on a metal surface

• US 8,858,854 B2
• Filed: 03/31/2011
• Issued: 10/14/2014
• Est. Priority Date: 04/01/2010
• Status: Active Grant

• Current Assignee: Flextronics America LLC (Flextronics International Limited)
• Original Assignee: Flextronics America LLC (Flextronics International Limited)
• Inventors: Oin, Jichen (Jeff)
• Primary Examiner(s): HEITBRINK, JILL LYNNE
• Application Number:
  US13/077,274
• Publication Number:
  US 20110250377A1
• Time in Patent Office: 1,293 Days
• Field of Search: 264/241, 264/259
• US Class Current: 264/241
• CPC Class Codes: B29C 2045/14868 Pretreatment of the insert, e.g. etching, cleaning
• CPC Class Codes: B29C 45/14311 using means for bonding the coating to the articles B29C45/14795 takes precedence
• CPC Class Codes: B29K 2705/00 Use of metals, their alloys or their compounds, for preformed parts, e.g. for inserts
• CPC Class Codes: B29K 2705/02 Aluminium
• CPC Class Codes: B32B 15/08 of synthetic resin
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2571/00 Protective equipment
• CPC Class Codes: B32B 27/286 comprising polysulphones; polysulfides
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/34 comprising polyamides
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 27/365 comprising polycarbonates
• CPC Class Codes: B32B 3/085 spaced apart pieces on the surface of a layer
• CPC Class Codes: Y10T 428/24008 including fastener for attaching to external surface
• CPC Class Codes: Y10T 428/31678 Of metal
• CPC Class Codes: Y10T 428/31681 Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31692 Next to addition polymer from unsaturated monomers

Abstract

A plastic-metal hybrid part includes an anodized metal substrate having plastic structures formed on the metal substrate. In a particular embodiment, the metal hybrid part is an electronic device enclosure and plastic structures are mounting features formed on the enclosure. Methods for manufacturing the plastic-metal hybrid part are also disclosed. In a particular embodiment, the metal substrate undergoes a pretreatment, is anodized after the pretreatment, and the plastic structures are molded directly on the anodized exterior surface of the metal substrate. In another embodiment, the anodized metal substrate is primed with a coupling agent before the plastic features are formed thereon.

Claims

1. A method for manufacturing a plastic-metal hybrid part, said method comprising:

providing a metal substrate having a first exterior surface;

providing a moldable plastic material;

anodizing said metal substrate to form irregularities on at least a portion of said first exterior surface of said metal substrate;

applying a primer material to said exterior surface of said metal substrate whereon said irregularities are formed, said step of applying said primer material to said exterior surface of said metal substrate being carried out after said step of anodizing said metal substrate and before said step of forming said plastic structure on said metal substrate, said primer material being adapted to bond to both said metal substrate and said moldable plastic material, wherein said primer material is selected from the group consisting of organosilane, titanate, aluminate, phosphate, and zirconate;

forming a plastic structure on said metal substrate by molding said moldable plastic material directly over said irregularities formed on said first exterior surface of said metal substrate; and

rinsing said metal substrate with deionized water after applying said primer material and before forming said plastic structure.

2. The method of claim 1, wherein said metal substrate is a stamped sheet metal substrate.

3. The method of claim 1, wherein said metal substrate is formed from a material selected from the group consisting of aluminum, 5052 aluminum, aluminum alloy, titanium, titanium alloy, magnesium, and magnesium alloy.

4. The method of claim 1, wherein said step of anodizing said metal substrate includes anodizing said metal substrate using an anodizing agent selected from the group consisting of chromic acid, phosphoric acid, sulfuric acid, oxalic acid, and boric acid.

5. The method of claim 1, wherein said step of molding said moldable plastic includes overmolding said moldable plastic over said irregularities formed on said first exterior surface of said metal substrate.

6. The method of claim 1, wherein said step of molding said moldable plastic includes injection molding said moldable plastic over said irregularities formed on said first exterior surface of said metal substrate.

7. The method of claim 1, wherein said moldable plastic material is selected from the group consisting of polyamide, polycarbonate, acrylonitrile butadiene styrene copolymer, polyphenyl sulfide, polypropylene, polybutylene terephthalate, and polyethylene terephthalate.

8. The method of claim 1, wherein said moldable plastic material is a thermoplastic.

9. The method of claim 1, wherein said moldable plastic material is a transfer moldable thermosetting plastic.

10. The method of claim 1, further comprising subjecting said metal substrate to a pretreatment process prior to said step of anodizing said metal substrate.

11. The method of claim 10, wherein said pretreatment process includes:

applying a degreasing agent to said metal substrate,

applying an alkaline solution to said metal substrate after said step of applying said degreasing agent to said metal substrate,

rinsing said metal substrate with deionized water after said step of applying an alkaline solution to said metal substrate,

applying an acid solution to said metal substrate after said step of rinsing said metal substrate in deionized water, and

rinsing said metal substrate with deionized water after said step of applying an acid solution to said metal substrate.

12. The method of claim 10, wherein said pretreatment process includes applying a degreasing agent to said metal substrate.

13. The method of claim 10, wherein said pretreatment process includes applying an alkaline solution to said metal substrate.

14. The method of claim 10, wherein said pretreatment process includes applying an acid solution to said metal substrate.

15. The method of claim 1, wherein said plastic structure is a fastener feature.

16. The method of claim 1, wherein said plastic structure is a mounting boss.

17. The method of claim 1, wherein said plastic structure is a snap-fit fastener.

18. The method of claim 1, wherein:

said metal substrate is a thin-walled structure; and

said plastic structure is a stiffener operative to rigidify said thin walled structure.