Anodizing of Aluminum Parts for Small Arms

Individual racking of parts during anodization processes is time consuming and inefficient. The objective of this proposed effort is to develop a process that can anodize large number of small parts, fabricated from aluminum alloys, using a non-racking approach while maintaining high surface quality to meet military standards. Two fixture design concepts, batch process and a non-racking fixture, are proposed. In the batch fixture design, ballasts made of porous metal foam are employed to eliminate surface defects due to contacting aluminum parts. The non-racking fixture utilizes highly porous metal foam as the electrical contact to allow maximum electrolyte diffusion, and minimize contact marks. Fixtures are attached to a vibrating axel for maximum agitation, and pulse anodizing methods are applied to achieve better surface finish quality. TRI/Austin will be teaming with two companies to assist in the development of anodizing fixtures and processes. Analytical tests will be conducted to evaluate the anodic film properties including visual appearance, film thickness, Rockwell hardness, abrasion, and corrosion resistance. The results of this research will be an efficient bulk anodizing process that is capable of high volume yield and outstanding surface finish quality.