Typical Stages of Anodizing

There are typically 5 stages in the anodizing process. Each stage is carefully monitored and controlled in accordance with documented Process Control Plans. These control plans are an integral part of our ISO 9001:2000 Quality System. The Laboratory Technicians test the cleaners, baths, rinses, dyes and sealers, around the clock, to ensure repeatable production conditions.
The production steps can include:

1. Cleaning - Acid or alkaline solutions are used to remove minor grease and dirt to ensure uniform pre-treatment.

2. Pre-treatment
   a) Etching - Alkaline solutions uniformly remove a very thin layer of metal creating an appealing matte finish. This process also removes small surface imperfections such as scratches and scuffs.
   b) Brightening - Acid solutions selectively chemically polish the surface to produce a near mirror finish. Small surface imperfections such as scratches and scuffs are not removed and sometimes can be accentuated. Proper handling and mechanical polishing of surfaces prior to brightening is generally required.

3. Anodizing - By passing an electrical current through an acid bath, where the parts are submerged, the anodic film is developed as an integral part of the metal.

4. Colouring
   a) Organic - Utilizing organic dyes, a wide variety of vibrant colours are possible. These dyes create finishes that have good light and weather fastness.
   b) Electrolytic - Electrically charged baths of metal salts produce very durable surfaces by depositing metal salts into the pores of the aluminum. These finishes are very light and weather resistant.

5. Sealing - A dual or 2-stage seal process is used to create the highest quality of seals. A nickel acetate solution prepares the metal prior to a hydrothermal (hot water) seal. This process closes the open pores of the metal to create a surface that is resistant to staining, abrasion, crazing and colour degradation.