Fit For Purpose requirement for device design and specification
New anodizing technology is now available for re-usable medical instruments, equipment and devices that require repeated cleaning and sterilization. Many commercial parts commonly require sulfuric acid anodizing, either in a softer, decorative Type II or hard but dark Type III. Type II is primarily used to generate a thin, clear film on parts that can be dyed a variety of bright colors and be finished from dull matt to high gloss. Due to the low current densities used to form the coating, the finish is susceptible to scratching and abrasion.
Type III or hard coat anodizing traditionally was used for machinery and military applications due to the exceptional durability achieved by high current densities and a thicker coating. However, the high voltage used to drive the current coupled with the cold electrolyte of the process tank to limit burning causes the resulting anodic coating to darken from a mid gray to a dark green/gray depending on coating thickness and alloy.
Type II and Type III while appropriate for many commercial products fall short when applied to re-usable medical equipment. The emerging “Fit For Purpose” Requirements focuses on three major influences, cleansing (sanitation), sterilization, and identification marking.
Both anodic coating standards are required to meet corrosion standards based on salt water spray testing.
For a detailed paper on “New Anodizing Technologies for Re-Usable Medical Equipment” go to www.micralox.com/fit
