Mechanical Finishing for Uniform Anodized Finishes

Q. We produce a 4-inch size aluminum machined part that requires a good visually uniformed anodized finish. Our machining lines are visual after anodizing and the anodize is not uniform. What can we do to solve this?—J.J.

A. A combination of mass finishing and blasting is the way to solve these problems.

The vibratory process will smooth your machining lines and the bead blasting will cover what imperfections are left, producing a surface that will give you a uniformed anodize finish.

Step 1. Run the part in a vibratory system with a medium-sized super fast cut ceramic media. The refinement process will remove most of your cutting lines. The refinement process takes approximately 2 hours.

Step 2. Blast the part in a medium-heavy (No. 9 or No. 10) glass bead at 70 psi.

We also recommend this process with stainless medical parts for a super sheen blast finish. This finish is achieved with a very fine No. 13 glass bead. The very fine beads will not hide many imperfections, so prior vibratory finishing is necessary to prepare the surface for blasting.

Originally published in the July 2015 issue.