Cleaning Machined Aluminum
Aluminum is a soft metal that is easily machined, and it tends to oxidize similarly to rust on steel. After machining, the metal surface needs to deburred and the tooling marks need to be removed. This is necessary prior to polishing the part.
If the part sits in a humid environment, it will also tend to darken due to oxidation of the metal surface. A tumbling process can be used to both deburr the part and clean the surface.
The part pictured on the left was tumbled with a Plastic Tumbling Media and a solution of Kramco 1030 Mild Acid Liquid Compound. The abrasiveness of the media removed any burrs and tooling marks. The proper media size and shape was chosen to not get stuck in any holes or slots and get to all areas of the part surface. The Compound used helped to clean the oxidation and leave a shiny, smooth surface ready for polishing.
A second step was needed to get the polish seen on the part on the right. A dry tumbling process using the Premium Treated Tumbling Media for a longer cycle time produced this bright, clean finish. Once done, no further processing (such as cleaning) was needed on the part.