Brass is relatively soft metal that oxidizes easily. Care needs to be taken to not damage the surface and to ensure that the correct compounds are used in a tumble deburring process.
These parts were relatively large (6” diameter) and have a relatively complex geometry and inside corners. The requirement was to deburr the part and leave uniform, satin-matte finish on the surface.
Given the size of the parts, a vibratory bowl was needed. A bowl is a better choice than both a vibratory and a barrel tumbler since a bowl will not only tumble the parts in two dimensions but will also tumble the parts around the circumference of the bowl. The three-dimensional tumbling action keeps the parts separated and minimizes damage from the parts impinging on each other.
A Ceramic Media was selected since the burrs were somewhat heavy on this part. Ceramic Media can often be harsh on softer metals, so a smaller media was used to produce a more uniform, ‘softer’ finish. Smaller media also does a better job of providing a uniform finish in tighter areas like slots. A very mildly alkaline compound was used to keep the brass bright and non-oxidized.