Mass Finishing

The various media used include plastic, ceramic, wood, corncob, and walnut shell products. The media will most often contain some abrasive agents such as; silicon carbide, aluminum oxide, or other less known abrasives. The amount and type of abrasive, along with the type of polymers used to bind it, such as plastic or ceramic, will greatly affect the cutting or material removal that occurs in the tumbling process.

The two effective processes that RPA use are high energy and vibratory. High energy is a process in which parts along with media, water, and a surfactant are placed in a barrel enclosed with a lid, this barrel is then rotated on a carousel that holds four barrels. Once the barrels are loaded and the machine is started, the carousel will spin in one direction as the barrels spin in the opposite direction creating great centrifugal force, thus placing the desired finish on the part. Vibratory tumble will use a vibrating action of the media against the parts to create the desired finish. These processes are called mass finishing because so many parts can be done at once.

Pictured above is one of the four MFI high-energy tumblers that RPA uses that features an 80-liter capacity. We also have two 120-liter capacity machines and a 12-liter machine. We use Mass Finishing Inc. machines as they are very durable, well regarded in the industry, and very dependable.

In addition to this equipment, we also have:

• 5 Cu.Ft. Ultramatic tubs
• 3 Cu.Ft. Ultramatic bowl
• 4 Cu.Ft. Sweco bowl
• 3 Cu.Ft. Sweco bowl
• 10 Cu.Ft. Torx bowl
• 2 Cu.Ft. Almco tub
• 1 Cu.Ft. vibe bowl

Which machine gets used depends on the number and size of the parts; often, we will do media changes in machines as parts warrant. RPA will estimate what media to use, test parts, and then make adjustments if needed.