Centrifugal Finishing, or barrel tumbling, is a high-energy polishing method used to improve the surface of parts. The process involves placing parts inside of a barrel which then rotates to remove burrs and create a superior finish.

Typically, this machine is made up of two to four barrels that are mounted on the outer edge of a turret. During the process, the turret is rotated in one direction while the barrels rotate in the opposite direction, mimicking the motion of a ferris wheel. This creates high levels of pressure inside the barrel and causes the parts to slide against the side of the barrel. The sliding action of the parts against the barrel is what removes burrs and creates a polished finish.

The benefits of Centrifugal Barrel Finishing include:

  • Stronger and tougher parts than before finishing
  • Parts undergo very little handling
  • Less costly than finishing parts by hand
  • Saves time because more parts can be processed at one time
  • Large batches can be run for longer periods of time, when necessary

There are two types of Centrifugal Barrel Finishing; wet barrel finishing and dry barrel finishing. While Centrifugal Barrel Finishing utilizes both methods for finishing parts, each serves its own purpose.

Wet Barrel Finishing

Wet barrel finishing works well for finishing metal parts. While the barrels rotate the same way mentioned above, the barrels for wet barrel finishing are usually a horizontal barrel in an octagonal or hexagonal shape. Due to their size and shape, these barrels are easier to load and unload, as well as able to hold larger capacities. The barrels themselves are typically made of steel and often lined with another material which helps to protect the barrel and parts during finishing. Without it, the parts would become scratched or blackened due to the abrasive media.

During wet finishing, water and other compounds are mixed with the parts to deburr, form radii, polish and clean them. The liquids carry the abrasive agents and help to cushion and protect the parts during the process. How long the finishing process takes will depend on the material and the degree of finishing required for the processed parts. When done, the parts are thoroughly rinsed with fresh water to prevent contamination, and dried.

Dry Centrifugal Barrel Finishing

Dry Centrifugal Barrel Finishing (CBF) is most often used when finishing delicate plastic or metal parts. This method uses horizontal octagonal barrels, which sometimes have a metal skin and protective inner lining.. To make them more versatile, the barrels can be divided into multiple compartments to further protect parts during the finishing process. total time it takes to finish parts with this process varies by material.

Rather than using liquid, dry barrel finishing utilizes abrasives like sand, corn cob grit, walnut shell grit, and pumice. Like wet barrel finishing, dry barrel finishing produces a smoother and higher finish upon completion. While both create a similar finished effect, dry barrel finishing is much more versatile. The type of finish can vary depending on what sort of abrasive material is used during the tumbling process. For example, plastic parts tumbled with wood pegs or corn cob grit can achieve a final finish similar to hand-buffing. In comparison, a bright high finish can be achieved by using wood pegs or walnut shells treated with wax.

ISO Finishing offers the highest quality surface finishes for manufacturing companies. Our team members have the expertise to tackle any polishing project to produce quality results.  To learn more information or for free sample processing, contact us at 1-844-623-7998.


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