Molded plastic parts often have flashing or excess material that needs to removed from the edges of the part (see part on left of picture). This can be accomplished in a variety of ways including a wet process using vibratory and barrel tumbling with an abrasive media (i.e., Plastic Media) or with an abrasive blasting process to blast the flash off the edges.
If the part is a hard plastic with a relatively simple geometry and the surface finish needs to be maintained, tumbling the part with a polishing media is ideal. The mass of a polishing media will knock the flash off the edges and will not change the surface finish since it is a non-abrasive media.
The part on the right was barrel tumbled with a KP Ceramic Angle Cut Cylinder that was small enough to pass through the ID of the part. These results were obtained in only 15 minutes. The parts were retrieved from the process clean, dry and ready for the next step in the production process.