There is no single lifespan for tumbling media. Wear depends on the media formulation, cutting rate, machine energy, cycle time, load size, part material, water and compound conditions, and the amount of media-to-media contact.
Ceramic, plastic, and synthetic cutting media gradually wear as they move against the parts and other pieces of media. In bonded media, this wear can expose fresh abrasive particles and help maintain the cutting action. Over time, however, the pieces become smaller and their contact characteristics change.
Media may need attention when:
- Processing cycles begin taking longer
- Burr removal or surface consistency declines
- Pieces become noticeably rounded or undersized
- Small media begins lodging in part features
- Separation becomes difficult
- The operating media level drops
- Finished parts show inconsistent results
One maintenance method is to add fresh media periodically while removing worn pieces through screening or classification. This produces an operating load containing a range of media sizes. Another method is to replace the complete load at defined intervals when tighter size control is required.
Steel and porcelain burnishing media generally have different wear characteristics than bonded cutting media, but they should still be inspected for contamination, corrosion, pitting, broken pieces, and dimensional changes.