Bead Blasting Guide
Bead blasting creates a uniform matte surface finish on metal parts, removing tool marks and surface contamination.
Media Comparison
| Media | Hardness | Finish (Ra) | Material Removal | Best For |
|---|---|---|---|---|
| Glass beads | 5-6 Mohs | 0.4-1.2µm | Minimal | Al, steel, stainless, plastics |
| Aluminum oxide | 9 Mohs | 1.0-3.5µm | Moderate | Hard metals, coating prep |
| Ceramic beads | 7-8 Mohs | 0.6-1.5µm | Low | Stainless, Ti, hard coatings |
| Walnut shells | 2-3 Mohs | 0.3-0.8µm | None | Soft metals, plastics, wood |
Process Parameters
- Pressure: 2-6 bar (30-90 PSI)
- Nozzle distance: 150-300mm from part
- Nozzle angle: 60-90°. Perpendicular is most aggressive
- Exposure: 10-60 seconds per area
- Media size: 40-80 mesh, 60-80 is standard for general matte
Design Considerations
- Plug or mask threaded features and blind holes
- Blasting removes ~1-5µm. For tolerances under ±0.02mm, blast before final pass
- Sharp corners get ~0.05-0.15mm radius. Plan edge-break specs accordingly
- Arrange parts so gravity helps media escape from cavities
Media Life
Glass beads break down after 5-15 cycles. A cyclone separator removes fines below 200 mesh. Replace 15-25% of media volume per shift for consistent quality.