After the raise-boring machine completes the pilot hole construction, thesmall-diameter pilot hole is enlarged to the designed shaft size by back reaming.
1. Rock crushing and cutting: The cutter head equipped with the carbide rollercutters or picks crushes the rock mass by rotation and axial pressure.
2. Shaft size control: The diameter of the cutter head directly determines the fin-ished shaft size and must strictly conform to the design specifications.
3. Cuttings discharge assist: When the cutter head rotates, the cuttings fallthrough the slag discharge chute or flushing system on the cutter head into thelower tunnel.
4. Power transmission and load bearing: The cutter head is connected to therotary drive of the drilling rig through the drill rod to bear extreme torque, axialtension, and vibration.
Cutter head configuration table (OEM)
| Cutter head diameter (mm) |
Tension rod diameter (mm) |
Type of cutter head | Number of complete sets |
Number of roller cutters |
|
| 520 | φ190 | Integral | 1 | 2 | |
| 670 | φ190 | Integral | 1 | 2 | |
| 900 | φ190 | Integral | 1 | 4 | |
| 1000 | φ190 | Integral | 1 | 6 | |
| 1200 | φ190 | Integral | 1 | 8 | |
| 1500 | φ190 | Integral | 1 | 8 | |
| 2000 | φ214 | Combined | Housing | 1 | 12 |
| 2000 | φ214 | Segment | 4 | ||
| 2500 | φ214 | Combined | Housing | 1 | 14 |
| 2500 | φ214 | Blade | 2 | ||
| 3000 | φ254 | Combined | Housing | 1 | 18 |
| 3000 | φ254 | Blade | 2 | ||
| 3500 | φ286 | Combined | Housing | 1 | 24 |
| 3500 | φ286 | Blade | 2 | ||
