Table 2.
Effect of sequential drilling on delamination and uncut fibers in fabricated composite specimens.
| Test | Final hole diameter (mm) |
Number of drills used | Drill bit diameter (mm) | Feed (mm min− 1) |
Spindle speed (rpm) |
Hole entrance | Hole exit | ||
|---|---|---|---|---|---|---|---|---|---|
| Fed | Fu | Fed | Fu | ||||||
| 1 | 7 | 1 | 7 | 1000 | 500 | 1.385 | 61.197 | 1.489 | 38.076 |
| 2 | 7 | 2 | 3–7 | 1000 | 500 | 1.374 | 72.01 | 1.378 | 37.523 |
| 3 | 7 | 3 | 3–5-7 | 1000 | 500 | 1.313 | 75.907 | 1.347 | 36.785 |
| 4 | 10.1 | 1 | 10.1 | 1000 | 500 | 1.321 | 63.142 | 1.261 | 14.107 |
| 5 | 10.1 | 2 | 5–10.1.1 | 1000 | 500 | 1.304 | 65.01 | 1.257 | 13.295 |
| 6 | 10.1 | 3 | 3–7-10.1 | 1000 | 500 | 1.281 | 62.704 | 1.231 | 1.92 |