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Table 2.
Coding of factors and levels for the first group.
| Coding | Factors | ||
|---|---|---|---|
| Groove rotation speed x1 (r/min) |
Lead Angle x2 (°) |
Groove number x3 |
|
| − 1 | 30 | 0 | 10 |
| 0 | 40 | 5 | 12 |
| 1 | 50 | 10 | 14 |