Rotation speed (r/min)

Drilling torque (N・m)

Feeding resistance (KN)

Maximum value (N・m)

average value (N・m)

standard deviation

Maximum value (KN)

average value (KN)

standard deviation

90

552.8

525.6

12.4

6.95

5.77

0.56

140

469.4

420.6

14.7

6.14

5.35

0.45

190

373.7

344.3

15.3

4.82

4.12

0.41

240

290

337.3

221.8

309.5

178.4

15.7

16.8

4.22

2.86

3.66

2.86

0.23

0.53