From: Experimental investigation of surface roughness, flank wear, chip morphology and cost estimation during machining of hardened AISI 4340 steel with coated carbide insert
Parameters
Symbol
Unit
Levels
1
2
3
Cutting speed
v
m/min
100
160
220
Feed
f
mm/rev
0.05
0.09
0.13
Depth of cut
d
mm
0.2
0.4
0.6