Optimization of Surface Quality and Power Consumption in Machining Hardened AISI 4340 Steel

Table 4

The results of experiments and S/N ratio values.

Exp. no.	Control factors			Surface roughness, Ra (um)	S/N ratio for Ra (dB)	Cutting power, Cp (kW)	S/N ratio for Cp (dB)
	Tool type	Cutting speed	Feed rate
1.	1	320	0.1	1.9008	15.8635	400	−52.0412
2.	1	320	0.18	1.2460	1.1698	416	−52.3819
3.	1	320	0.26	1.2484	−0.3072	450	−53.0643
4.	1	450	0.1	1.1564	−1.2215	615	−55.7775
5.	1	450	0.18	0.9371	−1.4229	620	−55.8478
6.	1	450	0.26	1.2001	−2.8353	640	−56.1236
7.	1	575	0.1	0.8501	−4.0770	722	−57.1707
8.	1	575	0.18	0.9792	−5.4739	765	−57.6732
9.	1	575	0.26	1.2236	−8.8245	788	−57.9305
10.	2	320	0.1	0.4162	−2.7976	385	−51.7092
11.	2	320	0.18	0.6624	−1.2742	395	−51.9319
12.	2	320	0.26	1.2525	−0.6443	421	−52.4856
13.	2	450	0.1	0.3642	−1.4008	580	−55.2686
14.	2	450	0.18	1.1123	−2.3785	594	−55.4757
15.	2	450	0.26	1.8492	−2.7661	602	−55.5919
16.	2	575	0.1	0.5494	−5.2822	691	−56.7896
17.	2	575	0.18	0.6016	−8.3361	751	−56.2716
18.	2	575	0.26	2.5646	−8.3361	771	−56.5345