Material Removal Rate, Electrode Wear Rate, and Surface Roughness Evaluation in Die Sinking EDM with Hollow Tool through Response Surface Methodology

Table 5

The analysis of variance for main and interaction effects of parameters on EWR.

Source	SS	DOF	MS	value	Prob >	At 95% CI	% contribution
Model	170.14	5	34.03	23.50	<0.0001	Significant
A	114.76	1	114.76	79.24	<0.0001	Significant	70.39
B	2.64	1	2.64	1.83	0.2037		3.25
C	1.36	1	1.36	0.94	0.3531		0.94
B^2	11.69	1	11.69	8.07	0.0161		0.09
BC	39.69	1	39.69	27.40	0.0003	Significant	0.39
Lack of fit	13.19	7	1.88	2.75	0.1725	Nonsignificant
	0.9144
Adjusted	0.8755
Predicted	0.7301

CI: confidence interval; DOF: degrees of freedom; MS: mean sum of squares; SS: sum of squares.