Optimization of Machining Parameters of Natural/Glass Fiber with Nanoclay Polymer Composite Using Response Surface Methodology

Table 3

Independent variables and levels used for design of experiments.

Independent factors	Unit	Notation	Levels
			−1	0	+1
Nanoclay	%	X1	3	6	9
Feed rate	mm/rev.	X2	0.1	0.2	0.3
Spindle speed	rpm	X3	16	24	32
Depth of cut	mm	X4	1.0	1.5	2.0