Optimization of Surface Roughness in Drilling Medium-Density Fiberboard with a Parallel Robot

Table 7

The mean response table for Ra factor.

Level	Control factors
	Surface roughness (Ra)
	A	B	C
Level 1	3.382	4.433	2.966
Level 2	4.138	3.653	3.752
Level 3	—	3.194	4.561
Delta	0.756	1.240	1.595