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

Table 5

The S/N response table for Ra factor.

Level	Control factors
	Surface roughness (Ra)
	A	B	C
Level 1	−10.321	−12.754	−9.289
Level 2	−12.157	−11.063	−11.359
Level 3	—	−9.900	−13.070
Delta	1.836	2.854	3.781