Optimization of Mechanical Properties and Surface Characteristics of PLA+ 3D Printing Materials

Table 10

Grey relational coefficients (GRCs) and grades (GRGs) of the four responses.

No.	Grey relational coefficients (GRCs)				GRG	Ranking
	Ultimate tensile strength (MPa)	Young’s modulus (GPa)	Tensile strain (%)	Surface roughness (Ra)
1	0.360	0.370	1	1	0.683	2
2	0.474	0.477	0.458	0.546	0.489	7
3	0.818	1	0.403	0.333	0.639	4
4	0.429	0.469	0.910	0.506	0.578	5
5	1	0.876	0.518	0.431	0.706	1
6	0.333	0.350	0.553	0.358	0.399	9
7	0.818	0.837	0.333	0.690	0.670	3
8	0.333	0.333	0.792	0.454	0.478	8
9	0.529	0.502	0.736	0.411	0.545	6

The bold values indicate significant values.