Optimization of AL6061-T6 Tube End Forming Process Using Response Surface Method

Table 6

Regression table for tube closing diameter and maximum resultant force .

Term
	Regression coefficient	value	value	Regression coefficient	value	value
Constant	16.520	79.31	≤0.001	15.4700	66.50	≤0.001
	-1.135	-8.59	≤0.001	-0.3506	-2.38	0.034
	-10.078	-76.27	≤0.001	10.5533	71.51	≤0.001
	-0.199	-1.51	0.156	0.3767	2.55	0.024
	-0.039	-0.30	0.773	0.1117	0.76	0.463
	1.277	9.66	≤0.001	-2.2839	-15.48	≤0.001
	0.172	0.48	0.640	0.2338	0.58	0.569
	-1.303	-3.64	0.003	3.1688	7.91	≤0.001
	0.604	1.68	0.116	-0.5112	-1.28	0.224
	-0.079	-0.22	0.828	0.1938	0.48	0.637
	1.162	3.24	0.006	0.2338	0.58	0.569
	0.007	0.05	0.963	0.4106	2.62	0.021
	-1.107	-7.90	≤0.001	1.0444	6.67	≤0.001
	-0.332	-2.37	0.034	-1.4819	-9.47	≤0.001
	,			,