Bending Angle Prediction Model Based on BPNN-Spline in Air Bending Springback Process

Table 2

Variable parameters with their levels.

Level	t (mm)	R (mm)	r (mm)	M	D (mm)
1	1	0.2	0.2	0.61	5
2	1.4	0.6	0.6	1.15	4.4
3	2	1	1	1.85	4
4	—	—	—	1.93	3
5	—	—	—	2.07	2.6