Bending tonnage estimation: P ≈ 1.42 × sheet thickness² × length × tensile strength / (1000 × V-die width); in practice, use the equipment manufacturer's formula and allow a 20% margin.

Key points: - V-die width is generally taken as 6-8 times the sheet thickness (use the larger value for stainless steel). - The punch R angle affects the inner radius and springback. - Bending long sheets requires consideration of deflection compensation (hydraulic cushion or mechanical compensation). - Stainless steel has large springback; prioritize equipment with CNC angle compensation.

When selecting, calculate based on the thickest and longest workpiece; avoid the "good enough" approach.