METHOD FOR DECIDING BENDING CONDITION OF METALLIC TUBE

PROBLEM TO BE SOLVED: To provide a method by which the optimum bending condition when a metallic tube is bent is easily decided. SOLUTION: In a trial bending stage (SA2), the metallic tube 20 is actually bent under a trial bending condition which is preliminarily set using a bending device 10 and measuring pressurizing die load L1act, measuring pressure die load L2act and measuring booster speed vbact are actually measured. In a strain calculating stage (SA4), by FEM analysis based on the measured measuring pressurizing die load L1act, measuring pressure die load L2act and measuring booster speed vbact, thickness strain t1 on the outside of bending and thickness strain t2 on the inside of bending of the metallic tube 20 corresponding to set pressurizing die load L1set, set original pressure P2set of a pressure die 34 and set booster speed vbset are calculated. In an optimum bending condition deciding stage (SA6), because the optimum bending condition is decided based on the thickness strain t1 on the outside of bending and thickness strain t2 on the inside of bending, the optimum bending condition is decided easily and in a short time.