PURPOSE: To quantitatively evaluate the failure of a press die at a design stage and to easily correct design graphic only by changing the value of a parameter.
CONSTITUTION: After the three-dimensional model 60 of a press product to be worked is prepared by using a parametric CAD device, an extrapolation surface (ripple restraint surface) 56 inclining at an inclined angle θk in the prescribed range of a location being away from the three-dimensional model 60 by an offset dimensional Lj in a press direction is prepared by defining the offset dimension Lj and the inclined angle θk as parameters. Subsequently, an interpolation surface 70 to be the three-dimensional shape of press stock at the inside of the extrapolation surface 56 is prepared when the press stock is brought into close contact with the extrapolation surface 56 and the propriety of the extrapolation surface 56 is judged from the distribution of the distance Ld in the press direction of the interpolation surface 70 and the three-dimensional model 60. When the extrapolation surface is not judged as a proper surface, the offset dimension Lj and inclined angle θk are changed the extrapolation surface 56 is prepared again.
NAKAGAWA NORIHIKO
NEGISHI TAKATOSHI
YAMADA NOBORU
