Patent ID: 8464591
Filing Date: 2013-06-18
Classification: B21D,G01N

Abstract:
1. A method of judging fracture in a metal stamped product which judges fracture in a metal stamped product formed using a punch and a die, using a strain measuring unit which measures strain of at least either of the punch and the die selected as a target die to be measured, and a storage unit which stores, as reference data, strain of the target die to be measured over the entire period or a partial period from the start time of stamping to the finishing time of stamping, and production conditions including at least sliding speed, with respect to a plurality of stamped product having no crack produced therein, the method comprising: an acquisition step which acquires, in a target stamping for fracture judgment, and as target data for fracture judgment, strain of the target die to be measured by the strain measuring unit over the entire period or a partial period from the start time of stamping to the finishing time of stamping, and acquires production conditions including at least sliding speed; an extraction step which extracts, from the reference data, the one satisfying a predetermined condition as comparative data, based on the production conditions of the reference data extracted from the storage unit, and also based on the production conditions of the target data for fracture judgment, and a judgment step which compares strain in the comparative data and strain in the target data for fracture judgment, and judges occurrence of a crack in a stamped product, if a predetermined condition is satisfied.