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.
(2)
The method of judging fracture in a metal stamped product according to (1), wherein the production conditions further includes, in addition to the sliding speed, at least one of production time, ambient temperature, humidity, blank holding force, lot number of work, blank process position information traceable from material lot, tensile strength of work, yield strength of work, amount of uniform elongation of work, and thickness of work.
(3)
The method of judging fracture in a metal stamped product, according to (1), wherein, the extraction step extracts the reference data, which gives the minimum
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 targef data for fracture judgment; and
a judgment process 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. (14)
A computer-readable recording medium storing program according to (13) .
ADVANTAGEOUS EFFECTS OF INVENTION [0038]
According to this invention, cracks possibly produced in the process of stamping of various metal materials such as those of iron-base, non-iron-base and stacked products may precisely be judged.
BRIEF DESCRIPTION OF THE DRAWINGS [0039]
FIG. 1 is a drawing illustrating configurations of a stamping press and a fracture judgment apparatus.
FIG. 2 is a flow chart regarding measurement of strain of a target die to be measured, and acquisition of production conditions.
FIG. 3 is a flow chart regarding judgment of fracture.
FIG. 4 is a flow chart regarding judgment of fracture.
FIG. 5 is a flow chart regarding judgment of