Blank Edge Two-Stage Cutting for Stretch Flange Crack Prevention
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Solution Overview
Problem
Existing methods for preventing edge cracks due to stretch flange deformation in press forming are either ineffective or constrain the shape of the pressed component, limiting its flexibility and formability.
Innovation Solution
A two-stage cutting processing method is employed, where a partial beam-shaped overhang portion is formed at the risk site in the first cutting step and cut off in the second step, reducing strain input and preventing edge cracks without constraining the component shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single cutting method is used, then manufacturing process is simple, but edge cracks occur due to stretch flange deformation
Solution Approach 1:
The cutting process is divided into two distinct stages: first cutting creates a partial overhang portion, and second cutting removes it. This segmentation allows the edge to be prepared in a way that prevents stretch flange deformation and edge cracks, while maintaining overall process manageability through clear separation of operations.
Solution Approach 2:
The first cutting creates a partial overhang portion as a preliminary structure before the final cutting is performed. This preliminary action modifies the edge geometry in advance to prevent the occurrence of edge cracks during subsequent press forming operations, addressing the root cause before final shaping.
2Reliability
If blank shape is constrained to prevent stretch flange crack, then edge crack is reduced, but degree of freedom of product shape is constrained
Solution Approach 1:
The cutting treatment is applied locally only to specific edges where stretch flange deformation and edge cracks are predicted to occur, rather than constraining the entire blank shape. This allows the majority of the product shape to maintain full design freedom while providing targeted protection against edge cracks at critical locations.
Data Source
AI summary
Provided is a technology capable of suppressing an edge crack occurring due to stretch flange deformation without being constrained by a target pressed component shape. The technology includes two-stage cutting processing of, when it is estimated that there is concern about risk of occurrence of an edge crack due to stretch flange deformation on an edge of a material (1) to be pressed in press forming, performing twice cutting processing on an edge including at least a site where there is concern about risk of occurrence of the edge crack as pre-processing for press forming in which there is concern about risk of occurrence of the edge crack. In the two-stage cutting processing, cutting to form a partial, beam-shaped overhang portion at a position including a site where there is concern about risk of occurrence of the edge crack is performed in the first cutting and the overhang portion is cut in the second cutting.