Curved Recessed Press Forming Part for Fracture and Wrinkle Control
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Solution Overview
Problem
Existing press forming technologies struggle to control fractures and wrinkles in high-strength metal sheets, particularly in parts with curved recessed shapes, due to inadequate material movement and increased tool size and cost issues.
Innovation Solution
A press forming part design with a curved recessed shape featuring a larger bending radius of the die shoulder in the middle portion, a minimum bending radius smaller than the punch shoulder, and additional features to restrain rotational motion, along with a wider flange width in the middle portion, facilitates controlled material movement to prevent fractures and wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high-strength metal sheet is used for press forming, then the collision safety and weight reduction are improved, but the ductility decreases causing fracture generation
Solution Approach 1:
The patent applies different bending radii to different regions of the die shoulder. The intermediate portion has a larger bending radius than the both-end portions, creating local quality variations in the curved portion. This local differentiation optimizes material flow specifically in the curved region where fractures are most likely to occur, while maintaining high strength properties of the metal sheet overall.
2Weight of moving object
If a high-strength metal sheet is used for press forming, then the weight reduction is achieved, but the yield strength increases causing wrinkle generation
Solution Approach 1:
The die shoulder is designed with non-uniform bending radius where the intermediate portion has a larger radius than the end portions. This local quality variation creates favorable stress distribution in the curved portion during press forming, preventing wrinkle generation in high-strength metal sheets while maintaining overall weight reduction benefits.
3Ease of manufacture
If a constant bending radius is used in the curved portion, then the manufacturing is simplified, but the material flow is inadequate causing fracture and wrinkles
Solution Approach 1:
Instead of using a constant bending radius throughout the curved portion, the patent implements local quality variation by making the intermediate portion's bending radius larger than the end portions. This design optimizes material flow in the critical curved region where fractures and wrinkles are most likely to occur, improving manufacturing precision without significantly complicating the manufacturing process.
4Reliability
If the bending radius of the die shoulder is increased uniformly, then the wrinkle generation is reduced, but the fracture control in the flange portion becomes inadequate
Solution Approach 1:
The patent avoids uniform increase of bending radius by implementing local differentiation: the intermediate portion has a larger bending radius to prevent wrinkles, while the end portions maintain smaller bending radii to ensure adequate material flow to the flange portion and prevent fractures. This local quality approach simultaneously addresses both wrinkle and fracture control requirements.
Data Source
AI summary
A press forming part includes: a top portion; a side wall portion continuous from the top portion via a punch shoulder; and a flange portion continuous from the side wall portion via a die shoulder, the press forming part having a curved portion curved in a recessed manner in a top view, wherein a bending radius of the die shoulder in the curved portion is increased from an end side toward a middle portion of the curve.