Press Forming with Deformation Space for Wrinkle Suppression
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Solution Overview
Problem
Press forming methods struggle to suppress wrinkles in formed products, especially when it is difficult to control the distance between a pad and a die, leading to increased equipment costs and reduced press tooling life, particularly when forming larger components with high-strength steel sheets.
Innovation Solution
A press forming method using a die with a curved support surface and a pad with corresponding deformation portions, where the metal sheet is pinched and then deformed along these features to form a single arc, allowing for effective suppression of wrinkles without precise control over the pad and die clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If press forming is performed with higher load to ensure pressurizing force and maintain clearance, then wrinkle suppression is improved, but equipment cost increases and press tooling life decreases
Solution Approach 1:
The method applies preliminary pinching action to the metal sheet using the die and pad before the main press forming operation. By pre-constraining the metal sheet at the flange portion, the material is prepared in advance to resist buckling during subsequent forming, eliminating the need for excessive pressurizing force and maintaining reasonable equipment specifications.
Solution Approach 2:
The press forming process is divided into distinct stages: a first step where the die and pad pinch the flange portion to constrain it, and a second step where the punch performs the main press forming. This segmentation allows each component to perform its specific function efficiently, with the pinching action preparing the material and the punch completing the forming, thereby reducing overall equipment requirements.
2Manufacturing precision
If press forming is performed with higher load to maintain clearance, then wrinkle suppression is improved, but press tooling life decreases
Solution Approach 1:
The preliminary pinching action constrains the metal sheet flange portion before the main press forming operation, preventing material instability in advance. This eliminates the need for excessive clearance control during the forming process, reducing peak loads on the press tooling and thereby extending its operational life.
Solution Approach 2:
The method dynamically adjusts the constraint mechanism by using the pinching action to adaptively control material flow during forming. This dynamic approach allows the process to maintain wrinkle suppression under varying conditions without requiring consistently high loads, thus protecting the tooling from excessive wear and extending its service life.
3Productivity
If larger components are formed by integrating multiple components, then productivity is improved, but the load required to suppress wrinkles increases making it difficult to secure pressurizing force
Solution Approach 1:
The forming process is segmented into a pinching step and a press forming step. The pinching action locally constrains the flange portion of large integrated components, preventing buckling in critical areas without requiring excessive overall pressurizing force. This enables the forming of larger integrated components with manageable force requirements.
Solution Approach 2:
Instead of applying uniform high pressure across the entire large component, the method applies localized pinching force at the flange portion where buckling is most likely to occur. This localized quality approach suppresses wrinkles at critical locations while maintaining reasonable overall pressurizing force levels, enabling productive formation of large integrated components.
Data Source
AI summary
A press forming method includes a first step of pinching one part of a metal sheet by means of a die and a pad, and a second step of moving a punch in a direction in which the punch approaches the die relatively to perform press forming on the metal sheet. The die has a first support surface which has an edge including a curved portion. The pad has a second support surface facing the first support surface of the die. The first support surface includes a first flat portion, and a first deformation portion which protrudes or is recessed with respect to the first flat portion. The second support surface includes a second flat portion which faces the first flat portion, and a second deformation portion which is recessed or protrudes with respect to the second flat portion so as to correspond to the first deformation portion. The first deformation portion is provided on a normal line of the curved portion as viewed from a pressing direction. When a space between the first deformation portion and the second deformation portion is assumed to be a deformation space, in the second step, press forming is performed so that portions of the metal sheet which are on both sides of the deformation space flow into the deformation space, and the metal sheet deforms along the first deformation portion and the second deformation portion in the deformation space.