Press Molding Die-Pad Geometry for Wrinkle Suppression
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Solution Overview
Problem
Existing press forming methods struggle to suppress wrinkles in formed products, especially when it is difficult to control the distance between the pad and the die, leading to increased equipment costs and reduced press tooling life, particularly when forming larger components with high-strength steel sheets.
Innovation Solution
The press forming method employs a press apparatus with a die and pad configuration that includes deformation portions with specific curvature and dimensions to pinched metal sheets, allowing for sufficient pad load application even without precise control of the pad and die clearance, thereby suppressing wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If higher load is applied 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 invention applies local quality by providing deformation portions with specific curvature radii (R1 ≥ 50mm, R2 ≥ 100mm) only in the regions where wrinkles are most likely to occur on the die and pad surfaces, rather than uniformly across the entire surface. This localized geometric modification enables effective wrinkle suppression while avoiding the need to increase overall pressurizing force, thus preventing increased equipment cost and tooling wear.
2Productivity
If larger components are formed by integrating multiple components, then productivity is improved, but the load required to suppress wrinkles increases making it more difficult to secure pressurizing force
Solution Approach 1:
The deformation portions with optimized curvature radii are strategically positioned at locations where wrinkles are most likely to form during press forming of large integrated components. This localized approach allows the pressurizing force to be effectively distributed and utilized where most needed, enabling the formation of larger integrated components without requiring a proportional increase in overall pressurizing force.
Solution Approach 2:
The invention employs curved surfaces with specific radius constraints (R1 ≥ 50mm, R2 ≥ 100mm) on the deformation portions of the die and pad. These curved geometries facilitate more uniform stress distribution and improve the effectiveness of pressurizing force in suppressing wrinkles across large component areas, enabling integration of multiple components into larger formed pieces.
Data Source
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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.