Press-Formed Panel Reverse Tooling for Wrinkle-Free High-Strength Walls
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Solution Overview
Problem
Existing methods for manufacturing press-formed articles with varying vertical wall heights and curved shapes in automobile body components often result in wrinkling or cracking, leading to increased manufacturing costs and complexity due to the need for multiple press formings or material modifications.
Innovation Solution
A manufacturing method and apparatus that utilize a single press forming process with strategically reversed tooling arrangements, where the metal sheet is held between a pad and punch in one step and between a die and blank holder in another, maintaining a vertically-reversing cross-sectional angle of 0° to 80° to prevent wrinkling and ensure consistent forming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high strength steel sheet is press-formed using normal drawing process or pad bending process to achieve varying vertical wall heights, then the required strength is ensured, but cracks or wrinkling occur in the press-formed article
Solution Approach 1:
The patent applies reverse forming by inverting the tooling arrangement during press forming. Specifically, the punch and blank holder are positioned on the die side while the pad is positioned on the opposite side, creating a vertically-reversing cross-sectional angle of 0° to 80°. This inverted configuration prevents wrinkling and cracking in the vertical walls while achieving the required varying heights and high strength properties.
2Shape
If multiple press formings or material modifications are performed to manufacture press-formed articles with curved shapes and varying vertical wall heights, then the desired shape is achieved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple forming operations into a single press forming process. By using the inverted tooling arrangement with the pad and punch configured to create a vertically-reversing cross-sectional angle, the method simultaneously achieves curved shapes, varying vertical wall heights, and prevents surface defects in one operation, eliminating the need for multiple separate press formings or material modifications.
3Manufacturing precision
If the number of press formings is increased to prevent wrinkling in curved parts, then the surface quality is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent eliminates the need for multiple press formings by inverting the tooling arrangement. The vertically-reversing cross-sectional angle of 0° to 80° created by positioning the punch and blank holder on the die side while the pad is on the opposite side prevents wrinkling in curved parts and varying height sections during a single press forming operation, thereby simplifying the manufacturing process while maintaining high surface quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the production of press-formed articles with high tensile strength (400 MPa or more) and complex shapes, such as those with curved parts, without wrinkling or cracking, in a single press forming step, reducing manufacturing costs and improving material yield.
Implementation Method 1
press forming is performed by inserting the punch into a die so that the punch presses the top plate, thereby making the top plate protrude in the opposite direction
Implementation Method 2
the bent region of the intermediate formed article is bent back in the opposite direction, thereby causing work hardening in the vertical walls of the press-formed article
Data Source
AI summary
The manufacturing method includes a first step in which a pad holding state is established and a second step in which pad draw forming is performed after the first step is completed. In the pad holding state, (a) a part of a blank 15 to be formed into a top plate 21 is held between a pad 13 and a punch 11, and a part of the blank 15 to be formed into a flange 25 is held between a die 14 and a blank holder 12, (b) in a specific press directional cross section of a part of the blank 15 to be formed into a first part, the position of the contacting surface of the blank holder 12 that makes contact with the blank 15 in the direction of pressing is located toward the punch 11 in the direction of arrangement of the pad 13 and the punch 11, compared with the position of the contacting surface of the pad 13 that makes contact with the blank 15 in the direction of pressing, (c) a vertically-reversing cross-sectional angle is more than 0° and equal to or less than 80°, and (d) in a press directional cross section that is different from the specific press directional cross section, the position of the contacting surface of the pad 13 that makes contact with the blank 15 in the direction of the pressing is located toward the pad 13 in the direction of the arrangement, compared with the position of the contacting surface of the blank holder 12 that makes contact with the blank 15 in the direction of pressing.