Preformed Bead Press Forming for Breakage and Wrinkle Control
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Solution Overview
Problem
Existing press forming methods for automobile components face issues with breakage and wrinkles, particularly in high-strength steel sheets, due to complex mold structures and restricted component forms, which increase manufacturing costs and limit formability.
Innovation Solution
A two-stage press forming method that preforms a convex or concave bead shape in strategic locations on the metal sheet to prevent breakage and wrinkles, using Finite Element Method (FEM) analysis to determine optimal bead shape and position, allowing for continuous formation of top board, vertical wall, and flange portions without a complicated mold structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the steel sheet strength is increased to improve weight saving and collision safety, then the strength increases, but poor forming such as breakage and wrinkles occurs in press forming
Solution Approach 1:
The invention applies preliminary action by pre-forming bead shapes (convex or concave) in strategic locations on the metal sheet before the final press forming operation. These pre-formed beads control material flow and strain distribution during subsequent forming, preventing breakage and wrinkles in high-strength steel sheets while maintaining the desired final component shape
2Manufacturing precision
If a divided wrinkle-pressing mold structure is used to optimize wrinkle-pressing force in each divided site, then wrinkle suppression improves, but the mold structure becomes complicated and manufacturing cost increases
Solution Approach 1:
Instead of using a complex divided mold structure, the invention pre-forms bead shapes in specific locations before the final press forming. This preliminary action controls material flow and reduces wrinkle-prone areas, achieving wrinkle suppression with a simpler, undivided mold structure
Solution Approach 2:
The invention applies local quality by creating bead shapes with specific dimensions and locations tailored to the particular risk areas of each component. The bead shape parameters (depth, length, position) are optimized for each application, providing localized wrinkle prevention without requiring a complex divided mold structure
3Manufacturing precision
If a variable press pressure bead is used to control inflow distribution and improve formability, then formability improves, but a more complicated mold structure is required increasing mold cost
Solution Approach 1:
The invention pre-forms bead shapes with optimized dimensions and positions before the final press forming operation. These pre-formed beads control material inflow distribution during forming, improving formability without requiring variable press pressure mechanisms or complicated mold structures
Solution Approach 2:
The invention changes geometric parameters by creating bead shapes with specific depths, lengths, and positions on the metal sheet. These parameter changes in the preform stage control material flow during pressing, achieving improved formability through geometric modification rather than complex pressure control mechanisms
4Manufacturing precision
If wrinkle-pressing force in the flange portion is increased to suppress wrinkles, then wrinkle suppression improves, but material inflow is constrained causing breakage
Solution Approach 1:
The invention pre-forms bead shapes in locations corresponding to risk sites for breakage and wrinkles before the final press forming. These pre-formed beads control material flow and strain distribution, suppressing wrinkles without requiring excessive wrinkle-pressing force that would cause breakage
Solution Approach 2:
The invention applies local quality by placing bead shapes with specific dimensions at strategic locations on the metal sheet corresponding to risk areas. This localized pre-forming controls material flow precisely where needed, suppressing wrinkles in flange portions without overly constraining overall material inflow and preventing breakage
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
This method effectively suppresses breakage and wrinkles, improving yield and formability while reducing manufacturing costs and component form restrictions, by collapsing the bead shape at risk areas to control material flow and strain distribution.
Implementation Method 1
a convex or concave bead shape is preformed in a position of a flat metal sheet as a raw material corresponding to a neighborhood of a position generating breakage or flange wrinkles when the raw material is formed into a product shape
Data Source
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AI summary
[TASK] It is to provide a press forming method comprising a press process of two or more stages, which suppresses the generation of breakage or wrinkles in the bulging or drawing without involving a mold of a complicated structure, an increase of a press process or a restriction of a component form and improves the yield and formability effectively. [SOLUTION FOR TASK] A method for press forming a product having a shape of a top board portion, a vertical wall portion continuously formed from the top board portion and a flange portion continuously formed from the vertical wall portion at a press process of two or more stages, characterized in that a convex or concave bead shape is preformed in a position of a flat metal sheet as a raw material corresponding to a neighborhood of a position generating breakage or flange wrinkles when the raw material is formed into a product shape, and thereafter a product shape is press formed from the raw material having the preformed bead shape.