Press Forming of Curved Side Walls Using Tilted Beads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing press forming methods for high-strength steel sheets often result in fractures and wrinkles, especially in curved automotive parts, due to limitations in material movement and surface accuracy, and previous solutions have issues with bead orientation and effectiveness in preventing deformation.
Innovation Solution
A press forming method involving a preforming process to create tilted bead portions on the side wall surfaces of convex and concave curve sites, followed by a final forming process that induces pseudo shear deformation to reduce compressive and tensile deformation, using angles between 5° to 60° and ensuring the bead orientation aligns with the forming direction to minimize line length differences and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If high-strength steel sheet is used to achieve weight reduction, then weight reduction is improved, but forming defects such as fractures and wrinkles occur more frequently
Solution Approach 1:
The patent applies preliminary action by pre-forming bead portions on the blank material before the main press forming process. These bead portions are strategically positioned and pre-shaped to control material flow during subsequent forming, preventing fractures and wrinkles that would otherwise occur when forming high-strength steel into curved shapes with flange portions.
2Ease of manufacture
If conventional press forming is used for curved parts with steep curves, then manufacturing simplicity is maintained, but fractures and wrinkles are likely to occur
Solution Approach 1:
The patent introduces a pre-forming step that creates bead portions on the blank material before main forming. This preliminary action prepares the material distribution in advance, enabling the subsequent forming process to achieve high surface accuracy in curved portions without increasing overall process complexity significantly.
Solution Approach 2:
The patent applies local quality by creating bead portions with specific shapes and orientations at localized regions where fractures and wrinkles are most likely to occur. The bead portions have different characteristics (convex/concave, tilted angles) positioned at specific locations to address local material flow issues rather than applying a uniform approach throughout the entire blank.
3Reliability
If bead portions are pre-formed to control material flow, then fractures and wrinkles are reduced, but the forming process becomes more complex
Solution Approach 1:
The patent uses preliminary action to pre-form bead portions that control material flow during the main forming process. This approach improves forming quality by preventing defects, while the complexity is managed by integrating the bead formation into the existing press forming workflow through systematic positioning and shaping of beads at critical regions.
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 reduces fractures and wrinkles in press-formed products with convex and concave shapes by controlling material movement through pseudo shear deformation, enhancing the surface accuracy and preventing deformation in the flange and top portions.
Implementation Method 1
a final forming process of forming the press-formed product by squashing the bead portions in the intermediate formed product and extending a surface portion corresponding to the side wall portion in a bead orthogonal direction orthogonal to a long axis of the bead portion such that pseudo shear deformation occurs to the surface portion corresponding to the side wall portion
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(b)
Figure 3
AI summary
A press forming method according to the present invention forms a press-formed product 1 including a top portion 3, a side wall portion 7, and a flange portion 9, the press-formed product 1 including a convex curve site 11 curved in a convex shape and a concave curve site 13 curved in a concave shape in a height direction. The press forming method includes a preforming process of forming an intermediate formed product 31 in which bead portions 37 are formed at side-wall corresponding surface portions 33 corresponding to the side wall portion 7 on both sides of each of the convex curve site 11 and the concave curve site 13 in a longitudinal direction, and a final forming process of forming the press-formed product 1 by squashing the bead portions 37 in the intermediate formed product 31 so that pseudo shear deformation occurs to the side-wall corresponding surface portions 33. At the preforming process, the bead portions 37 are each tilted so that an end part of the bead portion 37 on the convex curve site 11 side is farther from a baseline 35 corresponding to a top side ridge line portion 5 between the top portion 3 and the side wall portion 7 and the other end part of the bead portion 37 on the opposite side is closer to the baseline 35.