Two-Step Press Forming for Sharp Character Line Alignment
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Solution Overview
Problem
Existing methods for manufacturing press-formed products, such as automobile panels, often result in line misalignment and insufficient tension in sharp character lines due to deviations during the forming process, especially when forming sharp ridge line portions with high curvature and bending angles.
Innovation Solution
A two-step press-forming method where the blank material is first formed into an intermediate shape with a higher excess thickness portion, and then into a target shape with specific cross-sectional line lengths and curvature radii, using a press forming die with adjustable forming surfaces to prevent material deviation and ensure accurate formation of character lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If press forming is performed in one step to form sharp ridge line portions with high curvature, then the character line can be clearly formed, but line misalignment and material deviation occur during the forming process
Solution Approach 1:
The press forming process is divided into two distinct steps: first forming an intermediate shape with larger radius of curvature, then forming the final sharp ridge line portions. This segmentation allows the forming process to proceed in controlled stages, preventing material deviation while achieving the desired sharp character lines.
Solution Approach 2:
The intermediate shape is formed as a preliminary stage before the final forming. This preliminary action creates a controlled intermediate state that prepares the material for the subsequent sharp ridge line formation, ensuring proper material distribution and tension before the final character line formation.
2Shape
If the radius of curvature of ridge line portions is reduced to achieve sharp character lines, then aesthetic appearance is improved, but forming defects and line misalignment increase
Solution Approach 1:
The forming process is segmented into two steps with different radius of curvature requirements. The first step uses a larger radius (R1) for the intermediate shape, while the second step forms the final sharp ridge lines with smaller radius (R2). This segmentation allows each step to be optimized for its specific geometric requirements.
Solution Approach 2:
The radius of curvature parameter is changed between the two forming steps. The intermediate shape has a larger radius of curvature that is easier to form without defects, while the final product achieves the desired sharpness through controlled parameter adjustment in the second forming step.
3Reliability
If two-step press forming is used to prevent forming defects, then line misalignment is reduced, but the number of forming steps increases
Solution Approach 1:
The forming process is divided into two sequential steps: first forming an intermediate shape, then forming the final product with sharp ridge lines. This segmentation into controlled stages reduces line misalignment and forming defects compared to single-step forming.
Solution Approach 2:
The intermediate shape formation serves as a preliminary action that prepares the material for the final forming step. This preliminary stage establishes proper material distribution and tension, enabling successful formation of sharp ridge lines in the subsequent step.
4Manufacturing precision
If the excess thickness portion height is increased to prevent material deviation, then line alignment is improved, but the intermediate shape complexity increases
Solution Approach 1:
The height of the excess thickness portion is specifically controlled within the range of 5-15 mm in the intermediate shape. This parameter optimization ensures sufficient material availability to prevent deviation during final forming, while maintaining manageable intermediate shape complexity.
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 approach effectively prevents line misalignment and enhances the tension in the ridge line portions, allowing for the clear formation of sharp character lines with precise curvature and bending angles, improving the aesthetic appearance of press-formed products like automobile panels.
Implementation Method 1
press-forming a blank material (1) into an intermediate shape, and further press-forming the blank material from the intermediate shape into a press-formed product having a target shape
Data Source
AI summary
A press-formed product is manufactured by press-forming a blank material into an intermediate shape, and further press-forming the blank material from the intermediate shape into the press-formed product having a target shape. A product portion of the target shape includes a first ridge line portion and a second ridge line portion each having a radius of curvature of 20 mm or smaller and a bending angle of 130 degrees or larger. The product portion of the intermediate shape has a curved shape having a radius of curvature of 100 mm or larger or a linear shape in a specific cross section. A height of an excess thickness portion of the intermediate shape is higher than 10 mm with respect to a peripheral portion and lower than a height of the excess thickness portion of the target shape.