Hat-Shape Bending with Suspended Upright Wall Forming
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Solution Overview
Problem
Bending high-tensile strength steel plates into hat shapes using conventional methods often results in warping of the upright wall portion due to residual stress and bending/ironing, leading to wrinkles and strain.
Innovation Solution
A bending method and apparatus that clamps the workpiece with dies, moving the first-face forming die perpendicular to the workpiece and the second-face forming die parallel to it, suspending the upright wall portion to prevent bending and ironing, and using a cam mechanism with varying gradients to control movement speeds and reduce stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional draw forming or form molding is used to shape high-tensile strength steel plates into hat shapes, then the workpiece can be formed into the desired cross-section shape, but the upright wall portion becomes warped due to residual stress and bending/ironing
Solution Approach 1:
The forming process is segmented into two independent face-forming operations: first-face forming die shapes the first face and upright wall portion, while second-face forming die shapes the second face. This segmentation allows each die to operate independently without applying harmful bending or ironing to the upright wall portion, thereby preventing warping while achieving the desired hat shape cross-section
Solution Approach 2:
Instead of using a single die that applies bending and ironing to the upright wall portion (conventional approach), the invention inverts the approach by using two face-forming dies that shape the faces independently. The upright wall portion is formed as a result of the interaction between the two face-forming operations, rather than being directly bent by a die, thus eliminating the warping problem
2Productivity
If the second-face forming die moves quickly in the second direction during shaping, then productivity is improved, but excess occurs in the workpiece causing corrugation, wrinkles, and strain around the upright wall portion
Solution Approach 1:
The movement speed of the second-face forming die in the second direction is dynamically adjusted during the shaping process. The die moves at a controlled, variable speed rather than a constant high speed, allowing the workpiece material to flow appropriately without creating excess that would lead to corrugation or wrinkles, while still maintaining high overall productivity
Solution Approach 2:
The second-face forming die is positioned and moved in a predetermined manner before final contact with the workpiece. This preliminary positioning and controlled movement sequence ensures that the workpiece is properly prepared and that material flow is controlled, preventing excess and surface defects while maintaining efficient forming
Data Source
AI summary
A first-face forming portion of a workpiece and a second-face forming portion spaced apart from it by the length of an intermediate portion are clamped with a first-face forming die and a second-face forming die, respectively. The first-face forming die is moved either upward or downward and the second-face forming die is moved in a direction toward the first-face forming die, and the second-face forming die is pressed against the first-face forming die to shape the upright wall portion.