Gas-Spring Die Set for Wrinkle-Free Composite Plate Bending
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Solution Overview
Problem
Metal-based composite materials, such as those composed of aluminum and ceramic, are prone to rupture or wrinkling during bending due to tensile and compressive stresses when using existing bending methods, which fail to effectively manage stress distribution.
Innovation Solution
A die set with a lower movable part elastically supported by gas springs, allowing for controlled compressive loading from both top and bottom, and a curved pressing surface to distribute stress evenly, reducing tension accumulation and slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional bending methods are used on metal-based composite materials, then the workpiece can be bent into a desired geometry, but the material is likely to cause rupture or crack on the outer side of the bent portion due to tensile stress
Solution Approach 1:
The invention inverts the conventional bending approach by applying compressive stress from both the upper die and lower die simultaneously. Instead of only pressing from above, the lower die's movable part pushes upward against the workpiece's lower surface, creating bidirectional compression that prevents tensile stress concentration and material rupture during bending.
Solution Approach 2:
The invention changes the stress state parameters by transitioning from unidirectional compression to bidirectional compression. The lower movable part's upward push modifies the stress distribution, maintaining compressive stress on the outer side of the bent portion and preventing tensile stress that would cause rupture.
2Shape
If conventional bending methods are used on metal-based composite materials, then the workpiece can be bent, but the material is likely to produce wrinkle on the inner side of the bent portion due to compressive stress
Solution Approach 1:
The invention reverses the stress application direction by having the lower movable part push upward against the workpiece. This bidirectional compression approach balances the compressive stress distribution, preventing excessive compression on the inner side of the bent portion that would cause wrinkling.
Solution Approach 2:
The invention modifies the compressive stress parameters by applying compression from both upper and lower dies simultaneously. This changes the stress distribution pattern, reducing the concentration of compressive stress on the inner side of the bent portion and preventing wrinkle formation.
3Shape
If conventional bending methods are used, then the workpiece can be pressed with the upper punch, but tension generated from the origination point of bending accumulates in the gap between the punch and die, making it likely to rupture the workpiece
Solution Approach 1:
The invention inverts the stress application by having the lower movable part push upward against the workpiece's lower surface. This bidirectional compression prevents tension accumulation in the gap between dies by maintaining continuous compressive stress, eliminating the tension rupture risk.
Solution Approach 2:
The invention changes the stress state from unidirectional to bidirectional compression, modifying the tension parameter to eliminate it entirely. The upward push from the lower movable part maintains compressive stress throughout the bending process, preventing tension accumulation at the bending origination point.
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
The die set effectively suppresses rupture and wrinkling by maintaining stable compressive stress distribution, ensuring even bending across the workpiece length and reducing operational variations, while being cost-effective and easy to install.
Implementation Method 1
a reaction force generating member that elastically supports the lower movable part from below
Implementation Method 2
As the length of a piston outside of a cylinder becomes shorter by compression, reaction force created by a gas inside a cylinder increases
Data Source
AI summary
A die set for bending a metal plate workpiece includes a lower die for placing the workpiece, an upper die having a pressing surface which presses the workpiece toward the lower die by movement, a lower movable part provided in the lower die and being slidable in the same direction as the direction of the upper die movement, and a gas spring elastically supporting the lower movable part from below. The pressing surface of the upper die is moved, contacts with the upper surface of the workpiece and presses the workpiece toward the lower die. The lower movable part being elastically supported by the gas spring from below brings an opposing surface into contact with the lower surface of the workpiece and makes the upper die to be close to the lower die while applying force in the upward which is opposite direction of the upper die movement.