Hydraulic Press Forming With Two-Stage Die Closure for Aluminum Sheets
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Solution Overview
Problem
Existing methods for forming complex metal alloy components, such as those from high-strength lightweight aluminum alloys, face challenges like spring-back and low formability, particularly in T4 and T6 conditions, and require specialized tooling or press upgrades for high-speed die closure, which increases setup costs.
Innovation Solution
A process involving heating a metal alloy sheet to Solution Heat Treatment temperature, initiating formation with a fast, non-powered die closure followed by a slower powered closure, and holding the component in dies during cooling, allowing for complex component formation without significant press modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If high-speed die closure (above 100 mm/s) is used to form complex aluminum alloy components, then component complexity and draw depth are improved, but specialized tooling and press upgrades are required which substantially increases setup cost
Solution Approach 1:
The patent applies dynamic speed variation during the forming process by transitioning from a fast non-powered stroke (above 100 mm/s) for the majority of the forming stroke to a slower powered stroke (less than 100 mm/s) for the final completion. This dynamic approach allows complex components to be formed with high draw depth while using conventional presses without expensive high-speed upgrades, as the fast speed is only needed temporarily during the unpowered portion of the stroke.
Solution Approach 2:
The forming process is segmented into two distinct phases: a first phase using a fast non-powered stroke for the majority of the forming action, and a second phase using a slower powered stroke for completion. This segmentation allows each phase to use the most appropriate speed for its specific function, achieving complex component formation without requiring the entire press system to operate at high speed, thereby avoiding substantial setup costs.
2Ease of manufacture
If conventional hydraulic presses with slow powered stroke speed (less than 50 mm/s) are used, then setup cost is reduced, but component complexity and draw depth are limited
Solution Approach 1:
The patent transforms the conventional slow powered stroke into a dynamic two-stage process. The first stage utilizes a fast non-powered stroke (achieved by releasing the hydraulic hold and allowing gravity to accelerate the ram) to accomplish the majority of the forming action at high speed. The second stage uses the powered stroke to complete the forming at slower speed. This dynamic transformation allows conventional presses to achieve complex component formation capabilities typically reserved for high-speed presses.
Solution Approach 2:
The patent performs the majority of the forming action during the non-powered stroke before engaging the powered stroke for completion. By preparing the component and dies during the fast unpowered phase, the slower powered phase only needs to complete the remaining small portion of the stroke, thereby achieving complex component formation without requiring the powered stroke to operate at high speed throughout the entire process.
3Force
If the powered stroke is engaged early in the forming process, then forming force is sufficient, but dynamic impact increases and component quality decreases
Solution Approach 1:
The patent delays engagement of the powered stroke until the ram is within 10-50mm of the die cavity, after the majority of the forming action has already occurred during the non-powered stroke. This preliminary completion of most forming work during the fast unpowered phase means that when the powered stroke engages, only a small finishing force is needed, avoiding excessive dynamic impact and preventing damage to the formed component while still achieving sufficient forming force for the critical final stages.
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 process enhances component complexity and draw depth on conventional hydraulic presses, reduces dynamic impact, and maintains high-quality part production without the need for expensive press upgrades, using existing equipment.
Implementation Method 1
heating a metal alloy sheet blank to at least its Solution Heat Treatment temperature
Implementation Method 2
rapidly transferred to a set of cold dies which are immediately closed to form a shaped component
Implementation Method 3
The non-powered stroke may comprise allowing the press to close under the force of gravity
Data Source
AI summary
The invention is a process for forming a metal alloy component comprising: heating a metal alloy sheet blank to at least its Solution Heat Treatment temperature at a heating station; transferring the heated sheet blank to a press; initiating formation of a component by closing the press dies at a first speed then completing the formation by closing the press dies at a second speed, said second speed being slower than the first; and holding the formed component in the dies during cooling of the formed component.