Spring-Elastic Mandrel for Sheet-Metal Forming Dissimilar Cross-Sections
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Solution Overview
Problem
Existing forming tools for producing hollow components by sheet-metal forming require complex mandrel driving mechanisms, especially for creating cross-sectional geometries that are dissimilar along the longitudinal profile, which complicates the process and can lead to undesirable deformations or difficulties in mandrel withdrawal.
Innovation Solution
A forming tool with a mandrel and an auxiliary mandrel, both coupled to the upper tool via spring-elastic actuation means, allows for the simultaneous formation of U-to-O shapes by enabling the mandrel to bear on the preform component before the upper tool reaches its lower dead center, and the auxiliary mandrel to move laterally or at an angle, facilitating the creation of closed cross-sectional geometries with easier withdrawal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex mandrel driving mechanisms are used to create dissimilar cross-sectional geometries, then manufacturing capability is improved, but device complexity increases
Solution Approach 1:
The forming tool is divided into two independent mandrels: a first mandrel for creating the basic U-shape and a second mandrel for forming the closed O-shape. Each mandrel can be independently driven and withdrawn, allowing complex cross-sectional geometries to be achieved through sequential action of simpler components rather than a single complex mechanism.
Solution Approach 2:
The first mandrel performs preliminary forming by creating the U-shaped preform with dissimilar cross-sections before the second mandrel completes the closure to O-shape. This preliminary action allows the complex geometry to be established in stages, reducing the complexity required in each individual mandrel driving mechanism.
2Manufacturing precision
If mandrels are driven into the hollow component to form closed cross-sections, then manufacturing precision is improved, but ease of operation deteriorates due to withdrawal difficulties
Solution Approach 1:
The mandrel system is segmented into two separate mandrels that can be independently withdrawn. The second mandrel is withdrawn first after completing the O-shape closure, followed by the first mandrel. This segmentation allows each mandrel to be removed sequentially without the withdrawal difficulties that would occur with a single integrated mandrel system.
Solution Approach 2:
The mandrels are designed with dynamic driving and withdrawal capabilities through spring-elastic actuation means. This dynamic system allows the mandrels to be easily driven into the workpiece and just as easily withdrawn in reverse sequence, maintaining manufacturing precision while improving ease of operation.
3Ease of operation
If spring-elastic actuation means are used for mandrel coupling, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The spring-elastic actuation means provides self-service functionality by automatically driving the mandrels into the workpiece during the downward stroke and enabling their withdrawal during the upward stroke without requiring separate complex control systems. The springs self-regulate the driving and retracting actions, improving ease of operation while adding minimal complexity.
Solution Approach 2:
The spring-elastic actuation means operates in periodic cycles: compressing during the downward stroke to drive mandrels forward, and expanding during the upward stroke to enable withdrawal. This periodic action simplifies control compared to continuous actuation systems, as the springs naturally cycle with the tool's motion.
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 solution simplifies the mandrel driving process, allows for the generation of hollow components with mutually dissimilar cross-sectional geometries, and ensures that the auxiliary mandrel can be withdrawn without causing deformations, improving the efficiency and reliability of the U-to-O forming process.
Implementation Method 1
A mandrel (4) that is driven into the hollow component (10) to be formed and an auxiliary mandrel (5) that is repositionable relative to the mandrel (4) are disposed on the upper tool (2). The mandrel (4) and the auxiliary mandrel (5) are by way of in each case one spring-elastic actuation means (15, 18) preferably coupled to the upper tool (2).
Data Source
AI summary
A forming tool and a method of operating thereof for producing a hollow component by sheet-metal forming is disclosed having an upper tool and a lower tool, a mandrel that is driven into the hollow component to be formed and an auxiliary mandrel that is repositionable relative to the mandrel are positioned on the upper tool. The mandrel and the auxiliary mandrel are coupled to the upper tool by one spring-elastic actuation element in such a manner that the mandrel, when the upper tool is being lowered, is driven into the hollow component to be formed and comes to bear therein. A further lowering of the upper tool causes a compression of the coupling element, and the auxiliary mandrel carrying out a movement relative to the mandrel and being driven further into the hollow component.