Deep-drawing Pressure Pad with Tapered Surface for Wrinkle Control
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Solution Overview
Problem
Conventional deep-drawing methods for metal containers, such as seamless cans, often result in forming defects like cup side wall wrinkles and bottom collapse, especially when using thin metal sheets or high drawing ratios, which limits the drawing ratio and increases the number of processes required, leading to poor productivity and high facility costs.
Innovation Solution
A deep-drawing method and forming die design featuring a pressure pad with a flat inner edge surface, a tapered surface that deepens towards the outer circumference, and a flat outer edge surface, allowing controlled wrinkle formation and release to prevent wrinkles and bottom collapse, while maintaining effective clamping of the blank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wrinkle pressing pressure is increased to suppress the occurrence of wrinkles, then wrinkle suppression is improved, but large tension acts on the cup during deep-drawing and the bottom of the cup may collapse
Solution Approach 1:
The pressure pad surface is designed with different regions having different pressing characteristics: a first pressing region with higher pressing force to suppress wrinkles, and a second pressing region with lower pressing force to prevent bottom collapse. This local differentiation of pressing quality resolves the contradiction between wrinkle suppression and bottom protection.
Solution Approach 2:
The pressure pad surface is segmented into multiple functional regions (first pressing region and second pressing region) with different pressing forces. This segmentation allows independent control of wrinkle suppression and bottom protection, resolving the contradiction between these two requirements.
2Productivity
If the drawing ratio is increased to reduce the number of processes, then productivity is improved, but forming defects such as cup side wall wrinkles or collapse of the bottom occur
Solution Approach 1:
By applying different pressing forces to different regions of the blank, the invention enables higher drawing ratios without forming defects. The first pressing region prevents wrinkles while the second region protects the bottom, allowing increased productivity through reduced process steps.
3Weight of moving object
If a thin base metal sheet is used for weight reduction, then weight is reduced, but forming defects such as cup side wall wrinkles or collapse of the bottom are likely to occur during deep-drawing
Solution Approach 1:
The differentiated pressing regions provide tailored support for thin metal sheets: the first pressing region prevents wrinkles on the cup side wall while the second region protects the bottom from collapse. This local quality differentiation enables weight reduction without sacrificing forming quality.
Data Source
AI summary
The present invention provides a deep-drawing method and a forming die therefor which can prevent the occurrence of cup side wall wrinkles and the collapse of the bottom during the process of deep-drawing a blank and which can increase the drawing ratio. A wrinkle pressing surface of a pressure pad (1) or an upper surface of a draw die (2) includes a flat inner edge surface (11), a tapered surface (12) which becomes deeper as the surface advances from the flat inner edge surface toward an outer circumference, a deepest flat surface (13), and a flat outer edge surface (14), which are provided in that order from an inner edge through which a draw punch passes toward an outer edge.