Part-Time Draw Bead Stamping for High-Strength Blank Control
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Solution Overview
Problem
Conventional stamping apparatuses face challenges in shaping high-strength metal blanks, such as high-strength steel or aluminum alloys, due to excessive bowing and scrap generation, as the stake bead does not engage until the final stages, leading to inefficient stretching and increased springback.
Innovation Solution
A stamping apparatus with a lower die featuring a stake bead and a movable upper die with a draw bead that engages and disengages at specific stages to control the blank's movement, minimizing bowing and scrap by restricting movement with the draw bead initially and then fully gripping with the stake bead to enhance stretching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a stake bead is used on the lower die to crimp the metal blank, then the blank can be gripped and stretched during the drawing process, but the stake bead does not engage with the blank until the final stages, allowing excessive bowing to form
Solution Approach 1:
The blank holding mechanism is segmented into two distinct beads: a draw bead on the binder and a stake bead on the lower die. Each bead performs a specific function at different stages of the stamping process, with the draw bead controlling initial blank positioning and the stake bead providing final gripping and stretching control.
Solution Approach 2:
The draw bead on the binder performs preliminary action by engaging the blank edge at the beginning of the stamping process. This preliminary engagement prevents excessive bowing from forming before the stake bead becomes active, ensuring proper blank positioning and reducing springback.
2Strength
If the metal blank is made of high-strength material to improve part strength, then the material can withstand the stamping process, but the high-strength material is difficult to stretch into the proper shape
Solution Approach 1:
The system changes the mechanical parameters of blank control dynamically during the stamping process. The draw bead provides initial restraint with specific geometric parameters, then the stake bead engages with different parameters to control the stretching of high-strength material, adapting to the material's resistance to deformation.
3Reliability
If the stake bead is positioned to engage the blank edge, then the blank can be gripped, but the blank must have a greater size which creates excessive scrap
Solution Approach 1:
The solution adds a dimensional element by placing the draw bead on the binder (horizontal dimension) in addition to the stake bead on the lower die (vertical dimension). This two-dimensional blank holding approach provides reliable gripping without requiring excessive blank size, as the draw bead assists in controlling the blank edge during the stamping process.
Data Source
AI summary
A stamping apparatus that includes an upper die, a blank-holding binder, and fixed lower die. The fixed lower die features a drawing punch and the upper die features a corresponding cavity. The fixed lower die includes a stake bead and a corresponding depression is present on the upper die. The blank-holding binder includes a draw bead and a corresponding depression is present on the upper die. In the stamping process, the draw bead engages a blank in a first stage, causing the blank to begin to stretch into the shape of the drawing punch with a greater tightened partially finished panel shape. In a second stage, the draw bead disengages the blank as the blank is drawn towards the drawing punch. In a final stage, the stake bead engages the blank to tighten the blank around the drawing punch into a final shape.