Hot-press deep-drawing forming with dynamic blank holder and cooling control
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Solution Overview
Problem
Existing hot-press deep-drawing methods often result in forming defects such as wrinkles and breakage, especially in difficult-to-form parts, due to non-uniform contact and unintended heat removal during the process.
Innovation Solution
A hot-press deep-drawing forming method and apparatus that incorporates a pre-forming die movement step with a built-in cooling mechanism and a double action mechanism to prevent excessive heat removal, allowing for controlled movement of the blank holder and pre-forming die to suppress wrinkles, ensuring the scrap section abuts a bent corner without continuous contact with the die, thereby maintaining ductility and preventing forming defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If continuous contact between the die and workpiece is maintained during forming, then forming precision is improved, but heat removal is excessive causing impaired ductility and forming defects
Solution Approach 1:
The blank holder is designed to move dynamically during the forming process. In the initial stage, the blank holder contacts the workpiece to suppress wrinkles. In the final stage, the blank holder retracts to stop heat removal, maintaining workpiece temperature and ductility while completing the forming operation.
Solution Approach 2:
The cooling mechanism is activated preliminarily during the initial-stage forming when the blank holder contacts the workpiece. The cooling is then stopped in the final-stage forming, allowing the workpiece to maintain its temperature and ductility for the completion of forming without excessive heat removal.
2Reliability
If blank holder mechanism is used to suppress wrinkles, then wrinkle occurrence is reduced, but unintended heat removal impairs ductility and causes forming defects
Solution Approach 1:
The cooling mechanism operates periodically rather than continuously. Cooling is applied during the initial-stage forming when the blank holder contacts the workpiece to suppress wrinkles, then stopped during the final-stage forming to prevent excessive heat removal and maintain ductility.
3Adaptability or versatility
If step drawing is performed to form difficult-to-form parts, then forming capability is improved, but continuous contact with die causes excessive heat removal and forming defects
Solution Approach 1:
The blank holder position is dynamically adjusted during the forming process. The blank holder moves with the die during initial-stage forming to enable step drawing of difficult-to-form parts, then retracts in the final-stage forming to stop heat removal and prevent forming defects.
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 method effectively prevents wrinkles and breakage, enabling the formation of high-strength products with a U-shaped cross-sectional shape without forming defects, by controlling heat removal and maintaining ductility through the use of a cooling mechanism and double action mechanism.
Implementation Method 1
hot-press deep-drawing forming method of forming a product... through press-working of a workpiece made of a steel plate and heated at or above a transformation temperature
Data Source
AI summary
A hot-press deep-drawing forming apparatus includes a punch that constitutes a lower die and a die that constitutes an upper die. The punch has an inner-face forming surface that forms the inner face of a product, and a bent corner against which a scrap section S of a workpiece W abuts. The die has an outer-face forming surface that forms the outer surface of the product. A blank holder and a pre-forming die that clamp the scrap section are caused to move, together with the die, until the clamped scrap section abuts the bent corner. The movement of the blank holder and the pre-forming die is stopped after the scrap section has abutted the bent corner.