Servo Reverse Bulging in Deep Drawing Thin-Wall Curved Parts
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Solution Overview
Problem
Conventional methods for deep drawing large-sized thin-wall curved surface parts face issues such as wrinkling, cracking, excessive drawing load, and high manufacturing costs due to the use of liquid-filled drawing and multi-stage hydraulic systems, which require complex coordination and large equipment tonnage.
Innovation Solution
An apparatus and method utilizing a jacking unit with servo reverse bulging, replacing hydraulic pressure with a jacking unit to induce tensile stress in the suspended area, combined with a cooling system to control temperature and prevent wrinkling and cracking, and a power unit to manage the deformation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid-filled drawing is used to prevent wrinkling, then wrinkling is inhibited, but drawing load increases significantly
Solution Approach 1:
The patent extracts the liquid-filled cavity from the lower die and replaces it with a jacking unit that applies upward force directly to the blank. This removes the source of counterforce that causes excessive drawing load while maintaining the support function needed to prevent wrinkling in the suspended area.
Solution Approach 2:
The jacking unit provides a counterbalancing upward force to offset the downward drawing force on the blank. By applying this counterforce through solid mechanical contact rather than liquid pressure, the system prevents wrinkling without creating the excessive drawing load associated with liquid-filled drawing.
2Force
If multiple annular sleeves and oil cylinders are added to reduce drawing load, then drawing load decreases, but device complexity increases
Solution Approach 1:
The patent removes the complex multi-stage hydraulic control system with multiple annular sleeves and oil cylinders, replacing it with a single jacking unit. This simplifies the device structure while maintaining the ability to control deformation and reduce drawing load through servo control.
Solution Approach 2:
The jacking unit serves multiple functions: it provides upward support force to reduce drawing load, controls deformation through servo positioning, and prevents wrinkling by maintaining blank support. This single multi-functional component replaces the entire complex hydraulic system.
3Reliability
If external force is applied to suspended area to prevent wrinkling, then wrinkling is inhibited, but stress distribution becomes uneven causing cracking
Solution Approach 1:
The jacking unit applies localized upward force specifically to the suspended area of the blank where wrinkling occurs. This targeted support provides exactly the right amount of force where needed to prevent wrinkling without creating uneven stress distribution that would lead to cracking.
Solution Approach 2:
The servo control system dynamically adjusts the position and force of the jacking unit during the deep drawing process. This dynamic control ensures uniform stress distribution by adapting the support force to the changing deformation state of the blank, preventing both wrinkling and cracking.
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 solution effectively reduces drawing load, minimizes equipment tonnage, and prevents wrinkling and cracking, while allowing for easier implementation and control of the forming process, resulting in a simpler and more efficient manufacturing process.
Implementation Method 1
a jacking unit (2), disposed inside the lower die (12), adapted to move along a moving direction of the upper die (11) to deform the blank to be drawn
Implementation Method 2
The forming die (1) is provided with a cooling system
Data Source
AI summary
Disclosed are an apparatus and a method for deep drawing of large-sized thin-wall curved surface parts with servo reverse bulging, which pertain to the technical field of drawing of a thin-wall curved surface part. The apparatus includes a forming die, a jacking unit, and a power unit, wherein the forming die includes an upper die, a lower die, and a blank holder. The upper die and the blank holder are connected to a press machine, the blank holder is disposed above the lower die, and a blank to be drawn is placed between the lower die and the blank holder; the jacking unit is disposed inside the lower die and adapted to move along a moving direction of the upper die, enabling the blank to be drawn to deform by with reverse bulging. The method can inhibit defects of wrinkling and cracking in drawing processes effectively.