Double-Layer Cup Drawing Without a Blank Holder
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Solution Overview
Problem
There is a need for a cost-effective method to produce double layer reinforced cup-shaped parts, particularly bi-metal high-pressure reservoirs, using the deep drawing process without the risk of wrinkling and without requiring a blank material holder.
Innovation Solution
The method involves shaping a first material into a hollow cylinder and mounting it on a draw punch with a smaller lower punch portion, then using a draw die with a tractrix flare to form a double layer cup-shaped part by drawing a blank material over the die, where the inner layer forms an inner cylindrical layer and the outer material forms a cup-shaped layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blank material holder is used in deep drawing, then the risk of wrinkling is reduced, but the device complexity and production cost increase
Solution Approach 1:
The patent removes the blank material holder from the deep drawing system, using only the draw punch and draw die. The draw punch itself performs the function of both forming and restraining the blank material, eliminating the need for a separate holder and reducing device complexity while maintaining wrinkle prevention through proper punch geometry and drawing parameters
2Ease of manufacture
If conventional deep drawing is used for double layer parts, then production cost is reduced, but the manufacturing precision and attachment quality between layers deteriorate
Solution Approach 1:
The inner layer is pre-formed as a hollow cylinder with precise dimensions before the deep drawing process. This pre-formed inner layer serves as a mandrel that guides the drawing of the outer layer, ensuring proper alignment and attachment quality between layers while maintaining cost-effectiveness through a single-pass forming operation
Solution Approach 2:
The hollow cylinder (inner layer) is nested within the draw die cavity, and the blank material (outer layer) is drawn over it. This nested arrangement ensures intimate contact between the two layers during forming, creating strong attachment while maintaining simple equipment and low production cost
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 approach allows for the efficient production of double layer cup-shaped parts with different materials, such as brass, copper, and stainless steel, ensuring a strong attachment between the inner and outer layers, making it suitable for applications like bi-metal bushings and high-pressure vessels.
Implementation Method 1
a plate-like blank material may be formed into a cylindrical or box-shaped part by utilizing a draw punch that presses the blank material in a draw die cavity
Implementation Method 2
Mounting the hollow cylinder on the draw punch may include tightly fitting the hollow cylinder around the lower punch portion
Data Source
AI summary
A method for fabricating a double layer cup-shaped part may include shaping a first material into a hollow cylinder, mounting the hollow cylinder on a draw punch, where the draw punch may include an upper punch portion with a first diameter and a lower punch portion with a second smaller diameter. Mounting the hollow cylinder on the draw punch may include tightly fitting the hollow cylinder around the lower punch portion. The method may further include forming the double layer cup-shaped part by drawing a blank material through a draw die by placing the blank material over an upper opening of the draw die, and pressing the draw punch over the blank material. The first material may form an inner layer of the double layer cup-shaped part and the blank material may form an outer cup-shaped layer of the double layer cup-shaped part.