Bellows with Diffusion-Bonded Conductive Coating
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Solution Overview
Problem
Current methods for manufacturing bellows for vacuum applications face challenges such as low productivity, non-uniform conductive coating layers, and mechanical strength issues due to the use of plating processes, which can lead to metal fatigue and heat distribution problems.
Innovation Solution
A method involving diffusion-bonding a conductive coating layer onto a plate-shaped base body, forming a multilayer member, and then drawing it into a tubular shape, which allows for uniform thickness and improved mechanical and electric characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plating process is used to form conductive coating layer on bellows, then electric characteristics are improved, but manufacturing productivity decreases and coating uniformity deteriorates
Solution Approach 1:
The conductive coating layer is formed on the flat plate-shaped base body before the bellows shaping process. By performing the coating operation on a flat surface rather than on the final bellows shape, the manufacturing process is simplified and productivity is improved while maintaining coating uniformity.
Solution Approach 2:
Instead of forming the bellows shape first and then applying the conductive coating, the invention inverts the sequence by first forming the conductive coating on a flat plate and then shaping it into the bellows form. This reversal of the conventional process sequence resolves the contradiction between coating uniformity and manufacturing complexity.
2Reliability
If plating process is used to form conductive coating layer on bellows, then electric characteristics are improved, but coating thickness uniformity deteriorates
Solution Approach 1:
The conductive coating is applied to the flat plate-shaped base body before shaping into bellows. This preliminary coating action on a flat surface ensures uniform thickness because the coating process operates on a stable, flat substrate rather than a complex curved surface, thereby maintaining manufacturing precision.
Solution Approach 2:
The conventional sequence of shaping then coating is inverted to coating then shaping. This inversion allows the coating to be applied under optimal conditions on a flat surface, ensuring uniform thickness, and the subsequent shaping process maintains the coating's uniformity rather than degrading it.
3Strength
If nickel plating is performed as pretreatment, then adhesion is improved, but magnetic properties increase causing heat generation
Solution Approach 1:
The harmful nickel layer is completely removed from the base body. Instead of using nickel as an intermediate layer, the invention extracts this problematic element and directly applies the conductive coating material (copper, silver, or aluminum) to the stainless steel base body, thereby eliminating magnetic properties and heat generation while maintaining adhesion through proper surface treatment.
Solution Approach 2:
The invention replaces the multi-layer plating structure (including nickel) with a simpler direct coating approach. By eliminating the nickel intermediate layer and using direct bonding of conductive materials to the stainless steel base body, the process removes the source of magnetic heating while maintaining functional performance.
4Reliability
If bellows are shaped after electroplating, then conductive coating is formed, but coating thickness becomes non-uniform due to deformation
Solution Approach 1:
The conductive coating is formed on the flat plate-shaped base body before the bellows shaping process. By performing the coating operation in advance on a flat surface, the coating achieves uniform thickness, and the subsequent shaping process maintains this uniformity rather than creating variations.
Solution Approach 2:
The conventional sequence of shaping then coating is inverted to coating then shaping. This inversion ensures that the coating is applied to a stable flat surface where uniform thickness can be achieved, and the subsequent forming process preserves rather than degrades the coating uniformity.
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 results in bellows with highly uniform conductive coating layers and enhanced mechanical and electric characteristics, reducing the risk of metal fatigue and improving heat distribution, while simplifying the manufacturing process.
Implementation Method 1
arranging a flat conductive coating layer on at least one end surface side of a plate-shaped base body in layer; diffusion-bonding the base body and the conductive coating layer
Data Source
AI summary
A conductive coating layer 2a, 2b is formed on at least one of an inner peripheral side and an outer peripheral side of a base body 2 of bellows 1 by diffusion-bonding. Regarding the diffusion-bonding, the flat conductive coating layer 2a, 2b is layered on at least one end surface side of the plate-shaped base body 2, and these base body 2 and conductive coating layer 2a, 2b are diffusion-bonded. After forming this diffusion-bonded multilayer member into a tubular body by a drawing process, a side wall of the tubular body is formed into a bellows shape. With these processes, it is possible to obtain the bellows that has the conductive coating layer having a more uniform thickness on the base body of the bellows and has extremely good characteristics (the mechanical characteristics and the electric characteristics).