Silver Composite Contact Strip Manufacturing via Powder Metallurgy
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Solution Overview
Problem
Existing methods for producing semi-finished products for electrical contacts with silver-based composite materials face challenges in welding and soldering, and traditional production techniques like single pressing and extrusion are complex and inefficient, particularly for producing band-shaped or strand-like products.
Innovation Solution
A method involving powder metallurgy to create a block from silver-based composite material, followed by coating with silver powder, isostatic pressing, sintering, and hot extrusion to form a strand with a composite upper side and a silver or silver alloy underside, allowing for easy soldering and welding, and subsequent trimming and rolling to achieve a strip-shaped semi-finished product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single pressing technology is used to produce semi-finished products, then production complexity is reduced, but band-shaped semi-finished products cannot be produced
Solution Approach 1:
The patent combines multiple manufacturing steps (pressing, coating, extrusion) into an integrated process flow that produces band-shaped semi-finished products. The composite material block is pressed, coated with silver powder, pressed again, and then extruded to form the desired band shape, merging these operations into a cohesive manufacturing sequence.
Solution Approach 2:
The patent applies preliminary actions by first forming the composite material block through pressing and sintering, then coating it with silver powder before the final extrusion step. This preliminary preparation enables the subsequent extrusion to produce the band-shaped product with the required dual-layer structure.
2Adaptability or versatility
If composite extrusion is used to produce band-shaped semi-finished products, then product shape capability is improved, but production complexity increases due to tube fabrication and assembly
Solution Approach 1:
The patent segments the manufacturing process into distinct stages: block formation by pressing, silver coating application, and extrusion. This segmentation allows each stage to be optimized independently, avoiding the complexity of fabricating and assembling silver tubes while still achieving the desired band-shaped product with composite material core and silver coating.
3Reliability
If silver-based composite material is used for electrical contact surface, then electrical contact functionality is improved, but welding and soldering become difficult or impossible
Solution Approach 1:
The patent applies local quality by creating a dual-layer structure where the surface layer (composite material) provides excellent electrical contact properties while the underlying layer (silver or silver alloy) provides easy weldability and solderability. This spatial differentiation of material properties allows each layer to fulfill its specific function without compromising the other.
4Ease of manufacture
If powder coating and pressing is used to apply silver layer, then manufacturing simplicity is improved, but coating density and adhesion may be insufficient without optimal pressing parameters
Solution Approach 1:
The patent optimizes pressing parameters (pressure, temperature, duration) to achieve sufficient coating density and adhesion. By carefully controlling these parameters during the pressing step, the silver powder coating is compacted to form a dense, well-adhered layer on the composite material block, ensuring both manufacturing simplicity and coating quality.
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 method cost-effectively produces high-density, strand-like semi-finished products with a composite upper side and a solderable/weldable silver underside, ensuring reliable electrical contact functionality while maintaining mechanical properties.
Implementation Method 1
pressed to compact the powder coating, preferably at pressures of 500 bar to 2500 bar
Implementation Method 2
The block, which is preferably pressed isostatically, is sintered in a further production step
Implementation Method 3
formed, preferably hot-formed, by extrusion
Data Source
AI summary
The invention relates to a method for producing a strand-like, particularly band-like semi-finished part for electrical contacts, wherein the semi-finished part has a top side intended for making the electrical contact, said top side made from a silver-based composite material in which one or multiple metal oxides or carbon are embedded, and has a carrier layer supporting the composite material made of silver or a silver-based alloy, said method having the following steps: - Powder-metallurgic production of a block made from the silver-based composite material, - Encasing of the block made of the composite material with a powder made primarily of silver - Compressing the block, encased by the metal powder, to condense the metal powder, - Sintering the compressed block, - Reshaping the sintered block by extrusion pressing, - Creating a partial strand with a top side made from composite material and a bottom side made from silver or a silver-based alloy.