Additive Manufactured Fuse Body with Variable Density Sections
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Solution Overview
Problem
Ceramic fuse bodies used for overcurrent protection face challenges due to differing coefficients of thermal expansion between the extinguishing sand and the ceramic material, leading to potential bursting and increased manufacturing and logistics costs, especially as nominal currents increase.
Innovation Solution
A manufacturing method using additive manufacturing to produce a fuse body with sections of varying physical mass densities, allowing for adaptation to local mechanical stresses, thereby enhancing mechanical strength and versatility while reducing material usage and type variety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic fuse bodies are used for overcurrent protection, then electrical insulation capacity and heat resistance are improved, but the fuse body may burst due to thermal expansion differences between extinguishing sand and ceramic material
Solution Approach 1:
The fuse body is divided into different sections with varying material compositions. The first section contains only ceramic material, while the second section contains both ceramic material and extinguishing sand. This local differentiation allows each section to have optimized properties: the pure ceramic section resists thermal expansion stress, while the sand-filled section provides arc quenching.
Solution Approach 2:
The fuse body uses a composite structure combining ceramic material and extinguishing sand in specific regions. The second section is formed as a composite of ceramic and sand particles, leveraging the high heat resistance of ceramic and the arc-quenching properties of sand, while the first section uses pure ceramic to handle thermal expansion stresses.
2Adaptability or versatility
If different ceramic materials are used for different applications, then adaptability to specific applications is improved, but manufacturing complexity and logistics effort increase
Solution Approach 1:
A single fuse body design can serve multiple applications by varying the amount and distribution of extinguishing sand in the second section. The same basic structure with differentiated sections can be adapted for different rated currents and application requirements without requiring entirely different fuse body types, reducing manufacturing complexity.
Solution Approach 2:
The invention allows adjustment of parameters such as the volume fraction of extinguishing sand, the dimensions of different sections, and the density of the composite material to optimize performance for different applications. These parameter variations enable one base design to cover multiple applications.
3Power
If ceramic fuses are designed for higher rated currents, then current carrying capacity is improved, but the fuse body becomes more prone to rupture due to increased thermal stresses
Solution Approach 1:
The fuse body incorporates a first section made of pure ceramic material that is specifically designed to withstand high thermal expansion stresses. This localized pure ceramic region acts as a stress-resistant zone that prevents rupture in high-power applications where thermal stresses are elevated.
4Ease of manufacture
If standard ceramic fuse bodies are used, then manufacturing simplicity is maintained, but material usage efficiency and compactness are reduced
Solution Approach 1:
The fuse body is segmented into distinct functional sections: a first section with pure ceramic material and a second section with ceramic-sand composite. This segmentation allows optimization of material distribution, placing material only where needed for specific functions, thereby reducing overall weight and volume while maintaining manufacturing feasibility.
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 increases the strength and versatility of the fuse body, reduces material costs, and enables more compact designs with lower weight and volume, while maintaining mechanical strength in heavily stressed sections.
Implementation Method 1
a manufacturing method for producing a fuse body (10) for a fuse (1) for protecting an electrical circuit, wherein the fuse body (10) is manufactured in one piece from insulating material using an additive manufacturing process
Implementation Method 2
The fusible link, which has a reduced cross-section compared to the other conductors in the circuit, is heated by the current flowing through it and melts when the relevant rated current of the fuse is significantly exceeded for a predetermined period
Implementation Method 3
the fusible link first melts and then vaporizes due to the high temperature
Implementation Method 4
As the metal vapor from the vaporized fusible link condenses on the surface of the quartz sand grains, the arc is cooled
Implementation Method 5
the quenching sand surrounding the fusible link inside the ceramic fuse body and the ceramic body itself have different coefficients of thermal expansion. This difference in thermal expansion subjects the various sections or areas of the ceramic fuse body to varying forces
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
In the manufacturing process according to the invention for producing a fuse body (10) for a fuse (1) for protecting an electrical circuit, the fuse body (10) is manufactured in one piece from insulating material using an additive manufacturing process. The manufacturing process produces at least one predetermined first section (11) of the fuse body (10), which has a first physical mass density, and at least one predetermined second section (12) of the fuse body (10), which has a second physical mass density that differs from the first. In this way, the manufacturing process adapts the mechanical elasticity and mechanical strength of the at least one first section (11) and the at least one second section (12) to the respective local stresses on the fuse body (10).This offers the advantage that the product to be manufactured can be adapted to the expected, application-specific stresses as a digital structural model with regard to its elasticity and strength. In this way, the strength can be significantly increased with the same amount of material. Alternatively, with the same nominal currents, the amount of material can be significantly reduced without reducing the mechanical strength in the relevant sections (11, 12) of the fuse body (10). This makes it possible to realize more compact designs that are both lighter and smaller in volume.