Field Assisted Sintering for Electrical Switching Contact Elements

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Solution Overview

Problem

Existing methods for manufacturing electrical switching contacts for vacuum tubes are complex, time-consuming, and result in high reject rates due to material quality fluctuations, with conventional processes failing to achieve optimal conductivity and mechanical properties.

Innovation Solution

The use of Field Assisted Sintering Technologies (FAST) to produce contact elements with controlled material properties, such as density, grain size, and composition, allowing for precise adjustment of properties like porosity and component distribution, enabling the creation of contact elements with enhanced conductivity and mechanical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional manufacturing methods (hot pressing, sintering, casting) are used to produce contact elements, then the production process can be completed, but the process is complex, time-consuming, and results in high reject rates due to material quality fluctuations

Engineering Contradiction:
Improveproduction speedVSAvoidmanufacturing process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies Field Assisted Sintering Technologies (FAST) which use electric or electromagnetic fields to fundamentally change the sintering parameters. This enables rapid heating rates and precise temperature control, transforming the conventional slow, multi-step sintering process into a fast, controlled operation that reduces both time and complexity while maintaining material quality consistency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional mechanical heating and pressing systems with electric or electromagnetic field-based systems. This substitution enables more precise control over the sintering process, reduces mechanical complexity, and achieves faster processing speeds while improving material uniformity and reducing reject rates

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If conventional sintering processes are used, then contact elements can be manufactured, but porosity and grain size distribution are inconsistent leading to quality fluctuations and high reject rates

Engineering Contradiction:
Improvematerial quality consistencyVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent utilizes FAST processes to achieve precise control over sintering parameters including temperature, heating rate, and holding time. This enables consistent porosity control (achieving nearly 100% density) and uniform grain size distribution, dramatically improving material quality consistency while maintaining high production efficiency through rapid processing

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements process monitoring and control systems that provide feedback during the FAST sintering process. This enables real-time adjustment of parameters to maintain consistent material quality, ensuring uniform density, porosity, and grain size distribution across all produced contact elements, thereby reducing reject rates

Inventive Principle:
Principle #23Feedback

3Reliability

If contact elements are manufactured with high density and minimal porosity using FAST, then quality is improved, but the process requires precise control of material composition and properties before sintering

Engineering Contradiction:
Improvecontact element qualityVSAvoidprocess control complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent requires that contact material be provided in a predetermined state before the sintering process, with specific composition and initial properties. This preliminary preparation includes controlling the spatial distribution of components and ensuring proper material composition, which facilitates the subsequent FAST process and enables achievement of high density and minimal porosity with consistent quality results

Inventive Principle:
Principle #10Preliminary action

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

FAST processes enable the production of contact elements with nearly 100% density, minimal porosity, high purity, and precise control over material properties, reducing reject rates and simplifying quality checks, while allowing for cost-effective and efficient manufacturing of high-quality contact elements.

Implementation Method 1

Methods in which an electric or electromagnetic field supports and/or induces a sintering process are known from the prior art and are collectively referred to as FAST (field-assisted sintering technologies).

Methodology Applied
Scientific EffectField Assisted Sintering Technologies (FAST): Sintering

Implementation Method 2

All processes grouped under the term FAST process within the scope of this invention have in common that an electric or electromagnetic field supports the manufacturing process of the semi-finished products, for example in the form of disc-shaped contact elements, or the manufacturing process of the finished contact elements.

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2989650B1Method and device for producing contact elements for electrical switching contacts
Publication Date: 2020.04.15 SIEMENS AG
  • EP2989650B1 patent drawingFigure 1
  • EP2989650B1 patent drawingFigure 2~4
  • EP2989650B1 patent drawingFigure 5

AI summary

In order to optimize the production of electrical switching contacts (3, 4), particularly for vacuum tubes (1), the invention proposes a Field Assisted Sintering Technology (FAST) process in which an electrical or electromagnetic field supports and/or produces a sintering process for producing semifinished contact elements for electrical switching contacts (3, 4), contact elements (5) for electrical switching contacts (3, 4) and/or electrical switching contacts (3, 4), particularly for vacuum tubes (1). According to the invention, the contact material (19, 34, 35) prior to the sintering process is present in such a form that the material composition of the contact material (19, 34, 35) and/or at least one property of the contact material (19, 34, 35) varies in at least one body direction (38, 39) of the finished contact element (5).