Metal Fiber Network Assembly With Rapid Sintering Shape Control
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Solution Overview
Problem
Conventional methods for fabricating fiber networks lack control over fiber cross-section characteristics, leading to mechanical instability and inefficient filtration capacity due to relaxation processes before reaching fixation temperatures, resulting in unwanted shape changes and energy release.
Innovation Solution
A method involving rapid heating and cooling rates above 50 K/min to 100 K/min, with a fixation temperature between 50% to 98% of the melting point, and a cooling rate below 60% of the melting point, to minimize rearrangement and maintain fiber shape and length, ensuring controlled contact points and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional sintering processes are used with slow heating rates, then fibers have time to relax and rearrange, but this causes unwanted shape changes, rounding, and loss of stored energy
Solution Approach 1:
The patent applies rapid heating rates (10-100 K/min) to skip through the temperature range where relaxation processes occur, rushing the heating process to the sintering temperature before significant shape changes can happen. This allows the fibers to be sintered while maintaining their original cross-sectional shapes and stored energy states.
Solution Approach 2:
The patent fundamentally changes the heating rate parameter from conventional slow rates (10 K/min or less) to rapid rates (10-100 K/min), and similarly changes the cooling rate parameter. This parameter change transforms the sintering process from one that allows relaxation to one that preserves fiber characteristics while achieving bonding.
2Manufacturing precision
If rapid heating rates are used to prevent fiber relaxation, then fiber shape and stored energy are preserved, but the sintering process time is reduced
Solution Approach 1:
The rapid heating and cooling rates enable the process to rush through the critical temperature zones quickly, preventing relaxation while maintaining a relatively short overall process time. The fixation temperature is held for a brief period (1-30 minutes) just long enough to achieve bonding without allowing shape changes.
Solution Approach 2:
The fibers are pre-prepared through rapid cooling during manufacturing to store energy in a metastable state, which then enables rapid sintering without shape change. The preliminary rapid cooling creates the conditions necessary for subsequent rapid heating and fixation.
3Strength
If high pressure is applied during conventional sintering to connect fibers, then fiber bonding is achieved, but fiber shape changes and mechanical stability is compromised
Solution Approach 1:
The patent changes the temperature parameter to much higher values (fixation temperature at 50-98% of melting point) achieved through rapid heating, which enables bonding without requiring high pressure. The rapid heating rate allows reaching these temperatures before significant shape changes occur under pressure.
4Stability of the object's composition
If slow cooling is used after sintering, then fibers stabilize, but this allows additional relaxation and shape changes
Solution Approach 1:
Rapid cooling rates (10-100 K/min) are applied to rush through the temperature range where relaxation processes would occur during cooling. This prevents additional shape changes and rounding that would happen with slow cooling, while still achieving stable fiber network formation.
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
The method allows for the assembly of fiber networks with precise control over cross-sectional shape and mechanical stability, preventing unwanted rounding and constrictions, and enabling flexible deformation without degradation, while maintaining fiber length and electrical conductivity.
Implementation Method 1
The driving force for the above described process is the reduction of the surface of the fibers and the associated reduction in their free energy ΔG. The free energy ΔG can be divided into a surface component ΔGs, a volume component ΔGv and a grain boundary component ΔGB. The energy threshold to be exceeded here is the activation energy EA of the diffusion (equation (2)).
Implementation Method 2
cooling the plurality of fibers at a cooling rate higher than 20 K/min, preferably higher than 50 K/min, preferably higher than 100 K/min, in particular to a temperature below 60% of their melting point
Data Source
AI summary
The invention relates to a method of assembling a fiber network comprising a plurality of metal fibers, wherein the method comprises the following steps:providing a loose network out of the plurality of metal fibers at an assembling site; fixing the plurality of metal fibers to one another by forming contact points between the single metal fibers by heating the plurality of fibers at a heating rate higher than 50 K/min, in particular higher than 100 K/min, especially higher than 200 K/min, preferably higher than 1000 K/min, to a fixation temperature selected in the range of 50 to 98% of their melting point temperature; and cooling the plurality of fibers at a cooling rate higher than 50 K/min, preferably higher than 100 K/min. The invention further relates to a network of metal fibers comprising a plurality of metal fibers fixed one to another at contact points, wherein the metal fibers non-round cross section, in particular a rectangular, quadratic, partial circular or an elliptical cross section with a large axis and a small axis, or wherein the metal fibers comprise a round cross section, and wherein the fibers comprise a width which is generally constant along a length of the fiber such that a variation of the width of the fiber along its length is less than 40%, preferably less than 30%, in particular less than 20%.