Core-Shell Metal Particles for Rapid Thermal Sintering
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Solution Overview
Problem
Current 3D printing techniques are limited by slow thermal processing times and the risk of rupturing metal cores during the sintering process, particularly when working with metallic and ceramic powders.
Innovation Solution
The use of core-shell build material particles with a metal core and a higher melting point metal oxide shell, combined with a reactive chemical to selectively lower the melting point of the core, and rapid thermal processing (RTP) to achieve faster sintering and prevent core rupture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional thermal processing methods (selective laser sintering, electron beam additive manufacturing) are used, then sintering of metallic and ceramic powders can be achieved, but the processing time is slow and there is a risk of rupturing metal cores
Solution Approach 1:
The patent changes the thermal processing parameters by using rapid thermal processing (RTP) that heats the layer to 1000°C in less than a minute, compared to traditional slow thermal processing. This parameter change enables faster sintering while the metal oxide shell protects the metal core from rupturing during the rapid heating process
Solution Approach 2:
The patent uses composite core-shell build material particles where a metal core is surrounded by a metal oxide shell. The shell has a higher melting point than the core, protecting the core during thermal processing. This composite structure enables both high reliability (no core rupture) and improved productivity (faster processing)
2Productivity
If rapid thermal processing is used to heat layers to 1000°C in less than a minute, then throughput is dramatically increased, but this requires a protective mechanism to prevent core rupture
Solution Approach 1:
The metal oxide shell is formed on the metal core before the thermal processing step. This preliminary protective coating is applied in advance to prevent core rupture during the subsequent rapid thermal processing, enabling high throughput without compromising reliability
Solution Approach 2:
The metal oxide shell acts as a protective cushion or barrier that absorbs and distributes the thermal stress during rapid heating. This beforehand cushioning prevents the metal core from rupturing even under the extreme conditions of rapid thermal processing
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 significantly increases throughput by rapidly heating layers to 1000°C in less than a minute, while minimizing the risk of core rupture and enabling efficient sintering of metallic and ceramic powders, outperforming traditional techniques like selective laser sintering and electron beam additive manufacturing.
Implementation Method 1
The reactive chemical may be used to pattern respective layers of the core-shell build material particles, because those build material particles exposed to the reactive chemical will undergo a reaction to remove the shell and expose the core
Implementation Method 2
The use of rapid thermal processing (RPT) in the printing method and system disclosed herein heats the layer up to 1000° C. in a timescale of a minute or less
Implementation Method 3
When the entire layer is exposed to rapid thermal processing, the exposed cores will sinter and the intact build material particles will remain unsintered
Data Source
AI summary
In an example of a 3D printing method, build material particles are applied to form a layer. Each build material particle includes a metal core and a metal oxide outer shell. The layer is patterned by selectively applying a reactive chemical on at least a portion of the layer to initiate a redox reaction with the metal oxide outer shells of the build material particles in contact with the reactive chemical, which reduces the metal oxide outer shells of the build material particles in contact with the reactive chemical and exposes the metal cores of the build material particles in contact with the reactive chemical. The patterned layer is exposed to rapid thermal processing to sinter the exposed metal cores to form a part layer. Any intact build material particles remain unsintered.