3D Printing Fusing Agent Color Control via Electron Donor Reduction
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Solution Overview
Problem
Current 3D printing methods using fusing agents that absorb significant amounts of light in the 700 nm - 1400 nm range result in strongly colored parts, such as black, which are not suitable for applications requiring clear, white, or other colors, and face challenges in achieving rapid reduction of metal bis(dithiolene) complexes at higher contone levels due to oxidative effects and residual color issues.
Innovation Solution
A 3D printing composition comprising a build material with a polymer and an electron donor compound, combined with a fusing agent containing a metal bis(dithiolene) complex, a surfactant, a polar aprotic solvent, and water, where the electron donor compound facilitates the reduction of the metal bis(dithiolene) complex to its colorless form, enhancing jetting performance and reducing oxidative degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fusing agent with significant light absorption in the 700 nm - 1400 nm range is used, then the fusing efficiency and mechanical integrity of 3D parts are improved, but the parts become strongly colored (e.g., black) which is not suitable for applications requiring clear, white, or other colors
Solution Approach 1:
The patent changes the chemical composition parameters of the fusing agent by incorporating metal bis(dithiolene) complexes that can be reduced to colorless forms. This parameter change allows the fusing agent to maintain high light absorption for effective fusing while transitioning to a colorless state, thereby resolving the contradiction between mechanical integrity and color control.
Solution Approach 2:
The patent directly applies color change principles by using metal bis(dithiolene) complexes that can be reduced from colored to colorless forms. The reduction process transforms the fusing agent from a strongly colored state (useful for fusing) to a colorless state (desired for final parts), effectively resolving the color control issue while maintaining fusing efficiency.
2Manufacturing precision
If higher contone levels are used to improve print quality and reduce color artifacts, then the resolution and quality of 3D parts are improved, but the discoloration of the fusing agent becomes slower and more difficult to achieve
Solution Approach 1:
The patent applies preliminary action by incorporating electron donor compounds into the build material before printing. These pre-incorporated electron donors are ready to immediately reduce the metal bis(dithiolene) complex during and after printing, accelerating the discoloration process. This preliminary preparation enables faster discoloration even at higher contone levels, resolving the contradiction between print quality and discoloration speed.
Solution Approach 2:
The patent uses electron donor compounds as intermediaries to facilitate the reduction of metal bis(dithiolene) complexes. These intermediaries mediate the transfer of electrons from the build material to the fusing agent, accelerating the discoloration process. This intermediary mechanism enables rapid discoloration that keeps pace with higher contone level printing, resolving the productivity vs. precision contradiction.
3Device complexity
If traditional fusing agents are used without electron donor compounds, then the formulation is simpler and more stable, but oxidative degradation occurs during printing leading to residual color and reduced part quality
Solution Approach 1:
The patent applies self-service principles by incorporating electron donor compounds that enable the build material to self-reduce the metal bis(dithiolene) complex during and after printing. The build material itself provides the reducing agents needed to discolor the fusing agent, eliminating the need for external reducing agents or complex post-processing steps. This self-service mechanism improves part quality while maintaining formulation simplicity.
Solution Approach 2:
The patent converts the potentially harmful oxidative degradation into a beneficial reduction process. By incorporating electron donor compounds, the natural oxidation that would normally degrade the polymer is instead harnessed to reduce the metal bis(dithiolene) complex to its colorless form. This converts the harmful oxidative effect into a beneficial discoloration mechanism, improving part quality without significantly increasing formulation complexity.
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 solution enables the production of colorless or white 3D parts with improved mechanical properties and reduced oxidative degradation, allowing for higher contone levels and faster discoloration of the fusing agent, thereby overcoming the limitations of existing methods in achieving desired colors and part integrity.
Implementation Method 1
The fusing agent is capable of absorbing radiation and converting the absorbed radiation to thermal energy, which in turn melts or sinters the build material that is in contact with the fusing agent
Implementation Method 2
the electron donor compound facilitates the reduction of the metal bis(dithiolene) complex to its colorless form
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
Compositions and methods for 3D printing are described herein. In an example, a composition for 3D printing can comprise a build material comprising at least one polymer and at least one first electron donor compound; and a fusing agent comprising (i) a metal bis(dithiolene) complex, (ii) at least one surfactant, at least one second electron donor compound, or combinations thereof, (iii) a polar aprotic solvent, and (iv) water. The at least one first electron donor compound and the at least one second electron donor compound can be the same or different.