Dual-Cure Epoxy Formulations for Stable 3D Printing Layers
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Solution Overview
Problem
Existing 3D printing methods face issues with insufficient interlayer adhesion and deformation of printed parts due to low viscosity of reactive liquid compositions, particularly in layer-by-layer formation, especially when using filaments, which affects the stability and resolution of the printed structure.
Innovation Solution
A pasty epoxy composition with a specific viscosity factor (1.5/15) is used, which is both radiation and heat curable, ensuring dimensional stability through thixotropic behavior and maintaining good wettability, allowing for improved interlayer adhesion and a smooth surface finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If reactive liquid printable compositions are used for 3D printing, then the composition can be easily printed, but the low viscosity leads to deformation of the printed part and poor resolution
Solution Approach 1:
The patent changes the viscosity parameter of the printable composition by using a paste-like material instead of a low-viscosity liquid. The paste-like composition maintains printability while providing sufficient viscosity to prevent deformation and maintain dimensional stability during the printing process.
Solution Approach 2:
The patent utilizes a dual-cure system where the paste-like composition undergoes phase transition from a printable paste state to a cured solid state. The composition remains in a paste-like state during printing, then transitions to a dimensionally stable cured state through radiation and/or heat curing, eliminating deformation issues.
2Productivity
If the next layer is printed on top of a fully cooled and solidified layer, then the printing process can continue, but the interlayer adhesion becomes insufficient
Solution Approach 1:
The patent applies preliminary action by curing each printed layer immediately after deposition through radiation and/or heat curing. This preliminary curing creates a stable surface for the next layer while maintaining strong interlayer adhesion, as the uncured portion of the epoxy still provides wettability for bonding.
Solution Approach 2:
The patent ensures continuity of useful action by implementing a dual-cure system where radiation curing provides immediate stabilization and heat curing completes the crosslinking process. This continuous curing action maintains both interlayer adhesion and printing productivity throughout the layer-by-layer manufacturing process.
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 achieves stable, dimensionally accurate 3D printed parts with enhanced mechanical strength and chemical resistance, eliminating visible interfaces between layers and ensuring good interlayer adhesion.
Implementation Method 1
at least one monomer and/or prepolymer that is polymerizable by exposure to radiation, preferably a poly(meth)acylate; and at least one photoinitiator
Implementation Method 2
the paste-like epoxy compositions, which are at the same time radiation curable and heat curable, the thixotropic behaviour ensures that the printed layer is already dimensional stable
Implementation Method 3
a good wettability of the second layer is maintained due to the still uncured epoxy portion
Implementation Method 4
curing the printed layers of the reactive curable printable composition by heating to obtain the three-dimensional part
Data Source
AI summary
The present invention lies in the field of 3D printing methods. In particular, the invention relates to 3D printing methods for the production of a 3D part in a layer-by-layer manner, wherein the printable composition is a pasty epoxy composition comprising at least one epoxy resin, at least one monomer and/or prepolymer that is polymerizable by exposure to radiation and at least one photoinitiator, wherein the pasty epoxy composition has a viscosity factor (1.5/15) of at least 2 at application temperature.