Inkjet 3D Printing with Urea Curing for Support-Free Overhangs
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Solution Overview
Problem
Conventional 3D printing methods face limitations in printing large-sized and large-area structures due to the need for supporter structures, slow printing speeds, and difficulties in using high molecular weight oligomers or polymers, especially when dealing with overhang portions.
Innovation Solution
An inkjet-type 3D printing method using a urea reaction between a high molecular oligomer or polymer containing amine or isocyanate groups as the subject ink, which changes phase at room temperature, allowing for layer-by-layer printing with a hardener ink to form a solid structure without a separate supporter, utilizing a low-temperature environment for gelling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photocuring printing method is used to print large-sized printed matters, then printing precision can be maintained, but the printing speed becomes excessively slow and structural defects occur at connection parts
Solution Approach 1:
The patent replaces the photocuring method (optical system) with a urea reaction-based chemical curing method. The subject ink containing isocyanate groups reacts with water or amine groups to form urea crosslinks, eliminating the need for light irradiation systems and enabling faster processing of large-area structures without the limitations of light source geometry or panel connection defects
Solution Approach 2:
The patent changes the curing mechanism from photochemical reaction to chemical reaction (urea formation). By controlling temperature parameters and reaction conditions, the system achieves rapid curing of large-area printed matters without the speed-precision tradeoff inherent in photocuring methods, where larger areas require proportionally longer exposure times
2Manufacturing precision
If a photocuring printing method is used to print large-sized printed matters, then printing precision can be maintained, but structural defects occur at connection parts of LCD panels
Solution Approach 1:
The patent replaces the LCD panel-based optical system with a direct chemical reaction system. The urea reaction occurs uniformly across the entire printed area without dependence on panel boundaries or light uniformity, eliminating connection defects between multiple LCD panels and ensuring consistent structural integrity across large-area printed matters
Solution Approach 2:
The patent eliminates the need for segmented LCD panels by using a chemical reaction approach that can process the entire area continuously. The subject ink is applied and cured in a unified manner without interruption by panel boundaries, preventing defects at connection parts
3Strength
If conventional 3D printing methods are used, then overhang portions can be supported with supporter structures, but the working process becomes complicated and production costs increase
Solution Approach 1:
The patent enables the printed structure to support itself during the printing process through the rapid urea reaction. As each layer is deposited, it cures quickly to provide self-support, eliminating the need for separate supporter structures and their subsequent removal, thereby simplifying the entire workflow and reducing material waste
Solution Approach 2:
The patent incorporates support functionality directly into the printed structure through rapid curing. The previously printed layers are cured in advance to provide support for subsequent overhang portions, eliminating the need for additional supporter structures and simplifying the printing 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
Enables fast printing of large-area structures with improved speed and reduced material waste by omitting supporter structures and allowing the use of high molecular weight materials, while enhancing interlayer bonding strength.
Implementation Method 1
a phase change ink composition ink that exists in a liquid phase at room temperature but is frozen and gelled at a certain temperature or lower
Implementation Method 2
frozen and gelled at a certain temperature or lower
Implementation Method 3
the urea reaction between a hardener ink and the subject ink applied by an inkjet method
Data Source
AI summary
The present invention provides an inkjet-type 3D printing method using a urea reaction capable of quickly printing a large-area 3D structure regardless of a size of a printed matter by printing a 3D structure on a surface of a subject ink applied in units of layers through the urea reaction between a hardener ink and the subject ink applied by an inkjet method while omitting a separate supporter structure for supporting an overhang portion of the 3D structure to be printed during 3D printing by using, as the subject ink, a phase change ink composition ink that exists in a liquid phase at room temperature but is frozen and gelled at a certain temperature or lower.