Resin Interface Heating for Viscosity Control in Additive Manufacturing
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Solution Overview
Problem
Additive manufacturing processes face challenges in regulating temperature at the resin interface, leading to inconsistent crosslinking density and viscosity, which affects the dimensional accuracy and mechanical properties of the printed structures, especially when using high-viscosity resins or resins at room temperature.
Innovation Solution
A method and system for controlling the temperature of the resin reservoir, chamber environment, and resin interface using heating elements and thermal imaging to maintain target temperatures, allowing for precise photocuring and reducing temperature gradients, thereby controlling resin viscosity and crosslinking density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the resin is heated to reduce viscosity for better flow and layer formation, then the resin viscosity decreases and manufacturability improves, but the heat deflection temperature of the photocured resin may be exceeded causing deformation
Solution Approach 1:
The patent divides the resin system into two distinct components: a low-viscosity resin component that flows easily for good layer formation, and a high-crosslinking-density component that provides high heat deflection temperature. This segmentation allows each component to optimize its function without compromise - the low-viscosity resin ensures manufacturability while the high-crosslinking component ensures thermal stability above 100°C.
Solution Approach 2:
The patent creates a composite resin system by combining multiple resin components with different properties. The composite consists of a first resin component providing low viscosity for flowability and a second resin component providing high crosslinking density for thermal resistance. This composite material achieves both easy manufacture and high temperature resistance simultaneously.
2Strength
If high-viscosity resin is used to achieve desired material properties, then the mechanical properties and heat resistance improve, but the resin flow and layer formation become difficult
Solution Approach 1:
The patent segments the resin's functional requirements into two parts: flowability (handled by low-viscosity first component) and strength/heat resistance (handled by high-crosslinking second component). This allows the resin to flow easily during printing while achieving high mechanical properties and heat resistance in the final cured structure.
Solution Approach 2:
The patent employs a composite resin formulation where the first resin component ensures easy flow and layer formation, while the second resin component contributes high crosslinking density for superior mechanical strength and heat resistance. The synergistic combination resolves the contradiction between ease of manufacture and material strength.
3Productivity
If the photocuring process is accelerated to increase productivity, then the build speed increases, but the crosslinking density becomes inconsistent affecting dimensional accuracy
Solution Approach 1:
The patent modifies the chemical parameters of the resin system by incorporating a second resin component with high crosslinking density capability. This parameter change allows the photocuring process to proceed rapidly while maintaining consistent and high crosslinking density throughout the cured resin, thus achieving both high productivity and manufacturing precision.
Solution Approach 2:
The composite resin system combines a first component for rapid photocuring with a second component that ensures high and uniform crosslinking density. This composite formulation enables accelerated build speeds without sacrificing dimensional accuracy or crosslinking consistency, resolving the contradiction between productivity and precision.
4Ease of manufacture
If the resin temperature is increased to control viscosity, then the resin flow improves, but temperature gradients form causing internal stresses and reducing green strength
Solution Approach 1:
The patent changes the fundamental parameter of resin viscosity by using a low-viscosity first resin component instead of relying on temperature increase. This parameter change allows the resin to flow easily at lower temperatures, avoiding temperature gradients and internal stresses while maintaining good resin flow and layer formation.
Solution Approach 2:
The patent segments the viscosity control function from temperature control. Instead of using heat to reduce viscosity, the system uses a specifically formulated low-viscosity first resin component. This segmentation decouples viscosity management from thermal management, preventing temperature gradients and internal stresses while ensuring good flow properties.
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 approach enables the production of high-accuracy builds with controlled mechanical properties from high-viscosity resins by regulating resin viscosity and crosslinking density, reducing internal stresses, and enhancing the green strength of printed layers.
Implementation Method 1
heating an interface layer of the resin reservoir toward a target reaction temperature
Implementation Method 2
detecting a temperature distribution across an interface layer of the resin reservoir via a thermal image sensor
Implementation Method 3
projecting the infrared light projection toward the build window
Implementation Method 4
selectively photocuring a first volume of the resin reservoir to form a first layer of a build
Data Source
AI summary
A method for additive manufacturing includes: at a build tray arranged over a build window and containing a resin reservoir of a resin, heating the resin reservoir toward a target bulk resin temperature less than a heat deflection temperature of the resin in a photocured state; at a resin interface between a surface of the build window and the resin reservoir, heating an interface layer of the resin reservoir toward a target reaction temperature; and, in response to the resin reservoir exhibiting a first temperature proximal the target bulk resin temperature and to the interface layer exhibiting a second temperature proximal the target reaction temperature: at the resin interface, selectively photocuring a first volume of the resin to form a first layer of a build adhered to a build platform; and retracting the build platform away from the build window.