Resin Interface Heating for Uniform Photocuring in 3D Printing

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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 mechanical properties and dimensional accuracy of printed objects, especially when using high-viscosity resins or resins in a solid state at room temperature.

Innovation Solution

A method and system for additive manufacturing that involves heating the resin reservoir and chamber to specific target temperatures, and using infrared light to control the interface temperature, ensuring uniform temperature distribution and localized heating to maintain optimal photocuring conditions, thereby controlling resin viscosity and crosslinking density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the resin reservoir is heated to reduce viscosity, then the resin flow and manufacturability are improved, but the heat deflection temperature of the photocured resin may be exceeded causing deformation

Engineering Contradiction:

Improveresin flowVSAvoidheat deflection temperature

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The heating system is segmented into multiple heating zones with independent temperature control. The build chamber can be heated to a first temperature while the resin reservoir is heated to a second, higher temperature, allowing localized viscosity reduction without exposing the entire resin to temperatures that would cause deformation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the resin are maintained at different temperatures. The interface layer where photocuring occurs is kept at optimal temperature for crosslinking density, while the bulk resin reservoir is heated to reduce viscosity. This local temperature differentiation allows simultaneous improvement of resin flow and prevention of heat deflection.

Inventive Principle:

Principle #3Local quality

2Strength

If the interface temperature is increased to improve crosslinking density, then the mechanical properties are improved, but the temperature uniformity across the interface becomes inconsistent

Engineering Contradiction:

Improvecrosslinking densityVSAvoidtemperature uniformity

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The heating system dynamically adjusts power distribution across different heating zones based on real-time temperature feedback. The controller monitors temperatures at multiple locations and modulates heating element power to maintain uniform interface temperature while achieving target crosslinking density, preventing hot spots and ensuring consistent mechanical properties.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If multiple heating zones with independent control are implemented, then temperature control precision is improved, but the device complexity increases

Engineering Contradiction:

Improvetemperature control precisionVSAvoidheating system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The heating system uses a unified controller that manages multiple heating zones through a single interface. The same controller hardware and software architecture handles temperature regulation for the build chamber, resin reservoir, and interface layer, reducing the need for separate control systems and minimizing overall device complexity while maintaining precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 fabrication of objects with high dimensional accuracy and controlled mechanical properties from high-viscosity resins, reducing manufacturing time and increasing crosslinking density while maintaining consistent build quality.

Implementation Method 1

heating an interface layer of the resin reservoir toward a target reaction temperature... at a resin interface between a surface of the build window and the resin reservoir

Methodology Applied

Scientific EffectInfrared radiation heating: Infrared Radiation

Implementation Method 2

selectively photocuring a first volume of the resin reservoir to form a first layer of a build

Methodology Applied

Scientific EffectPhotocuring: Photopolymerisation

Data Source

PatentUS11707891B2Method for regulating temperature at a resin interface in an additive manufacturing process

Publication Date: 2023.07.25 STRATASYS INC

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.