Soft-Material 3D Printing With Rheology and Machine Pathing
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Solution Overview
Problem
Thermally cured thermoset polymers like epoxies and silicones are challenging to additively manufacture with high fidelity due to their prolonged liquid state and difficulty in maintaining intended geometry, especially when printing geometries such as overhangs and free-standing structures without support.
Innovation Solution
The use of rheological modifiers to create yield stress fluids with thixotropic properties, combined with optimized machine pathing and print parameters, allows for the deposition of structure materials through nozzles with controlled forces, ensuring precise geometry maintenance and complex structure formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoset polymers are used as structure material, then mechanical properties and chemical resistance are improved, but manufacturing precision deteriorates due to prolonged liquid state and geometry retention issues
Solution Approach 1:
The patent modifies the rheological parameters of thermoset polymers by adding yield-stress agents and thixotropic modifiers, transforming the material from a simple viscous liquid into a yield-stress fluid that can maintain geometry below a critical stress threshold while still being extrudable above that threshold
Solution Approach 2:
The patent creates a composite structure material by combining thermoset polymers with yield-stress agents (such as fumed silica, attapulgite, or calcium carbonate) and thixotropic modifiers, resulting in a material that exhibits both the desired mechanical properties of thermosets and the geometry-retention characteristics of yield-stress fluids
2Ease of manufacture
If thermoset polymers remain in liquid state for prolonged period, then ease of manufacture is improved, but manufacturing precision deteriorates due to material flowing and not retaining intended geometry
Solution Approach 1:
The patent introduces yield-stress behavior and thixotropy into the thermoset polymer system, creating a material that transitions between fluid and solid-like states based on applied stress, enabling both easy extrusion and precise geometry retention during printing
Solution Approach 2:
The patent creates a dynamic material response where the polymer exhibits fluid behavior under low stress (during extrusion) and solid-like behavior under high stress (during deposition), with time-dependent viscosity changes through thixotropy that allow the material to flow during printing but set immediately after deposition
3Manufacturing precision
If support material is used for overhangs and free-standing structures, then manufacturing precision is improved, but device complexity and ease of manufacture deteriorate
Solution Approach 1:
By modifying the rheological parameters of the structure material itself to include yield-stress and thixotropic properties, the patent eliminates the need for separate support materials, as the modified material can inherently support its own weight and maintain complex geometries without additional structural assistance
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 additive manufacturing of complex geometries with soft polymers by minimizing filament deformation and distortion, achieving high-fidelity printed constructs with improved mechanical properties.
Implementation Method 1
The structure material can comprises a yield stress, a thixotropic property, an increase viscosity due to the rheological modifier
Implementation Method 2
The structure material can comprises a yield stress... Applying the force to the structure material can comprises applying a force of at least the yield stress to the structure material
Data Source
AI summary
A method and system for additive manufacturing are provided herein. The method comprises depositing a structure material, by a nozzle (810), into a support material (808) by applying to the structure material such that the structure material flows through the nozzle. The structure material comprises a polymer and a rheological modifier. Depositing of the structure material is repeated as necessary to create an object (814). The support material is at least partially removed from object. In various examples, the method comprises varying a print parameter from a first portion of the object to a second portion of the object, moving the nozzle away from a previously deposited layer of the object when repositioning for deposition of a subsequent layer of the object, or a combination thereof.