Solid Freeform Fabrication Using Core–Envelope Materials for HDT and Impact
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Solution Overview
Problem
Existing additive manufacturing (AM) technologies face challenges in achieving a balance between heat deflection temperature (HDT) and impact resistance in printed objects, particularly when using multiple modeling materials, as well as in optimizing the mechanical properties of layered structures.
Innovation Solution
The use of two distinct modeling material formulations with different HDT and Izod Impact Resistance properties, where the first formulation has a higher HDT and the second has a lower HDT, combined in a voxelated manner to form core and envelope regions, along with controlled layer thicknesses and ratios, to achieve desired mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single modeling material formulation is used in additive manufacturing, then the manufacturing process is simple, but the object cannot achieve both high heat deflection temperature and high impact resistance simultaneously
Solution Approach 1:
The patent applies composite materials by combining two distinct modeling material formulations with different properties (first formulation with higher HDT, second formulation with lower HDT but higher impact resistance). These formulations are deposited in specific patterns (core and envelope regions) to create objects that achieve both high heat deflection temperature and high impact resistance simultaneously, resolving the contradiction between mechanical property reliability and material complexity.
Solution Approach 2:
The patent implements local quality by assigning different material formulations to different spatial regions within the object. The first formulation is used in core regions where high HDT is needed, while the second formulation is used in envelope regions where impact resistance is prioritized. This localized material assignment allows each region to optimize its mechanical properties for its specific functional requirements.
2Reliability
If multiple modeling material formulations are used to improve mechanical properties, then HDT and impact resistance are enhanced, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the object into distinct regions (core and envelope regions) that are filled with different material formulations. The manufacturing process segments the deposition operation into separate sequences: first depositing the core region with the first formulation, then depositing the envelope region with the second formulation. This segmentation strategy manages manufacturing complexity by organizing multi-material deposition into structured, repeatable steps while achieving superior mechanical properties.
3Reliability
If different material formulations are deposited in specific patterns, then the mechanical properties are optimized, but the manufacturing precision requirements increase
Solution Approach 1:
The patent implements local quality by precisely controlling which material formulation is deposited in which spatial region. The system assigns the first formulation to core regions and the second formulation to envelope regions based on the desired mechanical property optimization. This localized material assignment requires and achieves high manufacturing precision in material deposition, ensuring that each region receives the appropriate material for its functional requirements.
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 enhances the mechanical properties of printed objects by providing improved HDT and impact resistance, allowing for more stable and durable layered structures.
Implementation Method 1
Both the modeling and support materials are preferably liquid at the working temperature at which they are dispensed, and subsequently hardened, typically upon exposure to curing energy (e.g., UV curing), to form the required layer shape.
Data Source
Figure 1A~1G
Figure 2
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AI summary
Methods of layerwise fabrication of a three-dimensional object, and objected obtained thereby are provided. The methods are effected by dispensing at least a first modeling formulation and a second modeling formulation to form a core region using both said first and said second modeling formulations, an inner envelope region at least partially surrounding said core region using said first modeling formulation but not said second modeling formulation, and an outer envelope region at least partially surrounding said inner envelope region using said second modeling formulations but not said first modeling formulation; and exposing said layer to curing energy, thereby fabricating the object, The first and second modeling formulations are selected such they differ from one another, when hardened, by at least one of Heat Deflection Temperature (HDT), Izod Impact resistance, Tg and elastic modulus.