Additive Manufacturing Partial Curing for Shrinkage Control
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Solution Overview
Problem
Current additive manufacturing (AM) technologies face challenges with materials that exhibit high volume shrinkage and thermal instability, leading to object curling, deformation, and poor printing quality.
Innovation Solution
A dual stage hardening process is implemented, where the object is partially solidified during the AM process to form a green body, followed by a post-treatment thermal process to complete solidification. This approach uses a combination of reactive and non-reactive building material formulations, with a hardened shell encapsulating a partially cured core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complete solidification is applied during additive manufacturing, then manufacturing precision is improved, but productivity deteriorates due to extended curing time
Solution Approach 1:
The patent applies partial solidification during the additive manufacturing process, where only a portion of the material is cured to the required degree while other portions remain partially uncured. This allows the manufacturing process to continue at higher speeds without waiting for complete curing of all materials, thereby maintaining printing quality for critical regions while improving overall productivity.
2Manufacturing precision
If high reactivity photopolymerizable material is used, then manufacturing precision is improved through fast solidification, but object-generated harmful factors worsen due to curling and deformation
Solution Approach 1:
The patent implements local quality by applying different degrees of solidification to different regions of the printed object. Highly reactive photopolymerizable materials are used in regions requiring fast solidification and high precision, while other regions use materials with lower reactivity or different curing characteristics. This localized approach allows fast solidification where needed while minimizing curling and deformation in other areas.
Solution Approach 2:
The patent changes material parameters by using compositions with varying photoreactivity, viscosity, and curing characteristics in different regions of the object. This allows optimization of solidification speed in critical areas while controlling harmful effects like curling and deformation in other areas through parameter adjustment.
3Ease of manufacture
If material with high volume shrinkage is used, then ease of manufacture is improved by enabling printing with diverse materials, but manufacturing precision deteriorates due to object deformation
Solution Approach 1:
The patent applies local quality by using materials with high volume shrinkage only in regions where it is acceptable or beneficial, while using materials with low shrinkage in regions requiring high dimensional stability. This allows the use of diverse materials including those with high shrinkage characteristics without compromising the overall manufacturing precision of the final object.
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
The method effectively reduces object curling and deformation, enables printing with materials that undergo substantial shrinking, and improves the transparency and throughput of the additive manufacturing process.
Implementation Method 1
The uncured model material is a photopolymerizable or photocurable material that is cured, hardened or solidified upon exposure to ultraviolet (UV) light after it is jetted.
Implementation Method 2
followed by a post-treatment thermal process to complete solidification
Data Source
AI summary
A method of additive manufacturing (AM) includes dispensing a first building material formulation to form an outer region, and dispensing a second building material formulation to form an inner region, the outer region surrounding the inner region, the inner and outer regions being shaped to form a layer of the object; exposing the layer to a first curing condition, repeating the dispensing and the exposing to sequentially form a plurality of layers of the object and collectively exposing the plurality of layers to a second curing condition. The selections are such that the first building material formulation is hardened to a higher degree than the second building formulation. The outer regions form a hardened coating that at least partially encapsulates the inner regions. The second curing condition is other than the first curing condition and is selected to increase the degree that the inner region is hardened.