Elastomeric Additive Manufacturing for Soft-Tissue-Mimicking Objects
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Solution Overview
Problem
Current additive manufacturing techniques are unable to produce 3D objects with portions that mimic the mechanical and visual properties of soft bodily tissues, as existing materials harden to a Shore hardness exceeding the characteristics of soft tissues, leading to issues like low tensile strength, tear resistance, and dimensional instability.
Innovation Solution
The method involves dispensing elastomeric curable formulations with specific compositions, including silica particles, to form layers with interlaced locations and fibrous patterns, achieving Shore A hardness lower than 10 or Shore 00 hardness lower than 40, and combining these with non-curable polymeric materials to enhance mechanical properties and visual resemblance to soft tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional building materials are used in additive manufacturing, then the manufacturing process is simple and materials are easy to dispense, but the hardened material achieves Shore hardness exceeding the characteristics of soft tissues, resulting in poor mechanical properties
Solution Approach 1:
The patent changes the chemical composition parameters of the building material by incorporating specific ratios of elastomeric curable materials (polyester polyols, poly silicone oxazolidinone, poly carbonate) and non-curable polymeric materials (polyethylene glycol, polypropylene glycol). This parameter modification enables the material to achieve Shore A hardness lower than 10 while maintaining adequate tensile strength and tear resistance, resolving the contradiction between ease of manufacture and mechanical strength.
Solution Approach 2:
The patent creates a composite building material formulation combining curable elastomeric polymers with non-curable polymeric materials and functional additives. This composite approach allows the material to exhibit both the dispensability required for additive manufacturing and the soft mechanical properties (Shore A hardness lower than 10, high tensile strength, high tear resistance) needed to mimic soft bodily tissues, simultaneously satisfying manufacturing ease and strength requirements.
2Ease of manufacture
If conventional building materials are used, then the manufacturing process is straightforward, but the material lacks dimensional stability and visual resemblance to soft tissues
Solution Approach 1:
The patent modifies material parameters by incorporating non-curable polymeric materials (polyethylene glycol, polypropylene glycol) in specific amounts alongside curable elastomeric materials. This parameter adjustment provides dimensional stability to the hardened material while maintaining the softness (Shore A hardness lower than 10) and visual properties needed to resemble soft tissues, resolving the contradiction between process simplicity and compositional stability.
3Strength
If the material is made softer to resemble bodily tissue, then visual and mechanical properties improve, but the material becomes more viscous and difficult to dispense through printing nozzles
Solution Approach 1:
The patent adjusts the rheological parameters of the building material by selecting specific non-curable polymeric materials (polyethylene glycol, polypropylene glycol) and their concentrations. These parameter changes enable the material to achieve low Shore A hardness (softer than conventional materials) and high tear resistance while maintaining adequate viscosity for reliable dispensing through printing nozzles, resolving the contradiction between softness/tear resistance and dispensability.
Solution Approach 2:
The patent formulates a composite material combining elastomeric curable materials with non-curable polymeric materials and functional additives. This composite structure provides the right balance of properties: softness (Shore A hardness lower than 10) and tear resistance from the elastomeric component, while the non-curable polymeric component and additives ensure appropriate viscosity for dispensability through printing nozzles, simultaneously satisfying both 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
The process successfully creates 3D objects with mechanical and visual properties similar to soft bodily tissues, offering improved tear resistance, dimensional stability, and visual similarity, while avoiding biological materials.
Implementation Method 1
The building material is dispensed from a dispensing head having a set of nozzles to deposit layers on a supporting structure. Depending on the building material, the layers may then be cured or solidified using a suitable device.
Data Source
AI summary
Methods of fabricating three-dimensional objects featuring properties of a soft bodily tissue and three-dimensional objects featuring properties of a soft bodily tissue or of an organ comprising same are provided.