Silicone Elastomer 3D Printing in a Self-Healing Gel Support
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Solution Overview
Problem
Existing 3D printing methods for silicone elastomer articles face challenges in printing complex shapes due to issues with rheological and mechanical properties, particularly with compositions having overhangs greater than 40° or heights greater than 2 mm, and the use of support materials that are not reusable or require solvent washing, which can affect printing accuracy and nozzle integrity.
Innovation Solution
A gel composition comprising poloxamer and poly(oxyalkylene glycol) is used as a constrained environment for FRESH 3D printing, providing improved self-healing properties and enabling the printing of complex shapes by forming a gel at a specific temperature, allowing crosslinkable silicone compositions to be printed and then recovered without surface pollution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low viscosity silicone compositions are used for 3D printing, then printability is improved, but the ability to print complex shapes with overhangs greater than 40° or heights greater than 2 mm deteriorates
Solution Approach 1:
A gel support material acts as an intermediary medium during 3D printing, providing mechanical support for complex geometries while allowing low viscosity silicone compositions to be printed. The gel's yield stress properties enable it to support overhangs and bridges during printing, and its self-healing capability maintains structural integrity throughout the printing process.
Solution Approach 2:
The gel support material's rheological parameters are specifically tuned to provide optimal support during printing. By controlling the yield stress and self-healing properties of the gel, the system enables printing of complex shapes that would otherwise be impossible with low viscosity materials alone.
2Shape
If organic microgel support material is used for 3D printing, then complex shapes can be printed, but the support material requires solvent washing and is not reusable
Solution Approach 1:
The gel support material is reusable and can be recovered and reused for multiple printing cycles without requiring solvent washing. This self-service characteristic eliminates the need for complex removal processes and makes the support material sustainable for continuous use.
Solution Approach 2:
Instead of discarding the support material after one use, the gel is recovered and reused for subsequent printing operations. This recovering approach reduces waste and operational costs while maintaining printing quality.
3Manufacturing precision
If Carbopol 940 gel is used as support material, then surface aspect is improved, but pH and salt control is required which limits printing of different silicone types
Solution Approach 1:
The gel support material is designed to be universally compatible with various types of silicone compositions without requiring specific pH or salt control. This multi-functional gel can support different silicone formulations while maintaining good surface finish quality.
4Shape
If suspended hydrogels with high static yield stress are used, then complex objects can be supported, but the high yield stress causes bending of the printing nozzle and affects printing accuracy
Solution Approach 1:
The gel's rheological parameters are optimized to provide sufficient yield stress for supporting complex objects while maintaining low enough stress levels to prevent nozzle bending. The self-healing property allows the gel to recover from minor deformations, maintaining printing accuracy throughout the process.
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 allows for the production of silicone elastomer articles with good surface roughness and improved printing accuracy, enabling the creation of complex shapes with overhangs and bridges, while the gel composition is self-healing and reusable, maintaining printing precision and nozzle integrity.
Implementation Method 1
placing the container comprising the composition C at the required temperature T1 to form a gel
Implementation Method 2
the gel formed from composition C applies a constant pressure to the crosslinking silicone composition X during printing
Implementation Method 3
The gel formed from composition C has a great self-healing capability
Implementation Method 4
The printing nozzle will then apply a shear stress on the gel formed from composition C, which will lead to a deformation of the gel
Implementation Method 5
printing a crosslinkable silicone composition X into the gel obtained in 2) with a 3D printer at the required temperature T1; optionally allowing the printed composition X to partially or totally crosslink
Data Source
AI summary
The present invention relates to a process for manufacturing a silicone elastomer article comprising the following step: 1) providing a composition C, comprising water, at least one poloxamer and a poly(oxyalkylene glycol), into a container; 2) placing the container comprising the composition C at the required temperature T1 to form a gel; 3) printing a crosslinkable silicone composition X into the gel obtained in 2) with a 3D printer at the required temperature T1; 4) optionally allowing the printed composition X to partially or totally crosslink, optionally by heating, to obtain a silicone elastomer article, in the container; 5) optionally placing the container obtained in step 4) at a temperature T3 lower than the sol-gel transition temperature of composition C; 6) recovering the silicone elastomer article; and 7) optionally washing the obtained silicone elastomer article for example with water at a temperature T3 lower than the sol-gel transition temperature of composition C.