Sol-Gel Mold with Gas Permeable Walls for Uniform Drying
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Solution Overview
Problem
Conventional sol-gel processes face challenges with evaporative drying, leading to non-uniform drying, deformation, and fissuring in complex shapes due to high surface tensions and mechanical stresses, while supercritical drying lacks control over all object faces, especially when using open molds.
Innovation Solution
A closed-chamber mold with a material capable of evacuating gases formed during gelling and drying ensures uniform shrinkage and preservation of object dimensions, allowing for complex geometry and uniform microstructure, using elastomeric materials like polydimethylsiloxanes for gas evacuation and stress absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If evaporative drying is used in an open mold, then the drying process is simple, but the object deforms and develops fissures due to non-uniform drying and high surface tensions
Solution Approach 1:
The patent introduces a liquid support as an intermediary medium between the sol-gel solution and the environment. This liquid support provides a controlled interface that enables uniform drying from all directions while maintaining object integrity, resolving the contradiction between simple drying processes and shape fidelity
Solution Approach 2:
The patent creates a controlled environment using a mold filled with liquid support that isolates the sol-gel solution from direct atmospheric exposure. This controlled environment prevents harmful surface tension effects and non-uniform drying stresses, allowing simple evaporative drying to produce high-precision objects
2Stability of the object's composition
If a liquid support is used instead of a solid mold, then deformations during gelling and drying are reduced, but the object shape is limited to thin films and contamination risk increases
Solution Approach 1:
The patent makes the liquid support system universally applicable to various object shapes by combining it with a mold structure. The liquid support provides deformation control while the mold defines complex geometries, enabling the system to handle both simple and complex shapes beyond just thin films
Solution Approach 2:
The patent creates a composite system combining liquid support medium with mold material (solid or liquid). This composite approach integrates the deformation-control benefits of liquid support with the shape-defining capabilities of molds, resolving the limitation to thin films and enabling complex three-dimensional objects
3Manufacturing precision
If supercritical drying is used, then volume shrinkage is controlled, but control over all object faces is limited when using open molds
Solution Approach 1:
The patent transitions from surface-only control in open molds to three-dimensional control by immersing the object in a liquid support within a closed mold. This dimensional change allows uniform drying and stress control from all directions simultaneously, providing complete face control while maintaining volume shrinkage management
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 achieves uniform drying and preservation of object dimensions, preventing deformation and fissuring, enabling the production of complex-shaped objects with controlled microstructural characteristics, reducing the need for microstructuring and etching processes.
Implementation Method 1
comprises a material suitable for allowing the evacuation of the gases formed during step b) and/or step c)
Implementation Method 2
On contact with ambient humidity, the precursors contained in this sol-gel solution undergo, in part, a step of hydrolysis and a step of condensation
Implementation Method 3
a step of hydrolysis and a step of condensation, to form an oxide network
Implementation Method 4
The gel is then dried, to form at the end of said drying a monolithic object
Data Source
AI summary
A process for manufacturing an object made of a constituent material obtained from a sol-gel solution, the process including, successively: a) introducing the sol-gel solution into a mold of the object to be manufactured; b) gelling the sol-gel solution; c) drying the gel obtained in b) in the mold, by which the gel is converted into the constituent material of the object, wherein the mold includes a closed chamber and includes a material configured to allow evacuation of gases formed during b) and/or c).