Solid Freeform Fabrication Humidity Control for Precision

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Solution Overview

Problem

Existing methods for manufacturing solid freeform fabrication objects using photocurable liquid resins face challenges in precision and strength due to environmental temperature and humidity fluctuations, which affect the form and flexibility of the objects, particularly those made from hydrogels with high water content.

Innovation Solution

A method and device for manufacturing solid freeform fabrication objects that control absolute humidity between 5.5 to 20 g/m³ during the curing process, using an active energy ray curable liquid composition, to prevent moisture evaporation and absorption, thereby maintaining fabrication accuracy and precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photocurable liquid resin is used for manufacturing solid freeform fabrication objects, then the objects can be formed with complex and fine structures, but the fabrication precision and object strength are affected by environmental temperature and humidity fluctuations

Engineering Contradiction:

Improvefabrication precisionVSAvoidenvironmental humidity fluctuation effect

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies this principle by creating a controlled environment chamber that maintains constant absolute humidity (5-20 g/m³) and temperature (20-25°C) during the stereolithography process. This controlled atmosphere prevents moisture evaporation from and absorption by the hydrogel-based photocurable liquid resin, eliminating the harmful effects of environmental humidity fluctuations on fabrication precision and object strength.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Adaptability or versatility

If hydrogels with high water content are used to achieve flexibility and biological compatibility, then the objects become more suitable for medical applications, but moisture evaporation and absorption during manufacturing affects the object's mass and dimensional accuracy

Engineering Contradiction:

Improvebiological compatibilityVSAvoiddimensional accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent uses a controlled environment chamber that maintains constant absolute humidity (5-20 g/m³) to prevent moisture exchange between the hydrogel and the surrounding environment. This allows high-water-content hydrogels to be processed without moisture evaporation or absorption, preserving both their biological compatibility and dimensional accuracy throughout the manufacturing process.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent specifies precise parameter ranges for the controlled environment: absolute humidity of 5-20 g/m³ and temperature of 20-25°C. By controlling these parameters within specific ranges, the patent prevents moisture-related dimensional changes in hydrogel objects while maintaining their flexibility and biological compatibility for medical applications.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If environmental humidity is not controlled during the curing process, then the manufacturing process is simpler, but the object's mass and shape vary due to moisture evaporation and absorption

Engineering Contradiction:

Improveprocess simplicityVSAvoidobject mass consistency

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent implements a controlled environment chamber that maintains constant absolute humidity (5-20 g/m³) and temperature (20-25°C) during the stereolithography process. This controlled atmosphere prevents moisture evaporation from and absorption by the photocurable liquid resin and cured objects, ensuring consistent object mass and shape while remaining practically implementable in manufacturing settings.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 controlled humidity environment ensures precise fabrication by preventing moisture-related issues such as evaporation and swelling, resulting in solid freeform objects with consistent mass and height, improving the overall accuracy of the manufacturing process.

Implementation Method 1

irradiating a photocurable liquid resin with laser beams, in particular, ultraviolet rays, layer by layer to manufacture a three dimensional solid freeform fabrication object

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

control absolute humidity in an environment where the solid freeform fabrication object is manufactured to be from 5.5 to 20 g/m³ to prevent moisture evaporation and absorption

Methodology Applied

Scientific EffectEvaporation prevention: Evaporation

Data Source

PatentEP3339001B1Method of manufacturing solid freeform fabrication object and system for manufacturing solid freeform fabrication object

Publication Date: 2023.07.12 RICOH CO LTD

Figure 1

AI summary

A method of manufacturing a solid freeform fabrication object includes curing a liquid film made of an active energy ray curable liquid composition to form a layer; and laminating the layer to obtain the solid freeform fabrication object, wherein the solid freeform fabrication object is manufactured at an absolute humidity of from 5.5 to 20 g/m3.