Thermally Expandable Sheet Fabrication for High Protrusion Height

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Solution Overview

Problem

Existing methods for fabricating three-dimensional images from thermally expandable sheets often result in insufficient temperature rise in the foaming layer due to heat diffusion or absorption by the base layer, leading to reduced height of raised portions.

Innovation Solution

A method involving a formation sheet with a base and a thermally expansive layer, where the base is heated to a temperature lower than the expansion initiation temperature, and the thermally expansive layer is heated to a temperature higher than or equal to the expansion initiation temperature, using a forming apparatus with separate heating and expanding units to prevent heat diffusion and achieve higher protrusions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the base layer is made thick to provide structural support, then the structural strength is improved, but the heat diffusion increases causing insufficient temperature rise in the foaming layer

Engineering Contradiction:

Improvestructural strengthVSAvoidtemperature rise in foaming layer

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The heating process is segmented into two distinct stages: first heating the base layer to a temperature below the expansion initiation temperature, then heating the foaming layer to the expansion initiation temperature. This segmentation allows the thick base layer to provide structural support while preventing excessive heat diffusion that would reduce the temperature rise in the foaming layer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base layer is preliminarily heated to a temperature lower than the expansion initiation temperature before the foaming layer is heated. This preliminary action prepares the base layer structurally while controlling heat diffusion, enabling subsequent effective heating of the foaming layer to achieve the desired temperature rise for expansion.

Inventive Principle:

Principle #10Preliminary action

2Speed

If light irradiation is used to heat the image portions, then the heating speed is improved, but heat diffusion to the base layer occurs causing reduction in protrusion height

Engineering Contradiction:

Improveheating speedVSAvoidprotrusion height

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The base layer is preliminarily heated using light irradiation to a temperature below the expansion initiation temperature. This preliminary heating action achieves rapid heating speed while controlling the temperature to prevent excessive heat diffusion, thereby maintaining manufacturing precision for subsequent foaming layer expansion.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The heating process using light irradiation is segmented into two phases: first irradiating to heat the base layer to a controlled temperature below expansion initiation, then irradiating to heat the foaming layer to the expansion initiation temperature. This segmentation maintains both heating speed and protrusion height precision.

Inventive Principle:

Principle #1Segmentation

3Stability of the object's composition

If the base layer absorbs heat to provide thermal mass, then the thermal stability is improved, but the temperature rise in the foaming layer becomes insufficient

Engineering Contradiction:

Improvethermal stabilityVSAvoidtemperature rise in foaming layer

Core Design Contradiction:

Stability of the object's compositionVSTemperature

Solution Approach 1:

The base layer is preliminarily heated to a temperature below the expansion initiation temperature, establishing thermal stability through controlled heat absorption. This preliminary action ensures the base layer provides thermal mass without causing insufficient temperature rise in the foaming layer during the subsequent expansion phase.

Inventive Principle:

Principle #10Preliminary action

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

This approach allows for the fabrication of shaped objects with higher protrusions by controlling the heating process, preventing heat diffusion to the base and ensuring effective expansion of the thermally expansive layer, resulting in enhanced three-dimensional features.

Implementation Method 1

heating the thermally expansive layer of the formation sheet after heating of the base, to a temperature higher than or equal to an expansion initiation temperature at which the thermally expandable material starts to expand, thereby causing expansion of the thermally expansive layer

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

heating the base of the formation sheet to a temperature lower than an expansion initiation temperature

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

heat diffusion or absorption by the base layer

Methodology Applied

Scientific EffectConduction (thermal): Conduction (thermal)

Data Source

PatentUS11524456B2Method of fabricating shaped object and forming apparatus

Publication Date: 2022.12.13 CASIO COMPUTER CO LTD

AI summary

A method of fabricating a shaped object includes: preparing a formation sheet including a base and a thermally expansive layer stacked on a first main surface of the base, the thermally expansive layer including a binder and thermally expandable material; heating the base of the formation sheet to a temperature lower than an expansion initiation temperature at which the thermally expandable material starts to expand; and heating the thermally expansive layer of the formation sheet after heating of the base, to a temperature higher than or equal to the expansion initiation temperature at which the thermally expandable material starts to expand, thereby causing expansion of the thermally expansive layer.