Multilayered Thermoformable Foil Coating for Epoxy Cast Molds

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Solution Overview

Problem

Molds for epoxy castings, particularly 3D printed sand molds, exhibit high porosity and surface roughness, leading to unfavorable adhesion with the cast resin and requiring complex and costly anti-stick coatings that do not consistently deliver high surface quality.

Innovation Solution

A multilayered thermoformable foil coating is applied to the mold body, comprising an inner layer with varying hardness to fill surface roughness and a harder outer layer for exposure to epoxy resin, along with adhesive layers for improved adhesion and structural integrity, made from specific polymers and fluoropolymers for enhanced thermal and chemical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a mold body with high porosity and surface roughness is used, then the mold can be produced more easily and cost-effectively, but the adhesion with cast resin becomes unfavorable and surface quality deteriorates

Engineering Contradiction:
Improvemold production easeVSAvoidsurface quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The coating is divided into multiple layers with different functions: an inner layer that fills surface roughness and pores, and an outer layer that provides the final glossy surface quality. This segmentation allows each layer to optimize for its specific function, resolving the contradiction between easy mold production and high surface quality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite coating structure combining different materials with complementary properties. The inner layer material is selected to fill roughness effectively, while the outer layer material provides the desired surface finish and anti-stick properties, achieving both ease of manufacture and high surface quality

Inventive Principle:
Principle #40Composite materials

2Reliability

If complex anti-stick coatings are applied to prevent adhesion, then the anti-stick property improves, but the production process becomes more complicated and time-consuming

Engineering Contradiction:
Improveanti-stick propertyVSAvoidproduction process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges multiple functions into a single integrated coating structure. The multilayered coating simultaneously provides anti-stick properties, surface smoothing, and glossy finish in one application process, eliminating the need for separate coating steps and reducing production complexity while maintaining reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coating is applied as a thin film structure that conformally covers the mold body. This thin film approach provides effective anti-stick properties and surface quality improvement without requiring thick, complex coating applications, thereby simplifying the production process

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If multiple coating layers are applied to improve surface quality, then the surface quality improves, but the production time and cost increase

Engineering Contradiction:
Improvesurface qualityVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The inner layer is designed to preliminarily fill the surface roughness and pores before the outer layer is applied. This preliminary action of surface preparation within the coating structure itself eliminates the need for separate surface preparation steps, reducing production time while achieving high surface quality

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

The coating significantly reduces surface roughness and porosity, improves adhesion, and simplifies the mold production process by applying the coating in a single thermoforming step, resulting in a glossy surface with enhanced anti-stick properties and reduced production complexity.

Implementation Method 1

the inner layer fills the rough and porous surface of the mold body

Methodology Applied
Scientific EffectFlow and solidification of polymer material:

Implementation Method 2

A multilayered thermoformable foil coating is applied to the mold body

Methodology Applied
Scientific EffectThermoforming:

Data Source

PatentEP4223478A1A mold for epoxy castings and a method for producing molds for epoxy castings
Publication Date: 2023.08.09 ABB (SCHWEIZ) AG
  • EP4223478A1 patent drawingFigure 1~3
  • EP4223478A1 patent drawingFigure 4~5
  • EP4223478A1 patent drawing

AI summary

A mold (1) for epoxy castings comprising a mold body (2), and a coating (3) covering the mold body (2). The coating (3) is made of multilayered thermoformable foil comprising at least an inner layer (4) and at least an outer layer (5) for being exposed to the epoxy resin during casting. The inner layer (4) is located between the mold body (2) and the outer layer (5), wherein the inner layer (4) fills the rough and porous surface of the mold body (2). Furthermore, the layers of the multilayered thermoformable foil being made of different kinds of polymers.