Vapor-Phase Coloring of 3D-Printed Polymer Parts

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Solution Overview

Problem

Existing additive manufacturing (AM) polymer parts require inefficient, non-uniform, and environmentally harmful methods for colouring, particularly due to limited control parameters and waste generation in liquid dye immersion processes.

Innovation Solution

A method and apparatus using solvent vapor and suspended dye pigment particles in a gas to uniformly colour AM parts, with optional magnetic alignment for precise particle orientation, in a closed-loop system minimizing waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If liquid dye immersion is used to colour AM parts, then the parts can be coloured, but significant amounts of freshwater and waste water are consumed

Engineering Contradiction:
Improvecolouring capabilityVSAvoidfreshwater consumption
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The invention transitions the dye application process from liquid immersion to vapor-phase deposition. The dye is applied as a vapor or aerosol that condenses on the part surface, eliminating the need for liquid dye baths and water consumption. This phase transition resolves the contradiction by enabling colouring without liquid waste generation.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The invention extracts the harmful liquid immersion step from the colouring process. By removing the liquid dye bath and replacing it with vapor-phase application, the harmful element (liquid waste) is taken out while the essential function (colouring) is preserved through an alternative mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If liquid immersion is used for colouring, then parts can be coloured, but the process generates significant chemical and plastic microfiber waste

Engineering Contradiction:
Improvecolouring capabilityVSAvoidchemical and microfiber waste
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention converts the potential harm of waste generation into benefit by using a vapor-phase process that leaves no liquid waste. The vapor condenses directly on the part, and any excess vapor can be recovered or safely dissipated, transforming the harmful waste stream into a controllable process with minimal environmental impact.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The harmful chemical waste and plastic microfiber contamination are extracted from the process by eliminating liquid immersion entirely. The vapor-phase application method removes these harmful factors while maintaining the colouring function.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If liquid immersion is used for colouring, then parts can be coloured, but uniform and controlled colouring is difficult to achieve

Engineering Contradiction:
Improvecolouring capabilityVSAvoidcolour uniformity and control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention replaces the mechanical immersion process with a vapor-phase deposition system. This substitution allows for precise control of dye application through vapor concentration, temperature, and exposure time parameters, achieving uniform and controlled colouring that is difficult to obtain through liquid immersion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the physical parameters of the dye application process from liquid to vapor phase. This parameter change enables better control over colour saturation and uniformity through controllable vapor concentration, temperature, and exposure duration, resolving the precision issues of liquid immersion.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If liquid immersion is used for colouring, then parts can be coloured, but small holes or cavities may remain uncoloured due to capillary pressure

Engineering Contradiction:
Improvecolouring capabilityVSAvoidcolour saturation accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention uses vapor-phase deposition instead of liquid immersion. The vapor can penetrate small holes and cavities more effectively than liquid, and the condensation process ensures uniform dye distribution throughout the part structure, eliminating the capillary pressure problem that prevents liquid from entering small features.

Inventive Principle:
Principle #36Phase transitions

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

Achieves accurate, consistent, and environmentally friendly colouring of AM parts with improved surface finish and functional capabilities, reducing water consumption and emissions.

Implementation Method 1

a heater configured to vaporise a liquid solvent contained in the second reservoir

Methodology Applied
Scientific EffectVaporisation: Evaporation

Implementation Method 2

a first reservoir for containing dye pigment particles to be suspended in a gas

Methodology Applied
Scientific EffectSuspension in gas: Aerosol

Data Source

PatentEP3668705B1Additive manufacturing
Publication Date: 2025.12.24 ADDITIVE MANUFACTURING TECHNOLOGIES LIMITED
  • EP3668705B1 patent drawingFigure 1~2
  • EP3668705B1 patent drawingFigure 3~4b
  • EP3668705B1 patent drawingFigure 5a~6b

AI summary

The present application describes apparatus (100) for colouring an additively manufactured polymer part, comprising a chamber (106) for locating at least one additively manufactured polymer part (105) to be coloured, a first reservoir (102) for containing dye pigment particles to be suspended in a gas, and fluidly coupled to the chamber, and a further reservoir (104) for containing a solvent vapour, and fluidly coupled to the chamber. A method of colouring an additively manufactured polymer part is also described.