Wax Support Material for Additive Manufacturing

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Solution Overview

Problem

Existing generative manufacturing processes face challenges in producing three-dimensional shaped bodies with suitable support structures that have good printability over a wide temperature window, maintain dimensional stability during the printing process, and can be easily removed without damaging the final product.

Innovation Solution

A method involving the use of a shear-thinning viscoelastic support material composed of wax and particulate rheology additives, which is applied using a precise dosing system and crosslinked using radiation, allowing for the creation of support structures that can be easily removed after the structure-forming material has solidified.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional wax materials are used as support material, then the support structures can be easily removed, but the dimensional stability during printing deteriorates due to low dimensional stability of molten wax

Engineering Contradiction:
Improveease of removalVSAvoiddimensional stability
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The support material is formulated as a composite consisting of wax particles (30-70 wt%) combined with viscogen particles (20-50 wt%). This composite structure combines the ease of removal property of wax with the dimensional stability provided by the viscogen particles, resolving the contradiction between easy removal and dimensional stability during printing.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If the temperature window for printing is widened, then the printability is improved, but the dimensional stability deteriorates due to narrow processing temperature range

Engineering Contradiction:
Improvetemperature windowVSAvoiddimensional stability
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The support material composition is specifically designed to maintain optimal viscosity across a wide temperature range (10°C to 50°C above melting point). The combination of wax particles with viscogen particles creates a material whose viscosity changes gradually with temperature, allowing printing to be performed across a broad temperature window while maintaining dimensional stability throughout the process.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the support material viscosity is increased for better shape retention, then the dimensional stability is improved, but the printability deteriorates due to difficulty in dispensing

Engineering Contradiction:
Improveshape retentionVSAvoidprintability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The support material exhibits dynamic viscosity characteristics that adapt to processing conditions. At higher temperatures during dispensing, the viscosity is low enough to allow easy pumping and jetting through the nozzle. As the material cools during and after deposition, the viscosity increases to provide excellent shape retention and dimensional stability, thus resolving the contradiction between printability and shape retention.

Inventive Principle:
Principle #15Dynamics

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

Enables the production of three-dimensional molded bodies with support structures that exhibit excellent printability, dimensional stability, and easy removal, thereby overcoming the limitations of previous methods by providing a wide temperature window and stable geometric accuracy.

Implementation Method 1

The support material (SM) used according to the invention solidifies upon cooling

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

crosslinked using radiation

Methodology Applied
Scientific EffectRadiation crosslinking: Photopolymerisation

Implementation Method 3

shear-thinning viscoelastic support material

Methodology Applied
Scientific EffectShear thinning: Shear Thinning

Data Source

PatentEP3426729B1Generative method for producing molded bodies using a support material made of wax
Publication Date: 2019.09.25 WACKER CHEMIE AG
  • EP3426729B1 patent drawingFigure 1
  • EP3426729B1 patent drawingFigure 2~3
  • EP3426729B1 patent drawing

AI summary

The invention relates to a generative method for producing three-dimensional molded bodies (8), wherein the molded body is constructed gradually in that the structure-forming material (6b) is applied in liquid form in a location-specific manner. In addition, a second material made of wax is applied as a support material (6a) in regions that should remain free of the structure-forming material, and is removed after solidification of the structure-forming material. The support material has good dimensional stability and can preferably be processed within a wide temperature window.