Multi-Material 3D Printing via Thermal Bonding

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Solution Overview

Problem

Existing methods for producing plastic parts, such as injection molding and rapid manufacturing, face limitations when dealing with incompatible materials and complex geometries, particularly in achieving seamless connections and surface quality without molds.

Innovation Solution

A method involving the sequential discharge of solidifiable material drops from multiple reservoirs, allowing for direct assembly of complex geometries with van der Waals electron bonding between material components, forming edge regions that seamlessly merge into connecting structures, and optionally using intermediate layers for detachable or sliding connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If injection molding is used to produce plastic parts, then high-precision production of complex part geometries is achieved, but the process reaches its limits when materials that are not compatible with each other have to be processed or when there are problems with demoulding from the mold

Engineering Contradiction:
Improveproduction precision of complex geometriesVSAvoidcompatibility with different material components
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The process segments the manufacturing into discrete droplet deposition steps, allowing different material components to be placed sequentially without requiring full-mold compatibility. Each droplet acts as an independent unit that can be bonded to previous layers, enabling multi-material processing without the constraints of traditional injection molding

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The process changes the bonding mechanism from mechanical demoulding to thermal bonding at controlled temperatures. By maintaining temperatures above the glass transition temperature of the materials during processing, the system achieves seamless bonding of incompatible materials that would otherwise require demoulding from molds

Inventive Principle:
Principle #35Parameter changes

2Productivity

If rapid manufacturing processes are used for one-piece and small batch sizes, then short-term delivery and complex geometries are achieved, but the processes reach their limits when several different material components are to be processed next to each other

Engineering Contradiction:
Improvedelivery time for small batchesVSAvoidprocessing of multiple different material components
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The system uses a universal droplet deposition mechanism that can process any solidifiable material that can be melted and bonded thermally. This multi-functional approach replaces material-specific processes with a unified thermal bonding mechanism that works across different material types

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

By controlling temperature parameters above the glass transition temperature of all material components, the system enables seamless bonding of different materials in quick succession, achieving both rapid manufacturing and multi-material compatibility

Inventive Principle:
Principle #35Parameter changes

3Strength

If high pressure and high melting temperatures are used to create droplets with adhesive forces, then material bonding is achieved, but the requirements for pressure and temperature increase

Engineering Contradiction:
Improveadhesive bonding strengthVSAvoidmelting temperature requirement
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The process optimizes the temperature parameter range by operating above the glass transition temperature but below complete melting, achieving adequate adhesive forces without requiring extreme temperatures. This parameter optimization reduces energy requirements while maintaining bond strength

Inventive Principle:
Principle #35Parameter changes

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 complex geometries with improved material properties and surface quality, allowing for the creation of seamless connections between incompatible materials, similar to single-material processes, with the ability to produce objects down to a quantity of one, including features like cardan joints and ball joints.

Implementation Method 1

the solidifiable material is heated to a melting temperature, in particular above the glass transition temperature of the material

Methodology Applied
Scientific EffectGlass transition:

Implementation Method 2

Due to the adhesive forces of the material, high pressure and high melting temperatures are required for the material, especially since the droplet should have a size of 0.01 to 0.05 mm³

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 3

van der Waals electron bonding can occur at the ends of the plastic chains of each material

Methodology Applied
Scientific Effectvan der Waals bonding: Van der Waals Force

Data Source

PatentEP2739456B1Method for producing a three-dimensional object from solidifiable material and the object produced thereby
Publication Date: 2019.03.06 ARBURG GMBH & CO KG
  • EP2739456B1 patent drawingFigure 1~3b
  • EP2739456B1 patent drawingFigure 4

AI summary

A method for producing a three-dimensional object through generative building in a direct build sequence from solidifiable material that occurs in its natural state as a fluid or which can be liquefied. To that end, a plurality of material components are discharged through a plurality of alternately programmable discharge units and form, as a result of the discharge, adjoined various parts of the object (50, 50'), the geometric relationships attained during discharge already corresponding to the object (50, 50'). Because the material components (C, D) form among each other either limitless merging edge areas (51) or non-connecting, close running edge areas of the various material components, a method and hence a produced object can be provided, at which limits and border areas are formed between various material components "as from one section", even with complex geometries.