Rotating Cylinder Roller for 3D Printing Poorly Flowable Powders

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Solution Overview

Problem

Existing methods for rapid prototyping using powdery materials face issues with poorly flowable powders, leading to incomplete coating, surface defects, and the need for additives that can be undesirable in the final product, especially when using rotating rollers which can adhere to the powder.

Innovation Solution

A device featuring a rotating cylinder application device with a rough surface or brush trimming, allowing for the effective application of poorly flowable powders without additional rollers or squeegees, reducing the need for additives and minimizing surface defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rotating roller is used to apply powder, then the application process is simplified, but poorly flowable powders adhere to the roller and impede proper application

Engineering Contradiction:
Improvepowder application processVSAvoidpowder coating quality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention changes the surface parameter of the application roller by providing a rough surface structure with specific roughness (Rz ≥ 100 μm). This parameter change prevents poor flowable powders from adhering to the roller surface, allowing the simplified rotating roller application method to work reliably with difficult-to-apply powders.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If additives are added to improve powder flowability, then the powder can be applied more easily, but the additives become part of the final object and may be undesirable

Engineering Contradiction:
Improvepowder flowabilityVSAvoidobject purity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention extracts the flowability enhancement function from the powder composition itself and transfers it to the application device surface. By providing a rough surface on the roller, the system achieves good powder flow and application without adding any substances to the powder, thereby maintaining object purity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If a smooth roller surface is used, then the roller is easier to manufacture and clean, but it cannot properly apply poorly flowable powders without creating surface defects

Engineering Contradiction:
Improveroller manufacturingVSAvoidsurface defect prevention
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention specifies a particular roughness parameter range (Rz ≥ 100 μm) for the roller surface that balances manufacturability with performance. This parameter change enables the roller to handle poorly flowable powders effectively while remaining practical to manufacture and maintain.

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 successful application of powders with low flowability, reducing surface defects and eliminating the need for additives, resulting in high-quality three-dimensional objects with improved process efficiency.

Implementation Method 1

The application device (7') for applying a layer is designed in the form of a rotating cylinder which is provided with a brush trimming (15)... The roughness Rz of the lateral surface is preferably at least 175 μm... The cylinder is provided with a brush (15)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

selective laser sintering (SLS)... plastic powders are selectively briefly exposed to a laser beam in a chamber, causing the powder particles hit by the laser beam to melt. The melted particles run together and quickly solidify again into a solid mass

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

causing the powder particles hit by the laser beam to melt. The melted particles run together and quickly solidify again into a solid mass

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2612746B8Device for the layered production of three-dimensional objects by means of rotating application
Publication Date: 2015.08.19 EVONIK OPERATIONS GMBH

AI summary

The present invention relates to a device for the layer-by-layer production of three-dimensional objects, a method for layer-by-layer production, and corresponding molded bodies.