Ferromagnetic Powder Separation via Dynamic Magnet Manipulation

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Solution Overview

Problem

In additive manufacturing using multi-material laser beam melting, there is a challenge in reliably separating ferromagnetic and non-ferromagnetic powder particles to achieve high purity, which is essential for reusing leftover powder.

Innovation Solution

A device and method utilizing a sorting arrangement with magnets of alternating polarity and a non-magnetic separating layer, where the magnets are manipulated to deflect ferromagnetic powder particles and create a jumping motion over the separating layer, effectively separating the particles by moving them along a trajectory that superimposes a jump movement, allowing non-ferromagnetic particles to be shaken off.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnetic forces are used to separate ferromagnetic and non-ferromagnetic powder particles, then separation capability is improved, but powder purity is insufficient for additive manufacturing requirements

Engineering Contradiction:
Improveseparation capabilityVSAvoidpowder purity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the sorting arrangement manipulable through three independent mechanisms: moving the magnets opposite to the transport direction, cyclically reversing magnet polarity, and moving the separating layer along the transport direction. These dynamic adjustments enable precise control of ferromagnetic particle transport, allowing them to follow the separation layer's movement and be deposited at controlled locations, thereby achieving high powder purity required for additive manufacturing

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements periodic action through the cyclical reversal of magnet polarity. The magnets alternate between attracting and repelling ferromagnetic particles in a periodic manner, creating a rhythmic transport mechanism. This periodic magnetic field variation, combined with the movable separating layer, enables precise control over particle separation timing and location, improving both separation capability and final powder purity

Inventive Principle:
Principle #19Periodic action

2Productivity

If magnets attract ferromagnetic powder particles to the separating layer, then separation efficiency is improved, but particle contamination occurs

Engineering Contradiction:
Improveseparation efficiencyVSAvoidparticle purity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces a non-magnetic separating layer as an intermediary between the magnets and the powder particles. This separating layer serves multiple functions: it prevents direct contact between magnets and particles (avoiding contamination), provides a controllable surface for ferromagnetic particles to adhere to during separation, and acts as a movable carrier that can transport particles to designated deposition zones. The manipulability of this intermediary layer is key to achieving both high separation efficiency and particle purity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical contact-based separation with a magnetic field-based system. Instead of using mechanical screens or physical barriers that could contaminate particles, the invention uses magnetic forces acting through the non-magnetic separating layer. This substitution allows for contactless separation of ferromagnetic particles from non-ferromagnetic ones, significantly improving particle purity while maintaining high separation efficiency

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

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

This approach achieves high powder purity, enabling the reliable separation of ferromagnetic and non-ferromagnetic particles, suitable for additive manufacturing, by utilizing the dynamic interaction between magnets and the separating layer to efficiently separate and remove ferromagnetic particles while ensuring the purity of the remaining powder.

Implementation Method 1

the magnets deflect the ferromagnetic powder particles and attract them to the separating layer

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 2

the attracted ferromagnetic powder particles are transported away during the manipulation of the sorting arrangement with a jumping movement superimposed on the removal trajectory

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP4368292A1Device and method for separating ferromagnetic powder particles from non-ferromagnetic powder particles that are mixed therewith
Publication Date: 2024.05.15 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4368292A1 patent drawingFigure 1a
  • EP4368292A1 patent drawingFigure 1b
  • EP4368292A1 patent drawingFigure 2

AI summary

The invention relates to a device and a method for separating ferromagnetic powder particles (5) from non-ferromagnetic powder particles (6) mixed with them, in particular with particle sizes of 250 µm or less. The device comprises a sorting arrangement configured for transporting the ferromagnetic powder particles (6) along a transport trajectory (10), wherein the sorting arrangement comprises a plurality of magnets (1) arranged along the transport trajectory (10) with alternating polarity and a non-magnetic separating layer (4) that covers the magnets (1) from the ferromagnetic powder particles (5) to be transported.The sorting arrangement is designed to be manipulable and is configured for manipulation by moving the magnets (1) against a direction of the transport trajectory (10) and/or cyclically reversing the polarity of the magnets (1) and/or moving the separating layer (4) along the direction of the transport trajectory (10), wherein the device further comprises a transport arrangement (7) which is configured to receive the mixed powder particles (5, 6) and guide them to the sorting arrangement, so that the magnets (1) deflect the ferromagnetic powder particles (5) and attract them to the separating layer (4), and the attracted ferromagnetic powder particles (5) are transported away during manipulation of the sorting arrangement with a jumping motion superimposed on the transport trajectory (10) with respect to the separating layer (4).