Metal Sheet Additive Manufacturing via Pulsed Laser Droplet Ejection

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Solution Overview

Problem

Existing metal additive manufacturing (AM) systems face limitations in achieving high resolution and high deposition rates due to the use of metal powders, which result in inconsistent mechanical properties and high costs, while processes using wire-fed directed energy deposition offer poor resolution and high build rates, leading to trade-offs between feature size and build rate.

Innovation Solution

An additive manufacturing system utilizing a pulsed laser to liquefy and eject metal droplets from a metal sheet or ribbon feedstock, allowing for on-the-fly adjustment of process parameters such as pulse duration, power density, and spot size to achieve high-resolution parts with closer feature spacing and increased build rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If metal powder feedstock is used in selective laser melting, then deposition rate can be improved, but manufacturing precision deteriorates due to poor confinement of heating zone and minimum feature size limitation

Engineering Contradiction:

Improvedeposition rateVSAvoidminimum feature size

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameter of feedstock form from powder to thin sheet/ribbon, enabling precise thermal confinement while maintaining high deposition rates. The sheet feedstock allows the laser to melt and eject material in a controlled manner without the scattering issues inherent to powder feedstocks.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions (solid to liquid to ejected droplet) of the metal sheet material under pulsed laser irradiation. The rapid heating and cooling cycles create controlled phase changes that enable precise material deposition with sharp feature definition, resolving the contradiction between deposition rate and manufacturing precision.

Inventive Principle:

Principle #36Phase transitions

2Productivity

If metal powder feedstock is used, then deposition rate can be increased, but manufacturing precision deteriorates due to oxygen content and contamination variability

Engineering Contradiction:

Improvedeposition rateVSAvoidmechanical property consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs a continuous sheet feedstock that is processed in a controlled environment, eliminating the need for expensive high-purity powders. The sheet material can be processed rapidly without requiring the same level of purity control as powders, reducing both cost and variability in mechanical properties.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent processes the metal sheet in a protected atmosphere environment, preventing oxidation and contamination during the rapid deposition process. This inert environment maintains consistent material properties throughout production, resolving the variability issue associated with powder feedstocks during shipping and storage.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Productivity

If wire-fed directed energy deposition is used, then build rate can be improved, but manufacturing precision deteriorates with minimum feature size of approximately 16000 μm

Engineering Contradiction:

Improvebuild rateVSAvoidminimum feature size

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the material feedstock into thin sheets or ribbons rather than using continuous wire. This segmentation allows for better thermal confinement and more precise control of the molten pool, enabling feature sizes an order of magnitude smaller than wire-fed DED while maintaining high build rates.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses pulsed laser irradiation with controlled duty cycles to melt and eject material from the sheet feedstock. This periodic action allows for precise control of material deposition timing and location, achieving fine feature resolution while maintaining high overall deposition rates through rapid pulsing sequences.

Inventive Principle:

Principle #19Periodic action

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

The system enables the production of high-resolution parts with improved build rates and reduced material costs by controlling droplet features and print resolution, overcoming the limitations of existing technologies in metal AM.

Implementation Method 1

activate a pulsed laser to heat a selected portion of the feedstock to its melting temperature

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

heat a selected portion of the feedstock to its melting temperature to liquefy the selected portion of the feedstock

Methodology Applied

Scientific EffectSelective laser melting: Selective Laser Sintering

Implementation Method 3

liquefy the selected portion of the feedstock

Methodology Applied

Scientific EffectLiquefaction: Melting

Implementation Method 4

discharge a droplet of material from the feedstock onto the substrate

Methodology Applied

Scientific EffectDroplet ejection:

Data Source

PatentUS12151432B2Controlled molten metal deposition

Publication Date: 2024.11.26 CORNELL UNIVERSITY

AI summary

An additive manufacturing system includes an apparatus to facilitate production at the microscale using metal sheet as feedstock. This additive manufacturing system uses energy from a pulsed laser beam for ejection of metallic droplets to consolidate a part in a layer-by-layer manner.