Laser Additive Manufacturing With Ultrasonic Densification

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Solution Overview

Problem

Additive manufacturing of components, such as turbomachine parts, often results in material properties that are inferior to those of cast and forged parts, particularly in terms of strength, toughness, and surface hardness, which do not meet the high demands of components like gas turbine guide vanes or moving blades.

Innovation Solution

The method involves selectively layering material with an underlying layer or carrier, using a laser to bond the material thermally or chemically, and generating structure-borne sound waves through pulsed laser application to induce internal stresses and improve material properties, while also allowing for post-processing to refine the component's surface and edges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If additive manufacturing is used to produce components, then complex shapes and smaller batch sizes can be manufactured, but material properties such as strength, toughness, and surface hardness are inferior to cast and forged parts

Engineering Contradiction:
Improvecomplex component shapeVSAvoidmaterial strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent applies ultrasonic vibration through a piezoelectric transducer to the deposited material layer during the additive manufacturing process. This mechanical vibration densifies the material structure, reduces porosity, and improves bonding between layers, thereby enhancing strength and toughness while maintaining the ability to create complex shapes

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent implements continuous ultrasonic vibration during the entire material deposition and bonding process. This continuous application of mechanical energy ensures consistent material densification and bonding quality throughout the component build, preventing weak points that would otherwise occur with intermittent processing

Inventive Principle:
Principle #20Continuity of useful action

2Ease of manufacture

If laser sintering or welding is used to connect material particles, then layers can be selectively bonded, but material properties remain between cast and forged parts

Engineering Contradiction:
Improveselective layer bondingVSAvoidmaterial strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent combines laser heating with ultrasonic vibration in a single integrated process. The laser provides thermal energy for material melting and bonding, while the ultrasonic vibration simultaneously densifies the material and enhances interlayer bonding. This merging of thermal and mechanical energy sources creates superior material properties compared to using either method alone

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If mechanical compression of loose material is applied before laser sintering, then material density may improve, but pressurization equipment becomes problematic

Engineering Contradiction:
Improvematerial densityVSAvoidpressurization equipment
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the need for external mechanical pressurization equipment by generating ultrasonic vibrations directly within the material layer through a piezoelectric transducer. This substitution of external mechanical compression with internal ultrasonic densification achieves similar or superior density improvement without requiring complex pressurization systems

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 enhances the material properties, particularly strength and grain size, of the manufactured components, enabling the production of high-performance parts like gas turbine components with complex shapes, meeting the stringent requirements of turbomachine components.

Implementation Method 1

The material is selectively connected by a controlled laser beam, in that the laser beam exposes the desired layer cross-section and heats the material to such an extent that its particles combine with each other

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

A pulsed application makes it possible, in particular, to generate structure-borne sound waves, preferably ultrasonic waves, directly in the material

Methodology Applied
Scientific EffectPulsed laser generating ultrasonic waves: Ultrasound

Implementation Method 3

Additionally or alternatively, material can also be sublimated by the additional laser impingement before, during and/or after the connection. The pressure surge generated by the expansion of the sublimated material can in particular induce the structure-borne sound waves

Methodology Applied
Scientific EffectSublimation: Sublimation

Implementation Method 4

The material is selectively connected by a controlled laser beam, in that the laser beam exposes the desired layer cross-section and heats the material to such an extent that its particles combine with each other

Methodology Applied
Scientific EffectLaser sintering/welding: Welding

Data Source

PatentEP2782705B2Method of generative producing a component using a laser beam before, during and after the assembly
Publication Date: 2023.03.08 MTU AERO ENGINES GMBH
  • EP2782705B2 patent drawingFigure 1

AI summary

The invention relates to a method for the generative production of a component (3), in particular of a turbo-engine component, wherein material (4) is bonded layer-wise selectively to a layer or to a substrate (6) disposed therebeneath, wherein before, during and/or after the bonding a laser (1A; 1B; 2) additionally acts on the material (4).