Wire-based Metal Deposition

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ACAM

Wire-based Metal Deposition

Kai Winands

October 15, 2020

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Applications 5

Wire Materials and Wire Feeding 4

Wire-Based Metal Deposition with Wire-Arc (WAAM) 3

Wire-Based Metal Deposition with Laser (LMD-w) 2

Introduction 1

Introduction

Definition and Classification of Additive Manufacturing according to ASTM 52900

Distinction into the following 7 process categories:



Directed Energy Deposition (DED),



Binder Jetting (BJT),



Material Extrusion (MEX),



Material Jetting (MJT),



Powder Bed Fusion (PBF),



Sheet Lamination (SHL) and



Vat Photo Polymerization (VPP).

AM Process Classification

“Processes that allow the fabrication of components

from (digital) 3D model data, by joining material to components

layer by layer

(without the use of forming or cutting tools)

as opposed to subtractive and reshaping fabrication methods.”

Definition

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Introduction

Revenue distribution for Metal AM machines in 2019

85%

8%

2% 3% 2%

Revenue shares 2019

PBF LB/EB/Arc-DED Metal FDM BJT Others

Source: AMPOWER Report 2020

 Revenue share of DED related machines around 8% in 2019

 Indicates indirectly the market shares for different Metal AM technologies

 However, share grow of around 3% expected within the next 4 years

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Introduction

Definition of Directed Energy Deposition (DED) according to ASTM 52900

“Additive manufacturing process, in which focused thermal energy is used to unite material by melting during material deposition”

Wire-based Laser Metal Deposition (LMD-w)

Wire-Arc Additive Manufacturing (WAAM) Wire-based Metal Deposition

Powder-based Metal Deposition

Definition

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Introduction

Powder-based vs. wire-based metal deposition

Powder-based Metal Deposition Wire-based Metal Deposition

+ Range of available materials

+ Contactless process management

- Material efficiency due to overspray

- Working safety and health protection

- Powder encapsulated system design

+ High material efficiency (use of 100% wire / no overspray)

+ No contamination of machines and production environment

+ Easier system integration and machine retrofit

- Limited range of materials and alloys are available as wire

- Process more complex due to contact while deposition

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Introduction

Fields of applications for wire-based Metal Deposition

Part and feature manufacturing Surface coating and cladding Part repair

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Introduction

Main components for wire-based Metal Deposition

Energy Source

Wire Feed Material

Positioning System

 Machine tool

 Robot

 Gantry system

 Laser

 Electric arc

 Lateral

 Coaxial

 Broad metal range and alloy compositions

 Filler and solid wires

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Introduction

Main process parameters for wire-based Metal Deposition

Energy Source

Wire Feed Material

Positioning System

 Feed rate

 Tool path strategy

 Laser / electrical power

 Spot diameter

 Feed rate

 Material alloys

 Wire diameter

 Surface conditions

 Shielding gas

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Introduction

Process chain for wire-based Metal Deposition

Typical process chain for Wire-based Metal Deposition

Quality inspection Heat treatment Subtractive

post-processing Wire-based

metal deposition CAD / CAM

data preparation

 Heat treatment needed for the reduction of thermal induced tensions

 Subtractive post-processing substantial to achieve geometrical accuracy and sufficient surface finish

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Introduction

Machine solutions for wire-based Metal Deposition

»Classic«

n-processes are running on at least n-single machines

»Hybrid«

n-processes are running just on m-single machines (n > m)

Different machine concepts and solutions exist for the implementation of Metal Deposition processes into industrial process chains

Typical process chain for Wire-based Metal Deposition

Quality inspection Heat treatment Subtractive

post-processing Wire-based

metal deposition CAD / CAM

data preparation

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Applications 5

Introduction 1

Wire-based Laser Metal Deposition Main challenges to solve

Repeatability Stability Accuracy and surface finish

Thermal impacts

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Wire-based Laser Metal Deposition Main challenges to solve

Repeatability Stability Thermal impacts Accuracy and surface finish

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Process principles LMD-w

Laser metal deposition with lateral wire feeding

Laser beam

Substrate Bonding zone

Weld bead

Wire

Shielding gas Nozzle Feed direction

HAZ

(Heat Affected Zone)

Lateral wire head

Melt pool

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Process principles LMD-w

Laser metal deposition with lateral wire feeding

Laser beam

Weld bead

Wire

HAZ

Lateral wire head

Melt pool

Laser spot Wire position Nozzle

Position alignment y-axis Wire Laser spot

position

Nozzle

Position alignment x-axis

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Process principles LMD-w

Laser metal deposition with lateral wire feeding

Laser beam

Weld bead

Wire

HAZ

Lateral wire head

Melt pool

 Position alignment between wire and laser spot is crucial

 Alignment has to be performed for lateral wire feed in two axis

 Incomplete melting or droplet formation can occur, if misaligned

 Z-position of the wire head influences the alignment

 Thermal impact on the material low due to beam to wire diameter (1.5 : 1) Position alignment

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Process principles LMD-w

Laser metal deposition with coaxial wire feeding

HAZ

Laser beam

Substrate Wire

Shielding gas

Melt pool

Coaxial wire head

Feed direction

Weld bead

Bonding zone

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Process principles LMD-w

Comparison between lateral and coaxial LMD process

Lateral wire process

+ Process management is related to manual welding

+ Process head design cost saving and flexible

- Process related to process strategies less flexible

- Position alignment more time consuming

Coaxial wire process

+ High flexibility regarding process management

+ More robust regarding wire-beam alignment

- Head design more complex and expensive

- Edge processing due to beam design challenging

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Process principles LMD-wp

Simultaneous addition of powder for inline alloying of wire material

Additional shielding gas with powder

Laser beam

Weld bead

Wire

Hybrid

wire - powder head

HAZ

Melt pool

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Process principles LMD-wp

Simultaneous addition of powder for inline alloying of wire material

Additional shielding gas with powder

Laser beam

Weld bead

Wire

Hybrid

wire - powder head

HAZ

Melt pool

 Limited range of wire alloys can be extended

 Overspray very limited due to low amount of powder

 Material efficient and cost effective modification of mechanical properties

 Can be implemented for lateral as well as coaxial wire heads

Advantages

Developments funded in the project “MatLaMed” by the Federal Ministry of Education and Research under the grant agreement no. 02P17E000

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Process principles LMD-wp

Simultaneous addition of powder for inline alloying of wire material

Advantages

Developments funded in the project “MatLaMed” by the Federal Ministry of Education and Research under the grant agreement no. 02P17E000

0,0 0,5 1,0 1,5 2,0 2,5

200 250 300 350 400 450 500

Hardness [HV 0,3]

Distance [mm]

Hardness

 Substrate material: Steel 1.2343

 Wire material: Steel 1.5407

 Powder: TiC

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Wire-based Laser Metal Deposition

Solution to face challenges for rotation-symmetrical components

 Wire pre-positioning concept for cylindrical components

 Wire oscillation as critical process

factor during welding process does not occur anymore

 Feed rate is independent from wire feeding

 Faster deposition process especially for thick layers

 Higher process stability

 High automation potential

3 4

2 1

Winding of wire spiral

Preparation of cylindrical

substrate

Placement of spiral on cylinder

Welding Coated

cylinder

Laser

Approach

Advantages

Patent Pending by Fraunhofer IPT

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Wire-based Laser Metal Deposition

Solution to face challenges for rotation-symmetrical components

 Wire pre-positioning concept for cylindrical components

 Wire oscillation as critical process

factor during welding process does not occur anymore

 Feed rate is independent from wire feeding

 Faster deposition process especially for thick layers

 Higher process stability

 High automation potential Approach

Advantages

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Applications 5

Introduction 1

Metal deposition with electrical arc

HAZ

Nozzle

Substrate Melt pool

Feed direction

Weld bead

Bonding zone

WAAM Nozzle

Wire Electric

arc

Power source

- +

Shielding gas

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Comparison between LMD-w and WAAM

LMD-w

+ High deposition quality

+ Low and controlled thermal impact on material

- Efforts for process setup and management

- Limited wire diameters

WAAM

+ High deposition rates

+ Lower machine invest

- Thermal impact on material is high

- Low accuracy and surface quality

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Applications 5

Introduction 1

Wire material

Filler wire vs. solid wire

 Anisotropic

 Non-seamless wire coat

 Alloy formation during melting

 Higher wire stiffness

 Stable wire feeding

 Limited welding surface quality

voestalpine

Wire drum

Wire coil Wire stick

Filler wire Solid wire

Delivery form of wire

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Wire feeding

System overview

Wire storage

Control unit

Wire straightener Wire

Wire feeder engine

Processing head

Nozzle Wire inside coated wire liner

Substrate

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Wire feeding

Reduction of wire slip

Push principle by single wire feeder engine

Push-Pull principle by multi wire feeder engines Wire spool

Wire spool

Single wire feeder engine

1^st wire feeder engine

2^nd wire feeder engine

 Wire slip causes unstable wire provision

 Increased risk for process termination

 Occurs typically when using endless wire feeding over longer distances

 Push-pull wire feed reduces wire slip

 Recommended at transport distances >10 m

 Synchronization of wire feeder engines required for continuous wire transport

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Wire straightening Wire straightener

PA GmbH

 Wire straightener compensates wire bending in multi-directions caused by tensions in the wire

 Bending can cause problems during the process due to undefined movement of the free wire end

 Straightening rollers have different nut profiles, e.g. U-profile or V-profile

 Profile size has to be selected related to the wire diameter

WireTrex Ltd

U-profile

Roller profiles

V-profile Straightening in x direction

Straightening in y direction

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Wire straightening

Principle of wire straightening

Unstraighted wire

Straighted

Wire straightening

wire Wire

straightener with all rollers relaxed

Wire spool Wire spool Wire spool Wire spool

Wire

straightener with all rollers fastened

Force on wire due to roller clamping

Effect on wire end due to roller clamping

Force Force

Effect Effect

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Applications 5

Introduction 1

Introduction

Fields of applications for wire-based metal deposition

Part and feature manufacturing Surface coating and cladding Part repair

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Applications for wire-based Laser Metal Deposition

Extruder screw demonstrator with hollow fluid structure

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Applications for wire-based Laser Metal Deposition Mold repair with LMD-w

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Applications for wire-based Laser Metal Deposition Near-net shape LMD-w of a turbine blade profile

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 Wire-based metal deposition is a promising additive

manufacturing technology especially for large components

 The importance of wire-based metal deposition for

industrial applications will increase within the next years

 Different technologies and materials for wire-based metal deposition offering a clean and health safety for are

nowadays available

 Current developments are addressing the existing process challenges to increase productivity and quality

 New approaches will offer new possibilities for additive manufactured part features and functions