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Successes and Challenges of SLM and LMD for Industrial Production

March 27th – 28th 2017

Laser Additive Manufacturing Workshop

Schaumburg (IL)

Christoph Leyens, Frank Brückner, Elena Lopez, Mirko Riede

phone: +49 (0)351 83391-3420 email: christoph.leyens@iws.fraunhofer.de

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2004 - 2016: overall anual growth (CAGR) of ~20 %

2016: growth softened due to weak polymer players

market: expected to multiply by a factor of two to five by 2022

Additive Manufacturing (AM) Development of metallic AM-market

[Roland Berger 2017]

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Additive Manufacturing (AM) Landscape of metallic AM-technologies

[Roland Berger 2017]

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Additive Manufacturing (AM) Capabilities of metallic AM-technologies

[Roland Berger 2017]

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Additive Manufacturing Principle of Selective Laser Melting (SLM)

laser beam

remelted area

powder layer

melt pool solidificated metal

subjacent layer

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Additive Manufacturing Principle of Laser Metal Deposition (LMD)

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SLM versus LMD Selected materials

LMD

SLMCu

Inconel 718 AlSi10Mg

Al2O3

TNM-B1

316L

Ti6Al4V

MAR-M247

WC

Si-SiC

Maraging steel

Ta

CBN

Co W

CoNiCrAlY

NiCrAlTaFeY

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SLM versus LMD Multi-material processing

SLM Multi-Material Approach LMD Multi-Material Approach

approaches for SLM, e.g. IGCV sequential removal and deposition of

different powder materials

LMD approach by Fraunhofer IWS 3D in-situ selection and parallel mixing of

powder materials tailored localized mixture

Ti-6Al-4V

Ta

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SLM versus LMD Requirements for processed powders

Requirements for powder

controlled chemical composition low porosity spherical particle shape beneficial rheological properties defined (process dependent) particle size

distribution “the right material for the right

process”

irregular shape high porosity big particles “low cost” LMD application

spherical shape low porosity big particles LMD application

spherical shape low porosity small particles SLM application

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Additive Manufacturing Process chain

- CAD Software

- scanning systems (GOM, Creaform)

- simulation tools

- design experts

- design rules

- CAD-CAM software

- SKM DCAM

3D model scanner data

material testing

simulation design

slicing support

production

process control

post processing analysis

monitoring evaluation

AM process chain

- process technology

- nozzles, lasers

- metallographic analysis (size and form)

- alloying elements

- control systems (cameras, image processing tools, EMAQS)

- monitoring (high speed, infrared, temperature, powder flow, gases, etc.)

- software tools - interpretation

from experts

- NDT - Metallography

- surface optimization

- hybrid processes

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CAD CAM process part post process

Comparison of SLM and LMD Pros and cons along the process chain

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complexity for free support essential

support structures spec. data format automatic path

generation

preparation low build rate autonom. processing lead time

[amazonaws] support removal accessibility powder recycling surface quality

[3D hubs]

SLM

CAD CAM process part post process

Comparison of SLM and LMD Pros and cons along the process chain

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CAD CAM process part

complexity for free support essential

post process

build on pre-product specific design

support structures spec. data format automatic path

generation

open data format configurable semi-automatic five axis

tool path generation

preparation low build rate autonom. processing lead time

preparation, multi-material hybrid manufacturing adjustable during process process complexity, lead time

[amazonaws]

[DMG Mori]

support removal accessibility powder recycling surface quality

[3D hubs]

SLM

LMD

Comparison of SLM and LMD Pros and cons along the process chain

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Comparison of SLM and LMD Pros and cons along the process chain

Selective laser melting Direct metal deposition

support structures automatic path generation

support-less semi-automatic 5-axis path

generation

data import and preparation support placement parameter assignment 2D-slicing (horizontal planes) automatic hatching build-file generation

data import and preparation 3D-segmentation select build direction/s 3D-slicing (freeform) semi-automatic hatching parameter assignment build-file generation

3-axsis 5-axsis

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development based on design rules

improved functionality

manufacturing with SLM

features not manufacturable conventionally

original optimized design SLM prototype

higher heat flux = higher efficiency

Additive Manufacturing (AM) SLM - process development

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investigation of orientations and supporting strategies for manufacturing turbine blades

1 supporting the trailing edge strong distortion an the thin

trailing edge and on the blade foot low heat dissipation

high dimensional deviation: ±0,5 mm

2 supporting the leading edge almost no distortion smaller dimensional deviation:

±0,3mm

1. 2.

Additive Manufacturing (AM) SLM - process development

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Additive Manufacturing (AM) LMD - process development

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Additive Manufacturing (AM) LMD - process development

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helix pulsed laser

volute pulsed laser

longitudinal strategy pulsed laser

4-axis

transversal strategy pulsed laser

longitudinale strategy pulsed laser

double conturing 5-axis

Additive Manufacturing (AM) LMD - process development

long lead times due to feature adapted strategies

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smallest feature size: 3 mm

individual cladding strategies needed

overhangs with 5-axes

lead time / accuracy vs. build rate

smallest feature size: 500 µm

„complexity for free“

high accuracy

LMD (scale 2:1)

SLM (scale 1:1)

SLM vs. LMD Complexity vs. build-up rate

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SLM vs. LMD Complexity vs. build-up rate

LMD combustion chamber with nozzle Laser Metal Deposition corrosion resistant steel 316L build-up time: 6 hours height: 300 mm max. diameter: 180 mm

SLM thruster nozzle with conformal Cooling Channels: Selective Laser Melting corrosion resistant steel 316L build-up time: 24 hours height: 200 mm max. diameter: 150 mm

large part size low complexity short build-up time

complex cooling channels (1 mm² cross section)

high build-up time

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Application in…

blades – space and aerospace

Selective Laser Melting Laser Metal Deposition

microstructures medical and dental technology

reverse engineering

on existing parts or repair

cross section bone - bionic structures

High-power LMD

cooling channels and nozzles

SLM vs. LMD Applications

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SLM vs. LMD Microstructure - Ti6Al4V

very low porosity (< 0,1%) inhomogeneous grain size distribution

through layer-wise bi-directional scanning coarser grains increased melt pool size less anisotropic structure

low porosity (< 0,2%) homogenous grain size distribution through

layer-wise rotation of 67° finer grains epitactic solidification anisotropic structure

Selective laser melting Direct metal deposition

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SLM vs. LMD Conclusion

Selective laser melting Direct metal deposition

porosity < 0,5 % < 0,1 %

selectable materials limited large variety (multi material)

component dimensions max. 800x400x500 mm³ almost unlimited

complexity of component almost unlimited, overhangs (without support minimal angle >45°) limited, walls with an angle of < 20°

detail resolution typ. 100 µm 30 µm – 45 mm

roughness Rz 30 – 50 µm 60 – 100 µm

substrate form flat surface freeform

build-up rate 1-20 mm³/s 3-480 mm³/s

Source: Concept Laser

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SLM vs. LMD Conclusion

Evaluation of SLM vs. LMD:

Costs

Material selection

Material utilization

Mechanical properties

Geometrical complexity

Maximal part size

Build-up rate

Near net-shape

Free form ability

Surface quality

Selective Laser Melting (SLM) Laser Metal Deposition (LMD)

[Guo 2013; Srivatsan 2016; IFAM; IfWW; Sierra 2016; Backes 2015]

comparison of advantages and disadvantages based on actual state of the art in literature

selection of a suitable process for the right application

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The End

Thank you for your attention

Contact: Prof. Christoph Leyens Phone +49 (0)351 83391-3242 Christoph.Leyens@iws.fraunhofer.de