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Selective Laser Melting

Developemts in SLM Equipment d Pand Processes

Dr Chris Sutcliffe R+D Director MTT Technologies Group

Outline

• Introduction

• SLM process• SLM process

• Typical characteristics

• Various applications

• Validation

F t l tf• Future platforms

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SLM Technology Center - Stone - United Kingdom

Locations

MTT TechnologiesWhitebridge Way,Whitebridge Park, Stone,Staffordshire ST15 8LQ.England

Tel: +44 (0)1785 815651Fax: +44 (0)1785 812115

SLM Technology Center - Lübeck - Germany

Locations

MTT TechnologiesRoggenhorster Strasse 9 cD- 23556 LübeckGermany

Tel. +49 451/16082- 0Fax.+49 451/16082 – 250

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SLM timeline

1995-1998 Basic Research F&S and Fraunhofer1995 1998 Basic Research F&S and FraunhoferILT, University of Liverpool, University of Texas

1998-2002 F&S Research leading to IP

2002- F&S / MCP partner to develop, produce and market the MCP Realizer

2004 L h f SLM R li 2502004- Launch of SLM Realizer 250

2006 - Launch of SLM Realizer 100

2008- MTT/3DS partner to launch the machines in the USA

SLM timeline

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SLM timeline

SLM process characteristics

• SLM is a cyclic process consisting of– The application of thin powder layer

– exposure of the powder bed to laser beamexposure of the powder bed to laser beam

– lowering of the build platform

• Typical deposition rates of 5 – 30 cm³/h

• Typical powder particle size of between 10 and 50µm

• Laser powers of 200W and up to 400W (more of this later)

Hi h d f t i f d i il t SLA• High degree of geometric freedom similar to SLA

• Fully automated one-step manufacturing (more of this later)

• Ability to process reactive powders

• Very good levels of powder recyclability

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SLM process characteristics

Properties of typical parts

Surfaces Strength Accuracy

Residual Stress Density Hardness

± 25µm in 100 mmTypically as good

as parentRz 30 µm

up to 54 HRCup to 99.9 %Preheated powder

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Typical parts

Ti Al6 V4 Inconel 625

Al Si12 Mg1.4404

Typical uses

Heat sinks have beenHeat sinks have been designed and tested for avionics cooling

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Typical uses

• Material:

• 1 2344 tool steel• 1.2344 tool steel

• Dimensions:

• 170 x 46 x 18 [mm]

• Layer thickness:

• 75 µm

• Build time:Build time:

• 48 hours

• Post treatment:

• Manual polishing

Typical uses

• Considerable reduction of cycle time

• Ideal design of size, form and function of cooling channels

• Quality improvement of injection moulding

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Typical uses

• Mounting of four pre-fabricated cores on buildingfabricated cores on building platform

• Precise individual positioning of layer data to mounted cores

• Economic hybrid manufacturing

Interface between Rapid• Interface between Rapid Manufacturing / Conventional Tooling

Typical uses

• Up to 80 parts can be produced• Up to 80 parts can be produced in one run

• Customised parts can be produced

• Very good surface finish in many materials including CoCr, CoCrMb, CpTi, Ti6Al4V and Ti6 Al4NbAl4Nb

• Noble metals can be produced

• Low cost equipment is entering the market

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Trabecular lower jaw implant Dense skull plate

Not so typical uses

P ti t ifi t i• Patient specific geometries

• Specialist alloysTiAl6Nb7 in this case

• Incorporation of surgical fixtures

• Structured bone integration surfaces

• Bone-Implant modulus matching

Source: Royal Perth Hospital, Australia

Not so typical uses

• Following a severe climbing accident th ti t i THR hi hthe patient was given a THR which was revised a number of times until further revision was impossible

• 3D X-ray and computer tomography allowed analysis of existing patient bone

• Models were made of the geometry

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Source: Royal Perth Hospital, Australia

Customised SLM implants

• Cage designed to fit bone and give proper screw placement

• Results :minimum removal of healthy bone structure and reduction of operation time

Source: Royal Perth Hospital, Australia • Analysis of 3d data set, automatical generation of support structures

Customised SLM implants

pp

• SLM building of the cage

• with 0.05 mm thin layers (TiAl6Nb7 or TiAl6V4)

• Finish of the cage

• (removal of supports)

• SLM + Finish < 2 days

• Courier cage to Perth

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Source: Royal Perth Hospital, Australia

Customised SLM implants

• Analysis and sterilisation of built prostheses

• Preparation of the patient

• No fitting required during operation due to custom cage

• Insertion and screwing of the cage made of TiAl6Nb7g

• Operation time reduced to 2 h compared to 3 h with standard prostheses

• density gain by improved melting

Smart structures

Density gain by improved melting strategy, D>99,8%

Helium leakage test fulfilled up to 6x10-10 mbar

UHV compatible!

2 mm

strategy, D>99.9%

• helium leak test fulfilled up to 6x10-10 mbar

• UHV compatibleUHV compatible!

Material: 1.2344 tool steel

• simultaneous growth of dense and porous regions

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Smart structures

• Lightweight parts• Medical implants• Thermal management partsThermal management parts• Substitution of solid mass to

boost production• Engineered materials• Actuation

SOME EXAMPLESSmart structures

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Material name Material type Typical applications

Stainless Steel 1.4404 (316L) t i l t l

functional prototypes

Current materials

stainless steel

Tool Steel 1.2344 (H13) tool steel

Injection moulding tooling; functional prototypes

CpTi Commercially Pure Titanium

Implants and medical devices

Ti64 Ti6Al4V Implants and high performance functional components

Ti6Al7Nb Ti6Al7Nb Implantable devices

Aluminium Aluminum Silicon Alloy

Functional prototypes and series parts;

Cobalt Chrome CoCrMo superalloy

Functional prototypes and series parts; medical, dental

Previous equipment

SLM 100

• Build volume:

Ø• 125 mm Ø x 70 mm

• Layer thickness:

• 20 µm – 50 µm

• Fiber Laser 50 W or 100 W

• Spot size: 30– 100 µmSpot size: 30 100 µm

• Build speed: up to 70 tooth caps per shift

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Previous equipment

• Build volume 250 x 250 x 210mm

• Build speed: 5 cm3 –30 cm3 per h

• Layer thickness: 30 µm – 100 µm

• Fiber Laser:100 W –400 W cw400 W, cw

• Laser spot size: 80 µm – 250 µm

Future equipment?

• Custom build volumes

• Thinner layer thickness 10 µm – 100 µm

• Higher laser power 100 W – 1kW W, cw

Current equipment

Higher laser power 100 W 1kW W, cw

• Smaller spot size 50 µm – 2500 µm

• Smater materials delivery

• Better build atmospheres (sub 100ppm O2)

• Paletised substrates and removable build units

• Rugedised for the shop floor

• Simple controlled user interfaces

• Beam monitoring (now please)

• Powder handling

• HAZOP as standard

• Verifification as standard

• Data logging as standard

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Future machine SLM XXXCurrent equipment

Future machine SLM XXXSo what?

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Validation

Validation Documentation Relationships and Sequences

User requirement specification Performance qualification

Functional Specification

Design specification

Operational qualification

Installation qualification

Acceptance testing and commissioning

• The problem is that few if any of our RM machines have been fully validated for full production

of parts...this is particularly true if one considers highly stressed or sensitive environments parts

Likely issues- data

Is the design correct and controlled• Does it comply with specifications, regulations and standards• Was the movement of the design into the manufacturing phase monitored• Were typical manufacturing protocols followed yp g p

Did you check the CAD data• Are you sure you are making the right thing and the correct revision• What if you are making customised components• Have you taken steps to identify parts

Did you check the manufacturing data• The data not just for the overall geometry but also for the layer data must be checked at the very

minimum you must have a level of confidence that it is correct• It will be one of the first things a accident investigator will ask

Are your processes robustAre your processes robust• Was it sliced at the right layer thickness have the correct processing parameters been assigned• Are the shop floor practices correct were the protocols followed

Are the above documented and portable• Do you have an RM/PLM system in place

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Likely issues- machine

Material properties•Variation in material properties in the x/y/z direction is not acceptable full stop…lets not even bother having the argument I don’t care if you think you can design for it…you can’t.

Property variation on a machine•This is not acceptable the only property variation on a machine that is acceptable is random variation and this should be minimised.

Parameter variation between machines•All machines of a particular design must have the same machine parameters how else can you procreate and maintain validation.

Temporal Instability•Machines must be stable over time and they must be able to detect when they are outside limits…assuming those limits have been defined

Machine reliability•Will your machine stand up to production•Will it do its job day in day out for 10 plus years

Is the user interface simple enough•I want to drag someone in off the streets and get them to press go I do not want to employ PhD’s to work in my factory

Collection and storage of manufacturing data•Is the manufacturing data logged•Is it stored (75 years!)

Some Examples

The tensile strengths of samples are shown across 4 builds you can see the same characteristics on each build. It is clear this is NOT a random process variable…do you accept the parts…what if you part spans the whole p pbed…how do you design that out…

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Some Examples

The compressive strength of samples are shown across 4 builds on two different machines at the same machine settings you can see one build is significantly weaker than the other. …do you accept the machines knowing full well that you will have to validate them separately

Some Examples

EVERY LAYER PLEASE…its not good enough to build test samples by each part

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Some Examples

Thought I’d better put some stuff in on lasers

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The Future for Additive Manufacturing

Did I say I was going to give you a look at the future• Sorry to disappoint it seems I’m not quite as clever as I thought! hereSorry to disappoint it seems I m not quite as clever as I thought! …here

are some guesses

RM/PLM/MRP/whatever 3 letter acronym you care to choose• Data handling and portability of this data is key

Material handling• Come on powder filled workspaces must be stopped…contamination of

us and our parts is unacceptable

Machine performanceMachine performance• Stronger faster more repeatable and whilst your about it make them

easier to use• Make them validatable please

Can we do it now?

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THANKS FOR LISTENING

I was going to write someI was going to write some conclusions but to be honneset I guessed either you’d have seen enough of me by now or I’d have run out of time.

If you need any further information contact me on.

csutcliffe@mtt-group.com