Selective Laser Melting

Transcription

1 Selective Laser Melting Developemts in SLM Equipment and dprocesses Dr Chris Sutcliffe R+D Director MTT Technologies Group Outline Introduction SLM process Typical characteristics Various applications Validation Future platforms 1

2 Locations SLM Technology Center - Stone - United Kingdom MTT Technologies Whitebridge Way, Whitebridge Park, Stone, Staffordshire ST15 8LQ. England Tel: +44 (0) Fax: +44 (0) Locations SLM Technology Center - Lübeck - Germany MTT Technologies Roggenhorster Strasse 9 c D Lübeck Germany Tel / Fax /

3 SLM timeline Basic Research F&S and Fraunhofer ILT, University of Liverpool, University of Texas F&S Research leading to IP F&S / MCP partner to develop, produce and market the MCP Realizer Launch of SLM Realizer Launch of SLM Realizer MTT/3DS partner to launch the machines in the USA SLM timeline 3

4 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 beam exposure 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 4

5 SLM process characteristics Properties of typical parts Surfaces Strength Accuracy Rz 30 µm Typically as good as parent ± 25µm in 100 mm Residual Stress Density Hardness Preheated powder up to 99.9 % up to 54 HRC 5

6 Typical parts Ti Al6 V4 Inconel Al Si12 Mg Typical uses Heat sinks have been Heat sinks have been designed and tested for avionics cooling 6

7 Typical uses Material: tool steel Dimensions: 170 x 46 x 18 [mm] Layer thickness: 75 µm 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 7

8 Typical uses Mounting of four pre- fabricated cores on building platform Precise individual positioning of layer data to mounted cores Economic hybrid manufacturing Interface between Rapid Manufacturing / Conventional Tooling Typical uses 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 Al4Nb Noble metals can be produced Low cost equipment is entering the market 8

9 Not so typical uses Trabecular lower jaw implant Dense skull plate Patient t specific geometries Specialist alloystial6nb7 in this case Incorporation of surgical fixtures Structured bone integration surfaces Bone-Implant modulus matching Not so typical uses Source: Royal Perth Hospital, Australia Following a severe climbing accident the patient t was given a THR which h 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 9

10 Customised SLM implants Source: Royal Perth Hospital, Australia Cage designed to fit bone and give proper screw placement Results :minimum removal of healthy bone structure and reduction of operation time Customised SLM implants Source: Royal Perth Hospital, Australia Analysis of 3d data set, automatical generation of support structures 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 10

11 Customised SLM implants Source: Royal Perth Hospital, Australia 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 TiAl6Nb7 Operation time reduced to 2 h compared to 3 h with standard prostheses Smart structures Density gain by improved melting strategy, D>99,8% Helium leakage test fulfilled up to 6x10-10 mbar UHV compatible! Material: tool steel 2 mm density gain by improved melting strategy, D>99.9% helium leak test fulfilled up to 6x10-10 mbar UHV compatible simultaneous growth of dense and porous regions 11

12 Smart structures Lightweight parts Medical implants Thermal management parts Substitution of solid mass to boost production Engineered materials Actuation SOME EXAMPLES Smart structures 12

13 Current materials Material name Material type Typical applications Stainless Steel Tool Steel CpTi (316L) stainless steel (H13) tool steel Commercially Pure Titanium functional prototypes Injection moulding tooling; functional prototypes Implants and medical devices Ti64 Ti6Al4V Implants and high performance functional components Ti6Al7Nb Ti6Al7Nb Implantable devices Aluminium Cobalt Chrome Aluminum Silicon Alloy CoCrMo superalloy Functional prototypes and series parts; 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: µm Spot size: µm Build speed: up to 70 tooth caps per shift 13

14 Previous equipment Build volume 250 x 250 x 210mm Build speed: 5 cm 3 30 cm 3 per h Layer thickness: 30 µm 100 µm Fiber Laser:100 W 400 W, cw Laser spot size: 80 µm 250 µm Future Current equipment? equipment Custom build volumes Thinner layer thickness 10 µm 100 µm 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 14

15 Future Current machine equipment SLM XXX Future So what? machine SLM XXX 15

16 Validation Validation Documentation Relationships and Sequences User requirement specification Performance qualification Functional Specification Operational qualification Design specification 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 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 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 16

17 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 bed how do you design that out 17

18 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 18

19 Some Examples Thought I d better put some stuff in on lasers 19

20 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! 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 performance Stronger faster more repeatable and whilst your about it make them easier to use Make them validatable please Can we do it now? 20

21 THANKS FOR LISTENING I 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 21