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2019 Fall Meeting



3D printing and additive manufacturing for the industry of the future

3D printing and additive manufacturing processes are of strategic important for the industry of the future. This is the reason why our symposium is expected to cover the most innovative 3D fabrication techniques able to respond to the future market. A special attention will be given to the processes hybridation especially regarding economical and industrials aspects.


The symposium will cover the most innovative 3D manufacturing processes for the industry of future as detailed in the following list :

  • DED – CLAD powder deposition  induced by laser fusion
  • Solidification of powder under the action of a laser and  electron Beam (EBM) on various materials : Metal, ceramic, composites, Polymer, and Sand
  • Assembly of layers from plates: Stratoconception® (wood, polymer, metal)
  • Laminated Object Manufacturing (LOM)
  • Polymerization of a resin under the action of a laser: Stereolithography, Digital Light Processing (DLP)
  • Material Jetting 3D Printer: Polyjet
  • 3D laser micro and nano texturation of surfaces by combining soustractive and additive processes

Hot topics to be covered by the symposium:

3D printing and additive manufacturing of metals, ceramics and polymers are able to deliver tailored products with customized geometry and physical properties. These fully scalable processes offer cost-effective solutions for producing both small and large objects of different materials on a large scale in order to respond to the new market demands. The global 3D printing market is expected to reach $21 billion by 2020 — quadrupling its size in just four years. While 3D printing, also referred to as additive manufacturing, comes with many benefits, such as freedom of design, easy prototyping, customization and streamlined logistics, it also poses many challenges both from scientific and technological point of view, which will be covered by this symposium.

Tentative list of invited speakers:

  • Sebastian BREMEN (ILT, D): Component and system development for selective Laser melting
  • Philippe BAUER , (Thales Global Services, F): Mechanical modeling and additive fabrication
  • Michel BELLET (CEMEF MinesParisTech, F): Numerical simulation applied to additive fabrication
  • Alain BIERNEAUX (OPTEC SA, B): Recent advances in industrial laser systems for 3D printing and additive manufacturing
  • Pierre DUYSINX (University of Liège, B): Topological optimization in additive fabrication
  • Anath FISCHER (Technion, IL): Advanced methods for reconstruction of 3D objects
  • Arthur LEIS, (IFSW, D): Innovative aspects of laser Additive Manufacturing
  • Filomeno MARTINA, (Cranfiel University, GB): New advanced wire and arc additive manufacturing process
  • Vojislav PETROVIC, (AIMEN, SP): Additive Manufacturing Solutions for Improved Medical Implants
  • Arnaud SPANGENBERG, (IS2M, F): Micro / Nanofabrication additive by  biphotonics photopolymérisation

Tentative list of scientific committee members:

  • Philippe BERTRAND (ENISE, F)
  • Thomas GRAF, (IFSW, D)
  • Patrik HOFFMANN (EMPA, CH)
  • Jean-Daniel PENOT (CEA, F)
  • Patrice PEYRE (Arts et Métiers ParisTech, F)
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3D Micro and Nanoprinting : Cyril Pelaingre
Authors : Arnaud Spangenberg
Affiliations : Université de Haute-Alsace, CNRS, Institut de Science des Matériaux de Mulhouse (IS2M-UMR 7361), Mulhouse, France

Resume : Whereas different strategies have been successfully implemented for mass production of 2D/2.5D micro and nanostructures, fabrication of 3D micro and nanostructures is usually not trivial and required time-consuming multi-steps processes. In that context, additive manufacturing technology is particularly attractive but suffers from a lack of spatial resolution. Thereby, two-photon stereolithography (TPS) appears of high interest since it makes possible in a unique step the fabrication of intricate 3D structures with features sizes as small as 100 nm.[1] However, contrary to standard additive manufacturing, TPS has not reached a sufficient level of maturity to allow value-added commercial applications. For instance, until recently, due to the serial nature of the writing process, typical writing speed was ranged from few µm.s-1 to mm.s-1, thus preventing its widespread dissemination in academic community or industrial environment. I will first introduce some principles related to TPS, then I will discuss about recent achievements made by us and others both from instrumentation and material point of view. In particular a special attention will be paid to the difficulties encountered to design advanced functional materials compatible with TPS process. [2-5] Such materials are important building blocks for next generation of 3D printing, such as 4D printing. References: [1] Kawata et al. Nature, 2001, 412, 697. [2] Röhrig et al. Small, 2012, 8, 3009. [3] Jang et al. Nature Materials, 2013, 12, 893. [4] Chia Gomez et al. Advanced Materials, 2016, 28, 5931. [5] Yu et al. Advanced Materials, 2018, 30 (51), e1805093.

Authors : Jean schmitt, Jing Wang
Affiliations : ETH Zürich - Institute of Environmental Engineering ; EMPA - Advanced Analytical Technologies

Resume : Volatile organic compounds (VOCs) are major air pollutants, which are found especially inside buildings and can be harmful to humans. A lot of efforts are directed towards the development of devices measuring the level of VOCs in ambient air. Commercially available sensors are mostly based on silicon chips including metal oxides to interact with the pollutants at elevated temperatures. In this study we present a microsensor for VOC monitoring fabricated with 3D printing based on two-photon polymerization. The supporting structures as well as the sensing structures are made of photosensitive resin, polymerized during the printing process. A conductive polymer mesh is suspended between two electrodes and the exposure to various organic compounds leads to their uptake and the swelling of the polymer. The geometrical changes of the sensitive mesh cause a change of its electrical resistivity. The metal electrodes are sputtered and their shape can be easily modified during the development of the sensor by using PDMS sputtering masks based on 3D printed masters. This method makes the fabrication of the electrodes faster and easier by avoiding a lithography step. Taking advantage of the high resolution of two-photon polymerization, the sensitive mesh can be precisely shaped to maximize the effect of the VOC uptake on the electrical signal and therefore increase the sensitivity. Using polymer both as a sensitive material and as a structural material allows the fabrication of cheap and light sensors. The 3D printing process affords high degree of design freedom, flexible modification and fast implementation for the sensor development.

Authors : R. Winkler(1), J. Sattelkow(1), J. D. Fowlkes(2,3,4), P. D. Rack(2,3,4) and H. Plank(1,5,6)
Affiliations : (1) Christian Doppler Laboratory - DEFINE, Graz University of Technology, 8010 Graz, Austria; (2) Bredesen Center for Interdisciplinary Research, The University of Tennessee, Tennessee 37996, United States; (3) Nanofabrication Research Laboratory, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Tennessee 37831, United States; (4) Materials Science and Engineering Department, The University of Tennessee, Tennessee 37996, United States; (5) Graz Centre for Electron Microscopy, 8010 Graz, Austria; (6) Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010 Graz, Austria

Resume : While 3D printing of objects down to the micrometer scale is already well established in research and development, techniques for controlled additive manufacturing at the nanoscale are only few [1]. Based on the progress in recent years, Focused Electron Beam Induced Deposition (FEBID) has evolved into a true 3D nanoprinting technology, allowing mask-less, direct-write fabrication of even complex 3D nano-architectures on almost any material and substrate morphology. The growing availability of different precursor types continuously expand the functionalities of FEBID based structures from electrically over magnetically towards optically active purposes. Together with its 3D ability at the nanoscale, this approach paves the way for applications, which have been very challenging or even impossible in the past [2]. In this contribution, we introduce the audience into 3D-nanopringing via focused electron beams and sketch possibilities and limitations. In the following, we focus on recent advances in accuracy and predict-ability based on local nano-heating effects [3]. As an important step towards a generic 3D printing technology, we discuss simulations on 3D growth and 3D-FEBID software solutions. Finally, we present selected applications of such 3D-nanoprinted structures in research and industry. [1] Hirt et al., Adv. Mater. (2017) 201604211, 1 [2] Winkler et al., J. Appl. Phys. (2019), in print [3] Mutunga et al., ACS Nano (2019), in print

Authors : Anna Weitzer (1), Harald Plank (1,2,3)
Affiliations : 1) Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010 Graz, Austria; 2) Christian Doppler Laboratory - DEFINE, Institute of Electron Microscopy, Graz University of Technology, 8010 Graz, Austria; 3) Graz Centre for Electron Microscopy, 8010 Graz, Austria

Resume : Focused electron beam induced deposition (FEBID) is an aspiring technology for next-generation direct-write fabrication on the nano-scale. FEBID-based fabrication of mesh-like nano-architectures has already reached a high level of precision, predictability and reliability [1,2], we now take the next logical step towards closed and semi-closed 3D nano-architectures. This opens up numerous possibilities as well as new challenges that will need further research in the future. To gain fundamental understanding of their growth behavior, we studied the dependency of spatial inclination angles on width, height and shape of systematically built 3D structure series, designed with a new pattern generating software we are currently developing. Complimentary heat diffusion simulations (OpenFOAM) revealed the implications of thermal effects, which recently turned out to play a major role [3]. The goal of this combined approach between experiments and simulation is not only to get a closer insight into the underlying mechanisms of 3D FEBID but also to develop a general model for compensation. This will lead to predictable and reproducible fabrication of even complex 3D nano-architectures as essential element on the route towards a generic 3D nano-printing technology for future applications in various fields of research and development. [1] Winkler et al., J. Appl. Phys., 2019, in print [2] Fowlkes et al., ACS Appl. Nano Mat. 1(3), 2018 [3] Mutunga et al., ACS Nano, 2019, in print

Authors : J. Sattelkow(1), J. Fröch(2), R. Winkler(1), C. Schwalb(3), S. Hummel(3), H. Plank(1,2,4)
Affiliations : 1) Christian Doppler Laboratory - DEFINE, Graz University of Technology, 8010 Graz, Austria; 2) Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010 Graz, Austria; 3) GETec Microscopy Inc. & SCL Sensor.Tech. Fabrication Inc., 1220 Vienna, Austria; 4) Graz Centre of Electron Microscopy, 8010 Graz, Austria

Resume : Atomic Force Microscopy (AFM) is an essential tool in research and development due to quantitative 3D surface characterization with sub-nanometer resolution and the possibility to access magnetic, mechanical, optical, electrical or thermal surface properties. In contrast, AFM is analytically blind, which requires complementary techniques such as Scanning Electron Microscopy (SEM). Based on the motivation to combine both worlds, GETec Microscopy Inc. has designed an AFM system for seamless integration in highly space confined SEMs. The core elements of this technology are self-sensing cantilever, which enable electrical readout of the cantilever deflection, eliminating space consuming optical detection systems. In the past, the available measurements modes were restricted to morphological and mechanical characterisation. To overcome this limitation, we jointly develop new nano-probe concepts to access electric, magnetic and thermal surface properties. This talk starts with an introduction of our nanoprobe fabrication, using 3D nanoprinting via focused electron beam. We present our latest 3D nano-thermistor concept in detail. This range from simulation of the most stable geometry followed 3D fabrication over mechanical tuning for stable AFM operation towards thermal probing. As demonstrated, a 3D nano-thermistors allow for scan speeds up to 80 µm/s and quantitative temperature measurements with an accuracy of ±1 C° and fast dynamic responses of about 32 ms/K.

Authors : Jiukai Tang1,2,Guangyu Qiu1,2, Schmitt Jean1,2, Jing Wang1,2*
Affiliations : 1 Institute of Environmental Engineering, ETH Zürich, Zürich 8093, Switzerland 2 Laboratory for Advanced Analytical Technologies, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland

Resume : ...

10:40 Coffee Break    
3d Micro and Nanoprinting : Arnaud Spangenberg
Authors : A. Mitchell, M. Holynska, U. Lafont, C.O.A. Semprimoschnig
Affiliations : ESA

Resume : 4D printing is an emerging technology where a ‘smart material’ can respond in a pre-programmed way to external stimuli. Significant advances in computer aided design, additive manufacturing and materials science have opened up the possibilities of self-assembly systems, and complex geometries with multi-functional properties. The current materials capable of ‘4D printing’ deliver exciting proof of concepts for future designs, however further development and qualifications are needed for their use in the space environment. The reliability of 4D printing materials for space applications is assessed, together with a consideration of the impact due to long-term storage on the ground and its effect on 4D printing functionalities. A FDM high temperature (420oC) dual extruder which is capable of printing space qualified materials and other high strength thermoplastics, is being utilized to print a variety of proof of concept composite structures. Up to now a study of all printing parameters for each type of filament such as optimal printing speed, printing direction, the design; length /angle, and printing temperatures has been completed. Two phenomena occur when heating bi-layer materials with different CTE and modulus. Once heated the modulus of the stiffer polymer decreases at its glass transition temperature and the internal stress stored in the combined printed layer is released. The difference of the CTE between the materials increases the bending motion further, in line with the printing direction. 4D printing could feature in numerous aspects in the design of a satellite, but more specifically in the design of a deployment mechanism which has fewer components, is simpler to control and has a lower risk of mechanical failure. Deployment mechanisms may only have to operate once or multiple times throughout their service life. The reliability and precision of deployment is paramount, thus understanding how 4D printed materials behave and how the fixity, repeatability and reversibility is affected by microgravity, radiation exposure and extreme temperatures is a significant challenge. In this paper several examples of on-going 4D printing work at ESA will be presented. It will also highlight the specific challenges of using such materials in a space environment.

Authors : J. W. Hinum-Wagner(1), R. Winkler(1), G. Birnstingl(2,3), H. Plank(1,2,3)
Affiliations : 1) Christian Doppler Laboratory - DEFINE, Graz University of Technology, 8010 Graz, Austria; 2) Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010 Graz, Austria; 3) Graz Centre of Electron Microscopy, 8010 Graz, Austria

Resume : Focused Electron Beam Induced Deposition (FEBID) is a very promising technique for 3D-printing at the nanoscale, as it enables mask-less, direct-write fabrication of 3D nano-architectures. For precision and reliability, local precursor coverage is of highest importance, as it determines the incremental growth rates and by that reproducibility. Recently, reduced residence times of precursor molecules due to local beam heating was demonstrated, which explains observed stability problems for larger 3D structures [1]. While FEBID at cryogenic temperatures were studied before [2], we here focus on temperatures from room temperature down to 1 °C. For that, we designed, fabricated and tested a variable temperature stage using Peltier elements, which allows us to investigate the precursor dynamics in a range of +/- 30 K around room temperatures. The results do not only explain the origin of previously observed growth rate variations without any heating/cooling but also point out the importance of temperature stability for precision and reliability during 3D nanoprinting. We present FEBID experiments in dependency on temperature, which clearly shows a massive growth rate increase when approaching 1 °C. The focus lies on quasi-1D pillars and 3D multi-pod architectures, to demonstrate the boost in deposition rates at low temperatures. References: [1] Mutunga et al., ACS Nano 2019, in print [2] Bresin et al., Nanotechnology, 24, 2013

Authors : Francisco Gontad, Sara Vidal, Nerea Otero, Pablo Romero
Affiliations : AIMEN Technology Centre, O Porriño, ES36418, Pontevedra, Spain

Resume : The fabrication of micro and nanopatterned surfaces on polymers have been an area gathering a lot of interest from research and industrial parties. On the one hand, alternatives involving direct writing with charged particles or different kinds of illumination sources have demonstrated to provide an enormous design flexibility and modularity, but with a low throughput. On the other hand, industrial fabrication techniques such as injection moulding, while allowing a high throughput, were proven to bring an extremely low flexibility for changes in the fabrication pattern. In this work we will introduce the parallelization of a direct laser writing technique like two photon induced photopolymerization (TPP) as fabrication technique that may combine both; high throughput and fabrication flexibility. Diffractive Optical Elements (DOEs) were used for splitting the original laser beam into arrays of 3×3,11×11, 51×51 and 101×101 parallel beams. An ultrashort pulsed laser (280 ps) emitting visible radiation (515nm) was used for the photopolymerization of a commercial photoresist (Ormocomp©). In this way, large patterned areas were produced by single exposure steps with the parallel laser beams. Very well defined structures were fabricated with the 3×3 and 11×11 DOEs, proving the reliability of the technique. However, the proximity effect limited the definition of the structures fabricated with the larger DOEs. Still, a very high fabrication throughput was achieved for the fabrication of repetitive patterns with a high design flexibility.

12:20 Lunch Break    
Direct Energy Deposition Manufacturing : Didier Boisselier
Authors : Filomeno Martino
Affiliations : Welding Engineering and Laser Processing Centre Cranfield University, Bedfordshire, MK43 0AL

Resume : Directed-energy-deposition (DED) Additive manufacturing (AM) has many advantages for production of large scale engineering structures with significantly reduced manufacturing costs and lead times. This has proven particularly true for the Wire + Arc AM (WAAM) process. The presentation will cover how, based on 12 years of intensive world-leading research into all aspects of WAAM, we have printed critical airframe components up to 6m in aluminium and 2m in titanium, by developing a mature industrial ecosystem, which can also be translated to other DED processes. We will present the key elements of this system (software, machines, innovative sensors), and how it has been applied to large scale metallic parts (flanges, wing ribs, pressure vessels, landing gears, etc). The business benefits will be explained, with the support of industrially-relevant metrics, such as reduction of lead times from over a year to a few weeks, and reduction in cost of as much as 60%. A roadmap for future development, including WAAM commercialisation and industrialisation, will be announced.

Authors : Lakhindra Marandi, Sujith Kumar S, Vamsi K. Balla, Sandip Bysakh, David Piorunek, Gunther Eggeler, Mitun Das, Indrani Sen
Affiliations : Lakhindra Marandi; Sujith Kumar S; Indrani Sen; Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, India; Vamsi K. Balla; Sandip Bysakh; Mitun Das; Bioceramics and Coating Division, CSIR – Central Glass and Ceramic Research Institute, Kolkata, India; David Piorunek; Gunther Eggeler; Institute for Materials, Ruhr-University Bochum, Bochum, Germany; Vamsi K. Balla; Materials Innovation Guild, Department of Mechanical Engineering, University of Louisville, Louisville, KY 40208, USA.

Resume : NiTi alloy is the most used shape memory alloy used in a wide variety of applications such as in actuators, aerospace, automobiles and biomedical industries. The high strength, better corrosion resistance and biocompatibility of this material makes it a suitable candidate for biomedical application as stents, orthopedic implants, root canal instruments, and orthodontic archwires. In the present work, microstructure evolution and the consequent property development of an additively manufactured (Laser Engineered Net Shaping (LENS)) NiTi is investigated systematically. Effect of laser energy density on modifying the physical and mechanical properties have been included in the study. Increasing laser power increases microstructure homogeneity, as well as a decrease in porosity, have been observed. Austenite at room temperature is confirmed by DSC analysis which shows the materials intent to show pseudoelastic behavior. Furthermore, the effect of porosity developed during deposition plays a vital role in modifying mechanical properties. The mechanical properties are evaluated using indentation (spherical and Berkovich) and uniaxial tensile testing. Optimized processing conditions in terms of laser scan speed and rate are identified that yields the best pseudoelasticity. Indentation stress-strain curves are generated further from the nanoindentation results that closely match with the tensile stress-strain curves. Indentation size effect, as well as the size effect of tensile testing, have also been studied.

Authors : Damien Choron¤, Serge Naveos*, Marc Thomas*, Didier Boisselier¤, Johan Petit*
Affiliations : ¤ IREPA LASER, Parc d’Innovation, 67400 Illkirch, France * ONERA, DMAS, The French Aerospace Lab, Université Paris-Saclay, 92322 Châtillon, France

Resume : In the context of cost reduction, the increase of power to mass ratio of aircraft engines is a key issue that requires the development of light-weight, high temperature alloys. Due to their low density and strong hot mechanical properties and corrosion resistance, γ-TiAl are good candidates to replace nickel-based superalloys in the low-pressure turbine of the aircraft engines. The conventional processing route strongly limits the γ-TiAl achievable geometries and direct additive manufacturing, such as the DED-CLAD® process, is a good substitute to fabricate large scale complex functional parts. Due to their low thermal shock resistance, the key issue for their direct additive manufacturing is the control of the thermal gradient during and after powder deposition. In this work, a high temperature heating device with integrated control of the heating and cooling rate has been used. The model material is a first generation TiAl alloy, the composition of which is Ti48Al48Cr2Nb2, produced by gas atomisation. By using a 400 and 900°C heated substrate, a process operating point has been identified, which allowed to build massive blocks. They show very few unmelted particles, some micron-sized pores and a good cohesion to the substrate. In this work, the effects of the preheating temperature have been investigated. The beneficial effects of using temperatures above the brittle/ductile transition on the as-deposited microstructure soundness and mechanical properties are discussed.

Authors : Vaibhav Nain, Muriel Carin, Thierry Engel, Didier Boisselier, Christophe Cordier
Affiliations : IREPA LASER, Parc d’Innovation, 67400 Illkirch, France; Univ. Bretagne Sud, UMR CNRS 6027, IRDL, F-56100 Lorient, France; Institut National des Sciences Appliquées, 67000 Strasbourg, France; IREPA LASER, Parc d’Innovation, 67400 Illkirch, France; Institut National des Sciences Appliquées, 67000 Strasbourg, France

Resume : The Directed Energy Deposition - Construction Laser Additive and Direct (DED-CLAD®) technique is a free-form metal deposition process, which allows generating near-net shape structures through the interaction of a powder stream and a laser beam. With increasing industrial interest and significance of DED-CLAD®, the importance for profound process knowledge increases, so that large scale parts can be manufactured. Therefore, three different numerical thermal models for DED-CLAD® are presented named as Material Activation, Arbitrary Lagrangian Eulerian (ALE) free surface motion (horizontal) and Arbitrary Lagrangian Eulerian free surface motion (vertical) that allows a detailed study of the temperature evolution in the build part. Considering thin wall builds, numerical results obtained with COMSOL Multiphysics software are successfully compared with experimental data available in literature such as melt-pool dimensions, and thermocouple temperature measurements. Furthermore, a possible way to reduce the computation time and to increase the accuracy is also proposed. Keywords: DED-CLAD®, LMD, ALE, modeling, Simulation, Heat Source, Additive manufacturing, Material Activation

Authors : Marcos Diez, Sara Carracelas, Camilo Prieto, Carlos Gonzalez, Pilar Rey
Affiliations : Advanced Manufacturing Processes Area (AIMEN Technology Centre); Robotics and Control Area (AIMEN Technology Centre)

Resume : Additive Manufacturing, (AM), the industrial version of 3D printing is changing the way of manufacturing and delivering products. Laser metal deposition (LMD), a promising technique that falls in the category of AM direct energy deposition (DED), consists in fuse materials by melting as they are being deposited. Usually AM techniques was used when the component can´t be built by traditional processes or for in some cases, properties improvement, as in this case. The main goal of this work is to study the influence of process parameters and path planning on mechanical properties and microstructure. Samples made of stainless steel 316L powder were manufactured with a Trudisk Laser of 16kW and a BEO D70 head (TRUMPF) and a GTV powder feeder. The process parameters were maintained constant while different trajectories were explored, then we did the opposite. Sample microstructure were studied trough Optical and Scanning Microscopy. The cooling rate was studied with an infrared camera (Flir) and an on axis infrared sensor to measure the cooling rate of solidification area. On the other hand, microhardness measurements were also made on samples on the building and the scanning direction while tensile specimens were extracted from different planes and tested following the ASTM E8 Standard.

15:50 Coffee Break    
Advanced Power Bed Fusion : Ambroise Vandewynckèle
Authors : Artur Leis, Rudolf Weber, Thomas Graf
Affiliations : Artur Leis, Institut für Strahlwerkzeuge (IFSW) / Graduate School of Excellence advanced Manufacturing Engineering; Rudolf Weber, Institut für Strahlwerkzeuge (IFSW); Thomas Graf, Institut für Strahlwerkzeuge (IFSW)

Resume : The interaction of the fast moving laser beam and the metal powder during Laser Powder Bed Fusion (LPBF) can result in strong process fluctuations leading to the formation of weld defects, which significantly reduce the quality of the generated parts. In order to analyse these process fluctuations during the LPBF-process a model arrangement was set up, which allowed the simultaneous use of different monitoring tools for the observation of the interaction of the laser beam and the powder bed as well as the surrounding area. High-speed imaging in the visible wavelength range with high magnification and framerates of up to 10,000 fps was used to observe the interaction of the laser beam and the powder bed. High-speed imaging in the infrared wavelength range with up to 1,500 fps was used to analyse the temperature distribution and the solidification of the melt pool and the previous vectors. Additionally, off-axis Pyrometers and several on-axial diodes were used and the information obtained from the different sensors was compared. The results of the high-speed online process monitoring will be presented and discussed for each monitoring tool. Furthermore, it will be shown that the use of a closed-loop control system may be advantageous to achieve high part qualities.

Authors : Sebastian Bremen
Affiliations : ILT Fraunhofer

Resume : In progress

Authors : Agnieszka Chmielewska1,2; Bartłomiej Wysocki 1,2; Wojciech Święszkowski 1
Affiliations : 1 Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141 Str., Warsaw, Poland 2 MaterialsCare, LLC, Zwierzyniecka 10/1, 15-333 Bialystok, POLAND

Resume : In recent years Additive Manufacturing (AM), commonly called 3D printing, is of particular interest to the aerospace and biomedical device industries, due to the ability to manufacture low-volume, complexly-shaped parts with fine structures and gradient mechanical properties. Therefore, it is desirable to obtain sufficient rendering accuracy and surface quality of additively manufactured objects. In view of the nature of AM, unmelted powder particles become attached to each part’s outer surface. In order to obtain the required surface finish, those particles must be removed by postprocessing methods. In this study chemical polishing for 3D printed titanium and its alloys were studied. For each material, different concentrations were selected and investigated. As a result HF-HNO3 solutions for pure titanium as well as titanium alloys were determined in order to obtain the best surface quality and fabrication that is accurate to the original CAD dimensions of the part. Depending on a part geometry, concentration of the solutions and the time of polishing up to 30% of mass loss of the samples have been observed. Scanning Electron Microscopy of samples surface revealed the removal of powder particles and surface smoothing. Fabrication accuracy was determined by Micro Computed Tomography scanning of the samples before and after chemical etching and it showed high improvement of dimensions accuracy of the CAD model of chemically polished samples regarding to as- fabricated samples.

17:40 Break    
POSTER : Eric Fogarassy
Authors : Kyuhong Lee, Jonghwan Kim, Jae Jun Hwang, Eung Soo Kim, Ki Nam Kim, Sunghwan Kim, Yong Jin Jeong, Jong Man Park
Affiliations : Korea Atomic Energy Research Institute

Resume : The centrifugal atomization technology was developed for the fabrication of nuclear fuel powders such as Uranium Silicide and Uranium Molybdenum alloys by Korea Atomic Energy Research Institute (KAERI). The centrifugal atomization technology has several advantages compared to comminuting method for the powder fabrication. The powder which made by the atomization has very uniform and fine spherical shape as well as high purity with high yield rate, over 95%. KAERI has supplied the atomized powders to research institutes and commercial companies around the world such as ANL, INL, BWXT, CEA, CERCA, SCK∙CEN, and CNEA for the development of research reactor fuels. Due to the good external characteristic of the centrifugally atomized powder, it is very suitable for additive manufacturing technologies with metallic materials.

Authors : J. Sattelkow(1), J. Fröch(2), R. Winkler(1), C. Schwalb(3), S. Hummel(3), H. Plank(1,2,4)
Affiliations : 1) Christian Doppler Laboratory - DEFINE, Graz University of Technology, 8010 Graz, Austria; 2) Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010 Graz, Austria; 3) GETec Microscopy Inc. & SCL Sensor.Tech. Fabrication Inc., 1220 Vienna, Austria; 4) Graz Centre of Electron Microscopy, 8010 Graz, Austria

Resume : Atomic Force Microscopy (AFM) is an essential tool in research and development due to quantitative 3D surface characterization with sub-nanometer resolution and the possibility to access magnetic, mechanical, optical, electrical or thermal surface properties. In contrast, AFM is analytically blind, which requires complementary techniques such as Scanning Electron Microscopy (SEM). Based on the motivation to combine both worlds, GETec Microscopy Inc. has designed an AFM system for seamless integration in highly space confined SEMs. The core elements of this technology are self-sensing cantilever, which enable electrical readout of the cantilever deflection, eliminating space consuming optical detection systems. In the past, the available measurements modes were restricted to morphological and mechanical characterisation. To overcome this limitation, we jointly develop new nano-probe concepts to access electric, magnetic and thermal surface properties. This talk starts with an introduction of our nanoprobe fabrication, using 3D nanoprinting via focused electron beam. We present electric and magnetic nanoprobe concepts briefly, followed by our latest 3D nano-thermistor concept in more detail. This range from 3D fabrication over mechanical tuning for stable AFM operation towards thermal probing. As demonstrated, a 3D nano-thermistors allow for scan speeds up to 80 µm/s and quantitative temperature measurements with an accuracy of ±1 C° and fast dynamic responses of about 32 ms/K.

Authors : Kyung-Hyun Kim*1, Kyu-Sung Lee1, Ji-Young Oh1, Yong-Seok Yang1, and Hyun-Cheol Bae1
Affiliations : 1. Electronics and Telecommunications Research Institute (ETRI) 218 Gajeongno, Yuseong-gu, Daejeon, 34129, South Korea

Resume : 3D printing or additive manufacturing is expected to revolutionize the manufacturing of components in short period time. Specially, these techniques can be used various application fields, which are making prototypes for electronics, aerospace, automotive, and so on. In order to 3D printing technology to be applied to an electronic device or an automobile, a thermal-mechanical stability over 300oC must be secured. However, almost of commercialized 3D printers do not provide thermal-mechanical stability over 300oC due to thermoplastic properties. Therefore, we have designed a hybrid organic-inorganic composite material suitable for high temperatures stability and successfully made thermoplastic filaments using a mini-extruder machine for fused deposition modelling (FDM) printer. Also, we studied various composite materials, which are glass fiber, carbon fiber, and modified Basalt fiber for improving thermal, mechanical. The house-made filaments, including various composites, and 3D printed samples were measured by thermal mechanical analyzer (TMA), bending strength with micro-universal testing machine. Surface morphology and x-ray tomography of those are measured by scanning electron microscope (SEM) and X-ray microscopy (XRM). We will present the detailed experiment results and other analysis results for improved 3D printing materials. This work was partly supported by Institute for Information & communications Technology Promotion (IITP) grant funded by the Korea government (MSIT) (No.2018-0-01164, Development of high-speed(10g/hr) deposition source for OLED electrode) and Electronics and Telecommunications Research Institute (ETRI) (No.19ZB1900, Developments of organic-inorganic hybrid polymer material and packaging process for 3D Printing over 350 ℃)

Authors : Nima E. Gorji, Rob O'Connor, Dermot Brabazon
Affiliations : I-Form advance Manufacturing Research Centre, Dublin City University, Dublin 9, Ireland

Resume : X-ray computing tomography (XCT) is used to probe the fresh and recycled metallic powders for 3D printing applications. We have used XCT technique to characterize the particle size distribution and pore size distribution in both virgin and recycled powder and have shown that the recycled powder has a broader size distribution and the pore formation is more probable in a broad range of sizes from 2-10um. The particle size changes during the manufacturing of the parts and we can observe a broader range of sizes from 10-30um. XCT is a powerful technique to reveal also the pore formation inside the particles although the particles seem to be unaffected and have a perfectly spherical shape or clean surface. This understanding greatly serves to reuse the powders in the 3D printing process in order to reduce power consumption. There is no such compelling technique to visualize the porosity formation inside the powder particles in 3D format. Our characterizations indicate that the powder collection from the 3D printing machine must follow a protocol to separate the most affected and least affected particles as possible in order to retain the highly desired mechanical properties of the parts printed from recycled powders. XCT method has greatly shown that the in or out-diffusion of chemical elements can be a reason for pore formation inside the particles during the 3D printing process.

Authors : A.Czajka 1,2, B.Wysocki 1,2, M.Gloc 1, W.Święszkowski 1
Affiliations : 1. Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141 Str., Warsaw, Poland; 2. MaterialsCare, LLC, Zwierzyniecka 10/1, 15-333 Bialystok, POLAND;

Resume : The degree of crystallinity hence mechanical properties polyetheretherketone (PEEK), strongly depends on the processing parameters and the post-process thermal treatment. The aim of this work was to determine influence of the size and the filling degree of the 3D printed by FDM (Fused Deposition Modeling) technology PEEK subjected to thermal post-processing. For this purpose, three sizes of cylindrical shapes were printed: 1x0.1 cm; 2.5x2.5 cm; 5x5 cm with two filing degree levels: 50 and 100%. Tested samples were annealed to increase their degree of crystallinity to create an element with the same content of crystalline phase in the entire volume and minimize the anisotropy of mechanical properties. The degree of crystallinity was specified by determining the enthalpy of the crystalline phase melting by DSC (differential scanning calorimetry). The surface of the samples and their internal areas were analyzed. Our studies have shown that post-process thermal treatment of 3D printed PEEK increase the degree of crystallinity, but the content of the crystalline phase may vary depending on the sampling site. This effect can be caused by different heat conduction during fabrication and heat treatments. Results of our study showed that there is a high need to optimize the thermal post-processing of elements with different architectures manufactured using the FDM method from PEEK.

Authors : B.F.R. Silva1, N.M. Ferreira1, J. Carneiro2, C.M.S. Freitas1, R. Santos3, M.P. Seabra2, A.J.S. Fernandes1, F.M. Costa1*
Affiliations : 1 I3N & Physics Department, University of Aveiro, Aveiro, Portugal 2 CICECO & Materials and Ceramic Eng. Department, University of Aveiro, Aveiro, Portugal 3Technological Center Ceramic and Glass, Antanhol, Coimbra, Portugal

Resume : Sanitary ceramic ware usually present small visible defects in the outer glaze layer that hinder their commercialization. Nowadays, the solution to remove these defects requires a further firing of the entire piece. This process involves high energetic costs and high CO2 emission. This way, the development of a technological solution based on the localized repair of defects is strongly desirable. Laser technology accomplishes this requisite, since it provides a highly localized heat source, thus enabling obvious economic and environmental advantages. In this work, the interaction between a continuous wave CO2 laser and the glaze material to be repaired was studied. Different experimental conditions were explored, including several repair materials, distinct laser heating cycles, laser powers and intensities, among others. Although local glaze melting was successfully attained, some cracks appeared in the repaired area due to high thermal stresses. To attenuate this phenomenon, an additional diffused irradiation heat source from an infra-red lamp was explored. This combination significantly reduced the number of cracks and their dimensions in small samples, strongly reducing the defect perceptibility. However, in real pieces this approach leads to fatal damage by breakage due to unavoidable strong thermal stresses build-up. In alternative, a second firing at lower temperature was considered, using tailored compositions for the glaze filling of the defects.

Authors : Musa YILMAZa*, Necip Fazıl YILMAZa, Ali KILIÇa
Affiliations : aGaziantep University, Faculty of Engineering, Department of Mechanical Engineering, Turkey *

Resume : Polyetherimide (ULTEM) resin offers superior mechanical properties for a thermoplastic in fused deposition modeling (FDM) technology. Thermoplastic gears used at high velocity and loading in machine run is occurred to damages as wearing and fracture gear. In recent years, as a result of improvements in 3D printers, very complex and diverse parts can be manufactured. In this study, gears were produced by using additive manufacturing by using ULTEM material and damages of thermoplastic gears produced with FDM method, tested at the loading. In addition, thermoplastic gear and thermoplastic pair gear was investigated. As a result of this study, wearing depth occurred at the gear profile under the SEM microscope was examined. The opportunities and limitations of ULTEM material for the fabrication of gears are discussed in this paper.

Authors : Silvia Conti1, Carme Martinez-Domingo1, Fabiola Vilaseca2, Lluís Terés1, Eloi Ramon1
Affiliations : 1 Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Carrer dels Til·lers, 08193, Cerdanyola del Vallès, Barcelona, Spain. 2 Department of Chemical Engineering, Agricultural and Food Technology, Universitat de Girona, Maria Aurèlia Capmany 61, 17003, Girona, Spain

Resume : Over the past 20 years, the interest in organic and printed electronics has increased exponentially. Low-cost printed electronics seek to minimize the area limitations and number of steps associated with conventional silicon processing for applications that do not require high performances [1]. By using printing technologies, the process becomes all-additive without the need of expensive lithography or vacuum processes, resulting in a reduction of production costs. Furthermore, the development of novel multi-functional nanocomposites materials has gained tremendous research interest on using low-cost and renewable raw materials, to produce sustainable, biodegradable, and eco-friendly biomaterials to be used in electronic applications [2]. In this work, organic rectifying diodes fabricated by means of inkjet printing on nanopaper environmentally friendly substrates are presented. Figure 1a shows the scheme of the proposed structure: following a work recently published by our group [3], plastic substrates and bottom metal electrodes were substituted by the conductive nanopapers for the fabrication of organic rectifying diodes. Nanocellulose changes its electrical properties from being an insulator to a semiconductor and, eventually, becoming a conductor by the addition of conductive fillers [4]. Conductive nanopapers were obtained from two different cellulose pulps (high-purity softwood cellulose pulp CNF5 and eucalyptus pulp CNF15) adding conductive polymers (polythiophene (PT2, PH500) and polypyrrole (PPy) or Multi-Walled Carbon NanoTubes (MWCNTs). Poly-4vinylphenol (PVP), an epoxy insulator (SU8), and high permittivity (HK) Epoxy/Nanosilica insulator (UTDots) were investigated as the polymeric insulator layer. A commercial amorphous polymer (Merck Lisicon® SP400) was employed as the p-type semiconductor. The top electrodes were patterned using a commercial silver conductive paint (SCP03B). The quality of the printed film was highly affected by the roughness of the nanopapers. In some cases, a non- homogenous insulator layer results in a short-circuit through the structure. Figure 1b shows the best results obtained employing CNF5 as the substrate. Rectification Ratio (RR) is defined as the ratio of the maximum forward current to the maximum reverse current registered at the same voltage. The electrical performances of the diodes seem to be more dependent on the choice of the insulator than on the nanopaper formulations. The ternary formulation with the combination of PH500 mixed with PPy as substrate and UTDots as the insulator showed a maximum forward current of 2µA and a maximum reverse current of 1nA (Figure 1C). As a result, extremely high RR value was obtained (2000).

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Opportunities offering by 3D printing : Filomeno Martina
Authors : Alain Bierneaux
Affiliations : Optec

Resume : Technical ceramics are regularly honored in the industry. Their properties of hardness, lightness and unalterability are particularly sought after. The high-tech nature of these materials is intended primarily for high-end products. Ceramic models are currently mainly produced using ceramic injection (CIM), the only process that allows high productivity but has several limitations in terms of geometries and cost-effectiveness for small series. Among the other shaping processes, the use of milling (on pre-sintered or dense parts) remains limited in terms of geometry because of the risk of significant damage to parts. During our presentation, we will present new unconventional methods to circumvent the limits of injection and mechanical milling. The methods envisaged have the particularity of using a laser beam. We will discuss new developments in the subtractive field, the additive. Particular emphasis will be placed on a new hybrid process combining mechanical milling (blanking of parts) and laser machining (finishing of parts) in the green state. The laser is a tool perfectly adapted to the machining of fine details as evidenced by the photos below. In addition to the presentation of many examples, we will make a relevant comparison between the different techniques with regards to the geometry of the parts.

Authors : Vahid Asadi, Thomas E. Kodger, Jasper van der Gucht
Affiliations : Physical Chemistry and Soft Matter, Wageningen University and Research, Stippeneng 4, 6708WE Wageningen, The Netherlands

Resume : Along with new emerging additive manufacturing techniques, attention has been devoted to addressing the lack of 3D printable materials as a complement to this fast-growing processing industry. One interesting class of 3D printable materials is thermoplastic elastomers which can fabricate structures with elasticity and deformability; however, there is a lower limit in their modulus as dictated by topological constraints known as entanglements. Therefore, developing a thermoplastic elastomer which is super soft, non-swollen, solvent-free, reusable and easy to structure into complex objects by direct extrusion-based 3D printing could be a breakthrough in the 3D printing world in the direction of soft materials. In this ongoing research, we use living anionic polymerization and the "grafting onto" approach to synthesize new topologically well-defined ultra-soft elastomers possessing both fundamentally fascinating mechanical properties and thermoplastic reversible 3D printing ability. This feature originates from entanglement-free telechelic bottlebrush architecture where the phase separation of end blocks at room temperature leads to an elastic network without chemical crosslinks. Most importantly, having control over the final properties of resulting material by changing the structural parameters can significantly broaden its potential applications. To this end, rheological measurements were done to determine the best composition for the 3D printing process. This research opens a new window in fabrication of the next generation of soft implants, prosthetics, tissue scaffolds in biomedical applications, and also flexible and wearable electronics thanks to these innovative soft materials.

Authors : Idalina Gonçalves#1, Marta Rocha#1, Tiago L. Águeda#1, Bernardo Amorim#2, Pedro Duarte#2, André Santos#2, Manuel A. Coimbra#3, Paula M. Vilarinho#2, Paula Ferreira#3
Affiliations : 1. CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; 2. CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal; 3. QOPNA & LAQV/REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal

Resume : 3D printing offers time and cost-effective technologies that allows to produce 3D-products with complex geometries. Amongst the various 3D manufacturing processes, fused deposition modelling (FDM) is one of the most popular technique used. However, most of the FDM filaments have low or none biodegradability, compromising their environmental footprint. To minimize this issue, to use agrofood and recycled wastes on the development of 3D printer filaments may be considered. In this work, the influence of coffee roasting (coffee silverskin) and recycled rubber tire byproducts on optical, melt tenacity, wettability, and mechanical properties of starch-based formulations was studied. For comparison purpose, polylactic acid (PLA)/rubber tire filaments were used. Coffee silverskin and rubber tire give rise to brown and black starch-based filaments, respectively. Coffee silverskin increases the rigidity of starch-based formulations, reinforcing the intermolecular hydrogen bonding between its lignocellulosic material and the amylose/amylopectin chains. On the other hand, low amount of rubber tire increases the starch-based films elasticity, owing to the rubber tire additives that separate the polysaccharide chains, while higher dosages reinforce the starch structure, due to the rubber vulcanized structure. Coffee silverskin and rubber tire, due to their inherent hydrophobicity, decrease the wettability of starch-based formulations. Furthermore, starch/rubber tire filaments show higher homogeneity and flexibility than PLA/rubber tire filaments. All the developed filaments allow to produce 3D-printed objects, giving place to a green strategy that encourages the circular economy.

10:30 Coffee Break    
Authors : Joon Hyeok Jang, Woong-Ryeol Yu
Affiliations : Department of Material Science and Engineering and Research Institute of Advanced Materials (RIAM), Seoul National University

Resume : Functionally graded material (FGM) features gradual changes in the material properties due to variable composition and structure throughout the volume. These materials have been designed for specific functions ( high heat, corrosion resistance and damping properties) and applications such as space shuttle, automotive, artificial bone and building materials. Various fabrication methods, such as particulate processing, preform processing, layer processing and melt processing, have been developed for FGM, however, the fabrication of FGM with complex and finely graded structure is still challenging. On the other hand, ¬three-dimensional (3D) printing method has emerged as an efficient manufacturing method for the complex structure. In this study, we investigated the use of 3D printing method for manufacturing gradually porous FGM. Filament deposition modeling (FDM) type-3D printer and polylactic acid (PLA) were used. Porous FGMs with the pore size gradient from 400 to 800 μm were fabricated by varying infill density and pattern. By lowering the infill density throughout the volume (50~100%), graded porous internal structure can be created by control the distance between the printed infill patterns. Then, mechanical and thermal behavior of porous FGM were characterized and will be discussed in detail at the conference, focusing on the possibility of developing FGM using 3D printing for heat and eletromagnetic interference shield application.

Authors : M. Klein, S. Suresh Nair, S. Steenhusen, A. Heinrich, G. Domann, P. Löbmann
Affiliations : Fraunhofer ISC Würzburg, Hochschule Aalen

Resume : The interest in additive manufacturing has grown rapidly over the last few years. Today, it is possible to print mechanical parts consisting of polymers, metals and ceramics. 3D-printing of optical components, however, remains very challenging due to the extraordinary requirements the materials must meet: UV-curability with low shrinkage and high shape stability, high trans-parency and refractive index with no yellowing effect, stability vs. air and a high surface quality. In our project, we were able not only to print materials with excellent optical properties but also to include photoluminescence (PL) as an additional material function. Four different types of quantum dots were dispersed separately in an inorganic-organic hybrid material. They were printed (DLP-SLA) simultaneously on a transparent base to create a sensor-like demonstrator usable for biomedical applications. One great drawback in DLP printing is caused by the layer-wise curing scheme: It is not possible to create smooth surfaces without post processing. In contrast, inkjet technology allows for optical quality surfaces since the jetted wet thin film smooths out edges before it is cured. Hence, we develop and characterize new photosensitive materials for inkjet/polyjet technology based on the DLP resins. The focus lies on solvent free inks, which have superior properties for processing and curing. Additionally, different properties such as refractive index or add PL by introducing nanoparticles can be varied.

Authors : Musa YILMAZa*, Necip Fazıl YILMAZa, Ömer EYERCİOĞLUa
Affiliations : aGaziantep University, Faculty of Engineering, Department of Mechanical Engineering, Turkey *

Resume : Fused deposition modelling (FDM) is rapidly growing 3D-printing technology due to its ability of building functional parts having diverse and complex geometries. However, printing materials are limited to polylactic acid (PLA) or acrylonitrile butadiene styrene (ABS) in most FDM equipment. Here, information about polycarbonate (PC) material and polieterimide (ULTEM) material, which are a high-performance engineering material to overcome these shortcomings, is provided. The mechanical properties of a built part depend on several process parameters like layer thickness, air gap, build orientations, raster angle, raster width, fill pattern and model building temperature. The aim of this study is to determine the effect of layer thickness and raster angle on the mechanical performance of samples made with PC and ULTEM filaments manufactured in 3D printer. Samples with three different layer thickness and four different raster angle were built using PC polymer material in the 3D-printing system. Their tensile, hardness and impact tests were carried out and compared with each other. Keyword: Polycarbonate, Polieterimide, Layer Thickness, Raster Angle, 3D-Printing

Authors : Linas Jonusauskas1,2, Darius Gailevičius1,2, Greta Merkininkaite1,3, Dovile Andrijec1,2, Tomas Baravykas1 and Simas Sakirzanovas1,3
Affiliations : 1: Femtika, Sauletekio Ave. 15, Vilnius LT-10224, Lithuania 2: Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, Vilnius LT-10223, Lithuania 3: Faculty of Chemistry and Geoscience, Vilnius University, Naugarduko str. 24, Vilnius LT-03225, Lithuania

Resume : Femtosecond laser based multiphoton 3D nanolithography is a powerful tool to produce functional microstructures with unlimited 3D architecture for applications from photonics and microoptics to micromechanics and biomedicine. One of the key components of this technology is the correct choice of material used for printing. In this work we present fabrication opportunities enabled by the usage of hybrid organic-inorganic photopolymers purpose-designed for this technology. These include printing with minimal shrinkage (down to 1%), very high resolution (down to sub 150 nm) and capability to produce complex support-free micromechanics. The latter is possible as this material is hard gel during printing and act as a dissolvable support. Furthermore, thermal post processing allows to use these materials as a base for 3D nanoprinting of crystalline ceramics. It is shown that both nanolattices and bulk structures can be produced this way. The process allows both downscaling of features by 60% in isotropic manner as well as enhancing their general resiliency (in comparison to standard polymeric state). Considerations on material composition optimization (ratio between organic and inorganic part, photosensitization degree, etc.) for all named applications are provided. Further development directions are highlighted with the main attention given to possibility to use it in industrial applications.

12:20 Lunch Break    
New opportunities for better additive manufacturing : Didier Boisselier
Authors : Cyril Pelaingre, Claude Barlier, Benoit Delebecque
Affiliations : CIRTES

Resume : The current digital chain of Additive Manufacturing (AM) has its limits today due to its downward flow that leads to many losses of information. A part is designed in CAD, then converted into a mesh format (STL, AMF, ...). It is then transformed into a preparation proprietary format specific to the process (e.g. supports, hollowing, orientation) and finally into a toolpath file to control the machine. Thus, a modification of the initial CAD model results in the complete re-run of the cycle, creation of a multitude of files, and also a dependence on several software. In addition, the implementation of numerical simulation is complicated and difficult to achieve. Additive Manufacturing (AM) allows great design freedom, design of complex shapes, integration of new functions (e.g. conformable channels, sensors, etc.) and elimination of traditional manufacturing constraints. Design for Additive Manufacturing (DFAM) is a great way of design that allows to consider the constraints of AM processes, to optimize manufacturing and maximize part performance (weight, strength). The integration of this concept into the stratoconception AM process was taken in account since its origin in 1991 and it is claimed in the body its patent. The integration of AM into a global digital chain, thanks to tools for part design (topological optimization, generation of internal structures), process simulation and knowledge capitalization through data, allows to achieve a real digital continuity for AM. We will present an industrial example of a continuous AM digital chain for stratoconception: TopSolid'Strato - through the manufacture of measuring busts for testing protective helmets.

Authors : Thierry Engel (a,b), Ronny Elleb (a,c), Adeline Prévot (a), Frédéric Mermet (a)
Affiliations : a INSA Strasbourg, 24 blvd de la Victoire, 67084, Strasbourg cedex, France; b IREPA-LASER, Parc d'Activités, 67400 Illkirch, France; c IMMM, CNRS UMR 6120, Le Mans Université, Le Mans, France

Resume : Texturation of metals is a field that is in a great expansion for many years now. More specifically, Laser texturation allows some specific characteristics of the surfaces thanks to a very precise control of the energy driven to the target, both in time and space. One of those characteristics, called wettability, is of special concern to us. This behaviour is obtained with a special double-scale texturation: a few ten µm spatial period is made with a prescribed laser scanning of the surface, while the nanoscale is obtained with an auto-arrangement of it, called LIPSS (Laser Induced Periodic Surface Structure) effect. However, in the case of super-hydrophobic textured metallic surfaces, we can notice an evolution in the Water Contact Angle (WCA) over time. Indeed, we usually measure WCAs going from a low initial value right after texturation (hydrophylic state), to very high values after about 2 weeks with no extra treatment, reaching hydrophobic or even super-hydrophobic state [1][2]. This evolution, called maturation, appears to be a complex mix of situations, with numerous parameters, both physical and chemical, giving way to several explanations, that are somewhat contradictory [3]. Some literature mention also a modification of the type of wettability, changing from a Cassie-Baxter model limited to the peaks, to a Wenzel model using the whole surface. Thus the analysis of wettability should be made in respect to the physical roughness encountered on every part of the surface, taking also the chemical evolution aspects into account. Maturation has been investigated through several analysis (MEB, EDX, XPS, Raman) on different metals (Titanium, Stainless Steel), on several areas, tracking the evolution of the most variant constituants (Fe, O, C) over time. That presentation/paper make a point on the several maturation parameters and try to identify what the relevants are.

Authors : Dr. Gurdial Blugan, Dr. Alexandre Guiller, Samuel Clark Ligon
Affiliations : Empa, Laboratory for High Performance Ceramics

Resume : The possibilities of low cost 3D printing of ceramics using two different types of low cost SLA printers operating at two different wavelengths were investigated. Firstly, a propriety ceramic slurry consisting of alumina-silicate in a UV cross-linkable binder system were cross-linked into a master test component to evaluate the resolution capabilities of the printers and of the slurry system. The ceramic test components were sintered and the different features measured, including feature resolution, wall thickness, parallelness with print height, hole formation (radius and height). New slurries were then developed to improve the 3D printing performance by adjusting the properties of the ceramic components of the alumina silicate particles and thus the recipe. In the next step, different UV-active polymers were investigated to allow the development of new ceramic slurries. The results show the differences in the two SLAs, and how effective this technology can be to produce low cost advanced ceramic components.

15:30 End of symposium    

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Symposium organizers

Head of Advanced Manufacturing Department, Polígono Industrial de Cataboi SUR-PPI-2 (Sector 2) Parcela 3, 36418 O Porriño (Pontevedra), Spain

29bis, voie de l’Innovation, 88100 Saint-Dié-des Vosges, France

Pole API Parc d’Innovation 67400 Illkirch, France

Rue Bois Saint-Jean 12, 4102 Seraing, Belgium