Skip to main content
main-content

Über dieses Buch

These proceedings exchange ideas and knowledge among engineers, designers and managers on how to support real-world value chains by developing additive manufactured series products. The papers from the conference show a holistic, multidisciplinary view.

Inhaltsverzeichnis

Frontmatter

Design Tools and Methods

Frontmatter

Evolution of Design Guidelines for Additive Manufacturing - Highlighting Achievements and Open Issues by Revisiting an Early SLM Aircraft Bracket

Design knowledge is important for the success of new technologies. This is especially true for Additive Manufacturing technologies like Selective Laser Melting (SLM), which offer a higher degree of freedom, but also very different restriction in design compared to conventional manufacturing technologies. An analysis of current and previous designs from aerospace and motorsports identifies important drivers in Design for Additive Manufacturing. To visualize the advances in design knowledge an SLM aircraft bracket is re-designed based on today’s state of the art almost 10 years after its initial design for additive manufacturing. The analysis reveals important factors for a “good” design. In early designs the focus of engineers was on the manufacturability of the part itself, while the capabilities of CAD tools limited the designer. Nowadays designs show a more holistic view on the manufacturing process chain and the part’s application, e.g. by integrating provisions for conventional post-processing and fatigue optimized shapes and surfaces. Some issues are still open and need to be addressed in the next generation of guidelines, tools and equipment.

Christoph Klahn, Daniel Omidvarkarjan, Mirko Meboldt

A Design Method for SLM-Parts Using Internal Structures in an Extended Design Space

Selective laser melting enables the production of cavities as well as internal structures and thus opens up new lightweight potentials for mechanically loaded components. This paper describes a design method for weight-optimization by applying internal structures in an extended design space compared to conventional models. Based on a pedal crank as a demonstrator, the objective is a maximum weight reduction with predefined stresses and a homogeneous stress distribution. The basic dimensioning of the design space is limited by assembly and application restrictions. By using computer aided design tools and topology optimization in an iterative procedure, a step wise confinement of the design space takes place. Concerning the same interfaces and functions as the conventional pedal crank, new model generations with the advantage of force flow adapted structures are built up. Using Finite Element Method, a continuous evaluation of the impact from a change of design towards the weight/stress ratio is performed. The created models are evaluated regarding their weight reduction in order to select the most efficient one. The final model has a large-volume geometry with the simultaneous integration of internal structures and cavities. A validation compared to the initial model as well as to a model with conventional design space and selective areas with internal structures quantifies the optimization result. Based on the acquired knowledge from this comparison, an estimation of the weight reduction potential concerning the design method is given.

Rene Bastian Lippert, Roland Lachmayer

Exploring the Impact of Shape Complexity on Build Time for Material Extrusion and Material Jetting

“Complexity for free” has often been claimed as one of the main opportunities of additive manufacturing (AM). Many examples have proven how, for highly complex and intricate geometries, additive manufacturing is the only available route. However, the implications that shape complexity has on part cost have not been thoroughly explored. This is especially relevant for series production where optimisation of building time can lead to significant cost savings. This study explores how shape complexity impacts build time in Material Extrusion (ME) and Material Jetting (MJ). A screening experiment is presented where the impact of ‘area’, ‘size’ and ‘increase in perimeter’ on build time is analysed. The results show that these three factors influence building time in ME, while only ‘size’ has a significant effect in MJ. Our results challenge the mainstream assumption that all AM processes provide “Complexity for free” while presenting preliminary indications on how to design efficient components for ME and MJ.

Patrick Pradel, Richard Bibb, Zicheng Zhu, James Moultrie

Novel Optimised Structural Aluminium Cross-Sections Towards 3D Printing

In the last decades, the deployment of aluminium and its alloys in engineering fields has been increased significantly, due to the material’s special features accompanied by supportive technological and industrial development such as the extrusion manufacturing method. However, the extent of aluminium structural applications in building activities is still rather limited, and barriers related to strength and stability issues prevent its wider use. In the context of topology optimisation, appropriate design in aluminium cross-sections can overcome inherent deficiencies, such as the material’s low elastic modulus.The current study investigates the application of structural topology optimisation to the design of aluminium beam and column cross-sections, through a combination of 2D and 3D approaches, with focus on post-processing and manufacturability. Ten unique cross-sectional profiles are proposed based on structural testing through Finite Element Analysis (FEA). Conclusions attempt to highlight the general characteristics of the optimised aluminium cross-sections as well as the benefits of the using extrusion and 3D printed manufacturing methods in order to realise these results.

Konstantinos Daniel Tsavdaridis, Jack Antony Hughes, Lukas Grekavicius, Evangelos Efthymiou

Manufacturing Process Chain

Frontmatter

Finite Element Modeling of Ceramic Deposition by LBM(SLM) Additive Manufacturing

The Marangoni effect caused by surface tension gradient is modeled. The resulting convection flow in the melt pool is demonstrated with different values of the Marangoni coefficient. Its influence on the temperature distribution, the shape of melt pool and thus the shape of solidified track is presented. The role of Marangoni convection on the stability of melt pool and the surface quality of the final track are also discussed.

Qiang Chen, Gildas Guillemot, Charles-André Gandin, Michel Bellet

Analysis of the Influence of Shielding and Carrier Gases on the DED Powder Deposition Efficiency for a New Deposition Nozzle Design Solution

In Direct Energy Deposition of metal parts the powder deposition efficiency is defined as the ratio of the nominal metal powder feed rate to the amount of powder directly involved in the component manufacture. Generally, the powder particles falling into the molten pool represent only a small portion of the total amount of metal particles nominally provided by the feeding system (less than 50% for most of the commercial systems), deteriorating the process performances in terms of powder waste, production time and increasing the production costs. For constant laser power, laser scan speed, and laser spot diameter, the deposition efficiency is primarily associated to the nozzle geometry, feeding system, and powder characteristics (e.g. particle size distribution, particle shape and size).The current work focuses on the analysis and characterization of the performances of a new generation of high efficiency nozzles with an enhanced design which adopts the inert Argon gas for a double purpose of Shielding and Carrier. The proposed analysis consists in designing and executing an experimental campaign structured as a full factorial Design of Experiments to map the impact of Shielding gas, Carrier, and Ti-6Al-4V powder mass flow on the deposition efficiency by monitoring the resulting geometry of the powder flow. A numerical CFD simulation is also carried out to verify the possibility in deducing a control logic to modulate the aforementioned process parameters on a custom feeding system demonstrator. The metal powder and the benefit of the approach are assessed with regards to an industrial use case.

Federico Mazzucato, Andrea Marchetti, Anna Valente

On-Demand Spare Parts for the Marine Industry with Directed Energy Deposition: Propeller Use Case

As additive manufacturing (AM) gains greater industrial exposure, there is a drive towards defining practical, high-value processes and products. Defining viable business cases is critical to ensure successful technology adoption. Given the marine industry’s slow uptake of AM, the potential of Wire Arc Additive Manufacturing (WAAM) to produce spare parts on demand is promising. It has the potential to reduce storage and transportation costs of spare parts by bringing production closer to end use locations.Using a propeller as a familiar marine industry object for a case study, the authors focused and explored four different design iterations to highlight the opportunity and design freedom offered through AM for development time and cost reductions by producing components on a needs basis in close proximity to where they are required. Designing, preparing for manufacture, manufacturing and post processing these components exposes a considerable portion of the process chain from a hardware and software perspectives.Current trend towards producing locally along with the intersection of Wire and Arc AM, the flexibility offered by software and hardware coupled with high cost pressures of the marine industry make this spare part on-demand concept particularly attractive.

Wei Ya, Kelvin Hamilton

Macroscopic Finite Element Thermal Modelling of Selective Laser Melting for IN718 Real Part Geometries

A 3D finite element model is developed to study heat exchange during the selective laser melting (SLM) process. The level set functions are used to track the interface between the constructed workpiece and non-melted powder, and interface between the gas domain and the successive powder bed layers In order to reach the simulation in macroscopic scale of real part geometries in a reasonable simulation time, the energy input and the formation of the additive deposit are simplified by considering them at the scale of an entire layer or fraction of each layer. The layer fractions are identified directly from a description (e.g. using G-code) of the global laser scan plan of the part construction. Each fraction is heated during a time interval corresponding to the exposure time to the laser beam, and then cooled down during a time interval equal to the scan time of the laser beam over the considered layer fraction. The global heat transfer through the part under additive construction and the powder material non-exposed to the laser beam is simulated. To reduce the computational cost, mesh-adaptation is adopted during the construction process. The proposed model is able to predict the temperature distribution and evolution in the constructed workpiece and non-melted powder during the SLM process at the macroscale, for parts made of complex geometry. Application is shown for a nickel based material (IN718), but the numerical model can be easily extended to other materials by using their data sets.

Yancheng Zhang, Gildas Guillemot, Charles-André Gandin, Michel Bellet

Additive Manufacturing of Piezoelectric 3-3 Composite Structures

Fused deposition of ceramics (FDC) is an additive manufacturing technique, were thermoplastic filaments are used for the fabrication of intricate structures that are difficult or impossible to produce with traditional techniques. This processing technique is utilized in the domestic and industrial appliance market. However, this simple and cheap manufacturing method is not widely used for the fabrication of traditional, high performance or functional ceramics. The objective of this contribution is to manufacture grid structures by means of FDC and subsequently investigate their electromechanical properties. Highly loaded ceramic - EVA (ethyl vinyl acetate) based filament is produced, as a feedstock for FDC. After successful printing and sintering of the grid structures, ferroelectric investigations were performed. Moreover, the grid structures are impregnated with a polymer resin resulting in a piezoelectric 3-3 composite that can be used as a hydrophone in under water noise detection.

Miriam Bach, Tutu Sebastian, Mark Melnykowycz, Tony Lusiola, D. Scharf, Frank Clemens

Additive Manufacturing of Semiconductor Silicon on Silicon Using Direct Laser Melting

Currently, Additive Manufacturing (AM) is limited to three classes of materials: ceramics, polymers and metals. Even within these classes, only a small number of materials can be processed by AM, either in a powder bed approach or in a direct energy deposition approach.We propose to extend AM to a new class of materials: semiconductors. We process silicon powders by direct laser melting (DLM), and we present the experimental setup in details.AM in general and more precisely DLM of brittle materials is challenging due to thermal stresses and cracks that build up during the process. In this contribution, we demonstrate the possibility of attaching Si pillars built by DLM to a monocrystalline wafer by increasing the pre-heating temperature of the substrate thanks to a hot plate.

Marie Le Dantec, Mustafa Abdulstaar, Matthias Leistner, Marc Leparoux, Patrik Hoffmann

Additive Manufacturing of Complex Ceramic Architectures

Additive manufacturing (AM) has the potential to revolutionise engineering because of its advantages in the product development phase. The revolution consists in the fact that components can be designed for their function and no longer for their manufacturability. This is already a reality for plastic and metallic components where new disruptive designs have been already produced at competitive costs.Following the AM hype, the ceramic industry is now thinking to adopt this technique for industrial components. Stereolithography (SLA) is nowadays used to fabricate complex structures in all the material classes.Two components designed for their function and produced by SLA are here presented along with their unique features. These components were developed for industrial applications in the automotive industry as well as for heat management (production, transfer and storage).

Oscar Santoliquido, Giovanni Bianchi, Alberto Ortona

Process Chain Integration

Frontmatter

An Advanced STEP-NC Platform for Additive Manufacturing

Additive manufacturing processes, initially only reserved for the manufacturing of prototypes, now allow the manufacturing of high-value functional products with a wide range of materials. These processes can considerably change the process chain organization and therefore are growing interest in both academics and industrials. Despite these developments in this field, many problems remain on current digital chain that uses old format such as STL and G-code. A solution to challenge this issue is the development of a new digital chain based on the STEP-NC standard (Standard for the Exchange of Product Model Data compliant Numerical Control). This paper intends to propose a methodology for the integration of additive manufacturing to a new STEP-NC model. In order to illustrate this model’s possibilities a STEP-NC Platform for Advanced Additive Manufacturing is presented. Finally the integration of this platform in a multi-process context and satisfying Industry 4.0 requirements is highlighted as perspective.

Renan Bonnard

Additive Manufacturing on 3D Surfaces

Additive manufacturing (AM) is currently at the heart of the digital manufacturing trends. It englobes more than 15 different technologies. They are relying on the fabrication of a part made from mainly 1 or sometimes 2 materials with only 1 fabrication technology. In this study, we are developing technologies and materials to create 3D components on substrates or on 3D objects to form new components with an increase of functionality and complexity. We are particularly focusing on the realization of hybrids millimeter scale components for application in watch and medical field.One example that we are presenting is the key technologies for the realization of a 3D printed prosthesis fitting the patient’s morphology (for example a knee or an ankle) integrating printed force sensors for monitoring the pressure distribution over the prosthesis surface. It shall give the opportunity to analyze the motion of the prosthesis to detect potential need of kinesiotherapy, minor surgery for prosthesis adjustment or entire replacement in case of failure. It shall lead to a pain reduction and a better recovery of the motor function after surgery. The mechanical part of the prosthesis has been fabricated by Fused Deposition Modelling (FDM), electrical connections and sensors by Aerosol Jet Printing. Two different sensing technologies are under evaluation: LC resonant circuits, to avoid the need of communication circuit inside the prosthesis and resistive sensors.Several others examples are presented over previously cited application fields.

Olivier Chandran, Sebastien Lani, Danick Briand, Barthelemy Dunan, Guy Voirin

Integrated Platform for Multi-resolution Additive Manufacturing

The integration of several printing techniques into a single platform requires to miniaturize each additive manufacturing tool.With this aim in mind, we have developed a compact toolkit for high-resolution additive manufacturing of polymers. This toolkit is made of two ultra-thin nozzles, a multimode optical fiber (MMF) for the curing unit, and a glass capillary for the drop-on-demand device (DOD). Polymerization of micrometric patterns is achieved by delivering laser light in a structured manner through a 5-cm long, 200 $$\upmu $$m-wide MMF. Along with this curing unit, the combined DOD device is made of a 10-cm long and 300-$$\upmu $$m wide glass capillary through which viscous materials are delivered via laser-actuation.We envision that our compact additive manufacturing toolkit could be integrated within other manufacturing platforms as an add-on tool, thus enabling multi-resolution processing.

Paul Delrot, Damien Loterie, Demetri Psaltis, Christophe Moser

Enhanced Toolpath Generation for Direct Metal Deposition by Using Distinctive CAD Data

The additive process of Direct Metal Deposition shows great potential for the production and repair of large-scale metallic components due to its high deposition rate and easy integration into CNC machining and robot systems. Conventional CAM software applies only geometric information to calculate the toolpath, requiring still high manual input for the production of complex parts. An enhanced approach is proposed that gathers relevant information from product development and hands it over as “distinctive” CAD data, which describes a set of features that is used by the CAM system for the generation of the toolpath. Zigzag patterns, contour patterns as well as the combination called “hybrid toolpath” are discussed and distinctive data is applied to build thin-walled elements. The experimental validation reveals a high surface quality and shape accuracy of demonstrator parts built with optimized process parameters and toolpath strategies.

Daniel Eisenbarth, Florian Wirth, Kevin Spieldiener, Konrad Wegener

Performance Simulation and Verification of Vat Photopolymerization Based, Additively Manufactured Injection Molding Inserts with Micro-Features

Injection molding soft tooling inserts manufactured additively with vat photopolymerization represent a valid technology for prototyping and pilot production of polymer parts. However, a significant drawback is the low heat conductivity of photopolymers influencing cycle time and part quality. In this research, the thermal performance of a $$20 \times 20 \times 2.7\,\mathrm{mm}^{3}$$ injection molding insert was simulated. A thermal camera was used to assess the quality and accuracy of the simulation. Both, simulation and measurements showed that the temperature cycle during injection molding becomes stationary within 3 to 5 cycles. After 2800 injection molding cycles, the experiment was stopped and the insert was still intact.

Michael Mischkot, Thomas Hofstätter, Ifigeneia Michailidou, Carlos Herrán Chavarri, Andreas Lunzer, Guido Tosello, David Bue Pedersen, Hans Nørgaard Hansen

Additive Repair Design Approach: Case Study of Transverse Loading of Aluminum Beams

The repair process for complex components is complicated and time consuming, and the traditional repair methods cannot handle these challenges. Therefore, introducing new solutions to repair parts is a necessity in the industrial world. Additive manufacturing is considered one of the modest manufacturing techniques. Using this technique in components repair is the state of the art in the industry of maintenance. This paper is based on previous work to develop an additive repair design approach, with focus on the Selective Laser Melting technique. A bending load case on beams made of two metals (cast part and sintered part) is discussed, and the induced stresses and deflections are investigated for various building directions and interface planes geometries. The used metals of the cast parts are Al-6082 and Al-7075 alloys, and the used powder to build-over with the Selective Laser Melting machine is AlSi10Mg. The analysis carried out by means of a finite element numerical model to estimate bending loading and the induced flexural stresses. Experimental work is implemented, and all analytical and experimental results are discussed and compared. This work aims to develop scientific basics for parts repair using additive manufacturing technologies.

Zghair Yousif, Lachmayer Roland

Quality Assurance

Frontmatter

Controlled Porosity Structures in Aluminum and Titanium Alloys by Selective Laser Melting

Stochastic and non-stochastic porous structures, are used in a variety of applications such as biomedical implants, heat exchangers mass and gas separation, water purification, energy conversion and storage due to their interesting combinations of physical and mechanical properties, such as high stiffness in conjunction with very low specific weight or high gas permeability combined with high thermal conductivity. Among the technologies for the production of these porous structures, the additive manufacturing (AM) processes, such as the powder bed based selective laser melting (SLM), are of particular interest. In order to obtain this kind of structures with SLM, it is important to know the relationship between process parameters and material employed. A series of experiments were carried out to analyze the influence of the main SLM process parameters on the width and continuity of manufacture of non-stochastic porous structures and to manufacture stochastic porous structures through the scanning strategy.

Flaviana Calignano, Giulio Cattano, Luca Iuliano, Diego Manfredi

Development and Optimization of an Innovative Double Chamber Nozzle for Highly Efficient DMD

Injection nozzles design in Direct Metal Deposition (DMD) critically affects the performances of the process in terms of powder deposition efficiency. In fact, the fluid-dynamic behavior of the powder particles falling into the molten pool strongly depends both on the internal geometry of the deposition nozzle and on the geometry of the nozzle outlet. This efficiency, for commercial nozzles, is usually under 50%, thus implying an unaffordable powder waste. SUPSI implemented an innovative nozzle concept, designed as a coaxial double chamber that enables the concurrent flow of the powder-carrier gas mixture and of the shielding gas. In this configuration, the shielding gas allows to reduce the spread of the blown powder particles, constraining the carrier gas flow and limiting its divergence. Such innovative design also enables the integration of various modules - different in shape - to be nested to the bottom end of the nozzle, in order to adapt its outlet geometry. The main objective of the design is to influence the shape of the powder flux ejected from the nozzle outlet by exploiting the shielding gas while limiting oxidation processes. In order to assess the influence of the feeding parameters on the flow geometry, different concepts and shapes of nozzle outlet have been tested and investigated against the deposition efficiency, both numerically and experimentally. The testing campaign relies upon an image analysis performed on a demonstration setup where the powder flux is tracked using a high-speed camera. Experimental results demonstrate improved deposition efficiency through a significant (up to 18%) spread reduction.

Andrea Marchetti, Federico Mazzucato, Anna Valente

In Situ and Real-Time Monitoring of Powder-Bed AM by Combining Acoustic Emission and Artificial Intelligence

At present, the quality control in additive manufacturing is diligently based on temperature of the process zone or high resolution imaging. Hence, various sensors such as pyrometers, photo diodes and matrix CCD detectors are used. The discrepancies in temperature measurements and the real temperature distribution inside the powder medium reduce the reliability of this method. The high resolution imaging monitors the quality post factum, after a part is manufactured. So far, no methods are known to monitor the quality of additive manufacturing in situ and in real-time. To achieve the goal of accurate real-time quality control, we propose an approach that relies on acoustic emission, which is further analyzed within artificial intelligence framework. We show that the additive manufacturing process has a number of unique acoustic signatures that can be detected, extracted and interpreted in terms of quality.In this contribution, the processing parameters for the selective laser melting of a 316L steel were modified to create a specimen consisting of sections with three quality levels. During the process, the acoustic emission data were acquired and then processed prior validation. The confidence level achieved in the classification is 79–84% that demonstrates the applicability of this approach for in situ and real-time quality monitoring in additive manufacturing. Finally, the proposed method is very flexible in terms of realization and can be integrated in any additive manufacturing machine.

K. Wasmer, C. Kenel, C. Leinenbach, S. A. Shevchik

Quality Related Effects of the Preheating Temperature on Laser Melted High Carbon Content Steels

Additive manufacturing technology selective laser melting (SLM) is an emergent technology allowing generation of complex metal parts layer by layer. During the past years the range of available and processable materials for SLM has been widely extended. However, there is a still a lack of SLM processable high carbon content steels. In the fields of machine elements, especially in advanced cutting tools a large potential of laser melting is identified regarding function integration, topology optimisation and implementation of bionic concepts. In these fields of application high carbon content steels are frequently used. The M2 High Speed Steel (HSS) is a high carbon content steel that belongs to the group of tool steels. As other high carbon content steels, M2 HSS tends to a high susceptibility to cracking. Therefore, the strongly pronounced temperature gradients occurring during the laser melting process lead to part deformation and crack formation. Heating of the SLM baseplate represents a promising approach to reduce temperature gradients and internal stresses. In the present study the quality related effects of reduced temperature gradients on SLM parts were evaluated using a baseplate heating system. Optimized process parameters allowed a stable processing of M2 HSS leading to a relative part density of 99%. Residual stresses decreased with increasing baseplate temperature by trend.

Livia Zumofen, Christian Beck, Andreas Kirchheim, Hans-Jörg Dennig

Business Cases

Frontmatter

Additive Manufacturing in Automotive Spare Parts Supply Chains – A Conceptual Scenario Analysis of Possible Effects

The automotive sector has been very progressive to experiment with additive manufacturing (AM) and early started to adopt it for rapid prototyping. Nonetheless, until the present day the integration of AM in the production of car parts, such as spare parts, proved to be difficult. Spare parts are generally characterized by demand uncertainty. Therefore they require high inventory levels to guarantee short lead times and high service levels for maintenance, repair and overhaul firms. The deployment of AM technologies in spare parts production has the potential to overcome these supply chain-related challenges. This research conceptually investigates the effects of AM in the automotive spare parts business for different supply chain scenarios. As a main contribution of this paper, four scenarios are developed and systematically analyzed regarding their suitability and implications for an AM implementation in the automotive spare parts supply chain.The results suggest that centralized AM settings generally seem to be beneficial in terms of capacity utilization. Additionally, centralized production appears favorable when short lead-times and minimal downtime costs do not depict major priorities for OEMs. A hybrid scenario offers a high level of flexibility for OEMs to adjust to local demand patterns. In this case, AM is implemented in regional distribution centers. A decentralized production eventually signifies that spare parts are fabricated at repair shops of car dealers. This scenario implies high investment costs paired with considerable uncertainty concerning a sufficient capacity utilization. In contrast to that, a decentralized AM deployment seems to offer the highest potential for a customization of parts and timely deliveries. The outsourcing of AM to an external provider was considered as a fourth scenario. By transferring the production of spare parts to another company, the roles and responsibilities of the OEM shift considerably towards the management of the external production network.

Timo Eggenberger, Katrin Oettmeier, Erik Hofmann

Selection of High-Variety Components for Selective Laser Sintering: An Industrial Case Study

The tool-less manufacturing of lot-size one components by means of Selective Laser Sintering (SLS) can enable companies to enhance their manufacturing flexibility. Especially in the case of high variety manufacturing, companies adopting SLS can potentially reduce order lead times and manufacturing costs. This paper introduces a methodology suitable to assess different manufacturing strategies for high variety component families and leverages a case study from a global manufacturer of packaging machines to show the implications of AM adoption. The case study quantifies the reduction of both manufacturing costs and order lead time in the case of a component with a large amount of possible variants. In the case study, two possible operational strategies for the manufacturing of such with SLS are identified. In a first strategy, SLS adoption can be focused on optimising the specific volume-unit operating cost for producing all component variants, and thus obtain a total manufacturing cost reduction of up to $$17\%$$ compared to the current conventional set-up. As a second strategy, SLS can be employed for the improvement of service quality. By focusing on the reduction of order lead times over the whole component family, this can be reduced by $$48\%$$ compared the incumbent set-up. The trade-off among the two strategies is explained with the introduced concept of aggregated lot size.

Filippo Fontana, Enrico Marinelli, Mirko Meboldt

Process Setup for Manufacturing of a Pump Impeller by Selective Laser Melting

In the water industry a strong market demand exists for small, high pressure pump systems. However, the casting of impellers for such small pumps in the required quality is difficult or impossible because of their low wall thickness and their unfavorable ratio of impeller diameter to channel height. Selective Laser Melting (SLM), one of the primary metal additive manufacturing technologies, is well-suited to be used for such impellers as the full potential of SLM can be achieved best with such small, complex parts. In this work, we describe the SLM manufacturing of an already existing impeller design at the lower limit of castability. This is motivated by the fact that if this geometry can successfully be SLM-manufactured, there should be no major obstacle for a scale-down to smaller sizes (up to a certain limit), but this SLM-manufactured existing impeller design can be tested on an already existing pump prototype and directly compared to the cast counterpart. The effort described here therefore was to find the optimal orientation of build direction as well as to design suitable support structures. This was done in a heuristic and iterative process with concurrent manufacturing trials. The final SLM-processed prototype impeller fulfilled all geometrical requirements and will be tested in the existing prototype pump in the near future. While the full potential of SLM manufacturing is reached by fundamental part redesigns, the process setup (build orientation optimization and support structure design) for a pre-existing part geometry as performed here is of large practical importance in the service and reconditioning market in the water industry and beyond.

Marc Huber, Jonas Ess, Martin Hartmann, Andreas Würms, Robin Rettberg, Thomas Kränzler, Kaspar Löffel

Hybrid Integration; Case Study with Sun Sensor for Cube Satellites

An innovative electronic system assembly approach, i.e. hybrid integration combining printed electronic components with/on Flexible Circuit Boards (FCBs) equipped with conventional Surface-Mounted components (SMDs) was implemented in order to realize a sun sensor. Technology-wise, a clear benefit was achieved from the combination of the advantages of both large area printed electronics based on printing processes (e.g. flexibility, light weight, cost effectiveness, etc.) and SMDs with high-end functionalities and robustness. Printed electronics uses additive deposition methods similar to conventional press printing – such as inkjet printing, screen printing, gravure printing, etc. – applying a stack of layers on flexible substrates. By depositing electrically active layers (e.g. conductors, semiconductors and insulators), basic electronic building blocks such as resistors, capacitors, thin film transistors, etc. can be made. On the other hand, FCBs are commonly used where flexibility, space savings, or production constraints limit the use of rigid PCBs. Typically, conventional photolithography and standard SMD integration are combined to realize FCBs. A hybrid sun sensor was demonstrated within the Swiss Space Office funded project hybSat (2014–2016), by HIGHTEC and CSEM. The developed sun sensor comprises inkjet printed organic photodiodes (OPDs), printed resistors, printed capacitors, high-end SMDs and operational amplifiers on a FCB. The fabricated flexible sun sensor is suitable for cube satellites since it is extremely thin, light weight and cost effective. The exampled hybrid technology offers new possibilities to the system designers (towards smart PCBs), material providers (printable functional inks) and extends the current range of products (e.g. wearable, flexible electronics).

Nenad Marjanović, Jérémy Disser, Frédéric Zanella, Jürg Schleuniger, Alessandro Mustaccio, Rolando Ferrini, Marc Schnieper, Eyad Assaf

Temperature Monitoring of an SLM Part with Embedded Sensor

Selective Laser Melting (SLM) offers various new possibilities for the production of metallic components with respect to their design and complexity. The manufacturing process in layers enables accessibility and the possibility for manipulation and modification to each section of the part’s geometry. Hence the integration of sensors into the component during its manufacturing process is feasible. This approach is of enormous interest for various industrial sectors since sensor integration is a key enabler of industry 4.0. A sensor that has been embedded into a part during SLM production process facilitates not only a monitoring of this metallic part during its use phase in general but a monitoring of a spatially well-defined location within this part. The work presented in this paper specifically targets the integration of a temperature sensor into an SLM part. The sensor is embedded in a section of the part which is not accessible after the production process any more. Different concepts and strategies of sensor positioning and integration are investigated, focussing on an evaluation of the operating ability of these sensors after their embedding with the SLM process. Thus different methods to attach the sensor to the metallic part are presented. Furthermore the paper reports on the analysis of the influence of geometrical design features on the response behaviour and accuracy of the temperature measurement compared to conventionally conducted reference measurements.

Philipp Stoll, Bastian Leutenecker-Twelsiek, Adriaan Spierings, Christoph Klahn, Konrad Wegener

Unique Customer Benefits

Frontmatter

Integration of Fiber-Reinforced Polymers in a Life Cycle Assessment of Injection Molding Process Chains with Additive Manufacturing

Additive manufacturing technologies applied to injection molding process chain have acquired an increasingly important role in the context of tool inserts production, especially by vat polymerization. Despite the decreased lifetime during their use in the injection molding process, the inserts come with improvements in terms of production time, costs, flexibility, as well as potentially improved environmental performance as compared to conventional materials in a life cycle perspective.This contribution supports the development of additively manufactured injection molding inserts with the use of fiber-reinforced vat polymerization technology. The life cycle assessment of the prototyping process chain for rapid prototyping with high flexibility provides a base for industrial applications in injection molding.

Thomas Hofstätter, Niki Bey, Michael Mischkot, Philippe M. Stotz, David B. Pedersen, Guido Tosello, Hans N. Hansen

Advantages in Additive Manufacturing for a Medium Format Metrology Camera

The following paper describes the possibilities of additive manufacturing technology for small-series production of specialised measurement solutions for research and industry by means of the upgrade of a conventional medium format system camera for the photogrammetric solution ALPA 12 add|metric. Particular attention is paid to the description of the design process as well as to the comparison with the experience from conventionally produced predecessors. The resulting camera yields much better photogrammetric accuracy than previous models.

Ralph Rosenbauer, Filippo Fontana, Heidi Hastedt, Thomas Luhmann, David Ochsner, Dirk Rieke-Zapp, Robin Rofallski

Patient Specific Implants from a 3D Printer – An Innovative Manufacturing Process for Custom PEEK Implants in Cranio-Maxillofacial Surgery

Additive Manufacturing (AM) is rapidly gaining acceptance in healthcare. Computer-assisted planning of surgical procedures, fabrication of anatomical 3D models, and patient specific implants are well-established processes at the author’s department. Surgical planning and medical 3D printing are firmly integrated technologies in the clinical course of treatment at the University Hospital Basel.Polyether-ether-ketone (PEEK) has been observed, mainly in Cranio-maxillofacial surgery, Spine-, Neuro- and Hand surgery, as a reliable alternative to materials such as titanium for the production of patient-specific implants. The manufacture of medical PEEK implants has been limited mainly to subtractive manufacturing processes such as Computerized Numerical Control (CNC) milling. This production method leads to significant limitations as opposed to AM. 3D printing of PEEK allows construction of almost any complex geometry such as hollow implant bodies or implants in lightweight bio-mimicking design which cannot be manufactured using other technologies.Recently, it has become possible to process PEEK in the Fused Filament Fabrication (FFF) method, which opens up a number of innovative options for medical-surgical use. With the latest PEEK 3D printers which are now available, inexpensive and compact production intervals for custom implants are conceivable.Although the medical certification of this workflow is a challenge, the fabrication of patient-specific implants in the operating room in the near future could be possible. In this article, the possibilities and limitations of the production of patient-specific implants from PEEK by 3D printing methods are described, as well as the recent experiences in the field of 3D printing of PEEK implants.

Florian M. Thieringer, Neha Sharma, Azagen Mootien, Ralf Schumacher, Philipp Honigmann

Teaching and Training

Frontmatter

Work-Process Orientated and Competence Based Professional Training for Skilled Workers in Laser Additive Manufacturing

In production technology innovative machining methods such as additive manufacturing are changing the work-fields and work-processes of skilled workers and thus their professional training needs to be altered. Laser additive manufacturing currently experiences introduction in serial applications in aircraft or medical industry. In this context parts of very high quality are mandatory and to achieve this it is necessary to set up processing strategies and parameters. Nevertheless a high complexity in the relationship between parameter setting and process outcome is characteristic for additive technology. Due to this fact comprehensive experience and know-how, which is yet few to be found, is demanded from machine operators. Surveys conducted in the industry show that consequently changed qualification requirements upon skilled workers can already be defined in detail for additive manufacturing. Therefore a corresponding professional training was developed which is work-process orientated and focuses on the specialized competencies for professional decision-making and responsibilities. In this context the training approach explicitly does not concentrate only on simple machine or process instruction for additive manufacturing. Rather the methodical didactic concept bases on a blended learning approach which includes the combination of multiple learning locations as well as project based learning in a professional context. Here technical contents are connected to a sequence of tasks in form of modules each with a reference to the professional practice. In this way also the shift towards close to engineering tasks and methods for continuous self-learning are addressed. Finally learning systems regarding the infrastructure and capacities that are required for a learning environment are assessed. In conclusion additive manufacturing and its digital process chain represents a typical example for changing work settings for trained professionals in the context of increasingly interconnected industrial processes. Therefore the developed professional training can perspectively also be transferred to further processes in Industry 4.0.

Christian Daniel, Bianca Schmitt, Maren Petersen

Why Education and Training in the Field of Additive Manufacturing is a Necessity

The Right Way to Teach Students and Professionals

Complexity for free? This is one of the big advantages of additive manufacturing. But what does that mean in reality? In the case of additive manufacturing freedom in general is also a new restriction. For this reason, it needs appropriate education and further training to recognize the new possibilities and also the limits of the additive manufacturing.At the Centre for Product and Process Development (ZPP) of the Zurich University of Applied Sciences ZHAW, the additive production has been part of the training program for several years both in the teaching of mechanical engineering for students and in the continuing education of professionals.In this paper, the experiences with the new education and training modules “Additive Manufacturing” will be presented. The program includes theory and practice on the machines (AM Laboratory) including the economic and ecological aspects. In particular, a special semester-accompanying project work is carried out, in which the students learn the constructive and technological peculiarities of the product development up to the additive manufacturing process, after-treatment and quality control of the components. The education in bachelor degree relies on the problem-based learning concept, where the student learns about additive manufacturing through the experience of solving an open-ended problem.

Andreas Kirchheim, Hans-Jörg Dennig, Livia Zumofen

The Experience Transfer Model for New Technologies - Application on Design for Additive Manufacturing

To apply new technologies in industry, it requires knowledge about the specific technology. Since a new technology, such as Additive Manufacturing (AM), enters the industry slow, the knowledge transfer must be supported. AM is capable to produce end user parts by serial production. To implement this new technology into industry an Experience Transfer Model (ETM) supports the transfer of knowledge from the academic environment to professional engineers in industry. This paper presents the concept of the ETM, which transfer experience knowledge about identification expertise and design expertise in three steps: Input of theory, implementation of the theoretical knowledge and reflection of the approach. The validation of the ETM with Swiss SME showed a successful implementation of experience knowledge.

Bastian Leutenecker-Twelsiek, Julian Ferchow, Christoph Klahn, Mirko Meboldt

Decision-Making in Additive Manufacturing – Survey on AM Experience and Expertise of Designers

Technological advancements in additive manufacturing (AM) has enabled the usage of AM for end-use parts more than ever before. Deciding whether or not to apply AM for final parts and knowing how to design for AM is fundamental in the design phase, which is why Design for AM (DfAM) methods are currently being elaborated.This paper analyzes the current experiences and knowing of designers concerning additive manufacturing technologies and, hence, provides a foundation for the development of DfAM methods. This study presents a survey with designers asking them about their experience with and knowledge on additive manufacturing technologies. The study reveals the disparate experience with AM, reaching from highly skilled AM experts to designers who have never held an AM part in the own hands before. While a good basic knowledge concerning AM seems present, detailed knowledge is lacking, especially with regard to general restrictions and the differentiation of the AM technologies. Interest and intentions in using AM for final part production is high, combined with a slight skepticism. For further implementations of AM in final part production, DfAM methods are meaningful and desired by designers, e.g. for decision-making processes for direct AM. These DfAM approaches should be focused on AM specific requirements and characteristics while covering the proven discrepancies in the experiences and the skills of designers concerning AM.

Johanna Spallek, Dieter Krause

Backmatter

Weitere Informationen

Premium Partner

    Marktübersichten

    Die im Laufe eines Jahres in der „adhäsion“ veröffentlichten Marktübersichten helfen Anwendern verschiedenster Branchen, sich einen gezielten Überblick über Lieferantenangebote zu verschaffen. 

    Bildnachweise