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Lattice structure tensile specimen manufactured with laser melting (LM) process out of the material H13. Bildinformationen anzeigen
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Quality control during a Laser Sinter (LS) build job by a researcher of the DMRC Bildinformationen anzeigen
Fused Deposition Modeling (FDM) process during the manufacture of an Ultem 9085 part Bildinformationen anzeigen
Additive manufactured reaction wheel bracket for telecomunication satellites Bildinformationen anzeigen
Employees of the DMRC working with the "freeformer" from Arburg Bildinformationen anzeigen
Powder particles are used as raw material for laser-based additive manufacturing Bildinformationen anzeigen

For more information, please go to the DMRC Download section: https://dmrc.uni-paderborn.de/content/downloads/

Lattice structure tensile specimen manufactured with laser melting (LM) process out of the material H13.

Quality control during a Laser Sinter (LS) build job by a researcher of the DMRC

Fused Deposition Modeling (FDM) process during the manufacture of an Ultem 9085 part

Additive manufactured reaction wheel bracket for telecomunication satellites

Employees of the DMRC working with the "freeformer" from Arburg

Powder particles are used as raw material for laser-based additive manufacturing

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2019


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Priorisierung von Anforderungen für die Entwicklung mechatronischer Systeme

I. Gräßler, H. Thiele, C. Oleff, P. Scholle, V. Schulze, in: International Conference on Engineering Design (ICED19), 2019, pp. 1265-1274

In diesem Beitrag wird ein Ansatz vorgestellt, welcher die Bewertung des Risikos von Anforderungsänderungen in der Entwicklung mechatronischer Systeme ermöglicht. Ausgehend von einer Anforderungsliste werden die Wechselwirkungen in einer Requirements Structure Matrix (RSM) teilautomatisch erfasst. Parallel werden Anforderungen in Bezug auf ihren Ursprung („Einflussbereich“) kategorisiert und darauf aufbauend priorisiert. Diese Priorisierung basiert auf dem Veränderungsrisiko und wird durch die drei Kriterien „Dynamik“, „Unsicherheit der Wissensbasis“ und „Relevanz für den Entwicklungsprozess“ charakterisiert. Das Vorgehen wird anhand strukturierter Interviews mit Projektleitern und Entwicklern und der Fallstudie eines Pedelecs als mechatronischem System validiert. Durch die Anwendung der Methode können disziplinübergreifende Abhängigkeiten von Anforderungen zur Reduktion von Iterationen in der Entwicklung mechatronischer Systeme – wie dem Pedelec – berücksichtigt werden.


    Strukturoptimierung durch den Einsatz des Laser-Strahlschmelzprozesses zur realitätsnäheren Erfassung von Fahrzeug-Lastdaten

    J. Brüggemann, L. Risse, S. Woodcock, T. Duffe, J. Neumann, J. Vidner, G. Kullmer, H. Richard, in: DVM-Bericht 404, Arbeitskreis: Additiv gefertigte Bauteile und Strukturen, Deutscher Verband für Materialforschung und -prüfung e.V., 2019, pp. 69-82


    Rissausbreitungsmechanismen in FDM-Verstärkungsstrukturen unter dynamischer Beanspruchung

    E. Moritzer, A. Hirsch, S. Paulus, Springer Vieweg, 2019, pp. 185-198

    Das Fused Deposition Modeling (FDM) ist ein etabliertes additives Fertigungsverfahren zur Her-stellung von thermoplastischen Kunststoffbauteilen. In dem vorliegenden Beitrag sind FDM-Verstärkungsstrukturen aus dem Material Ultem 9085 dynamischen Langzeituntersuchungen un-terzogen worden. Dabei wurde die innere Struktur der Probekörper über eine Parametervariation verändert, sodass anschließend die signifikanten Einflussfaktoren auf die Langzeitfestigkeit un-ter dynamischer Belastung identifiziert und analysiert werden konnten. Mit dieser Vorgehens-weise sollte gleichzeitig eine Optimierung der FDM-Verstärkungsstrukturen hinsichtlich der dy-namischen Langzeiteigenschaften bei Biege- und Druckbelastungen vorgenommen werden. Des Weiteren sind anhand der Probekörper die auftretenden Bruch- und Rissausbreitungsmechanis-men analysiert worden. Anhand der ermittelten Wöhlerkurven kann die Lebensdauer unter dy-namischer Belastung abgeschätzt werden. Außerdem zeigen die Untersuchungen, dass Fehlstel-len durch eine hohe Strangbreite und Überfüllungen im Bauteil für Schwachstellen in den FDM-Verstärkungsstrukturen sorgen, an denen Risse bei Druckbelastung entstanden sind und sich dadurch schneller ausbreiten konnten.


      Einsatz ingenieurmäßiger Methoden zur Lösung chirurgischer Herausforderungen

      L. Risse, S. Woodcock, G. Kullmer, B. Schramm, H. Richard, 2019, pp. 35-56


      Schall mittels Pulver dämpfen

      T. Künneke, D. Zimmer, konstruktionspraxis (2019), 6, pp. 24-26


      Einflussfaktoren auf Bauteilgüte lasergeschmolzener Strukturen

      J. Brüggemann, L. Risse, H. Richard, G. Kullmer, in: DVM - Bericht 251, Arbeitskreis: Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen, Deutscher Verband für Materialforschung und -prüfung e.V., 2019, pp. 207-218


      Investigation of the Processability of Different PEEK Materials in the FDM Process with Regard to the Weld Seam Strength

      E. Moritzer, J. Wächter, M. Elsner, in: 30th Annual International Solid Freeform Fabrication Symposium, 2019, pp. 856-863

      Due to the great popularity of the Fused Deposition Modeling (FDM) process, the material market is growing. In particular, processing of high-temperature materials such as PEEK is demanding. The aim of the investigations is to test different PEEK materials regarding their processability in the FDM process. An unreinforced PEEK, a thermally conductive PEEK as well as a carbon fiber reinforced PEEK are investigated. The processability is assessed with the help of the weld seam strength. The assessment of the weld seam strength is carried out by building tests. For this purpose, a special method developed at the DMRC is used. In addition, a welding width factor between the strands deposited on each other is calculated and compared. Finally, a welding factor is determined to enable the comparison between the different materials. With this procedure, the influence of varying nozzle and build chamber temperatures on the achievable weld seam strengths is evaluated.


        Process Parameter Optimization to Improve the Mechanical Properties of Arburg Plastic Freeformed Components

        E. Moritzer, A. Hirsch, F. Hecker, in: 30th Annual International Solid Freeform Fabrication Symposium, 2019, pp. 705-714

        The Arburg Plastic Freeforming (APF) is an additive manufacturing process that allows three-dimensional, thermoplastic components to be produced in layer by layer. The components are generated by depositing fine, molten plastic droplets. One of the main advantages of the APF process is the open machine control. Thus, the process parameters can be adapted and optimized for the individual applications. The optimization is carried out on the basis of a variation of the process parameters using a statistical design of experiments. Relevant process parameters are the layer thickness, the form factor, the raster and delta angle as well as the overlap between the contour and the filling of a layer. In addition, the nozzle and build chamber temperatures are varied. Using this procedure, the effects of the influencing parameters on the mechanical properties and the interactions between the influencing parameters are analyzed and converted into mathematical models. On the basis of the results and the models, guidelines will be developed to assist the user of APF technology in the systematic process configuration for their own applications. The material used is ABS, one of the most frequently used amorphous thermoplastics in additive manufacturing. The mechanical properties are determined on the basis of tensile tests and the characteristic values tensile strength, elongation at break and Young's modulus. The results should show the performance of the APF technology in regard to the mechanical properties.


          A Method to Evaluate the Process-Specific Warpage for Different Polymers in the FDM Process

          V. Schoeppner, C. Schumacher, C. Fels, in: AIP Conference Proceedings, AIP Publishing, 2019

          Additive manufacturing processes, like the Fused Deposition Modeling (FDM) process, do not need product-specific tools and create parts directly from the CAD data. In the FDM process, the semi-finished product, a wire of a thermoplastic polymer, is melted and forced through a nozzle. The continuous positioning of this nozzle allows the polymer to weld together strand by strand and layer by layer to produce a component. Because no mold is used in the FDM process, no holding pressure can be generated as in injection molding processes, in which the holding pressure is used to minimize the shrinkage and warpage of the part. In the FDM process, the part is generated in an ambient pressure environment. Each strand cools down and shrinks separately. This causes residual stresses in the part that can lead to major warpage and a complete stoppage of the process. This is the main reason why the material selection in the FDM process is restricted in comparison to conventional polymer processing technologies. In this paper, the warpage of different polymers is quantified as a criterion for evaluating the processability of polymers in the FDM process. Due to the process principle, the part properties in the FDM process are mainly influenced by the machine quality and the data processing, so that it is difficult to test a material for FDM independently of the machine and the data processing. Considering these influences, a custom-built specimen is created to test and quantify the warpage of different types of blended and reinforced polyamide 6. Considering the experimentally investigated warpage, the materials can be evaluated and the warpage can be related to the shrinkage investigated in pvT measurements. This procedure allows the machine- and process-independent rating of the processability in terms of warpage for different materials. Alongside other criteria, this is a necessary step to develop new materials with good processability in the FDM process.


            Bewertung von verschieden gearteten Gitterstrukturen in Bezug auf ihre Einsatzfähigkeit in Bandscheibenimplantaten

            S. Woodcock, L. Risse, G. Kullmer, H. Richard, in: DVM - Bericht 404, Arbeitskreis: Additiv gefertigte Bauteile und Strukturen, Deutscher Verband für Materialforschung und -prüfung e.V., 2019, pp. 151-162


            Methodik zur Qualifizierung des Lasersinter Prozesses für die Serienfertigung

            S.H. Klippstein, H. Schmid, in: Proceedings of the 16th Rapid.Tech Conference, 2019

            Zuverlässige, wiederholbare Bauteileigenschaften sind unabdingbar um das Herstellungsverfahren Polymer Lasersintern im industriellen Prozess-Portfolio vieler Firmen aufnehmen zu können. Einige Unternehmen und Institute haben sich daher in jüngster Zeit mit dem Thema der reproduzierbaren Bauteileigenschaften beschäftigt. Mit der hier vorgestellten und angewandten Methodik wird nicht nur der Prozessablauf vom Bauteil bis zu Nachbearbeitung betrachtet, sondern auch die Maschinenperformance in einem Ringversuch und über einen längeren Zeitraum geprüft. Rückgrat dieser Untersuchung bildet hierbei der aus der Six Sigma Lehre stammende DMAIC (Define - Measure - Analyse - Improve - Control) Verbesserungszyklus. Hierfür wird ein Standard-Prozess definiert. Diesem folgend werden die für die Industrie oder den Anwender interessanten Messungen aufgenommen und analysiert. Anschließend wird der Prozess sowie die Messmethodik optimiert und auch Kontrollmethoden definiert. Für die Anwendung der entwickelten Methodik wird exemplarisch der Maschinentyp EOS P396 mit PA2200 untersucht. Daten für die Bestimmung der Mechanik, der Optik und der Haptik sowie für die Dimensionen und die Bauteildichte werden als Qualitätskriterium aufgenommen und über einen längeren Zeitraum analysiert. Weiteres Ziel ist es, den Messaufwand zu reduzieren und die Qualitätssicherung im Serienbtrieb zu gewährleisten.


              Plastic droplet welding: bond strength between plastic freeforming structures and continuous fiber-reinforced thermoplastic composites

              E. Moritzer, A. Hirsch, H. Heim, C. Cherif, W. Truemper, Welding in the World (2019), 63, pp. 867-873

              Plastic freeforming (PF) is an additive-manufacturing process for producing three-dimensional plastic parts based on 3D CAD data by applying plastic droplets in layers. This process is used to produce customer-specific and complex geometries (prototypes and small series) on organic sheets. A comparable serial process is the injection of a second component onto organic sheets by injection molding. A sufficient bond between the PF structure and the organic sheets is of particular importance for each application. If this is not guaranteed, the composite system cannot withstand the mechanical load and fails. The force exerted on the system can no longer be transmitted between the PF structure and the organic sheet. The organic sheet is made of glass fiber-reinforced polypropylene (PP). The connection between the organic sheet and the PF structure is achieved by welding the molten polymer droplets and the surface of the organic sheet. The PF structures are made of PP to ensure sufficient compatibility with regard to the weldability of the components. The processing of PP in the PF process is a challenge because PP is a semicrystalline material. The shrinkage of semi-crystalline materials is significantly higher compared to amorphous materials. Due to the layered structure of the components, the shrinkage of the individual layers results in undesired warpage. The adhesive strength between the organic sheet and the PF structure is investigated by determining the bending strength in the 3-point bending test. The investigations include an optimization of the process parameters to maximize the adhesive strength. The experimental investigations show that an increase of the nozzle and build chamber temperature leads to a higher adhesive strength. In further investigations, the temperature of the nozzle shows no significant influence on the surface temperature despite the expected heat radiation. The surface temperature is almost only dependent on the temperature of the build chamber.


                Development and Modeling of Design and Process Guidelines for FDM Structures for the Partial Reinforcement of Hybrid Structures

                E. Moritzer, A. Hirsch, F. Buerenhaus, in: AIP Conference Proceedings, AIP Publishing, 2019

                The mechanical properties of thin-walled plastic components are limited. One approach to improve the strength or stiffness of these components is to reinforce the thin-walled areas with an individually adapted Fused Deposition Modeling structure. Fused Deposition Modeling (FDM) is one of the most commonly used additive manufacturing processes. This process is characterized by the deposition of a fused, thermoplastic filament. Depending on the form of the reinforcement structure, the resulting hybrid structure should show higher strength or stiffness. The objective of the project is to determine constructive design and process guidelines for FDM structures. The FDM structure is to be used as a partial reinforcement for lightweight components and be adapted to the respective load conditions. Because of the lightweight application, the FDM structure should also have the lowest possible weight. The optimization of the FDM parts for different load cases is realized by adapting the design parameters. These parameters influence the layer generation and therefore also the inner structure of the FDM parts. In preliminary studies, the manufacturing restrictions of the FDM process are defined. The specimens are manufactured based on the Design of Experiments. To determine the static strength properties, different tests (tensile, compression, flexural, torsion and impact) are carried out. The investigations show that the filling strategy affects the mechanical properties. As a result of the investigations, design and process guidelines for the FDM structures are established according to the load conditions.


                  Guidelines for post processing oriented design of additive manufactured parts for use in topology optimization

                  S. Lammers, J. Tominski, D. Zimmer, in: II International Conference on Simulation for Additive Manufacturing Sim-AM 2019 11-13 September, 2019, 2019, pp. 174-185

                  According to ISO / ASTM 52900, additive manufacturing (AM) is defined as "the process of joining materials to make parts from 3D model data, usually layer upon layer, as opposed to conventional manufacturing including subtractive manufacturing technologies and formative manufacturing methodologies” [1]. This results in significant advantages over conventional manufacturing methodologies, such as the production of topologically optimized, complex structures, lower material consumption or shorter product development cycles. In order to be able to use these advantages, the possibilities and restrictions of the processes must be known. In particular, selective laser beam melting (SLM), in which a powdery metallic starting material is melted by means of a laser, requires a sound understanding of the process. For this purpose, design guidelines have been presented in various scientific papers. These design guidelines help to design a component in such a way that it can be manufactured successfully using additive manufacturing. These so-called “AMsuitable design guidelines” can be found among others at Adam, Kranz and Thomas [2,3,4,5]. In contrast to established manufacturing processes, the post-processing of additive components is divided into two steps. First, the AM immanent post processing, such as the removing of the component from the building platform or the removing of the remaining powder. These post-processing steps are in the following referred to “post-processing”. Secondly, the subsequent post-processing steps to improve the component properties, such as milling and turning or a stress-relief annealing. These are referred to as “finishing” and form the focus of this paper. With regard to a successful finishing of additively manufactured components, design guidelines must be taken into account that consider the finishing inherent restrictions and possibilities. In the following, these design guidelines are referred to “finishing suitable”. They can deviate significantly from those of conventionally manufactured components in the case of additively manufactured components. Although there are some investigations that deal with the post-processing of additively manufactured components [6,7], there are hardly any design guidelines that are suitable for finishing [8]. Therefore, knowledge about the finishing of additively manufactured components is based on experimental experience rather than on scientific knowledge. For this reason, design guidelines for a finishing suitable design must be methodically determined and quantified. These quantified design guidelines can be used for an automated design check on complex components like topology optimized geometries.


                    Risikoorientierte Analyse und Handhabung von Anforderungsänderungen

                    I. Gräßler, C. Oleff, in: Design for X - Beiträge zum 30. DfX-Symposium , 2019, pp. 49-60

                    Requirement changes are a major cause for project failure. A systematic approach to manage those changes from the very beginning should be an in-tegral part of each development project. Although this is accepted in both sci-ence and industry, there is no adequate approach to tackle the issue, especially in the context of interdisciplinary systems. In this paper, a secondary analysis is done to identify all information that is necessary to manage those changes efficiently. The demanded information is pictured in a reference model and then mapped with the capabilities of existing approaches. Based on this, research gaps are identified and used to guide future research efforts.


                      Einflussfaktoren auf Bauteilgüte lasergeschmolzener Strukturen

                      J. Brüggemann, L. Risse, H. Richard, G. Kullmer, in: DVM-Bericht 251, Arbeitskreis: Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen, Deutscher Verband für Materialforschung und -prüfung e.V., 2019, pp. 207-218


                      Entwicklung von Optimierungsstrategien für Strukturbauteile unter Ausnutzung der Potentiale des Laser-Strahlschmelzens

                      J. Brüggemann, L. Risse, G. Kullmer, H. Richard, in: Additive Fertigung von Bauteilen und Strukturen – Neue Erkenntnisse und Praxisbeispiele, 2019, pp. 1-22


                      Reconstruction of a defective finger joint surface and development of an adapted external fixator

                      L. Risse, S. Woodcock, G. Kullmer, B. Schramm, H. Richard, in: Lecture Notes in Computational Vision and Biomechanics , 2019, pp. 230-238


                      Advancing into New Dimensions

                      E. Moritzer, F. Buerenhaus, A. Hirsch, Kunststoffe international (2019), 109(3), pp. 48-52

                      Additive manufacturing processes provide a very high degree of design freedom and short development times. However, the nature of the process and the limited size of build chambers restrict the size of such components. Adhesive bonding enables additively manufactured components to be joined together to form large parts.


                        Adhesive Bonding of FDM-Manufactured Parts Made of ULTEM 9085 Considering Surface Treatment, Surface Structure, and Joint Design

                        E. Moritzer, F. Buerenhaus, A. Hirsch, Welding in the World (2019), 63, pp. 1819-1832

                        Additive manufacturing has become increasingly popular over the past years. One of the most commonly used additive manufacturing process is the fused deposition modeling (FDM). In FDM, components are produced by depositing a molten plastic filament layer by layer on a build platform. The deposition takes place in a heated build chamber. Despite the many positive characteristics, the process principle leads to one main disadvantage. The maximum size of FDM-manufactured parts is limited by the size of the build chamber. Bigger parts can only be realized as an assembly group. Adhesive bonding is a commonly used joining method in the industry to produce resilient parts especially for lightweight applications and to join dissimilar materials. The aim of this study is to investigate the influence of the adhesive type, the surface character of FDM parts, and the design of the bond area on the bond strength. The parts to be investigated are made of ULTEM 9085. Six different adhesives (acrylate resin, polyurethane adhesive, and epoxy resins) and their compatibility with the ULTEM 9085 parts are investigated. Considering the surface character, the influence of different pretreatments (mechanical roughening, plasma activation) and different surface structures are tested. The surface is modified by adding a positive air gap and an interface structure, and by varying the raster angle of the top layer. Regarding the design of the bond area, six different designs (finger, scarf, butt, tongue-groove, t-peel, and overlap joint) are investigated. The results show that the maximum lap shear strength can be achieved by using two-component epoxy resins. The adhesion between the ULTEM 9085 and the polyurethane as well as for the acrylate resin is insufficient but can be increased by roughening the surface mechanically or by adding a positive air gap to the surface. The investigations also show a positive effect of the plasma treatment but only for the combination of ULTEM 9085 with the polyurethane adhesive. The best results for different bond designs are reached with the scarf and the finger joint.


                          Design guidelines for post-processing of laser beam melting in context of support structures

                          T. Künneke, T. Lieneke, S. Lammers, D. Zimmer, in: Proceedings of the Special Interest Group meeting on Advancing Precision in Additive Manufacturing, 2019, pp. 137-140

                          Laser Beam Melting (LBM) is an Additive Manufacturing (AM) process on the threshold of serial production. Therefore, LBM has to overcome different problems such as a low productivity and minor economic efficiency. Support structures are essential for LBM; however, these structures contribute to the mentioned topics, because their removal is time consuming and cost intensive. To enable design engineers and operators to increase the efficiency of LBM, design guidelinesfor support structures suitable for post-processing are developed. For this purpose, the effect of different design parameters on various evaluation criteria is considered. Suitability for post-processing can be evaluated in terms of cost, quality and time. Therefore, test specimens are built and parameter impacts on material consumption as well as the post-processing time is examined. Furthermore, the roughness of the parts is analyzed and used as an indicator for the removability of the support structure. In addition, warpage is measured and the impact of the parameters on this criterion is examined. Based on the results, suitable design guidelines and hints for support structures are developed in order to reduce time and costs during manufacturing and post-processing.


                            Devolopment, Production and post-processing of a topology optimized aircraft bracket

                            S.H. Klippstein, A. Duchting, T. Reiher, F. Hengsbach, D. Menge, H. Schmid, in: 30th Annual International Solid Freeform Fabrication Symposium, 2019, pp. 1932-1945

                            Structural parts for aviation have very high demands on the development and production process. Therefore, the entire process must be considered in order to produce high-quality AM metal parts. In this case study, a conventional part was selected to be optimized for AM. The process presented includes component selection, design improvement with a novel approach for topology optimization based on the AMendate algorithm as basis of MSC Apex Generative Design,component production on a SLM 250 HL and post-processing including heat treatment and surface smoothing. With the topology optimization a weight reduction of ~60 % could be realized, whereby the stress distribution is more homogeneous. Furthermore, the challenges of support optimization and post-processing have to be addressed, in order to produce competitive parts.


                              Priorisierung von Anforderungen für die Entwicklung mechatronischer Systeme

                              I. Gräßler, C. Oleff, P. Scholle, in: Fachtagung Mechatronik 2019 Paderborn, 2019, pp. S. 1-6

                              In diesem Beitrag wird ein Ansatz vorgestellt, welcher die Bewertung des Risikos von Anforderungsänderungen in der Entwicklung mechatronischer Systeme ermöglicht. Ausgehend von einer Anforderungsliste werden die Wechselwirkungen in einer Requirements Structure Matrix (RSM) teilautomatisch erfasst. Parallel werden Anforderungen in Bezug auf ihren Ursprung („Einflussbereich“) kategorisiert und darauf aufbauend priorisiert. Diese Priorisierung basiert auf dem Veränderungsrisiko und wird durch die drei Kriterien „Dynamik“, „Unsicherheit der Wissensbasis“ und „Relevanz für den Entwicklungsprozess“ charakterisiert. Das Vorgehen wird anhand strukturierter Interviews mit Projektleitern und Entwicklern und der Fallstudie eines Pedelecs als mechatronischem System validiert. Durch die Anwendung der Methode können disziplinübergreifende Abhängigkeiten von Anforderungen zur Reduktion von Iterationen in der Entwicklung mechatronischer Systeme – wie dem Pedelec – berücksichtigt werden.


                                Potentiale des Einsatzes individueller, additiv gefertigter medizinischer Hilfsmittel

                                L. Risse, S. Woodcock, G. Kullmer, B. Schramm, F. Schlenker, H. Richard, in: DVM-Bericht 404, Arbeitskreis: Additiv gefertigte Bauteile und Strukturen, 2019, pp. 139-150


                                Möglichkeiten additiver Fertigungsverfahren im Zuge der Digitalisierung für den Planungsprozess chirurgischer Eingriffe

                                L. Risse, B. Schramm, in: DVM - Bericht 1685, DVM-Tag 2019 – Bauteil verstehen, 2019, pp. 103-120


                                Vorstoß in neue Dimensionen

                                E. Moritzer, F. Buerenhaus, A. Hirsch, Kunststoffe (2019), 109(2), pp. 68-72

                                Additive Fertigungsverfahren ermöglichen eine sehr große Gestaltungsfreiheit und kurze Entwicklungszeiten. Bedingt durch das Verfahrensprinzip und die beschränkten Bauräume der Anlagen ist die maximale Größe solcher Bauteile jedoch begrenzt. Durch das Kleben lassen sich additiv gefertigte Komponenten zu großen Bauteilen zusammenfügen.


                                  Manufacturing Accuracy In Additive Manufacturing: A Method To Determine Geometrical Tolerances

                                  T. Lieneke, T. Künneke, F. Schlenker, V. Denzer, D. Zimmer, in: Special Interest Group Meeting: Advancing Precision in Additive Manufacturing, 2019

                                  Additive Manufacturing (AM) processes generate plastic or metal parts layer-by-layer without using formative tools. The resulting advantages highlight the capability of AM to become an inherent part within the product development. However, process specific challenges such as a high surface roughness, the stair-stepping effect or geometrical deviations inhibit the industrial establishment. Thus, additively manufactured parts often need to be post-processed using established manufacturing processes. Many process parameters and geometrical factors influence the manufacturing accuracy in AM which can lead to large deviations and high scatterings. Published results concerning these deviations are also difficult to compare, because they are based on several geometries that are manufactured using different processes, materials and machine settings. It is emphasized that reliable tolerances for AM are difficult to define in standards. Within this investigation, a uniform method was developed regarding relevant test specimens to examine geometrical deviations for Laser Beam Melting (LBM), Fused Deposition Modeling (FDM) and Selective Laser Sintering (SLS) in order to derive geometrical tolerance values. The manufactured test specimens were measured using tactile and optical systems to examine the occurring geometrical deviations. The results show possible geometrical tolerance values that were classified according to the international standard DIN EN ISO 286-1.


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                                    2018


                                    Liste im Research Information System öffnen

                                    Selective Laser Melting of Ti6Al4V with High Build Rates and Following Hot Isostatic Pressing

                                    D. Ahlers, T. Tröster, S. Hermann, P. Koppa, P. Gloetter, M. Schaper, M. Peters, M. Burns, F. Hengsbach, A. Altmann, in: Contributed Papers from MS&T17, 2018


                                    SEMI-AUTOMATIZED ASSESSMENT OF REQUIREMENT INTERRELATIONS

                                    I. Graessler, P. Scholle, J. Hentze, C. Oleff, in: Proceedings of the DESIGN 2018 15th International Design Conference, 2018


                                    Validierung der strukturmechanischen Funktionsfähigkeit durch experimentelle Bauteilprüfungen additiv gefertigter Leichtbaustrukturen

                                    J. Brüggemann, L. Risse, A. Grübel, H. Richard, G. Kullmer, in: DVM - Bericht 250, Arbeitskreis: Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen, Deutscher Verband für Materialforschung und -prüfung e.V., 2018, pp. 89-98


                                    CAE-gestützte Optimierung eines Hüftimplantats durch Ausnutzung der Potentiale additiver Fertigungsverfahren

                                    L. Risse, B. Schramm, J. Brüggemann, S. Woodcock, G. Kullmer, H. Richard, in: DVM-Bericht 403, Arbeitskreis: Additiv gefertigte Bauteile und Strukturen, Deutscher Verband für Materialforschung und -prüfung e.V., 2018, pp. 89-100


                                    Thermoplastic Elastomer Part Color as Function of Temperature Histories and Oxygen Atmosphere During Selective Laser Sinterung

                                    C. Kummert, S. Josupeit, H. Schmid, Journal of Minerals, Metals and Materials Society (2018), 70(3), pp. 425-430

                                    The influence of selective laser sintering (SLS) parameters on PA12 part properties is well known, but research on other materials is rare. One alternative material is a thermoplastic elastomer (TPE) called PrimePart ST that is more elastic and shows a distinct SLS processing behavior. It undergoes a three-dimensional temperature distribution during the SLS process within the TPE part cake. To examine this further, a temperature measurement system that allows temperature measurements inside the part cake is applied to TPE in the present work. Position-dependent temperature histories are directly correlated with the color and mechanical properties of built parts and are in very good agreement with artificial heat treatment in a furnace. Furthermore, it is clearly shown that the yellowish discoloration of parts in different intensities is not only temperature dependent but also influenced by the residual oxygen content in the process atmosphere. Nevertheless, the discoloration has no influence on the mechanical part properties.


                                      Optimization of the fracture mechanical properties of additively manufactured EN AW-7075

                                      J. Brüggemann, L. Risse, G. Kullmer, B. Schramm, H. Richard, in: Procedia Structural Integrity, 2018, pp. in press


                                      Additive Fertigung in der modernen Orthopädietechnik - Anwendung und Forschungsansätze -

                                      T. Schafran, B. Schramm, L. Risse, in: DVM - AK Implantate und Biostrukturen, 2018


                                      Influence of the Layer Time on the Resulting Part Properties in the Fused Deposition Modeling Process

                                      F. Knoop, V. Schoeppner, in: SPE ANTEC 2018, Society of Plastics Engineers , 2018

                                      The Fused Deposition Modeling (FDM) process by Stratasys is an additive manufacturing (AM) technique that can be used to produce complex thermoplastic parts without the need of a forming tool. A big challenge of this process is that there are several influencing factors with unknown effect on the resulting part properties. One of these factors is the layer time. The aim of this study is to examine the influence of the layer time on the resulting dimensional accuracy and mechanical properties of FDM components manufactured with the amorphous polymer ABS-M30. For this purpose a special job layout was designed to vary the layer time within a certain range. The investigations in this paper show a significant influence on the dimensional accuracy and also on the mechanical properties.


                                        Konstruktionsrichtlinien für eine softwaregestützte Anpassung von additiv gefertigten Bauteilen im Hinblick auf eine robuste Fertigung

                                        S. Lammers, J. Tominski, S. Magerkohl, T. Künneke, T. Lieneke, D. Zimmer, in: Proceedings of the 15th Rapid.Tech Conference, 2018, pp. 81-94

                                        Neue Konstruktionsabläufe und Potentiale bei der Gestaltung additiv hergestellter Bauteile verlangen insbesondere im Konstruktionsprozess ein Umdenken. Fehlende Kenntnisse über die additive Fertigungstechnologie hemmen zusätzlich dieses Umdenken [HHD06, WC15]. Um die verhältnismäßig neue Fertigungstechnologie zugänglicher zu machen, wurden in den letzten Jahren verschiedene Konstruktionsempfehlungen erarbeitet. Die Vielzahl an Empfehlungen erschwert dem Konstrukteur allerdings einen entsprechenden Überblick zu behalten und für ihn relevante von nicht relevanten Empfehlungen zu sondieren. Aus diesem Grund wurden öffentlich zugängliche Empfehlungen für das Laser-Strahlschmelzen zusammengetragen und einer Priorisierung unterzogen. Das Ergebnis beinhaltet Konstruktionsempfehlungen, die einen relevanten Einfluss auf die Bauteilfertigung, die Bauteilqualität und -funktion haben. Durch Abstraktion dieser Empfehlungen konnten Richtlinien erarbeitet werden, die für eine softwareseitige Gestaltprüfung verwendet werden können. Durch diese Gestaltprüfung können Bauteile beliebiger Komplexität, zum Beispiel feine Gitter oder topologieoptimierte Strukturen, bereits vor der Fertigung hinsichtlich der Einhaltung relevanter Konstruktionsrichtlinien überprüft werden. Der Gestaltprüfer greift dabei auf eine Datenbank zurück, die zulässige, quantitative Grenzwerte von Konstruktionsrichtlinien enthält. Diese Grenzwerte werden im Folgenden Attributsausprägungen genannt und können experimentell ermittelt werden. Hierfür wurden standardisierte Prüfkörperbaujobs entwickelt, die alle notwendigen Prüfkörper zur Ermittlung der Attributsausprägungen enthalten und deren Auswertung eine Erweiterung der Datenbank hinsichtlich


                                          Software-assisted design check of additive manufactured components

                                          J. Tominski, S. Lammers, in: 14th PERMAS Users' Conference, 2018


                                          Erarbeitung von Konstruktionsregeln für Hybridbauteile: Integration von metallischen Einlegern in FDM-Strukturen

                                          F. Knoop, M. Köhler, T. Lieneke, D. Zimmer, V. Schöppner, Konstruktion - Zeitschrift für Produktentwicklung und Ingenieur-Werkstoffe (2018), 10, pp. 83-88


                                          Semi-Automatized Assessment of Requirement Interrelations

                                          I. Gräßler, P. Scholle, J. Hentze, C. Oleff, in: 15th International Design Conference, 2018, pp. S. 325-334

                                          Changing requirements have a broad impact on product development processes. In this paper, a novel approach towards structuring requirements is proposed. Based on a requirements list, interrelations of requirements are assessed semi-automatically by a rule basis. Here, generic interrelations funded on either physical fundamentals or working principles are recorded. By this approach, requirements structure matrices are derived semi-automatically. Combined with selecting critical requirements based on structured criterions, iterations due to changing requirements will be reduced.


                                            Entwicklung von steifigkeitsangepassten, lasergeschmolzenen Kurzschaft-Hüftendoprothesen

                                            L. Risse, B. Schramm, J. Brüggemann, G. Kullmer, H. Richard, in: Proceedings of the 15th Rapid.Tech Conference, 2018, pp. 405-417


                                            Fracture mechanical investigations on selective laser melted TiAl6V4

                                            J. Brüggemann, L. Risse, G. Kullmer, H. Richard, in: Procedia Structural Integrity, 2018, pp. in press


                                            Additive manufacturing for medical applications

                                            B. Schramm, L. Risse, J. Brüggemann, H. Richard, G. Kullmer, Journal of 3D Printing in medicine (2018), 2


                                            Method for a Software-based Design Check of Additively Manufactured Components

                                            J. Tominski, S. Lammers, C. Wulf, D. Zimmer, in: 29th Annual International Solid Freeform Fabrication Symposium, 2018

                                            This paper reports on the experimental development and the theoretical analysis of the scanning laser epitaxy (SLE) process that is currently being investigated and developed at the Georgia Institute of Technology. SLE is a laser-based manufacturing process for deposition of equiaxed, directionally solidified and single-crystal nickel superalloys onto superalloy substrates through the selective melting and re-solidification of superalloy powders. The thermal modeling of the system, done in a commercial CFD software package, simulates a heat source moving over a powder bed and considers the approximate change in the property values for consolidating CMSX-4 nickel superalloy powder. The theoretical melt depth is obtained from the melting temperature criteria and the resulting plots are presented alongside matching experimental micrographs obtained through cross-sectional metallography. The influence of the processing parameters on the microstructural evolution, as evidenced through observations made from the micrographs, is discussed. This work is sponsored by the Office of Naval Research, through grants N00173-07-1-G031 and N00014-10-1-0526.


                                              Additive Fertigung nach Maß

                                              F. Knoop, T. Lieneke, V. Schoeppner, D. Zimmer, Kunststoffe (2018), 6, pp. 70-73



                                              Additive Manufacturing of Porous Structures for Unmanned Aerial Vehicles Applications

                                              S.H. Klippstein, H. Hassanin, A. Diaz De Cerio Sanchez, Y. Zweiri, L. Seneviratne, Advanced Engineering Materials (2018), 20(2)


                                              Methode zur Bewertung von Anforderungsänderungen additiv gefertigter Produkte.

                                              I. Gräßler, C. Oleff, P. Scholle, in: Design for X - Beiträge zum 29. DfX-Symposium, 2018, pp. 333-344

                                              In this paper, a novel approach towards risk classification of requirements of additively manufactured (AM) products is presented. The classification of an individual requirement is based on two aspects: a) influence factors implying dynamics of its specification and b) network indices quantifying the degree of cross-linkage with other requirements. Both aspects can indicate requirement changes. Influences on a requirement are assessed by a priority index based on criteria ‘uncertainty’, ‘dynamics’ and ‘relevance for product development’. Effects from other requirements are captured by network theoretical indices such as active and passive sum. In the end, requirements are classified accord-ing to their criticality. By this approach, requirements can be identified which might strongly affect the product development process of AM products.


                                                Entwicklung und Umsetzung eines Qualitätssicherungskonzeptes für die additive Fertigung

                                                A. Dsuban, J. Lohn, J. Brüggemann, G. Kullmer, in: DVM - Bericht 403, Arbeitskreis: Additiv gefertigte Bauteile und Strukturen, Deutscher Verband für Materialforschung und -prüfung e.V., 2018, pp. 110-110

                                                although it shows great potential. In this paper, first approaches


                                                  The Influence of Contour Scanning Parameters and Strategy on Selective Laser Sintering PA613 Build Part Properties

                                                  C. Kummert, H. Schmid, in: 29th Annual International Solid Freeform Fabrication Symposium, 2018


                                                  Welche ingenieurstechnischen Perspektiven bietet die Versorgung durch additiv gefertigte Orthesen?

                                                  L. Risse, B. Schramm, T. Schafran, in: PreDay AK Fußchirurgie, 2018


                                                  Processing Short Fiber Reinforced Polymers in the Fused Deposition Modeling Process

                                                  C. Schumacher, V. Schoeppner, S. Gnaase, in: 29th Annual International Solid Freeform Fabrication Symposium, 2018, pp. 1112-1120

                                                  By adding fibers to a polymer matrix, a reinforcement of the material can be achieved. Short fiber-reinforced polymers can easily be processed by the Fused Deposition Modeling (FDM) process without major modifications to the processing machine. For instance, short fiber-reinforcedfilaments can be processed to produce short fiber-reinforced components in the FDM process. In many other additive manufacturing processes this is not possible at this low cost. The choice of the matrix material, fiber type, fiber length and fiber orientation have a major influence on the properties of the produced component. In this paper, short fiber-reinforced filaments are processed by the FDM process. The processing properties and the resulting part properties are investigatedwith regard to fiber-specific influences. Additionally, the effects of different strand geometries and thus changed flow fields on the fiber orientation and mechanical part properties are investigated.


                                                    Ein Beitrag zur Anpassung bestehender Konstruktionsmethodiken an die additiven Fertigungsverfahren

                                                    T. Künneke, S. Bücker, T. Lieneke, D. Zimmer, in: Proceedings of the 15th Rapid.Tech Conference, Carl Hanser Verlag GmbH & Co. KG, 2018, pp. 128-143

                                                    In der Industrie entsteht aufgrund des dynamischen Wettbewerbsumfelds ein zunehmender Drang nach verkürzten Produktentstehungszeiten, hoher Funktionsintegration und individualisierten Produkten. Mithin erlangen additive Fertigungsverfahren eine zunehmende industrielle Bedeutung. Das Laser-Strahlschmelzen (LBM) als additives Verfahren ist hierbei beispielhaft hervorzuheben, da es bereits im Bereich des Prototypenbaus und der Kleinserienfertigung ein etabliertes Verfahren ist, das an der Schwelle zum Einsatz in der Serienproduktion steht. Entscheidendes Hemmnis für den Einsatz der additiven Fertigungsverfahren bildet die fehlende methodische Ausnutzung der gestalterischen Freiheiten und Randbedingungen durch die vergleichsweise neuartige Gruppe an Fertigungsverfahren im gesamten Produktentstehungsprozess. In der Produktentwicklung bildet die Konstruktionsmethodik einen möglichen Ansatz, um gestalterische Freiheiten und Vorteile additiver Fertigungsverfahren bereits in frühen Phasen der Entwicklung gezielt zu berücksichtigen. Hierfür werden aufgrund bestehender und allgemein anerkannter Konstruktionsmethoden (z.B. VDI2221, Pahl/Beitz, etc.) Anknüpfungspunkte aufgezeigt, die eine Implementierung, speziell des Laser-Strahlschmelzens, ermöglichen. Besonderes Augenmerk wird in dieser Veröffentlichung auf die beiden Konstruktionsphasen Konzeption und Gestaltung gelegt. Hierzu werden Ergänzungen oder Anpassungen der bestehenden Konstruktionsmethoden vorgestellt. In besonderer Weise wird dabei auf die Einbringung und die Vorteile der additiven Fertigungsverfahren eingegangen.


                                                      Additive Manufacturing of a Soft Magnetic Rotor Active Part and Shaft for a Permanent Magnet Synchronous Machine

                                                      S. Urbanek, B. Ponick, A. Taube, K. Hoyer, M. Schaper, S. Lammers, T. Lieneke, D. Zimmer, in: Conference paper, 2018 IEEE Transportation Electrification Conference and Expo (ITEC), Juni 2018, DOI: 10.1109/ITEC.2018.8450250, 2018


                                                      Entwicklung von Optimierungsstrategien unter Ausnutzung des Potentials der additiven Fer-tigung

                                                      J. Brüggemann, L. Risse, H. Richard, G. Kullmer, in: DVM - Bericht 403, Arbeitskreis: Additiv gefertigte Bauteile und Strukturen, Deutscher Verband für Materialforschung und -prüfung e.V., 2018, pp. 11-21


                                                      Crack Growth Simulation with Adapcrack3D in 3D Structures under the influence of Temperature

                                                      T. Joy, J. Brüggemann, G. Kullmer, in: Procedia Structural Integrity, 2018, pp. in press

                                                      results clearly demonstrate the great potential of additive


                                                        Processing Short Fiber Reinforced Polymers in the Fused Deposition Modeling Process

                                                        C. Schumacher, V. Schoeppner, S. Gnaase, in: 29th Annual International Solid Freeform Fabrication Symposium, 2018, pp. 1112-1120

                                                        By adding fibers to a polymer matrix, a reinforcement of the material can be achieved. Short fiber-reinforced polymers can easily be processed by the Fused Deposition Modeling (FDM) process without major modifications to the processing machine. For instance,short fiber-reinforced filaments can be processed to produce short fiber-reinforced components in the FDM process. In many other additive manufacturing processes this is not possible at this low cost. The choice of the matrix material, fiber type, fiber length and fiber orientation have a major influence on the properties of the produced component. In this paper, short fiber-reinforced filaments are processed by the FDM process. The processing properties and the resulting part properties are investigated with regard to fiber-specific influences. Additionally, the effects of different strand geometries and thus changed flow fields on the fiber orientation and mechanical part properties are investigated.


                                                          Iterative Produktentwicklung und Produktionsplanung für die Additive Fertigung

                                                          A. Jacob, T. Künneke, T. Lieneke, T. Baumann, N. Stricker, D. Zimmer, G. Lanza, ZWF Zeitschrift für wirtschaftlichen Fabrikbetrieb (2018), 113(11), pp. 742-745

                                                          Die Additive Fertigung eröffnet neue Freiheitsgrade in der Produktentwicklung. Unsicherheiten über die Wirtschaftlichkeit und Leistungsfähigkeit der aus der Konstruktion ableitbaren Fertigungstechnologieketten sind zu beachten. In diesem Beitrag wird eine Methode vorgestellt, welche die Anpassung einer bestehenden Konstruktionsmethode berücksichtigt und eine iterative Bewertung der Konstruktionsentscheidungen anhand von Technologieketten ermöglicht. Hiermit können die Potenziale der additiven Fertigungstechnologien zielgerichtet realisiert werden.


                                                            Design Guidelines for a Software-supported Adaptation of Additively Manufactured Components with Regard to a Robust Production

                                                            S. Lammers, J. Tominski, S. Magerkohl, T. Lieneke, T. Künneke, D. Zimmer, in: 29th Annual International Solid Freeform Fabrication Symposium, 2018

                                                            The design of additively manufactured components requires a rethinking in the design process. This is inhibited by a lack of knowledge about additive manufacturing technologies. For this reason, a large number of design guidelines have been developed in recent years. In their present form the design guidelines are not suitable for processing in a software algorithm, since the guidelines have a certain redundancy and partly influence each other. This paper describes several steps to consolidate the existing guidelines and to prepare them in a way that they can be used in a software algorithm for a design check. Therefore, existing guidelines are collected, prioritized and quantified with regard to their relevance for a robust production. To quantify the guidelines, test specimens are developed, produced and evaluated in order to obtain a limit value for the geometric properties. With these limit values, quantifiable design guidelines can be applied to designers and software tools.


                                                              Elektromechanische Antriebe

                                                              U. Brückner, T. Künneke, M.H. Schadomsky, M. Strop, D. Zimmer, Carl Hanser Verlag, 2018, pp. 247-290


                                                              Topology Optimized Heat Transfer Using the Example of an Electronic Housing

                                                              D. Menge, P. Delfs, M. Töws, H. Schmid, in: 29th Annual International Solid Freeform Fabrication Symposium, 2018, pp. 687-697

                                                              Function integration is a key issue for an efficient and economic usage of Additive Manufacturing. An efficient heat transfer by topology optimized structures is a rarely considered approach which will be outlined with an exemplary electronic housing which has been newly designed. A commercial projector unit, whose electrical components in total produce 38 W, shall be integrated in the closed housing and passively cooled by natural convection. Topology optimized structures shall be generated in the inner part of the housing to transfer the heat homogenously from the projector components to the housing wall while simultaneously minimizing the mass. At the outside of the housing walls, lattice and rib structures are applied to increase the effective surface for heat transfer by natural convection and radiation. Furthermore, the housing geometry is optimized regarding a minimization of support structures to reduce the post-processing effort. Finally, the housing shall be built of AlSi10Mg by SLM.


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                                                                Fused Deposition Modeling for Unmanned Aerial Vehicles (UAVs): A Review

                                                                S.H. Klippstein, A. Diaz De Cerio Sanchez, H. Hassanin, Y. Zweiri, L. Seneviratne, Advanced Engineering Materials (2017)

                                                                Additive Manufacturing (AM) is a game changing production technology for aerospace applications. Fused deposition modeling is one of the most widely used AM technologies and recently has gained much attention in the advancement of many products. This paper introduces an extensive review of fused deposition modeling and its application in the development of high performance unmanned aerial vehicles. The process methodology, materials, post processing, and properties of its products are discussed in details. Successful examples of using this technology for making functional, lightweight, and high endurance unmanned aerial vehicles are also highlighted. In addition, major opportunities, limitations, and outlook of fused deposition modeling are also explored. The paper shows that the emerge of fused deposition modeling as a robust technique for unmanned aerial vehicles represents a good opportunity to produce compact, strong, lightweight structures, and functional parts with embedded electronic.


                                                                  Strukturoptimierung von Kurzschaft-Hüftendoprothesen durch den Einsatz der additiven Fertigung

                                                                  L. Risse, J. Brüggemann, B. Schramm, G. Kullmer, H. Richard, in: DVM - Tagung - Zuverlässigkeit von Implataten und Biostrukturen, 2017

                                                                  improved sensorless control of PMSM are pointed out. The


                                                                    Risslängenmessung in additiv gefertigten Kunststoffproben auf Basis von Steifigkeitsänderungen infolge Ermüdungswachstum.

                                                                    B. Bauer, W. Reschetnik, G. Kullmer, H. Richard, in: DVM - Tagung - Additiv gefertigte Bauteile und Strukturen, 2017, pp. 77-88


                                                                    Crack length measurement of additive manufactured plastics based on the current potential drop method.

                                                                    B. Bauer, W. Reschetnik, G. Kullmer, H. Richard, in: Symposium on Fatigue and Fracture of Additive Manufactured Materials and Components, 2017


                                                                    Mechanische und mikrostrukturellen Eigenschaften additiv hergestellter Gitterstrukturen

                                                                    A. Taube, in: Hannover Messe Industrie, 2017, Hannover, 2017


                                                                    Corrosion properties of bioresorbable FeMn-Ag alloys prepared by selective laser melting

                                                                    M. Wiesener, K. Peters, A. Taube, A. Keller, K. Hoyer, T. Niendorf, G. Grundmeier, Materials and Corrosion (2017), 68(10), pp. 1028-1036

                                                                    FeMn-Ag alloys as potential bioresorbable implant materials were prepared by selective laser melting (SLM) from mixed powders of FeMn and Ag. The microstructure of the samples is characterized by presence of few micrometers to several tens of micrometer large Ag-phases within the FeMn matrix. The microstructure dependent corrosion and biomineralization processes in simulated body fluid (SBF) were studied in-situ by means of electrochemical impedance spectroscopy (EIS). The microstructure and local surface film formation were analyzed by electron microscopy (FE-SEM) and Raman microscopy. The results clearly show that the Ag-phase acts as a local cathode within the FeMn matrix. However, surface film formation is observed both for the Ag- and the FeMn-phases, which potentially lowers the self-corrosion as well as the galvanic coupling of the two phases. The formation of AgCl on the Ag-phases and mixed metal phosphates on the FeMn-phases can be observed by local Raman spectroscopic analysis in combination with FE-SEM characterization.


                                                                      Fatigue Behavior of FDM Parts Manufactured with Ultem 9085

                                                                      M. Fischer, V. Schoeppner, JOM: The Journal of The Minerals. Metals & Materials Society (TMS) (2017), pp. 563-568

                                                                      The mechanical characterization of fused deposition modeling (FDM) parts is mostly done by static tests. In many applications, parts are also dynamically loaded. Here, fatigue tests can help to identify the expected lifetime of a part. This article discusses the fatigue behavior of FDM specimens manufactured with Ultem 9085. For this, tensile bars are manufactured according to ASTM D638 in different build orientations. Tests are performed in a range of pulsating tensile stresses, and S-N curves are documented for different build orientations. For higher loads, the FDM anisotropy characterizes the lifetime of used specimens, which is similar to static tensile bars. For lower loads, including a higher number of cycles to failure, S-N curves of different build orientations converge. In further tests, tensile bars were chemically smoothed with chloroform vapor. Chemical smoothing reduces surface roughness and increases tensile strength of specimens in the upright build direction. Fatigue tests of chemically treated specimens show no significant lifetime increase.


                                                                        Universal Micromachining Platform and Basic Technologies for the Manufacture and Marking of Microphysiological Systems

                                                                        K. Günther, F. Sonntag, E. Moritzer, A. Hirsch, U. Klotzbach, A. Lasagni, Micromachines (2017), 8(246)

                                                                        Micro Physiological Systems (MPS), also known as Multi-Organ-Chip, Organ-on-a-Chip, or Body-on-a-Chip, are advanced microfluidic systems that allow the cultivation of different types of cells and tissue in just one common circuit. Furthermore, they thus can also adjust the interaction of these different tissues. Perspectival MPS will replace animal testing. For fast and flexible manufacturing and marking of MPS, a concept for a universal micromachining platform has been developed which provides the following latest key technologies: laser micro cutting of polymer foils, laser micro- and sub-micro-structuring of polymer foils, 3D printing of polymer components as well as optical inspection and online process control. The combination of different laser sources, processing optics, inspection systems, and print heads on multiple axes allows the change and exactly positioning to the workpiece during the process. Therewith, the realization of MPS including 3D printed components as well as direct laser interference patterned surfaces for well-defined cell adhesion and product protection is possible. Additional basic technologies for the generation of periodical line-like structures at polycarbonate foils using special Direct Laser Interference Patterning (DLIP) optics as well as for the 3D printing of fluid-tight cell culture reservoirs made of Acrylonitrile Butadiene Styrene directly onto polycarbonate microfluidics were established. A first prototype of the universal micromachining platform combining different lasers with Direct Laser Writing and DLIP is shown. With this laser micro cutting as well as laser micro-structuring of polycarbonate (PC) foils and therewith functionalization for MPS application could be successfully demonstrated.


                                                                          Geometrical Accuracy of Holes and Cylinders Manufactured with Fused Deposition Modeling

                                                                          F. Knoop, V. Schoeppner, in: 28th Annual International Solid Freeform Fabrication Symposium, 2017, pp. 2757-2776

                                                                          A widely used Additive Manufacturing (AM) technology is Fused Deposition Modeling (FDM) to create prototypes and end-use parts with close-to-production thermoplastics. For their use as a final product, it is necessary that additively manufactured parts strictly adhere to the geometrical requirements of the technical drawing. In this paper, the holes and cylinders of the cylindrical elements are investigated in terms of achievable geometrical accuracy. For this purpose, different test specimens that allow a measurement of inner and outer diameters from 3 to 80 mm were designed. All specimens were measured with a coordinate measuring machine (CMM) to evaluate deviations from the nominal dimension and form deviations. The measuring method includes a scanning of the surface to record the course of dimensional deviations over the diameter. Thus, it was possible to visualize how deviations on cylindrical elements manufactured in FDM occur. In order to counteract these deviations and to improve the dimensional accuracy, different shrink factors and filling patterns were investigated. Consequently, an improvement of the dimensional accuracy was achieved.


                                                                            Reproduzierbarkeit der Maßhaltigkeit im Fused Deposition Modeling

                                                                            F. Knoop, T. Lieneke, V. Schoeppner, in: Rapid Tech - International Trade Show & Conference for Additive Manufacturing, 2017, pp. 52-66

                                                                            Fused Deposition Modeling (FDM) is used for prototypes, single-partproduction and small batch productions of thermoplastic components. This manufacturing technique has the huge benefit that no forming tool is needed. The knowledge about dimensional deviations which occur in the FDM process is necessary for calculating fits and for determining tolerances. A major challenge is the reproducibility of the dimensional accuracy of FDM parts and the reproducibility between different FDM machines. There are many influential factors on the dimensional accuracy in the FDM process for example geometric, material-specific or process-specific factors, which are considered in this paper. The influence of the part position on the build platform of a Stratasys Fortus 400mc is analyzed in terms of the achievable dimensional accuracy. For this purpose, the temperature distribution in the actively heated build chamber is investigated and possible correlations to the dimensional accuracy are identified. The reproducibility of one machine is examined by a multiple production of the test specimens. In addition, a comparison with three other FDM machines from Stratasys is made. Afterwards, the long-term reproducibility of the dimensional accuracy is verified to consider how environmental influences such as maintenance or modification of machine components affect the dimensional accuracy of the FDM process.


                                                                              Geometrische Toleranzen für additive Fertigungsverfahren

                                                                              T. Lieneke, V. Denzer, D. Zimmer, in: 3. Summer School Toleranzmangement 2017, 2017


                                                                              Entwicklung und additive Herstellung einer Leichtbau-Rotorwelle für eine permanentmagneterregte Synchronmaschine

                                                                              S. Lammers, F. Quattrone, R. Mrozek, D. Zimmer, H. Schmid, B. Ponick, M. Hoffmann, in: Proceedings of the 14th Rapid.Tech Conference, Hanser Verlag, 2017, pp. 80-93

                                                                              Additive Fertigungsverfahren (engl.: Additive Manufacturing, kurz: AM) ermöglichen die werkzeuglose Herstellung von Komponenten und kompletten Baugruppen direkt aus dem 3D-CAD-Modell. Insbesondere additiv hergestellte Leichtbaukonstruktionen weisen ein hohes Potential für den Elektromaschinenbau auf. In diesem Paper werden erste Ansätze zur additiven Fertigung einer Rotorwelle für eine permanentmagneterregte Synchronmaschine (PMSM) aufgezeigt. Die Verbesserung einer ausgeprägten Leichtbaukonstruktion der Rotorwelle sowie die Charakterisierung des additiv verarbeiteten Werkstoffs werden aufgeführt. Hierzu wurden Prüfkörper aus dem Werkstoffs H13 (1.2344) hergestellt. Des Weiteren wurden Prüfkörper additiv gefertigter Gitterstrukturen entwickelt und untersucht. Zur Werkstoffcharakterisierung wurden sowohl mechanische Eigenschaften ermittelt, wie die Streckgrenze, die Zugfestigkeit und die Härte als auch elektromagnetische Eigenschaften, wie die Koerzitivfeldstärke, die elektrische Leitfähigkeit und die Permeabilität. Die Ergebnisse zeigen, dass die magnetischen Eigenschaften von H13 durch eine angeschlossene Wärmebehandlung deutlich verbessert werden konnten. Im Anschluss an die Werkstoffcharakterisierung wurde ein innovatives Leichtbau-Rotorwellenkonzept mit internen Gitterstrukturen entwickelt. Verglichen mit einem konventionell gefertigten Rotor konnte die Rotormasse um 25% reduziert werden sowie das Massenträgheitsmoment um 23% reduziert werden bei einer Testdrehzahl von 3000 U/min und einem Drehmoment von 71,98 Nm.


                                                                                Additively manufactured acoustic diffuser structures for ultrasonic measurement applications

                                                                                L. Claes, H. Zeipert, P. Koppa, T. Tröster, B. Henning, in: Proceedings of Meetings on Acoustics, 2017, pp. 030004




                                                                                Vergleich zweier Optimierungsstrategien am Beispiel additiv gefertigter Rennradvorbauten

                                                                                J. Brüggemann, L. Risse, H. Richard, G. Kullmer, in: DVM Tagung - Additiv gefertigte Bauteile und Strukturen, 2017, pp. 49-66


                                                                                Kombination etablierter und additiver Fertigung: Wirtschaftlicher Einsatz des Laser-Strahlschmelzens (LBM) durch die Kombination mit etablierten Fertigungsverfahren in einer Prozesskette

                                                                                N. Eschner, R. Kopf, T. Lieneke, T. Künneke, D. Berger, B. Häfner, G. Lanza, D. Zimmer, ZWF Zeitschrift für wirtschaftlichen Fabrikbetrieb (2017), 112(7-8), pp. 469-472

                                                                                Der Serieneinsatz der additiven Fertigung ist maßgeblich durch die hohen Kosten und der geringen Produktivität der Verfahren limitiert. Der hier vorgestellte Ansatz zeigt, wie die Wirtschaftlichkeit des Laser-Strahlschmelzens (LBM) durch die Kombination mit etablierten Fertigungsverfahren erhöht werden kann. Ziel ist es, nur solche Funktionsträger additiv zu fertigen, die einen höheren Kundennutzen bringen. Dazu werden Konstruktionsrichtlinien definiert, Prozessketten erarbeitet und eine Qualitätssicherung mittels Ultraschallüberwachung realisiert.


                                                                                  Maßtoleranzen für die additive Fertigung: Experimentelle Untersuchungen für das Lasersintern

                                                                                  T. Lieneke, G. Adam, S. Josupeit, P. Delfs, D. Zimmer, in: Proceedings of the 14th Rapid.Tech Conference, Hanser Verlag, 2017, pp. 327-344


                                                                                  Funktionsintegration additiv gefertigter Dämpfungsstrukturen bei Biegeschwingungen

                                                                                  T. Künneke, D. Zimmer, Springer Fachmedien Wiesbaden GmbH, 2017, pp. 61-74

                                                                                  Schwingungen und Vibrationen sind in Technik und Alltag häufig anzutreffen. Meist sind sie unerwünscht und müssen durch Dämpfung reduziert werden. Hierzu werden aktuell häufig zusätzlich zu montierende Dämpfungselemente eingesetzt. Diese sind durch zusätzlichen Montageaufwand und erhöhte Kosten gekennzeichnet. Durch die zusätzliche Masse wird Leichtbauansätzen widersprochen. Additive Fertigungsverfahren bieten große Freiheiten in der Bauteilgestaltung. Dies ermöglicht ein hohes Maß an Funktionsintegration. So ergeben sich auch im Bereich der Schwingungsdämpfung Möglichkeiten zur gezielten Integration von Dämpfungsfunktionen durch die Eigenschaften der additiven Fertigungsverfahren. Mittels der pulverbasierten Verfahren kann disperses Stützmaterial innerhalb von Hohlräumen in der Struktur belassen werden. Dieses Pulvermaterial kann als Partikeldämpfer fungieren. Durch die Freiheiten in der Bauteilgestalt kann die Dämpfungswirkung über die geometrischen Merkmale der Hohlräume gezielt eingestellt werden. Im Rahmen dieses Beitrags werden speziell Untersuchungen zur Dämpfungswirkung additiv gefertigter Bauteile bei freien Biegeschwingungen betrachtet. Die praxisnahe Umsetzung zur Funktionsintegration von Dämpfungsstrukturen erfolgt am Beispiel der Ankerscheibe einer Federkraftbremse. Hier kann durch die additive Fertigung verbunden mit der Funktionsintegration von Partikeldämpfern eine Reduzierung der Schallabstrahlung für den Schaltvorgang der Bremse erreicht werden.


                                                                                    Bruchmechanische Charakterisierung von laserstrahlgeschmolzenen Werkstoffen

                                                                                    W. Reschetnik, J. Brüggemann, G. Kullmer, H. Richard, in: DVM - Tagung - Additiv gefertigte Bauteile und Strukturen, Deutscher Verband für Materialforschung und -prüfung e.V., 2017, pp. 147-156


                                                                                    Konzepte zur Risslängenmessung an additive gefertigten Kunststoffen

                                                                                    B. Bauer, W. Reschetnik, G. Kullmer, H. Richard, in: DVM Tagung - Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen, 2017, pp. 21-30


                                                                                    Entwicklung von Fahrradtretkurbelsystemen mittels additiver Fertigung

                                                                                    J. Brüggemann, L. Risse, A. Riemer, W. Reschetnik, G. Kullmer, H. Richard, in: Additive Fertigung von Bauteilen und Strukturen – Neue Erkenntnisse und Praxisbeispiele, 2017


                                                                                    Quality Improvement of FDM Parts by Parameter Optimization

                                                                                    F. Knoop, A. Kloke, V. Schoeppner, in: 32nd International Conference of the Polymer Processing Society, American Institute of Physics, 2017

                                                                                    Fused Deposition Modeling (FDM) is an Additive Manufacturing (AM) technology which is used for prototypes, single-part-production and also small batch productions. For use as a final product, it is important that the parts have good mechanical properties, a high dimensional accuracy and smooth surfaces. The knowledge of the mechanical properties is very important for the design engineer when it comes to the component design. In this paper, investigations were conducted with the polymer ABS-M30 from Stratasys Inc. To achieve a quality improvement of FDM parts, various toolpath parameters and orientations were used. Within the mechanical properties, the tensile, flexural and impact strength were evaluated. Furthermore, the tensile strength of FDM parts is compared to injection molded specimens. With optimized parameters, an increase of the tensile strength by up to 28 % and a doubling of the impact strength were possible.


                                                                                      Considering machine- and process-specific influences to create custom-built specimens for the Fused Deposition Modeling process

                                                                                      C. Schumacher, V. Schoeppner, J. Guntermann, in: 28th Annual International Solid Freeform Fabrication Symposium, 2017, pp. 470-484

                                                                                      Compared to conventional polymer processing technologies the material selection in the Fused Deposition Modelling (FDM) process is restricted. To expand the range of materials the requirements for the material properties and the semi-finished products (filaments) must be clarified. For this, a machine- and process-independent rating of the processability is necessary. The established standards for the tensile strength test apply to specimens with nearly isotropic mechanical properties. The FDM process generates anisotropic parts. The properties are mainly influenced by the machine quality and the data processing. It is not possible to test a material for FDM independently of the machine and the data processing. In this paper, machine and process specific influences are investigated. Considering these influences, a custom-built specimen is created to test the tensile strength of the welding seams for polyamide 6. This procedure allows a machine- and process-independent rating of the processability in terms of tensile strength for different materials.


                                                                                        Dimensional Tolerances for Additive Manufacturing: Fused Deposition Modeling

                                                                                        F. Knoop, T. Lieneke, in: Inside 3D Printing 2017, 2017


                                                                                        Entwicklung einer additiv gefertigten Fußorthese

                                                                                        J. Brüggemann, L. Risse, B. Schramm, H. Richard, in: Rapid Tech - International Trade Show & Conference for Additive Manufacturing, 2017, pp. 26-37


                                                                                        Increasing process speed in the laser melting process of Ti6Al4V and the reduction of pores during hot isostatic pressing

                                                                                        D. Ahlers, P. Koppa, F. Hengsbach, P. Gloetter, A. Altmann, M. Schaper, T. Tröster, in: Proceedings of the 28th Annual InternationalSolid Freeform Fabrication Symposium – An Additive Manufacturing Conference, 2017


                                                                                        Optimierung der Werkstoffeigenschaften von selektiv lasergeschmolzenen Aluminium 7075

                                                                                        J. Brüggemann, W. Reschetnik, M. Aydinöz, H. Richard, G. Kullmer, K. Hoyer, M. Schaper, in: DVM - Tagung - Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen, Deutscher Verband für Materialforschung und -prüfung e.V., 2017, pp. 11-20


                                                                                        Methods for crack length measurement for the determination of fracture mechanical parameters of additive manufactured plastics

                                                                                        B. Bauer, W. Reschetnik, G. Kullmer, H. Richard, in: 14th International Conference on Fracture, 2017


                                                                                        Experimental analysis and modeling of local ageing effects during laser sintering of polyamide 12 in regard to individual thermal histories

                                                                                        S. Josupeit, H. Schmid, Journal of Applied Polymer Science (2017), 134(42)

                                                                                        Polymer laser sintering (LS) is an important additive manufacturing (AM) technology. Individual and complex parts are directly produced from CAD data without the need of specific tools. The raw material is a polymer powder, which is deposited layerwise and melted selectively with a laser. Built parts are embedded in residual unmolten powder, the so-called part cake, which undergoes thermal ageing effects due to the exposure to high temperatures for long times during the manufacturing process. Hence, the recyclability of the unmolten powder is limited. This article focuses on a fundamental analysis of the ageing kinetics dependent on time, temperature, and oxygen content in the gas atmosphere. A model is developed and applied to measured, position-dependent process temperature histories to successfully predict the ageing distribution within a part cake. The results can be used to optimize the thermal process management in LS and to develop new efficient powder recycling methods.


                                                                                          Beurteilung der Schweißnahtfestigkeiten verschiedener Kunststoffe im FDM-Prozess

                                                                                          V. Schöppner, C. Schumacher, J. Guntermann, Jahresmagazin Kunststofftechnik (2017), 1(1), pp. 108-114

                                                                                          Um die Materialauswahl für den FDM-Prozess zu steigern, sollten die durch den FDM-Prozess an das Material gestellten Anforderungen bekannt sein. Dazu ist eine von der Maschine und der individuellen Datenaufbereitung möglichst unabhängige Bewertung der FDM-Verarbeitungseignung wünschenswert. In diesem Artikel werden eine Prüfmethode und ein dazu entwickelter Probekörper vorgestellt, mit dem die Schweißnahtfestigkeit verschiedener Polyamid 6 Typen im FDM-Prozess ermittelt und verglichen wird.


                                                                                            Betriebssichere Auslegung einer lasergeschmolzenen Fünfstern-Tretkurbel

                                                                                            D. Menge, S. Josupeit, H. Schmid, in: Rapid Tech - International Trade Show & Conference for Additive Manufacturing, 2017, pp. 94-107


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                                                                                            2016


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                                                                                            Fatigue crack growth behavior and mechanical properties of additively processed EN AW-7075 aluminium alloy

                                                                                            W. Reschetnik, J. Brüggemann, M. Aydinöz, O. Grydin, K. Hoyer, G. Kullmer, H. Richard, in: Procedia Structural Integrity, 2016, pp. 3040-3048

                                                                                            manufacturing in electrical engineering applications.


                                                                                              Fatigue Behavior of FDM Parts Manufactured with Ultem 9085

                                                                                              M. Fischer, V. Schoeppner, in: 27th Annual International Solid Freeform Fabrication Symposium , 2016, pp. 563–568

                                                                                              The mechanical characterization of fused deposition modeling (FDM) parts is mostly done by static tests. In many applications, parts are also dynamically loaded. Here, fatigue tests can help to identify the expected lifetime of a part. This article discusses the fatigue behavior of FDM specimens manufactured with Ultem 9085. For this, tensile bars are manufactured according to ASTM D638 in different build orientations. Tests are performed in a range of pulsating tensile stresses, and S-N curves are documented for different build orientations. For higher loads, the FDM anisotropy characterizes the lifetime of used specimens, which is similar to static tensile bars. For lower loads, including a higher number of cycles to failure, S-N curves of different build orientations converge. In further tests, tensile bars were chemically smoothed with chloroform vapor. Chemical smoothing reduces surface roughness and increases tensile strength of specimens in the upright build direction. Fatigue tests of chemically treated specimens show no significant lifetime increase.


                                                                                                Data Management for additive manufacturing: survey on requirements and current state

                                                                                                I. Gräßler, P. Taplick, J. Pottebaum, P. Scholle, T. Reiher, in: 14th International DESIGN Conference 2016, 2016

                                                                                                The paper gives an overview of actually used Additive Manufacturing (AM) data formats and AM data infrastructure. Based on empirical analysis of the actual situation, necessary improvement of data management and exchange formats in context with AM technology is derived. The purpose of this paper is to understand the actual use of data formats and management in the field of AM. The paper draws conclusions based on an empirical analysis of the used data formats dependent on stakeholder groups. The results of the expert survey show a necessity to improve or develop new AM specific data formats.


                                                                                                  Optimierung von Fahrradtretkurbeln mittels additiver Fertigung

                                                                                                  J. Brüggemann, A. Riemer, W. Reschetnik, M. Aydinöz, G. Kullmer, H. Richard, M. Schaper, in: DVM - Tagung - Additiv gefertigte Bauteile und Strukturen, Deutscher Verband für Materialforschung und -prüfung e.V., 2016, pp. 101-112


                                                                                                  Lebensdauerbeeinflussung durch Additive Fertigung

                                                                                                  W. Reschetnik, J. Brüggemann, M. Aydinöz, G. Kullmer, H. Richard, M. Schaper, in: DVM - Tagung - Additiv gefertigte Bauteile und Strukturen, Deutscher Verband für Materialforschung und -prüfung e.V., 2016, pp. 131-140


                                                                                                  Fatigue Life Manipulation of SLM Parts

                                                                                                  W. Reschetnik, R. Grylls, B. Bauer, H. Richard, G. Kullmer, 2016


                                                                                                  Optimized build orientation of additive manufactured parts for improved surface quality and build time

                                                                                                  P. Delfs, M. Tows, H. Schmid, Additive Manufacturing (2016), 2(12, Part B), pp. 214-320

                                                                                                  The layered structure of Additive Manufacturing processes results in a stair- stepping effect of the surface topographies. In general, the impact of this effect strongly depends on the build angle of a surface, whereas the overall surface roughness is additionally caused by the resolution of the specific AM process. The aim of this work is the prediction of the surface quality in dependence of the building orientation of a part. These results can finally be used to optimize the orientation to get a desired surface quality. As not all parts of the component surface are equally important, a preselection of areas can be used to improve the overall surface quality of relevant areas. The model uses the digital AMF format of a part. Each triangle is assigned with a roughness value and by testing different orientations the best one can be found. This approach needs a database for the surface qualities. This must be done separately for each Additive Manufacturing process and is shown exemplarily with a surface topography simulation for the laser sintering process.


                                                                                                    Chemical Surface Treatment of Ultem 9085 Parts

                                                                                                    M. Fischer, O. Seewald, V. Schoeppner, in: Rapid Tech - International Trade Show & Conference for Additive Manufacturing, Carl Hanser Verlag GmbH & Co. KG, 2016, pp. 121-133

                                                                                                    The material Ultem 9085 is a flame-retardant thermoplastic polymer, which can be processed with Fused Deposition Modeling (FDM). Due to ist high strength-to-weight ratio and FST rating, Ultem 9085 parts are used in aviation. Process related staircase effects on rounded and slanting part areas require a surface treatment for end use parts. These processes include smoothing by mass finishing or coating in order to reduce surface roughness. An alternative smoothing technique is chemical surface treatment, such as the use of Acetone for ABS materials. In this paper, the surface of Ultem 9085 parts is treated with Chloroform vapor in order to solve material at the surface and smooth it. Therefore, specimens built in different build orientations are treated and tested with regard to surface roughness values and mechancial strength properties. The analysis of surface roughness and treatment time shows a significantly higher efficiency for chemical treatment in comparison to mass finishing. By employing chemical treatment, it is possible to reduce surface roughness by more than 80 % to Rz values of approximately 15 µm. Mechanical tests and measurements of the Melt Volume Rate (MVR) show no material destruction for chemical surface treatment at room temperature for less than 150 min.


                                                                                                      Dimensional accuracy of polymer laser sintered parts: Influences and measures

                                                                                                      S. Josupeit, P. Delfs, T. Lieneke, G. Adam, M. Gessler, H. Pfisterer, H. Schmid, in: Rapid Tech - International Trade Show & Conference for Additive Manufacturing , 2016, pp. 107-120

                                                                                                      In the polymer laser sinter process, part quality depends on many influencing factors along the process chain. For application of the technology in series production and an integration of laser sintered parts into a technical environment, the dimensional accuracy of parts has to be taken into account. Therefore, occuring deviatons and their scattering have to be reduced and homogenized based on process parameters and build job layout. In this work, the dimensional accuracy of laser sintered parts is analyzed for varied parameter values. Influences of different process and geometrical build job parameters on dimensional deviatons are figured out. The experimental results allow an evaluation of more and less important influences. Finally, measures are deduced to reduce and homogenize dimensional deviations.


                                                                                                        Manufacturability and Mechanical Characterization of Laser Sintered Lattice Structures

                                                                                                        S. Josupeit, P. Delfs, D. Menge, H. Schmid, in: 27th Annual International Solid Freeform Fabrication Symposium , 2016, pp. 2077-2086

                                                                                                        The implementation of lattice structures into additive manufactured parts is an important method to decrease part weight maintaining a high specific payload. However, the manufacturability of lattice structures and mechanical properties for polymer laser sintering are quite unknown yet. To examine the manufacturability, sandwich structures with different cell types, cell sizes and lattice bar widths were designed, manufactured and evaluated. A decisive criterion is for example a sufficient powder removal. In a second step, manufacturable structures were analyzed using four-point-bending tests. Experimental data is compared to the density of the lattice structures and allows for a direct comparison of different cell types with varied geometrical attributes. The results of this work are guidelines for the design and dimensioning of laser sintered lattice structures.


                                                                                                          Influences on the dimensional Accuracy of Laser Sintered Parts along the Process Chain

                                                                                                          S. Josupeit, P. Delfs, T. Lieneke, H. Schmid, in: 27th Annual International Solid Freeform Fabrication Symposium , 2016


                                                                                                          Funktionsintegration additiv gefertigter Dämpfungsstrukturen bei Biegeschwingungen

                                                                                                          T. Künneke, D. Zimmer, in: DVM Tagung - Additiv gefertigte Bauteile und Strukturen, 2016, pp. 151-160

                                                                                                          Additive manufacturing processes offer great freedom in the design of components. This enables a high level of function integration. Also in terms of vibration damping, additive manufacturing yields opportunities for the selective implementation of damping functions due to their characteristics. In powder-based processes the disperse support material can be kept inside the cavities of the structure. This powder material can act as a particle damper. Due to the freedoms in design, the damping behavior can be adjusted selectively by varying the geometrical features of the cavities. Within this paper, investigations on the damping behavior of additive manufactured parts regarding free bending vibrations are focused.


                                                                                                            Reproducibility of the Dimensional Accuracy - Investigations for FDM

                                                                                                            F. Knoop, T. Lieneke, V. Schoeppner, in: ASPE Spring Topical Meeting, 2016, pp. S.3-8


                                                                                                            Materialkennwerte lasergeschmolzener Werkstoffe

                                                                                                            A. Riemer, L. Leuders, G. Kullmer, H. Richard, in: DVM - Tagung - Additiv gefertigte Bauteile und Strukturen, Deutscher Verband für Materialforschung und -prüfung e.V., 2016, pp. 161-174


                                                                                                            Crack Propagation in Additive Manufactured Materials and Structures

                                                                                                            A. Riemer, H. Richard, in: Procedia Structural Integrity, 2016, pp. 1229-1236


                                                                                                            Thermal properties of polyamide 12 powder for application in laser sintering

                                                                                                            S. Josupeit, H. Schmid, in: International Congress on Particle Technology (PARTEC) , 2016


                                                                                                            Additive Manufacturing of a Lightweight Rotor for a Permanent Magnet Synchronous Machine

                                                                                                            S. Lammers, G. Adam, H. Schmid, R. Mrozek, R. Oberacker, M. Hoffmann, F. Quattrone, B. Ponick, in: EDPC 2016, 2016

                                                                                                            Additive Manufacturing (AM), also known as 3D printing, is a relatively new technology which enables the toolless production of components and entire assemblies directly from a CAD file. Today, the technology is still not widely used in industrial production. It is mainly limited to special applications, although it shows great potential. In this paper, first approaches are shown to apply AM to the production of rotors for permanent magnet synchronous machines (PMSM). The possibilities of a lightweight design with a low moment of inertia as well as the influence on the magnetic anisotropy for an improved sensorless control of PMSM are pointed out. The results clearly demonstrate the great potential of additive manufacturing in electrical engineering applications.


                                                                                                              Dimensional tolerances for additive manufacturing: Experimental investigation of manufacturing accuracy for selective laser melting

                                                                                                              T. Lieneke, S. de Groot, G. Adam, D. Zimmer, in: ASPE 2016 Summer Topical Meeting, 2016, pp. S.9-15


                                                                                                              Reproducibility of the Dimensional Accuracy - Investigations for FDM

                                                                                                              F. Knoop, T. Lieneke, V. Schoeppner, in: Summer Topical Meeting 2016, 2016


                                                                                                              Neue Prototypen-Werkzeugtechnologie für Bipolarplatten und Batteriekomponenten

                                                                                                              T. Hickmann, D. Ahlers, T. Tröster, Der Stahlformenbauer (2016)(5)


                                                                                                              Festigkeits- und leichtbauoptimierte Konstruktion und Auslegung eines additiv gefertigten Fahrradvorbaus

                                                                                                              J. Brüggemann, W. Reschetnik, H. Richard, G. Kullmer, B. Schramm, in: Rapid Tech - International Trade Show & Conference for Additive Manufacturing, 2016, pp. 290-300

                                                                                                              Die Zielsetzung beim Radfahren ist das Leistungspotential des Fahrers vollständig auszunutzen. Dabei muss das Fahrrad optimal an die Körpermaße des Fahrers angepasst werden. Besonders im Radrennsport ist neben dem hohen Leichtbaupotential eine aerodynamische Sitzhaltung von enormer Bedeutung. Unter Berücksichtigung dieser Anforderungen sind individuelle Bauteile und Strukturen zu entwickeln, da nicht in allen Fällen die Abmessungen der Standardbauteile eine optimale Anpassung zulassen. Im Hinblick auf einen groß gewachsenen Fahrer ist ein verlängerter Vorbau – Gabel-Lenker-Verbindung – für eine aerodynamische Sitzhaltung und somit einen geringen Luftwiderstand unumgänglich. Für die Herstellung solcher maßgeschneiderten Strukturen ist die additive Fertigung aufgrund der hohen gestalterischen Freiheiten und des hohen Individualisierungsgrades besonders geeignet. Im Rahmen dieses Beitrags wird ein Fahrradvorbau für einen überdurchschnittlich langen Fahrer festigkeits- und leichtbauoptimiert konstruiert und nach der Norm DIN EN ISO4210 unter Berücksichtigung der verfahrensspezifischen Randbedingungen beziehungsweise Gestaltungsrichtlinien des Laserstrahlschmelzens ausgelegt. Ausgangsbasis für die Geometriegestaltung sind die Grundlagen der Festigkeitsberechnung. Ein CAD-Modell wird erstellt und aufgrund der komplexen Belastungssituation mit Hilfe der Finite-Elemente-Methode numerisch untersucht sowie optimiert. Nach mehreren Iterationsschritten wird für den Werkstoff TiAl6V4 ein gewichtsreduzierter überlanger Fahrradvorbau von 140mm entwickelt und generativ hergestellt. Der anschließende Vergleich zu einem handelsüblichen Vorbau zeigt eine Gewichtsreduktion von ca. 30%.


                                                                                                                Universelle Mikrobearbeitungsplaffform und Basistechnologien für das Fertigen und Markieren mikrophysiologischer Systeme

                                                                                                                K. Günther, E. Moritzer, A. Hirsch, S. Teutoburg-Weiss, A. Lasagni, U. Klotzbach, F. Sonntag, 6. Dresdner Medizintechnik-Symposium, Biomedizinische Technik - interdisziplinär, integrativ und innovativ (2016), 6, pp. 65-70

                                                                                                                Das Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS etablierte in enger Kooperation mit Partnern in den letzten Jahren erfolgreich eine geschlossene Technologiekette zur Umsetzung maßgeschneiderter mikrophysiologischer Systeme. Darauf aufbauend wurde eine universelle Mikrobearbeitungsplattform zum automatisierten Fertigen konzipiert und entwickelt. Dies umfasst neue Technologien für Schlüsselprozesse wie das Herstellen mikrofluidischer Komponenten mittels ARBURG Kunststoff-Freiformen sowie das Erzeugen funktionaler Strukturen und das Einbringen von Produktschutzmerkmalen auf innenliegenden Polymergrenzflächen mittels Direktem Laserinterferenz-Verfahren.


                                                                                                                  Extended Analysis of the Surface Topography of Laser Sintered Polymer Parts

                                                                                                                  P. Delfs, H. Schmid, in: Fraunhofer Direct Digital Manufacturing Conference, 2016, pp. 411-414


                                                                                                                  Dimensional tolerances for additive manufacturing: Experimental investigation for Fused Deposition Modeling

                                                                                                                  T. Lieneke, V. Denzer, G. Adam, D. Zimmer, in: CAT 2016, 2016, pp. 286-291

                                                                                                                  Additive manufacturing creates parts in layers without using formative tools. Compared to established manufacturing processes, additive manufacturing offers many advantages. However, only a few research institutions and technology-leading companies use additive manufacturing for end-use part production because relevant challenges have not been sufficiently researched yet. Missing restrictions become apparent in the available geometrical accuracy. The objective of this investigation was the experimental determination of dimensional tolerances using standard parameters. To this end, a methodical procedure was set up. Based on experimentally determined deviations, dimensional tolerances were derived.


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