Additive Fertigung
Filtern
Dokumenttyp
- Vortrag (242)
- Zeitschriftenartikel (196)
- Posterpräsentation (69)
- Beitrag zu einem Tagungsband (42)
- Forschungsdatensatz (9)
- Buchkapitel (3)
- Dissertation (3)
- Sonstiges (1)
- Preprint (1)
Sprache
- Englisch (566) (entfernen)
Schlagworte
- Additive manufacturing (204)
- Additive Manufacturing (152)
- Residual stress (51)
- Laser powder bed fusion (49)
- Thermography (47)
- Laser Powder Bed Fusion (29)
- Computed tomography (28)
- Microstructure (27)
- 316L (23)
- Ti-6Al-4V (20)
Organisationseinheit der BAM
- 8 Zerstörungsfreie Prüfung (274)
- 9 Komponentensicherheit (264)
- 8.5 Röntgenbildgebung (204)
- 5 Werkstofftechnik (166)
- 9.3 Schweißtechnische Fertigungsverfahren (102)
- 9.4 Integrität von Schweißverbindungen (95)
- 5.4 Multimateriale Fertigungsprozesse (83)
- 9.6 Additive Fertigung metallischer Komponenten (83)
- 8.3 Thermografische Verfahren (72)
- 5.2 Metallische Hochtemperaturwerkstoffe (47)
- 5.1 Mikrostruktur Design und Degradation (37)
- 6 Materialchemie (34)
- 9.2 Versuchsanlagen und Prüftechnik (24)
- 6.6 Physik und chemische Analytik der Polymere (20)
- 8.0 Abteilungsleitung und andere (17)
- 7 Bauwerkssicherheit (16)
- 1 Analytische Chemie; Referenzmaterialien (13)
- 5.0 Abteilungsleitung und andere (13)
- 4 Material und Umwelt (12)
- 5.5 Materialmodellierung (12)
- 8.4 Akustische und elektromagnetische Verfahren (10)
- 4.2 Material-Mikrobiom Wechselwirkungen (7)
- 1.9 Chemische und optische Sensorik (6)
- 6.0 Abteilungsleitung und andere (6)
- 6.1 Oberflächen- und Dünnschichtanalyse (6)
- 7.4 Baustofftechnologie (6)
- 9.0 Abteilungsleitung und andere (6)
- 6.5 Synthese und Streuverfahren nanostrukturierter Materialien (5)
- 1.4 Prozessanalytik (4)
- 6.3 Strukturanalytik (4)
- 7.7 Modellierung und Simulation (4)
- 1.5 Proteinanalytik (3)
- 4.5 Kunst- und Kulturgutanalyse (3)
- 7.6 Korrosion und Korrosionsschutz (3)
- 4.1 Biologische Materialschädigung und Referenzorganismen (2)
- 5.6 Glas (2)
- 6.7 Materialsynthese und Design (2)
- 7.5 Technische Eigenschaften von Polymerwerkstoffen (2)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (2)
- S Qualitätsinfrastruktur (2)
- 1.6 Anorganische Referenzmaterialien (1)
- 4.0 Abteilungsleitung und andere (1)
- 7.1 Baustoffe (1)
- S.0 Abteilungsleitung und andere (1)
- S.2 Digitalisierung der Qualitätsinfrastruktur (1)
Paper des Monats
- ja (7)
The Layerwise Slurry Deposition is a technology for the deposition of highly packed powder layers. A powder bed is achieved by depositing and drying layers of a ceramic suspension by means of a doctor blade. This deposition technique was combined with the binder jetting technology to develop a novel Additive Manufacturing technology, named LSD-print. The LSD-print was applied to a porcelain ceramic. It is shown that it was possible to produce parts with high definition, good surface finish and at the same time having physical and mechanical properties close to those of traditionally processed porcelain, e.g. by slip casting.
This technology shows high future potential for being integrated alongside traditional production of porce-lain, as it is easily scalable to large areas while maintaining a good definition. Both the Layerwise Slurry Deposition method and the binder jetting technologies are readily scalable to areas as large as > 1 m2.
A shape evolution approach based on the thermally activated self-organization of 3D printed parts into minimal surface area structures is presented. With this strategy, the present communication opposes currently established additive manufacturing strategies aiming to stipulate each individual volumetric element (voxel) of a part. Instead, a 3D structure is roughly defined in a 3D printing process, with all its advantages, and an externally triggered self-organization allows the formation of structural elements with a definition greatly exceeding the volumetric resolution of the printing process. For enabling the self-organization of printed objects by viscous flow of material, functionally graded structures are printed as rigid frame and melting filler. This approach uniquely combines the freedom in design, provided by 3D printing, with the mathematical formulation of minimal surface structures and the knowledge of the physical potentials governing self-organization, to overcome the paradigm which strictly orrelates the geometrical definition of 3D printed parts to the volumetric resolution of the printing process. Moreover, a transient liquid phase allows local programming of functionalities, such as the alignment of functional particles, by means of electric or magnetic fields.
Tricalcium phosphate (b-TCP) can be used as bone graft, exhibiting suitable bioabsorption and osteoconduction properties. The presence of silica may induce the formation of a hydroxyapatite layer, enhancing the integration between implant and bone tissue. Preceramic polymers present silicon in their composition, being a source of SiO2 after thermal treatment. Using the versatility of 3D printing, b-TCP and a polysiloxane were combined to manufacture a bulkb-TCP with a silica coating. For the additive manufacturing process, PMMA powder was used as passive binder for the b-TCP particles, and polymethylsilsesquioxane (MK), dissolved in an organic solvent, was used both as a printing binder (ink) and as the source of SiO2 for the coating. Five distinct coating compositions were printed with increasing amounts of MK. The structures were then submitted to heat treatment at 1180 °C for 4 h. XRD and FTIR showed no chemical reaction between the calcium phosphate and silica. SEM allowed observation of a silicon-based ating on the structure surface. Mechanical strength of the sintered porous structures was within the range of that of trabecular bones.
Distortions in Additive Manufacturing (AM) Laser Metal Deposition (LMD) occur in the newly-built component due to rapid heating and solidification and can lead to shape deviations and cracking. This paper presents a novel approach to quantify the distortions experimentally and to use the results in numerical simulation validation. Digital Image Correlation (DIC) is applied together with optical filters to measure in-situ distortions directly on a wall geometry produced with LMD. The wall shows cyclic Expansion and shrinking with the edges bending inward and the top of the sample exhibiting a slight u-shape as residual distortions. Subsequently, a structural Finite Element Analysis (FEA) of the experiment is established, calibrated against experimental temperature profiles and used to predict the in-situ distortions of the sample. A comparison of the experimental and numerical results reveals a good agreement in length direction of the sample and quantitative deviations in height direction, which are attributed to the material model used. The suitability of the novel experimental approach for measurements on an AM sample is shown and the potential for the validated numerical model as a predictive tool to reduce trial-and-error and improve part quality is evaluated.
Having been introduced almost two decades ago, Additive Manufacturing (AM) of metals has become industrially viable for a large variety of applications, including aerospace, automotive and medicine. Powder bed techniques such as Selective Laser Melting (SLM) based on layer-by-layer deposition and laser melt enable numerous degrees of freedom for the geometrical design. Developing during the manufacturing process, residual stresses may limit the application of SLM parts by reducing the load bearing capacity as well as induce unwanted distortion depending on the boundary conditions specified in manufacturing.
The residual stress distribution in IN718 elongated prisms produced by SLM was studied non-destructively by means of neutron (bulk) and laboratory X-ray (surface) diffraction. The samples with different scanning strategies, i.e. hatching length, were measured in as-build condition (on a build plate) and after removal from the build plate.
The absolute values of all stress components decreased after removal from the build plate. Together with surface scan utilizing a coordinate-measuring machine (CMM), it is possible to link the stress release to the sample distortion. Obtained results indicated different residual stress states for each of the transversal, longitudinal and normal component depending on the thermal gradient in the respective direction.
Having been introduced almost two decades ago, Additive Manufacturing (AM) of metals has become industrially viable for a large variety of applications, including aerospace, automotive and medicine. Powder bed techniques such as Selective Laser Melting (SLM) based on layer-by-layer deposition and laser melt enable numerous degrees of freedom for the geometrical design. Developing during the manufacturing process, residual stresses may limit the application of SLM parts by reducing the load bearing capacity as well as induce unwanted distortion depending on the boundary conditions specified in manufacturing.
The residual stress distribution in IN718 elongated prisms produced by SLM was studied non-destructively by means of neutron (bulk) and laboratory X-ray (surface) diffraction. The samples with different scanning strategies, i.e. hatching length, were measured in as-build condition (on a build plate) and after removal from the build plate.
The absolute values of all stress components decreased after removal from the build plate. Together with surface scan utilizing a coordinate-measuring machine (CMM), it is possible to link the stress release to the sample distortion. Obtained results indicated different residual stress states for each of the transversal, longitudinal and normal component depending on the thermal gradient in the respective direction.
Build-up strategies for temperature control using laser metal deposition for additive manufacturing
(2018)
The track geometry created with laser metal deposition (LMD) is influenced by various parameters. In this case, the laser power has an influence on the width of the track because of an increasing energy input. A larger melt pool is caused by a rising temperature. In the case of a longer welding process, there is also a rise in temperature, resulting in a change of the track geometry. This paper deals with the temperature profiles of different zigzag strategies and spiral strategies for additive manufacturing. A two-color pyrometer is used for temperature measurement on the component surface near the melt pool. Thermocouples measure the temperatures in deeper regions of a component. The welds are located in the center and in the edge area on a test part to investigate the temperature evolution under different boundary conditions. The experiments are carried out on substrates made from mild steel 1.0038 and with the filler material 316L. The investigations show an influence on the temperature evolution by the travel path strategy as well as the position on the part. This shows the necessity for the development and selection of build-up strategies for different part geometries in additive manufacturing by LMD.
Additive Manufacturing (AM) through the Selective Laser Melting (SLM) route offers ample scope for producing geometrically complex parts compared to the conventional subtractive manufacturing strategies. Nevertheless, the residual stresses which develop during the fabrication can limit application of the SLM components by reducing the load bearing capacity and by inducing unwanted distortion, depending on the boundary conditions specified during manufacturing. The present study aims at characterizing the residual stress states in the SLM parts using different diffraction methods. The material used is the nickel based superalloy Inconel 718. Microstructure as well as the surface and bulk residual stresses were characterized. For the residual stress analysis, X-ray, synchrotron and neutron diffraction methods were used. The measurements were performed at BAM, at the EDDI beamline of -BESSY II synchrotronand the E3 line -BER II neutron reactor- of the Helmholtz-Zentrum für Materialien und Energie (HZB) Berlin. The results reveal significant differences in the residual stress states for the different characterization techniques employed, which indicates the dependence of the residual state on the penetration depth in the sample. For the surface residual stresses, longitudinal and transverse stress components from X-ray and synchrotron agree well and the obtained values were around the yield strength of the material. Furthermore, synchrotron mapping disclosed gradients along the width and length of the sample for the longitudinal and transverse stress components. On the other hand, lower residual stresses were found in the bulk of the material measured using neutron diffraction. The longitudinal component was tensile and decreased towards the boundary of the sample. In contrast, the normal component was nearly constant and compressive in nature. The transversal component was almost negligible. The results indicate that a stress re-distribution takes place during the deposition of the consecutive layers. Further investigations are planned to study the phenomenon in detail.
Additive manufacturing (AM) offers an effective solution to the medical sector. It enables the production, on demand, of customised implants which match the patient’s anatomy, with grafts that promote bone growth, as well as surgical guides that help the surgeons.
The objective of this project is to provide a comprehensive basis to enable the safe use of medical AM products with traceable and reliable dimensionalmeasurements. This will guarantee the reliability of medical AM products to notified bodies and facilitate acceptance of AM in the medical sector for a better quality of life.