Additive Fertigung
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- Additive manufacturing (15)
- Additive Manufacturing (12)
- Laser powder bed fusion (7)
- Thermography (7)
- Laser Metal Deposition (4)
- Laser Powder Bed Fusion (4)
- Inconel 718 (3)
- L-PBF (3)
- Laser metal deposition (3)
- Selective Laser Melting (3)
- 316L (2)
- AlSi10Mg (2)
- Directed Energy Deposition (2)
- Hybrid components (2)
- In-situ monitoring (2)
- Infrared thermography (2)
- Porosity (2)
- Position detection (2)
- Process monitoring (2)
- Residual stress (2)
- Selective laser melting (2)
- 3D Druck (1)
- 3D printing (1)
- AM (1)
- Active thermography (1)
- Additive Fertigung (1)
- Additive Manufacturing (AM) (1)
- Additive manufacturing (AM) (1)
- Advanced Manufacturing (1)
- Aerosol measurements (1)
- Air-coupled ultrasonic testing (1)
- Alumina (1)
- Analytical model (1)
- Anisotropy (1)
- Artificial weathering (1)
- Atmospheric pressure plasma (1)
- Bridging voids (1)
- Build direction (1)
- Build-up Orientation (1)
- Calculation time (1)
- Camera calibration (1)
- Cold Spray (1)
- Computer Aided Manufacturing (1)
- Copper powder particles (1)
- Crystal plasticity (1)
- Cyclic R-curve (1)
- DED (1)
- Data Integrity (1)
- Defect Detection (1)
- Defect detection (1)
- Design for Additive Manufacturing (DfAM) (1)
- Dielectric properties (1)
- Diffraction (1)
- Digital Twin (1)
- Digitalisation (1)
- Direct energy deposition (1)
- Directed energy deposition (1)
- Distortion simulation (1)
- Edge effects (1)
- Efficient modelling (1)
- Electrical conductivity (1)
- European Metrology Network (EMN) (1)
- Fatigue crack growth (1)
- Fume (1)
- Gas discharges (1)
- Haynes 282 (1)
- Heat accumulation (1)
- Heat treatment (1)
- Heat treatments (1)
- High-resolution camera (1)
- High-strength structural steels (1)
- Hybrid Part (1)
- Hybrid build-up (1)
- Hybrid repair (1)
- IN718 (1)
- ISRU (1)
- Infrastructure (1)
- Keyhole porosity (1)
- LMD (1)
- LW (1)
- Laboratory specimens (1)
- Large electrical high-voltage machine (1)
- Laser Powder Bed Fusion (L-PBF) (1)
- Laser Powder Bed Fusion (PBF-LB/M) (1)
- Laser Pulver Auftragsschweißen (1)
- Laser Welding (1)
- Laser beam melting (LBM) (1)
- Laser powderbed fusion (1)
- Laser thermography (1)
- Laser welding (1)
- Liquation Cracking (1)
- Lunar habitat (1)
- MPI (1)
- MPLS (1)
- Machine Learning (1)
- Magnetic swimmers (1)
- Maritime Components (1)
- Mechanical properties (1)
- Melt-pool-monitoring (1)
- Metrology (1)
- Micro-CT (1)
- Multispectral thermography (1)
- Neutron diffraction (1)
- Nickel-based superalloy (1)
- Nondestructive Testing (1)
- Nondestructive testing (1)
- Optical tomography (1)
- PBF-LB/M (1)
- PBF/LB-M (1)
- Particle gas emission (1)
- Path planning (1)
- Paving (1)
- Plasma acoustics (1)
- Plume (1)
- Polymer (1)
- Pores (1)
- Powder Analysis (1)
- Pre-weld Preparation (1)
- ProMoAM (1)
- Process Chain Integration (1)
- Process parameter optimization (1)
- Quality Assurance (1)
- Recycling (1)
- Repair of gas turbine blades (1)
- Reproducibility (1)
- Residual Stress (1)
- Residual Stresses (1)
- Residual stresses (1)
- Round robin (1)
- SLM (1)
- SWIR camera (1)
- Scale-bridging (1)
- Selective Laser Melting (SLM) (1)
- Selective laser melting (SLM) (1)
- Solar sintering (1)
- Solidification behaviour (1)
- Spatter (1)
- Stainless Steel (1)
- Strategic Research Agenda (SRA) (1)
- Supportless (1)
- Synchrotron X-ray diffraction (1)
- TES (1)
- Temperature behavior (1)
- Temperature emissivity separation (1)
- Tensile performance (1)
- Thermal Spray (1)
- Thermografie (1)
- Ti-6Al-4V (1)
- Time over threshold (1)
- Two-Photon Polymerization (1)
- Vickers hardness (1)
- Virtual experiments (1)
- Wire Arc Additive Manufacturing (1)
Organisationseinheit der BAM
- 9 Komponentensicherheit (28)
- 8 Zerstörungsfreie Prüfung (18)
- 9.6 Additive Fertigung metallischer Komponenten (13)
- 8.0 Abteilungsleitung und andere (11)
- 9.3 Schweißtechnische Fertigungsverfahren (10)
- 8.5 Röntgenbildgebung (7)
- 5 Werkstofftechnik (5)
- 9.4 Integrität von Schweißverbindungen (5)
- 5.0 Abteilungsleitung und andere (2)
- 5.4 Multimateriale Fertigungsprozesse (2)
3D microstructures with sub-micron resolution can be manufactured in additive manner applying multi-photon laser structuring technique. This paper is focused on the incorporation of superparamagnetic iron oxide nanoparticles into the photoresist in order to manufacture micrometer-sized devices featuring a magnetic moment. The aim of the project is to achieve untethered actuation of the presented objects through externally applied magnetic fields. Future medical application scenarios such as drug delivery and tissue engineering are targeted by this research.
In this paper shortwave infrared (SWIR) thermographic measurements of the manufacturing of thin single-line walls via laser metal deposition (LMD) are presented. As the thermographic camera is mounted fixed to the welding arm, an acceleration sensor was used to assist in reconstructing the spatial position from the predefined welding path. Hereby we could obtain data sets containing the size of the molten pool and the oxide covered areas as functions of the position in the workpiece. Furthermore, the influence of the acquisition wavelength onto the thermograms was investigated in a spectral range from 1250 nm to 1550 nm. All wavelengths turned out to be usable for the in-situ process monitoring of the LMD process. The longer wavelengths are shown to be beneficial for the lower temperature range, while shorter wavelengths show more details within the molten pool.
Additive manufacturing is no longer just used for the production of prototypes but already found its way into the industrial production. However, the fabrication of massive metallic parts with high geometrical complexity is still too time-consuming to be economically viable. The combination of the powder bed-based selective laser melting process (SLM), known for its geometrical freedom and accuracy, and the nozzle-based laser metal deposition process (LMD), known for its high build-up rates, has great potential to reduce the process duration. For the industrial application of the SLM-LMD hybrid process chain it is necessary to investigate the interaction of the processes and its effect on the material properties to guarantee part quality and prevent component failure. Therefore, hybrid components are manufactured and examined before and after the heat treatment regarding the microstructure and the hardness in the SLM-LMD transition zone. The experiments are conducted using the nickel-based alloy Inconel 718.
Virtual-lab-based determination of a macroscopic yield function for additively manufactured parts
(2018)
This work presents a method for the yield function determination of additively manufactured parts of S316L steel. A crystal plasticity model is calibrated with test results and used afterwards to perform so-called virtual experiments, that account for the specific process-related microstructure including crystallographic and morphological textures. These simulations are undertaken on a representative volume element (RVE), that is generated from EBSD/CT-Scans on in-house additively manufactured specimen, considering grain structure and crystal orientations. The results of the virtual experiments are used to determine an anisotropic Barlat yield function, that can be used in a macroscopical continuum-sense afterwards. This scale-bridging approach enables the calculation of large-scale parts, that would be numerically too expensive to be simulated by a crystal plasticity model.
Modern and energy-efficient materials are essential for innovative designs for aerospace and automotive industries. Current technologies for rapid manufacturing such as additive manufacturing and liquid composite moulding by polymer Extrusion allow innovative ways of creating robust and lightweight constructions. Commercially available printing devices often use polylactide (PLA) or acrylonitrile butadiene styrene (ABS) as raw material. Therefore, parameters like the infill ratio, influencing the ability to resist mechanical stress, may have a beneficial impact on the lifetime of components.
These manufacturing technologies require a good knowledge about materials and even adapted non-destructive testing technologies and methods. Airborne ultrasonic testing has beneficial advantages for testing those lightweight constructions. It is a contact-free testing method, which does not require a liquid couplant. Therefore, it allows fast test cycles without any unwanted alternations of the material properties due to interactions with any coupling liquid. This contribution deals with the characterisation of printed specimens based on PLA by using airborne ultrasound and presents the current edge of non-destructive testing and evaluation using airborne ultrasonic transducers. The specimens, manufactured by polymer extrusion, are printed as thin plates. The infill ratio, as well as the material thickness, were varied to model density imperfections with different geometric shapes and properties. For better understanding of the limits of airborne ultrasonic testing in transmission, we compared own-developed transducers based on different physical principles: on ferroelectrets, on the thermoacoustic effect, as well as a new type of transducers based on gas discharges.
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 a range of novel applications. However, the manufacturing process is complex and the production of defect-free parts with high reliability and durability is still a challenge. Thermography is a valuable tool for process surveillance, especially in metal AM processes. The high process temperatures allow one to use cameras usually operating in the visible spectral range. Here, we compare the results of measurements during the manufacturing process of a commercial laser metal deposition setup using a mid-wavelength-IR camera with those from a visual spectrum high-speed camera with band pass filter in the near-IR range.
Additively manufactured test specimens made of polyamide 12 (PA 12) by Laser Sintering (LS) as well as of acrylnitril-butadien-styrol (ABS) by Fused Layer Modeling (FLM), were tested with active thermography. For this, two different excitation methods (flash and impulse excitation) were used and compared, regarding the suitability for the detection of constructed and imprinted defects. To increase the quality of the thermograms, data processing methods like thermal signal reconstruction (TSR) and Fourier-Transformation were applied. Furthermore, the long-term stability of the probes towards environmental stress, like UV-radiation, heat, water contact and frost is being investigated in the presented project with artificial weathering tests.
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 the bulk of IN718 elongated prisms produced by SLM was studied non-destructively by means of neutron 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.
Synchrotron X-ray diffraction is a powerful non-destructive technique for the analysis of the material stress-state. High cooling rates and heterogeneous temperature distributions during additive manufacturing lead to high residual stresses. These high residual stresses play a crucial role in the ability to achieve complex geometries with accuracy since they can promote distortion of parts during manufacturing. Furthermore, residual stresses are critical for the mechanical performance of parts in terms of durability and safety.
In the present study, Ti-6Al-4V bridge-like specimens were manufactured additively by selective laser melting (SLM) under different laser scanning speed conditions in order to compare the effect of process energy density on the residual stress state. Subsurface residual stress analysis was conducted by means of synchrotron X-ray diffraction in energy dispersive mode for three conditions: as-built on base plate, released from base plate, and after heat treatment on the base plate. The quantitative residual stress characterization shows a correlation with the qualitative bridge curvature method. Computed tomography (CT) was carried out to ensure that no stress relief took place owing to the presence of porosity. CT allows obtaining spatial and size pores distribution which helps in optimization of the SLM process.
High tensile residual stresses were found at the lateral surface for samples in the as-built conditions. We observed that higher laser energy density during fabrication leads to lower residual stresses. Samples in released condition showed redistribution of the stresses due to distortion.