Prozessmanagement für das Laser-Pulver-Auftragschweißen

Möller, Mauritz Leander Birger

doi:10.1007/978-3-662-62225-4

Cited by 8 publications

(11 citation statements)

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“…An approach to prevent this, is a layer-adaptive laser power adjustment of the process. According to Moeller [10], a wall structure can be divided into three regions where different boundary conditions directly influence the parameter adaptation. The first region is the bottom region of the geometry, where a rapid decrease of the laser power is needed to counteract the heat accumulation through the substrate material.…”

Section: Methodsmentioning

confidence: 99%

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Powder-based laser metal deposition of VDM Alloy 780: strategy development for efficient buildup of thin-walled components

Paulus

Ruppert

Vielhaber

et al. 2023

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems XII

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Powder-based laser metal deposition (LMD) represents a future-oriented additive manufacturing process given the large number of available materials as well as the high degree of geometric freedom. These potentials are further enhanced by high build rates and a better material utilization compared to turning or milling. However, the LMD process is very complex as a result of the large number of machine and process parameters. Different thermal conditions occur during layer-by-layer buildup. Newly supplied energy due to the laser-material interaction with the newest layer is supplemented by the heat energy still stored in the solidified component, which is distributed inhomogeneously depending on material and part geometry. In order to avoid dimensional deviations and microstructural defects, the machining parameters have to be adjusted during the LMD process. The following paper presents a strategy for the efficient and process-safe buildup of thin-walled VDM Alloy 780 geometries on 316L substrates using powder-based LMD. Adaptive adjustment of parameters and monitoring of cooling times improve the dimensional accuracy of the geometry while avoiding defects. The fabricated specimens are then analyzed using optical microscopy, SEM and EDX. Porosity analysis is performed by various methods. In addition, mechanical properties are determined by tensile tests in perpendicular and parallel directions as well as by macrohardness tests.

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Section: Methodsmentioning

confidence: 99%

“…Studies of Abioye et al [9] revealed that a nearly linear adjustment of laser power as a function of build layer has positive effects on geometry accuracy for Ti6Al4V parts. Moeller [10] uses non-linear parameter sets and achieves near-net-shape geometries with small deviation.…”

Section: Introductionmentioning

confidence: 99%

Powder-based laser metal deposition of VDM Alloy 780: strategy development for efficient buildup of thin-walled components

Paulus

Ruppert

Vielhaber

et al. 2023

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems XII

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“…However, the main process parameters, i.e., laser power, feed rate and powder mass flow, are crucial for a qualitative results [43]. The quality of the clad is evaluated by the degree of dilution [44,45], density [46], cracks [47,48] and the microstructure. Furthermore, economical aspects such as powder efficiency and build rate are considered.…”

Section: Introductionmentioning

confidence: 99%

“…The parameters for the experimental study are defined on the basis of the literature data for comparable materials such as Inconel 718 [29] and 625 [39]. In advance, the laser power is determined by an approximation equation based on literature informa-tion [46]. The equation describes the required laser power as a function of machineand material-specific factors.…”

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confidence: 99%

Process Map Definition for Laser Metal Deposition of VDM Alloy 780 on the 316L Substrate

Paulus

Ruppert

Vielhaber

et al. 2023

JMMP

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VDM Alloy 780 is a novel Ni-based superalloy that allows for approximately 50 °C higher operating temperatures, compared to Inconel 718, without a significant decrease in mechanical properties. The age hardenable NiCoCr Alloy combines increased temperature strength with oxidation resistance, as well as improved microstructural stability due to γ′-precipitation. These advantages make it suitable for wear- and corrosion-resistant coatings that can be used in high temperature applications. However, VDM Alloy 780 has not yet been sufficiently investigated for laser metal deposition applications. A design of experiments with single tracks on 316L specimens was carried out to evaluate the influence of the process parameters on clad quality. Subsequently, the quality of the clads was evaluated by means of destructive and non-destructive testing methods, in order to verify the suitability of VDM Alloy 780 for laser metal deposition applications. The single-track experiments provide a basis for coating or additive manufacturing applications. For conveying the results, scatter plots with regression lines are presented, which illustrate the influence of specific energy density on the resulting porosity, dilution, powder efficiency, aspect ratio, width and height. Finally, the clad quality, in terms of porosity, is visualized by two process maps with different mass per unit lengths.

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“…Laser-based directed energy deposition with metal powder (DED-LB/M) offers such a flexible process, as it can be used for coating, welding, repairing and additive manufacturing without major change in hardware [8][9][10]. To weld single DED tracks, which are the basis of all mentioned applications, powder is transported to the process zone and the laser beam melts both powder and workpiece leading to a metallurgic bonding [11][12][13]. The geometry of the DED tracks and the corresponding height of the produced layers are influenced by the process parameters such as velocity v, laser power P, powder flow rate ṁ and the diameter d L of the laser beam on the surface of the workpiece.…”

Section: Introductionmentioning

confidence: 99%

Data-Driven Prediction and Uncertainty Quantification of Process Parameters for Directed Energy Deposition

Hermann,

Michalowski,

Brünnette

et al. 2023

Materials

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Laser-based directed energy deposition using metal powder (DED-LB/M) offers great potential for a flexible production mainly defined by software. To exploit this potential, knowledge of the process parameters required to achieve a specific track geometry is essential. Existing analytical, numerical, and machine-learning approaches, however, are not yet able to predict the process parameters in a satisfactory way. A trial-&-error approach is therefore usually applied to find the best process parameters. This paper presents a novel user-centric decision-making workflow, in which several combinations of process parameters that are most likely to yield the desired track geometry are proposed to the user. For this purpose, a Gaussian Process Regression (GPR) model, which has the advantage of including uncertainty quantification (UQ), was trained with experimental data to predict the geometry of single DED tracks based on the process parameters. The inherent UQ of the GPR together with the expert knowledge of the user can subsequently be leveraged for the inverse question of finding the best sets of process parameters by minimizing the expected squared deviation between target and actual track geometry. The GPR was trained and validated with a total of 379 cross sections of single tracks and the benefit of the workflow is demonstrated by two exemplary use cases.

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Prozessmanagement für das Laser-Pulver-Auftragschweißen

Cited by 8 publications

References 0 publications

Powder-based laser metal deposition of VDM Alloy 780: strategy development for efficient buildup of thin-walled components

Powder-based laser metal deposition of VDM Alloy 780: strategy development for efficient buildup of thin-walled components

Process Map Definition for Laser Metal Deposition of VDM Alloy 780 on the 316L Substrate

Data-Driven Prediction and Uncertainty Quantification of Process Parameters for Directed Energy Deposition

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