The influence of the workpiece illumination proportion in annular laser beam wire deposition process

Kotar, Matjaž; Govekar, Edvard

doi:10.1016/j.procir.2018.08.100

Cited by 7 publications

(8 citation statements)

References 5 publications

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“…Studies also show that the size of the ring-shaped laser spot can be deliberately used to partially or fully hit the wire before it enters the melt pool when a smaller inner diameter than the diameter of the wire is chosen [39]. Consequently, an additional process parameter, the workpiece illumination proportion (WIP), was proposed to characterize the distribution of the energy applied to the part and the wire [40]. The height of the part plays a crucial role for a defect-free multi-layer process [41] since a non-conformity between the height increment used in the path planning and the actual growth rate of the part would alter the WIP and would lead to process failures.…”

Section: Process Development For Lmd With Coaxial Wire Feedingmentioning

confidence: 99%

Investigation on the Cause-Effect Relationships between the Process Parameters and the Resulting Geometric Properties for Wire-Based Coaxial Laser Metal Deposition

Zapata

Bernauer

Stadter

et al. 2022

Metals

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Coaxial Laser Metal Deposition with wire (LMD-w) is a valuable complement to the already established Additive Manufacturing processes in production because it allows a direction-independent process with high deposition rates and high deposition accuracy. However, there is a lack of knowledge regarding the adjustment of the process parameters during process development to build defect-free parts. Therefore, in this work, a process development for coaxial LMD-w was conducted using an aluminum wire AlMg4,5MnZr and a stainless steel wire AISI 316L. At first, the boundaries for parameter combinations that led to a defect-free process were identified. The proportion between the process parameters energy per unit length and speed ratio proved crucial for a defect-free process. Then, the influence of the process parameters on the height and width of single beads for both materials was analyzed using a regression analysis. It was shown that linear models are suitable for describing the correlation between the process parameters and the dimensions of the beads. Lastly, a material-independent formula is presented to calculate the height increment per layer needed for an additive process. For future studies, the results of this work will be an aid for process development with different materials.

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Section: Process Development For Lmd With Coaxial Wire Feedingmentioning

confidence: 99%

Investigation on the Cause-Effect Relationships between the Process Parameters and the Resulting Geometric Properties for Wire-Based Coaxial Laser Metal Deposition

Zapata

Bernauer

Stadter

et al. 2022

Metals

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“…1(a), consists of an ALB-DWD head, a wire-feeding unit, a workpiece translation stage, a process-monitoring system and a continuous, 2.5-kW, fiber laser source with a wavelength of 1080 nm. Using a laser beam shaping unit in the ALB-DWD head [8,9], a collimated laser beam is transformed into an ALB. By means of two reflective mirrors, the ALB is guided coaxially to the axis of the wire-guiding tube and focused on the workpiece surface using focusing optics.…”

Section: Annular Laser Beam Wire-deposition Setup and Wipmentioning

confidence: 99%

“…This enables the symmetrical and simultaneous heating of the workpiece and the wire-end surface over its circumference using an annular laser beam. In order to characterize the proportion of the laser beam's energy input into the workpiece and the wire-end, introduced in [8], an experimental estimation of the workpiece irradiation proportion (WIP) is proposed. In the third section, different strategies for the initial transient phase of the ALB-DWD process, with respect to the wire-end initial position, are proposed and analysed, while in the fourth section the process stability is analysed.…”

Section: Introductionmentioning

confidence: 99%

Initial transient phase and stability of annular laser beam direct wire deposition

Kotar

Fujishima

Levy³

et al. 2019

CIRP Annals

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In this paper the stability of the annular laser beam (ALB) direct wire-deposition process, which enables process symmetry and a well-defined ALB workpiece irradiation proportion (WIP) and related energy input onto the workpiece and the wire surface is considered. Various initial process phase strategies with respect to different initial wire-end positions and WIPs were analysed based on the process visualization and outcome, and the melt pool temperature. It was shown that in addition to a precise synchronization of the mutually time-dependent ALB power, wire and workpiece feeding velocity, the fastest and the most robust transition into a stable stationary process could be achieved with the initial position of the wire-end on the workpiece surface. Additionally, the WIP was shown to have a strong and nonlinear influence on the process stability.

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“…Wu et al [15] presented an approach for achieving deposition direction independence in which the welding torch rotated according to the deposition direction in a process of wire arc additive manufacturing (WAAM). Some recently developed LMWD heads [16,17,18,19,20] solve the direction dependence issue by inserting the wire perpendicular to the substrate, so the laser beam is divided within the head and then refocused on the working plane. This introduces the additional complexity of accurately reconstructing the laser beam.…”

Section: Introductionmentioning

confidence: 99%

Development of an Intra-Layer Adaptive Toolpath Generation Control Procedure in the Laser Metal Wire Deposition Process

et al. 2019

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Recently developed concentric laser metal wire deposition (LMWD) heads allow metal addition processes which are independent of the deposition direction, thus enabling complex paths to be generated. The sensitivity of the process to height deviations has experimentally been observed to be greater with this type of head than with powder ones, therefore requiring more precise and local process control algorithms to be implemented. This work developed a methodology for measuring the part, layer by layer, using a 3D scanner based on structured laser light. Height corrections were applied to the mean and intra-layer height deviations by recalculating the deposition trajectories of the next layer to be deposited. Local height deviations were adjusted by varying the scanning speed, thus increasing the feed rate in the lower areas and decreasing it in the higher ones. Defects generated in the purpose, with height differences within the layer, were successfully corrected. A flat layer was re-established through the application of the control strategy. The internal integrity of the parts due to the scanning speed variation was analyzed, resulting in fully dense parts. The structured light measurement and height correction systems are found to be an affordable and time-efficient solution that can be integrated into an LMWD environment, thereby improving the process robustness.

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The influence of the workpiece illumination proportion in annular laser beam wire deposition process

Cited by 7 publications

References 5 publications

Investigation on the Cause-Effect Relationships between the Process Parameters and the Resulting Geometric Properties for Wire-Based Coaxial Laser Metal Deposition

Investigation on the Cause-Effect Relationships between the Process Parameters and the Resulting Geometric Properties for Wire-Based Coaxial Laser Metal Deposition

Initial transient phase and stability of annular laser beam direct wire deposition

Development of an Intra-Layer Adaptive Toolpath Generation Control Procedure in the Laser Metal Wire Deposition Process

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