An improved methodology of melt pool monitoring of direct energy deposition processes

Sampson, Robert E.; Lancaster, Robert; Sutcliffe, Mark; Carswell, David; Hauser, Carl; Barras, Josh

doi:10.1016/j.optlastec.2020.106194

Cited by 52 publications

(26 citation statements)

References 21 publications

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“…5a (blue arrow) show the interphase is enriched with Cu. Similar interphase in aged Al-Zn-Mg-Cu alloys reinforced with TiB 2 was reported previously [71]. The repeated cycle of laser heating and the preheated platform (150 °C, which is very close to 170 °C ageing temperature) in LPBF provided a higher temperature in situ ageing environment for the printed TiB 2 /Al-Cu composite, thus allowing interphase to be formed, which might reduce the mismatch of the TiB 2 / Al interface [71,72].…”

Section: Secondary Particles (Al 2 Cu and Tib 2 )supporting

confidence: 79%

Synchrotron Characterisation of Ultra-Fine Grain TiB2/Al-Cu Composite Fabricated by Laser Powder Bed Fusion

Cai

Duan

et al. 2021

Acta Metall. Sin. (Engl. Lett.)

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Isotropy in microstructure and mechanical properties remains a challenge for laser powder bed fusion (LPBF) processed materials due to the epitaxial growth and rapid cooling in LPBF. In this study, a high-strength TiB2/Al-Cu composite with random texture was successfully fabricated by laser powder bed fusion (LPBF) using pre-doped TiB2/Al-Cu composite powder. A series of advanced characterisation techniques, including synchrotron X-ray tomography, correlative focussed ion beam–scanning electron microscopy (FIB-SEM), scanning transmission electron microscopy (STEM), and synchrotron in situ X-ray diffraction, were applied to investigate the defects and microstructure of the as-fabricated TiB2/Al-Cu composite across multiple length scales. The study showed ultra-fine grains with an average grain size of about 0.86 μm, and a random texture was formed in the as-fabricated condition due to rapid solidification and the TiB2 particles promoting heterogeneous nucleation. The yield strength and total elongation of the as-fabricated composite were 317 MPa and 10%, respectively. The contributions of fine grains, solid solutions, dislocations, particles, and Guinier–Preston (GP) zones were calculated. Failure was found to be initiated from the largest lack-of-fusion pore, as revealed by in situ synchrotron tomography during tensile loading. In situ synchrotron diffraction was used to characterise the lattice strain evolution during tensile loading, providing important data for the development of crystal-plasticity models.

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Section: Secondary Particles (Al 2 Cu and Tib 2 )supporting

confidence: 79%

Synchrotron Characterisation of Ultra-Fine Grain TiB2/Al-Cu Composite Fabricated by Laser Powder Bed Fusion

Cai

Duan

et al. 2021

Acta Metall. Sin. (Engl. Lett.)

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“…The threshold value was chosen to be 80, as mentioned in the study by Akbari and Kovacevic [ 18 ]. However, the classical image segmentation methods (edge detection and thresholding) present problems due to the incapability to approximate edges with a single binary threshold, as mentioned in [ 7 , 20 ]. The latter operates by finding discontinuities in the brightness intensity of the image.…”

Section: Resultsmentioning

confidence: 99%

“…The effect of preheating of the substrate (up to 300 °C) was also evaluated, proving that an increase of the melt pool size by more than 20% at all examined laser power values was observed. Sampson et al [ 20 ] implemented a new image processing algorithm for improving the accuracy and performance of melt pool measurements. It was based not on emissivity or material dependency but on a parametric study, comparing it to a study based on emissivity.…”

Section: Review Of Main In-situ Monitoring Systemsmentioning

confidence: 99%

Coaxial Monitoring of AISI 316L Thin Walls Fabricated by Direct Metal Laser Deposition

et al. 2021

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Direct metal laser deposition (DMLD) is an additive manufacturing technique suitable for coating and repair, which has been gaining a growing interest in 3D manufacturing applications in recent years. However, its diffusion in the manufacturing industry is still limited due to technical challenges to be solved—both the sub-optimal quality of the final parts and the low repeatability of the process make the DMLD inadequate for high-value applications requiring high-performance standards. Thus, real-time monitoring and process control are indispensable requirements for improving the DMLD process. The aim of this study was the optimization of deposition strategies for the fabrication of thin walls in AISI 316L stainless steel. For this purpose, a coaxial monitoring system and image processing algorithms were employed to study the melt pool geometry. The comparison tests carried out highlighted how the region-based active contour algorithm used for image processing is more efficient and stable than others covered in the literature. The results allowed the identification of the best deposition strategy. Therefore, it is shown how this monitoring methodology proved to be suitable for designing and implementing the right building strategy for DMLD manufactured 3D components. A fast and stable image processing method was achieved, which can be considered for future closed-loop monitoring in real-time applications.

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“…Melt pool tracking were performed by emissivity based melt detection technique. 34 Yan et al 35 conducted measurement of thermal gradient and heating area to relate their effect on part and substrate distortion in laser cladding operation. Their work features the implementation of IR imaging.…”

Section: Introductionmentioning

confidence: 99%

Analysis of novel induction heating extruder for additive manufacturing using aluminum filament

Sharma

Pant

Jain

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part B:

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Induction Heating (IH) method is gaining traction in the field of Additive Manufacturing (AM) as it is a low cost, clean, safe, and precise energy source. Wire as a feedstock material is highly efficient as compared to the powder form in terms of material utilization and economic viability. Thus, the combination of IH and wire feedstock delivery to additive manufacture a part has been explored on an in-house developed novel AM setup. The processing of aluminum wire (Al-5356) in semi-solid form from the extruder, heated using IH method has been performed. The approach adopted in this paper is to perform an in situ infrared imaging to analyze the evolution of thermal field during the extruder heating and metal deposition process. An effective thermal cartography has been undertaken to acquire temperature history of filament, extruder, and deposition process. The temperature profile plot is utilized to understand the temperature distribution and average temperature in the heating, extrusion, and layering process during layer fabrication. The presented work facilitates a priori anticipation to utilize IH as a potential energy source for the metal AM systems.

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An improved methodology of melt pool monitoring of direct energy deposition processes

Cited by 52 publications

References 21 publications

Synchrotron Characterisation of Ultra-Fine Grain TiB2/Al-Cu Composite Fabricated by Laser Powder Bed Fusion

Synchrotron Characterisation of Ultra-Fine Grain TiB2/Al-Cu Composite Fabricated by Laser Powder Bed Fusion

Coaxial Monitoring of AISI 316L Thin Walls Fabricated by Direct Metal Laser Deposition

Analysis of novel induction heating extruder for additive manufacturing using aluminum filament

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