Process control on laser cladding by coaxial vision for direct manufacturing of 3D metallic structures

Aubry, Pascal; Guiraud, Mehdi; Malot, T.; Verdier, Kevin

doi:10.2351/1.5057047

Cited by 1 publication

(1 citation statement)

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“…With respect to LMD, harsh environmental conditions of LMD and the resulting high temperature dictate the usage of non-contact height measuring techniques, thus optical techniques are considered the most suitable [13][14][15]. Various approaches for height monitoring systems in the DED processes have been reported in the literature: charged couple device (CCD) cameras [13][14][15][16][17][18][19][20][21][22], laser triangulation displacement sensors [23][24][25][26][27][28], stigmometer [29], structured light 3D imaging [30], and optical coherence tomography [31,32].…”

Section: Introductionmentioning

confidence: 99%

In-Line Height Measurement Technique for Directed Energy Deposition Processes

Borovkov

Yedra

Zurutuza

et al. 2021

JMMP

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Directed energy deposition (DED) is a family of additive manufacturing technologies. With these processes, metal parts are built layer by layer, introducing dynamics that propagate in time and layer-domains, which implies additional complexity and consequently, the resulting part quality is hard to predict. Control of the deposit layer thickness and height is a critical issue since it impacts on geometrical accuracy, process stability, and the overall quality of the product. Therefore, online feedback height control for DED processes with proper sensor strategies is required. This work presents a novel vision-based triangulation technique through an off-axis located CCD camera synchronized with a 640 nm wavelength pulsed illumination laser. Image processing and machine vision techniques allow in-line height measurement right after metal solidification. The linearity and the precision of the proposed setup are validated through off-and in-process trials in the laser metal deposition (LMD) process. Besides, the performance of the developed in-line inspection system has also been tested for the Arc based DED process and compared against experimental weld bead characterization data. In this last case, the system additionally allowed for the measurement of weld bead width and contact angles, which are critical in first runs of multilayer buildups.

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