Real-time control of microstructure in laser additive manufacturing

Farshidianfar, Mohammad H.; Khajepour, Amir; Gerlich, A.P.

doi:10.1007/s00170-015-7423-5

Cited by 106 publications

(36 citation statements)

References 20 publications

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“…For example, Yang et al 44 used an IR camera to collect the surface temperature of the deposited parts and studied the thermal behavior. Farshidianfar et al 45,46 used IR cameras and image processing technology to capture the temperature changes and cooling rates in real time.…”

Section: Temperature Signature Monitoringmentioning

confidence: 99%

Review on adaptive control of laser-directed energy deposition

et al. 2020

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Laser directed energy deposition (LDED) is one of the most important parts of metal additive manufacturing, which can provide fast building speed, allows for large building volumes, and is suitable for part repair. LDED can manufacture components layer by layer through processes of rapid heating, melting, solidification, and cooling with the laser beam as a heat source. However, deposition quality and repeatability of components produced by LDED are poor because of the complex thermal cycle and processing environment, hindering the spread of this technique. Adaptive control technology (ACT) is consistently considered an effective and potential way to solve the problem. Many studies have focused on LDED and established the relations of process parameters, process signatures, and product qualities, which promote the rapid development of ACT, with the development of monitoring devices and data processing technology. We review and discuss the problems existing in the ACT of LDED.

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Section: Temperature Signature Monitoringmentioning

confidence: 99%

Review on adaptive control of laser-directed energy deposition

et al. 2020

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“…These are related to laser source, motion of workpiece, powder-substrate material combinations, clad geometry, powder flow dynamics, shrouding gas flow and so on. Significant research efforts are being invested for analytical [4][5][6][7], numerical [2, 9-11] and empirical modelling [12], and in-process monitoring and control [13][14][15][16][17][18][19][20] of laser cladding process. The numerical models are both two dimensional (2D) [2, 11] and three dimensional (3D) [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…Multiple responses such as clad track width, clad height, cladding zone temperature, cooling rate, etc. have been successfully monitored in real time [9,[13][14][15][16][17][18][19][20]. However, practical implementation of real time control have been so far reported for either laser power or scan speed or powder flow rate.…”

Section: Introductionmentioning

confidence: 99%

Estimation of dilution in laser cladding based on energy balance approach using regression analysis

Chakraborty

Dutta

2019

Sādhanā

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Laser cladding is a complex manufacturing process involving more than 19 variables related to laser source, workpiece movement, powder-substrate material combinations, clad geometry, powder flow dynamics, shrouding gas flow and so on. Significant research efforts have been directed to analytical-numericalempirical modelling of laser cladding and also in-process monitoring and control of the process. Still, due to complicated physics there is a dearth of simple analytical model for estimation of dilution in laser cladding. Its experimental measurement requires suitable micrographs of the clad cross section perpendicular to the clad path. This is a time-consuming and destructive way of measurement. Numerical models are time consuming to evaluate and hence not suitable for fast decision making or real-time control implementation. The analytical models available, despite having many approximations, are a little complicated, require fair amount computer programming and often need suitable prior guessing of range of output parameters for adjustment of constant values in the models. This poses some challenges for use and having an intuitive guidance, for a beginner/ unskilled operator. Besides, their complexity may erect barrier in the way of their implementation for real time monitoring and control. This work proposes a simple linear regression model, formed based on energy balance approach, to estimate dilution in laser cladding. After fitting to a set of data, within a suitable process parameterwindow, for a particular clad-substrate material combination, this model can estimate dilution as a function of input/easily measureable parameters, viz. laser power, scan speed, clad width and clad height. The model fitted well to the experimental data taken from literature.

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“…Temperature control is a critical regulatory process in wide variety of systems. Without it, sustainable operation is not possible in arguably everything from the functionality of biological organisms [1] to the reliability of electronic [2,3], photonic [4], and electro-chemical devices [5] to high-speed transportation [6] and materials manufacturing [7]. For today's technologies, there seems to be a ubiquitous trend toward increasingly smaller, more capable, and higher energy or power density devices.…”

Section: Introductionmentioning

confidence: 99%

Probing the Local Heat Transfer Coefficient of Water-Cooled Microchannels Using Time-Domain Thermoreflectance

Mehrvand

Putnam

2017

Journal of Heat Transfer

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The demands for increasingly smaller, more capable, and higher power density technologies have heightened the need for new methods to manage and characterize extreme heat fluxes. This work presents the use of an anisotropic version of the time-domain thermoreflectance (TDTR) technique to characterize the local heat transfer coefficient (HTC) of a water-cooled rectangular microchannel in a combined hot-spot heating and subcooled channel-flow configuration. Studies focused on room temperature, single-phase, degassed water flowing at an average velocity of ≈3.5 m/s in a ≈480 μm hydraulic diameter microchannel (e.g., Re ≈ 1850), where the TDTR pump heating laser induces a local heat flux of ≈900 W/cm2 in the center of the microchannel with a hot-spot area of ≈250 μm2. By using a differential TDTR measurement approach, we show that thermal effusivity distribution of the water coolant over the hot-spot is correlated to the single-phase convective heat transfer coefficient, where both the stagnant fluid (i.e., conduction and natural convection) and flowing fluid (i.e., forced convection) contributions are decoupled from each other. Our measurements of the local enhancement in the HTC over the hot-spot are in good agreement with established Nusselt number correlations. For example, our flow cooling results using a Ti metal wall support a maximum HTC enhancement via forced convection of ≈1060 ± 190 kW/m2 K, where the Nusselt number correlations predict ≈900 ± 150 kW/m2 K.

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Real-time control of microstructure in laser additive manufacturing

Cited by 106 publications

References 20 publications

Review on adaptive control of laser-directed energy deposition

Review on adaptive control of laser-directed energy deposition

Estimation of dilution in laser cladding based on energy balance approach using regression analysis

Probing the Local Heat Transfer Coefficient of Water-Cooled Microchannels Using Time-Domain Thermoreflectance

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