Development mechanism and solidification morphology of molten pool generated by laser cladding

In the high-piled up process of laser cladding rapid forming , the distance between aser molten pool center and flour will increase along with the cladding layer ,which will cause the effect of light powder coupling getting worse, even directly lead to failure. The article proposed characteristics of the double-spot ,formed by molten pool and reflection of laser surface;used VC++ 6.0 as the development platform of image processing to calculate two spot centroid distance by dealing two spot image with the process of gray processing, Gaussian smoothing, binary threshold segmentation, area centroid calculation, the centroid coordinate distance calculation.At the same time , controlling laser head Z to move in accordance with the value increment,to increase the stability of forming process and forming quality.

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Design of Forming Shape Measurement System for Laser Molten Pool in Laser Fabricating

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.37-38.327 ◽

2010 ◽

Vol 37-38 ◽

pp. 327-330 ◽

Cited By ~ 4

Author(s):

Jian Bo Lei ◽

Zhen Wang ◽

Li Feng Liu

Keyword(s):

Laser Cladding ◽

Molten Pool ◽

Detection System ◽

Shape Measurement ◽

Optical Elements ◽

Shape Distribution ◽

Special Software ◽

Measurement Results ◽

Destructive Measurement ◽

Non Destructive

In order to study forming shape distribution of laser molten pool in laser fabricating, a CCD-based image detection system was developed. The system mainly consists of a CCD-based detector, optical elements, an image acquisition card and its special software. Experiments on shape measurement of the laser molten pool were carried out. It was shown that 2D morphology and the dimension of laser molten pool could be measured in real time. The (X, Y) dimension of the laser molten pool in laser cladding was (2.6 mm, 2.5 mm) with an approximately ellipsoidal shape. Laser cladding parameters were optimized according to the measurement results. It was a non-destructive measurement method, which would be a new method for online measurement and feedback control in laser fabricating.

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Effects of electromagnetic compound field on the escape behavior of pores in molten pool during laser cladding

Surface and Coatings Technology ◽

10.1016/j.surfcoat.2019.125198 ◽

2020 ◽

Vol 383 ◽

pp. 125198 ◽

Cited By ~ 3

Author(s):

Yong Hu ◽

Liang Wang ◽

Jianhua Yao ◽

Hongchao Xia ◽

Juehui Li ◽

...

Keyword(s):

Laser Cladding ◽

Molten Pool ◽

Escape Behavior

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Modeling of temperature distribution and clad geometry of the molten pool during laser cladding of TiAlSi alloys

Optics & Laser Technology ◽

10.1016/j.optlastec.2021.107277 ◽

2021 ◽

Vol 142 ◽

pp. 107277

Author(s):

Chen Shen ◽

Chonggui Li ◽

Yajun Guo ◽

Chuanming Liu ◽

Xuanjun Zhang ◽

...

Keyword(s):

Temperature Distribution ◽

Laser Cladding ◽

Molten Pool

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Heat Input Control in 3D Laser Cladding Based on Infrared Sensing

10.1115/imece2001/med-23337 ◽

2001 ◽

Author(s):

Dongming Hu ◽

Yunxin Wu ◽

Radovan Kovacevic

Keyword(s):

Laser Cladding ◽

Heat Input ◽

Molten Pool ◽

Closed Loop ◽

Solid Freeform Fabrication ◽

Infrared Image ◽

Frame Rate ◽

Closed Loop Control ◽

Loop Control ◽

Infrared Sensing

Abstract Solid Freeform Fabrication (SFF) methods for building metallic part, such as 3D laser cladding, are generally less stable and less repeatable than other rapid prototyping methods. The infrared image of the molten pool is a promising sensing technique for the closed-loop control of the cladding process. In this paper, the closed-loop control of heat input based on infrared image sensing in 3D laser cladding is introduced. A high frame-rate (up to 800frame/s) camera is installed coaxially at the top of the laser-nozzle setup. A full view of the infrared images of the molten pool can be acquired with a short nozzle-substrate distance in different scanning directions, eliminating the noise from the metal powder. The features of the images show a clear relationship with the variation of the cladding process parameters. The closed-loop control results show a great improvement in the geometrical accuracy and microstructure of the built part.

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A lumped parametric analytical model for predicting molten pool temperature and clad geometry in pre-placed powder laser cladding

Optik ◽

10.1016/j.ijleo.2021.168015 ◽

2021 ◽

pp. 168015

Author(s):

Shrey Bhatnagar ◽

Suvradip Mullick ◽

Muvvala Gopinath

Keyword(s):

Analytical Model ◽

Laser Cladding ◽

Molten Pool

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Simulation Study of the Temperature Field for Squashed Presetting Laser Cladding Based on ANSYS

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.458.319 ◽

2010 ◽

Vol 458 ◽

pp. 319-324 ◽

Cited By ~ 1

Author(s):

Gang Chen ◽

Xiang Feng Li ◽

Dun Wen Zuo ◽

Hong Yu Wang ◽

Yan Jiang

Keyword(s):

Temperature Field ◽

Temperature Gradient ◽

Contact Resistance ◽

Laser Cladding ◽

Process Parameters ◽

Simulation Study ◽

Molten Pool ◽

Organizational Form ◽

Physical Parameters ◽

Pore Model

In the process of modeling the squashed piece of powders for the simulation of the temperature field of laser cladding, the metallurgical model and the pore model were proposed separately. The effects of the organizational form, the contact resistance and the thickness of the squashed piece of powders on the temperature were considered. Different values of physical parameters of the squashed piece of powders were converted, different contact resistances were calculated and the laser absorptivity for different process parameters of laser cladding was determined. The temperature curves of six typical nodes and the temperature gradient of two nodes in the molten pool of the substrate were discussed from different aspects.

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Temperature Field Numerical Simulation of Screwy Thin-Walled Part Cladded by Hollow Laser Beam

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.779-780.410 ◽

2013 ◽

Vol 779-780 ◽

pp. 410-413

Author(s):

Hao Lin ◽

Shi Hong Shi

Keyword(s):

Numerical Simulation ◽

Temperature Field ◽

Laser Beam ◽

Laser Cladding ◽

Molten Pool ◽

Laser Power ◽

Forming Process ◽

Single Laser ◽

Thin Walled ◽

Hollow Laser Beam

A numerical simulation model of laser cladding based on internal powder feeding through a hollow laser beam is set up by the Ansys Parametric Design Language (APDL). Through analyzing this model, the saddle-shaped distribution of energy absorbed in scanning direction is found and the molten pool temperature field of single laser cladding is observed like a comet[. Base on the single laser cladding experiments, the initial parameters and test plans of laser cladding and the screwy thin-walled part forming are confirmed. The finite element model of laser cladding forming screwy thin-walled part is established. The evolution of temperature field and thermal cycle of the nodes are studied during the screwy thin-walled part forming process. In the emulation laser power is controlled real time according to the analyses above, and the changing value of laser power is obtained to keep the molten pool temperature steady. The screwy thin-walled part is formed successfully based on these data.

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