A comprehensive study on meltpool depth in laser-based powder bed fusion of Inconel 718

Mahyar Khorasani*, Amir Hossein Ghasemi, Martin Leary*, Laura Cordova, Elmira Sharabian, Ehsan Farabi, Ian Gibson, Milan Brandt, Bernard Rolfe

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

19 Citations (Scopus)
332 Downloads (Pure)

Abstract

One problematic task in the laser-based powder bed fusion (LB-PBF) process is the estimation of meltpool depth, which is a function of the process parameters and thermophysical properties of the materials. In this research, the effective factors that drive the meltpool depth such as optical penetration depth, angle of incidence, the ratio of laser power to scan speed, surface properties and plasma formation are discussed. The model is useful to estimate the meltpool depth for various manufacturing conditions. A proposed methodology is based on the simulation of a set of process parameters to obtain the variation of meltpool depth and temperature, followed by validation with reference to experimental test data. Numerical simulation of the LB-PBF process was performed using the computational scientific tool “Flow3D Version 11.2” to obtain the meltpool features. The simulation data was then developed into a predictive analytical model for meltpool depth and temperature based on the thermophysical powder properties and associated parameters. The novelty and contribution of this research are characterising the fundamental governing factors on meltpool depth and developing an analytical model based on process parameters and powder properties. The predictor model helps to accurately estimate the meltpool depth which is important and has to be sufficient to effectively fuse the powder to the build plate or the previously solidified layers ensuring proper bonding quality. Results showed that the developed analytical model has a high accuracy to predict the meltpool depth. The model is useful to rapidly estimate the optimal process window before setting up the manufacturing tasks and can therefore save on lead-time and cost. This methodology is generally applied to Inconel 718 processing and is generalisable for any powder of interest. The discussions identified how the effective physical factors govern the induced heat versus meltpool depth which can affect the bonding and the quality of LB-PBF components.

Original languageEnglish
Pages (from-to)2345-2362
Number of pages18
JournalInternational journal of advanced manufacturing technology
Volume120
Issue number3-4
Early online date22 Feb 2022
DOIs
Publication statusPublished - May 2022

Keywords

  • Additive manufacturing
  • Laser irradiation
  • Laser-based powder bed fusion
  • Meltpool depth
  • Wavelength

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