Predicting melt pool depth and grain length using multiple signatures from in-situ single camera two-wavelength imaging pyrometry for laser powder bed fusion

Chaitanya Krishna Prasad Vallabh, Soumya Sridar, Wei Xiong, Xiayun Zhao

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

In laser powder bed fusion (LPBF), the in-situ process signatures are known to have a direct correlation with the microstructural properties of the solidified melt pool (MP). It is known that the MP cooling and heating rates, and laser processing parameters can critically determine the grain structure and thereby affect the part properties. The objective of this work is to study the feasibility of using in-process, high-speed imaging pyrometry for evaluating the solidified MP properties “below” the surface, such as depth and microstructural properties. To accomplish this, we employ an in-house single camera-based two-wavelength imaging pyrometry (STWIP) system for monitoring the printing of single-scan tracks with Inconel 718 on a commercial LPBF printer (EOS M290). The lab designed STWIP system is a coaxial high-speed (>10,000 fps) imaging system capable of monitoring MP temperature, morphology, and intensity profiles. The temperature measurements from STWIP are emissivity independent. The STWIP measured MP signatures of the printed tracks are correlated with the ex-situ microscopy characterized MP depth and the average grain lengths. From the data analysis, using support vector machine (SVM)-based regression models, we found that the MP temperature signatures are crucial for an accurate prediction of MP depth and the grain length, thus validating the novelty and necessity of the developed in-situ monitoring methods and analysis.

Original languageEnglish
Article number117724
JournalJournal of Materials Processing Technology
Volume308
DOIs
StatePublished - Oct 2022

Keywords

  • Coaxial high-speed imaging
  • In-situ melt pool monitoring
  • Inconel 718
  • Laser powder bed fusion
  • Melt pool morphology
  • Melt pool temperature

Fingerprint

Dive into the research topics of 'Predicting melt pool depth and grain length using multiple signatures from in-situ single camera two-wavelength imaging pyrometry for laser powder bed fusion'. Together they form a unique fingerprint.

Cite this