Multispectral Imaging on Ruihang Dai

In-situ Multispectral Melt Pool Monitoring

Mon, 01 Jan 2024 00:00:00 +0100

Off-axial and co-axial multispectral imaging systems that deliver absolute temperature and emissivity maps of the melt pool during PBF-LB/M.

Temperature control in powder bed fusion of metals via inverse-designed laser beam shapes

Sun, 01 Feb 2026 00:00:00 +0100

This work demonstrates that numerically optimized, inverse-designed laser beam shapes can control surface temperature fields in powder bed fusion of metals. Simulated surface temperatures agree well with absolute temperature maps measured by multispectral imaging, and the experimental validation of a diverse set of inverse-designed beam shapes shows that numerical optimization can guide advanced beam shaping for improved process control in PBF-LB/M.

Impact of beam shaping on melt pool behavior in laser processing of stainless steel 316L: Thermal analysis using multispectral imaging

Tue, 01 Apr 2025 00:00:00 +0200

Using calibrated multispectral imaging, this study analyzes how ring-shaped laser beam profiles change melt pool temperature distributions in laser processing of stainless steel 316L compared to a Gaussian beam. Gaussian beams produce a concentrated heat zone with linearly increasing peak temperature, while ring-shaped profiles shift the melting behavior and produce characteristic half-moon-shaped temperature distributions, with direct implications for process stability and beam shape selection in PBF-LB/M.

Temperature measurement in laser–metal processing using optical sensing: Radiometric calibration and validation of a multispectral camera

Wed, 01 Jan 2025 00:00:00 +0100

This work establishes a radiometric calibration and validation methodology for a multispectral camera used in laser–metal processing. Capturing multiple spectral bands enables the simultaneous determination of absolute temperature and surface emissivity. The calibrated system reaches around 2% error for solid-state temperature measurement and accurately resolves liquid-phase temperatures during phase transition, providing a quantitative foundation for melt pool thermography in laser-based additive manufacturing.