Speaker
Prof.
James Fraser
(Queen's University)
Description
Laser materials processing can differ by orders of magnitude in terms of both the light-matter interaction times and the spatial dimensions of the interaction regions. This multiplicity has stymied efforts to develop a universal tool for on-line laser process monitoring and control. Previously, we developed a diagnostic called inline coherent imaging (ICI) for real-time, in-situ measurements of laser-induced sample morphology changes [1]. ICI is similar to optical coherence tomography (a medical imaging technique), and provides micron-scale axial resolution. Now with a dynamic range exceeding 60 dB and line rates above 300 kHz, we show that ICI allows us to monitor and study the volcanic stochasticity of kW-class laser welding, and to control this highly dynamic process on the fly. More recently, we have implemented fully automatic laser micro-milling with an ICI-enabled feedback system, reproducing complicated 3D shapes in heterogeneous materials as distinct as wood and bovine cortical bone. In effect, we have a non-contact CNC capable of replicating features down to micron resolution in arbitrary materials. ICI provides highly adaptable process control as well as a window into previously concealed dynamics at the tip of a high-power laser beam.
[1]. Webster, P.J.L. *et al.* In situ 24 kHz coherent imaging of morphology change in laser percussion drilling. Opt. Lett. **35**, 646-648 (2010).
Author
Prof.
James Fraser
(Queen's University)
Co-authors
Ms
Alison Kinross
(Queen's University)
Mr
Christopher Galbraith
(Queen's University)
Dr
Cole Van Vlack
(Laser Depth Dynamics)
Mr
Logan Wright
(Queen's University)
Dr
Paul Webster
(Laser Depth Dynamics)
Mr
Yang Ji
(Queen's University)
