Department of Physics, Engineering Physics & Astronomy

Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

CMP Seminar- "In situ process monitoring of selective laser melting at 200 kHz" by  Jordan Kanko and "Depth feedback-controlled hard tissue ablation with one-micron industrial fiber laser" by Cara Chenman Yin

Jordan Kanko and Cara Chenman Yin, both are MASc candidates with James Fraser
Queen's Physics 

 

Thursday, January 29th, 2015
10:30 am @ Stirling 401

Abstract:

"In situ process monitoring of selective laser melting at 200 kHz"
Jordan Kanko, Physics M.A.Sc. candidate
 
In this work we directly monitor the selective laser melting (SLM) process using an inline low-coherence interferometric technique termed Inline Coherent Imaging (ICI). This technique is used to optically monitor selective laser melting at 200 kHz measurement rates, and its application to SLM provides unique insight into process dynamics undetectable by temperature-based melt pool measurements. Using ICI, we follow single track processing dynamics, image powder melting and solidification processes on microsecond timescales, and perform in situ process parameter optimization. The ability of ICI to monitor melt pool dynamics at 200 kHz offers immense potential for future online feedback control.
 
 
"Depth feedback-controlled hard tissue ablation with one-micron industrial fiber laser"
Cara Chenman Yin, Physics M.A.Sc. candidate
 
Although laser ablation has the advantage of high transverse precision, axial etching depth control has been a long-standing challenge. In-line coherent imaging (ICI), an OCT-based imaging tool, provides a solution to such problems. It is capable of performing in-situ monitoring of laser ablation depth in real time. Recently, an interesting carbon-absorption-mediated laser bone ablation regime has been found where "self-cleaning" ablation was achieved with a 1μm industrial laser. With closed-loop depth feedback control of ICI, user-defined complicated 3D structures were created on cortical bone where little carbonization remains after the process. This ability appears particularly promising for surgical applications.