Optical focus control system for laser welding and direct casting

D. P. Hand, M. D T Fox, Frank Haran, C. Peters, S. A. Morgan, M. A. McLean, W. M. Steen, J. D C Jones

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


A non-intrusive optical sensor system has been developed for focus control of laser welding. This detects the light generated by the process through the laser delivery optics, and exploits the chromatic aberrations of these optics to detect any laser focal error at the workpiece. This system works for a wide range of materials and welding parameters, and example results are presented. The sensor has also been applied to laser `direct casting', a process in which 3-D structures are built by flowing metal powder into a focused laser beam. In this case, melt pool temperature is also important, and so additional optics are incorporated into the sensor to provide a pyrometric temperature measurement which is used to control the laser power.

Original languageEnglish
Pages (from-to)415-427
Number of pages13
JournalOptics and Lasers in Engineering
Issue number4-6
Publication statusPublished - Oct 2000


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