Among methods for irradiation onto a metal surface, the mirror oscillation method has been developed and adopted at Tsukuba FMSC test plant, because the laser heat treated width is desired to be varied flexibly, depending on the parts involved.
Gears and shafts were selected as testpieces because quite a few of them are used in small batch production composite parts.
Liquid graphite was selected as a surface coating material to absorb CO2 laser beam because of its easy utilization for coating. A surface coating station has also been developed, which includes degreasing process to remove machining oil and drying process after coating.
Using these devices, a laser heat treatment experiment has been carried out for the object parts. The maximum hardened width and its hardened depth were 25mm and 0.5mm, respectively. Also, workpiece deformation after heat treatment was measured and found negligible.