Abstract
A frequency band required for an oscillation technique on an electron beam welding was discussed by analyzing vibration frequencies of molten metal. Lower limits of beam scanning velocity not melting surfaces of work-pieces were also discussed by calculating temperature rise. A high-speed beam deflecting device to satisfy above conditions was developed and some applications of high-speed beam deflection were studied.
The conclusions obtained are summarized as follows:
(1) The vibration frequencies of the molten metal are less than 10 kHz and a beam oscillation with higher frequencies than 10 kHz is necessary to control distribution of an input power to a work-piece regardless of molten metal vibration.
(2) A beam scanning velocity of more than 10000 m/min is required not to melt a steel surface for a beam power of 10 kW
(3) A cutoff frequency of 60 kHz (-3dB) in small signal region and a maximum scanning velocity of 23000 m/min (deflection distance 300 nun) are realized using a deflecting device newly developed.
(4) The high-speed deflection technique is very effective for the new-field of electron beam application such as marking, patterning, simultaneous multi-beam welding, surface hardening, and so forth.
