公开(公告)号：US20170154750A1

公开(公告)日：2017-06-01

申请号：US14785730

申请日：2015-01-09

Applicant: TECHNOLOGY RESEARCH ASSOCIATION FOR FUTURE ADDITIVE MANUFACTURING

Inventor： Takashi SATO

IPC: H01J37/065

CPC classification number: H01J37/065 ,  B22F3/1055 ,  B22F2003/1056 ,  B22F2003/1057 ,  B22F2999/00 ,  B33Y30/00 ,  H01J3/08 ,  H01J3/12 ,  H01J37/06 ,  H01J37/304 ,  H01J2237/06308 ,  H01J2237/0653 ,  Y02P10/295 ,  B22F2203/03 ,  B22F2202/06 ,  B22F2202/11

Abstract: When an emission current is changed, a decrease in brightness of an electron beam is prevented. An electron gun includes a cathode that emits thermoelectrons, a Wehnelt electrode that focuses the thermoelectrons, a control electrode that extracts the thermoelectrons from a distal end of said cathode, an anode that accelerates the thermoelectrons and irradiates a powder with the thermoelectrons as an electron beam, and an optimum condition collection controller that changes at least one of a bias voltage to be applied to the Wehnelt electrode and a control electrode voltage to be applied to the control electrode, and decides a combination of the bias voltage and the control electrode voltage at which the brightness of the electron beam reaches a peak.