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5127 |
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Wednesday, March 22, 2017, Hall Ford 11:35 AM Process Diagnostics / Simulation |
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Development of a new electron probing device and analyses method to ensure the weld quality in time |
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Peter Oving* / Techmeta - Groupe Bodycote, France |
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The quality of electron beam welds depends on two conditions: - operator defined parameters of the welding equipment at an instant t, like gun voltage and current, focus current, welding distance and speed - constant beam characteristics with time Due to wear, the electron beam will exhibit beam characteristics variations with time by the changes in electrode geometry as well as the changes of the electron emission surface. To ensure the quality of the welds and to keep the beam quality inside a narrow approved parameter window, a new probing device has been developped using a rotating disc scanner. This paper presents the design of the probing device, the operating mode and the processing of the acquired signals. The sensitivity of the device is enhenced by the absence of beam deflection during the scan and the use of a slightly underfocused beam. The device generates an undistorted magnified image of the electron beam power density distribution. The analyses system makes comparisons on a time scale and indicates the necessary corrections to stay in the narrow quality window. The high scan speed permits the analyses of medium to high power beams without the need of cooling. The probing device is in use by an aeronautic manufacturer to determine precisely the approved parameter window. |