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CN-116810119-B - Bypass wire feeding additive manufacturing system based on field emission cathode

CN116810119BCN 116810119 BCN116810119 BCN 116810119BCN-116810119-B

Abstract

The invention discloses a bypass wire feeding additive manufacturing system based on a field emission cathode, which comprises an electron gun which is arranged in a vacuum chamber and adopts a field emission block cathode, wherein a forming substrate is arranged in the electron beam outlet direction of the electron gun, a wire feeder is arranged between the electron gun and the forming substrate, the wire feeder is fixed on the side wall of the vacuum chamber, the electron gun is connected with an electron gun control system and is used for controlling the opening and closing of the electron gun, beam size adjustment, electron beam focusing, deflection and astigmatism elimination functions, the wire feeder is connected with the wire feeding control system and is used for conveying metal wires from a bypass to the forming substrate, the forming substrate is connected with a motion control system and is used for controlling the motion direction of the forming substrate, and the vacuum chamber is connected with the vacuum control system and is used for controlling the vacuum degree of the vacuum chamber.

Inventors

  • JI QIANYU
  • GUO WENHUA
  • LU BINGHENG
  • ZHANG DAIHUI

Assignees

  • 西安交通大学

Dates

Publication Date
20260505
Application Date
20230817

Claims (6)

  1. 1. The bypass wire feeding additive manufacturing system based on the field emission cathode is characterized by comprising an electron gun (1) adopting a field emission bulk cathode (102), wherein the electron gun (1) is arranged in a vacuum chamber (3), a forming substrate (301) is arranged in the electron beam outlet direction of the electron gun (1), a wire feeder (201) is arranged between the electron gun (1) and the forming substrate (301), the wire feeder (201) is fixed on the side wall of the vacuum chamber (3), the electron gun (1) is connected with an electron gun control system (10) and used for controlling the functions of opening and closing the electron gun (1), adjusting the beam size, focusing, deflecting and eliminating astigmatism of the electron beam, the wire feeder (201) is connected with a wire feeding control system (20) and used for conveying a metal wire (202) from a bypass to the forming substrate (301), the forming substrate (301) is connected with a motion control system (30) and used for controlling the motion direction of the forming substrate (301), and the vacuum chamber (3) is connected with a vacuum control system (40) and used for controlling the vacuum degree of the vacuum chamber (3); The electron gun (1) comprises a cathode base (101), a field emission block cathode (102), a grid electrode (103), an anode (104), a dissipation coil (105), a deflection coil (106) and a focusing coil (107) which are coaxially arranged in sequence from top to bottom, wherein the field emission block cathode (102) is vertically arranged on the central axis of one side of the cathode base (101) facing the anode (104); the field emission bulk cathode (102) is a bulk graphene field emission cathode or a bulk graphene/carbon nanotube composite field emission cathode; the bulk graphene/carbon nano tube composite field emission cathode is prepared by mixing and cold-pressing a carbon nano tube and high-quality graphene; The high-quality graphene is graphene powder with the number of layers of 2-5, the defect ratio of 0.08-0.2 and the C/O atomic ratio of 32.25-76.92.
  2. 2. The field emission cathode-based bypass wire feed additive manufacturing system according to claim 1, wherein the negative high voltage applied by the field emission bulk cathode (102) is 30kV-60kV, the negative high voltage applied by the grid (103) is 0kV-5kV lower than the cathode base (101), the anode (104) is grounded, and the vacuum chamber (3) is grounded.
  3. 3. A field emission cathode based bypass wire feed additive manufacturing system according to claim 1, characterized in that the electron gun (1) employs bypass wire feed with a wire feed angle of 0 ° to 45 °.
  4. 4. The field emission cathode-based bypass wire feed additive manufacturing system according to claim 1, wherein a three-dimensional motion platform is arranged at the bottom of the forming substrate (301), and the motion control system (30) is connected with the three-dimensional motion platform for controlling the movement of the three-dimensional motion platform.
  5. 5. The field emission cathode based bypass wire feed additive manufacturing system of claim 4 wherein the motion control system (30) controls three-dimensional motion stage movement based on a slice path of the molded part.
  6. 6. A field emission cathode based bypass wire feed additive manufacturing system according to claim 1, wherein the field emission bulk cathode (102) has a height of 10mm-15mm, a width of 2 mm-4 mm, a thickness of 300 μm-500 μm and an emission current of 0 mA-20 mA.

Description

Bypass wire feeding additive manufacturing system based on field emission cathode Technical Field The invention belongs to the technical field of additive manufacturing, and particularly relates to a bypass wire feeding additive manufacturing system based on a field emission cathode. Background Compared with the arc fuse and laser fuse additive manufacturing technology, the electron beam fuse additive manufacturing technology has remarkable advantages in the aspects of high-quality, high-efficiency and rapid manufacturing of large-scale metal components, and is mainly applied to the aspects of machine body internal frames, reinforcing ribs, wallboard structures and the like. The electron emission of the conventional electron beam fuse additive manufacturing equipment is mainly in a hot cathode mode represented by tungsten and lanthanum hexaboride, and the heating mode of the cathode is mainly in a direct heating mode and an indirect heating mode. The direct heating mode is to apply a current across the cathode and heat the cathode to a specified temperature using joule heating principles. In the mode, the magnetic field change caused by the fluctuation of heating current during the heating process can influence the magnetic field around the electron gun, so that the beam spot shape changes, and the forming quality is further influenced. The indirect heating mode mainly uses laser, electron beam and the like to bombard the cathode to reach a specified temperature, and the mode can avoid the problem of direct heating, but additionally introduces heating equipment outside the electron gun, thereby increasing the cost of the equipment. In either the direct heating or the indirect heating mode, a cooling passage is required to be introduced into the cathode to cool the clamping base and the grid around the cathode, thereby increasing the mechanical complexity of the device. At the same time, additional heating control systems are also designed. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a bypass wire feeding additive manufacturing system based on a field emission cathode, wherein the electron gun cathode adopts the field emission cathode, so that the magnetic field around the electron gun is prevented from changing due to cathode heating, additional heating and cooling equipment is avoided, and the complexity of the equipment structure and the complexity of a control system are reduced. The bypass wire feeding additive manufacturing system based on the field emission cathode comprises an electron gun adopting a field emission block cathode, wherein the electron gun is arranged in a vacuum chamber, a forming substrate is arranged in the direction of an electron beam outlet of the electron gun, a wire feeder is arranged between the electron gun and the forming substrate and fixed on the side wall of the vacuum chamber, the electron gun is connected with an electron gun control system for controlling the functions of opening and closing the electron gun, adjusting the beam current, focusing, deflecting and eliminating astigmatism of the electron beam, the wire feeder is connected with the wire feeding control system for conveying a metal wire from a bypass to the forming substrate, the forming substrate is connected with a motion control system for controlling the motion direction of the forming substrate, and the vacuum chamber is connected with the vacuum control system for controlling the vacuum degree of the vacuum chamber to reach the vacuum degree required by working. Further, the electron gun comprises a cathode base, a field emission block cathode, a grid electrode, an anode, a dissipation coil, a deflection coil and a focusing coil which are coaxially installed in sequence from top to bottom, wherein the field emission block cathode is vertically arranged on the central axis of one side of the cathode base facing the anode. Further, the field emission bulk cathode is a bulk graphene field emission cathode or a bulk graphene/carbon nanotube composite field emission cathode. Further, the bulk graphene field emission cathode is prepared by adopting high-quality graphene cold press molding, and the bulk graphene/carbon nanotube composite field emission cathode is prepared by adopting carbon nanotube and high-quality graphene mixed cold press molding. Further, the high-quality graphene is graphene powder with the number of layers of 2-5, the defect ratio of 0.08-0.2 and the C/O atomic ratio of 32.25-76.92. Further, the negative high voltage applied by the cathode of the field emission block is 30kV-60kV, the negative high voltage applied by the grid is 0kV-5kV lower than that applied by the cathode base, the anode is grounded, and the vacuum chamber is grounded. Further, the electron gun adopts bypass wire feeding, and the wire feeding angle is 0-45 degrees. Further, a three-dimensional motion platform is arranged at the bottom of the forming substrate, and a