"Dancing" on the filament, he wants to make insect robots "crawl" from science fiction into reality

With the help of a microbeam "electron gun" that makes electrons "dance" on the filament, Zeng Fanguang, a professor at the School of Materials of Zhengzhou Institute of Aeronautical Industry Management, guided his students to win the first prize in the "Challenge Cup" National College Student Competition. Currently, this technology and supporting equipment are blank in the world.

Zeng Fanguang studied physics when he was young, but he has taken his students on a new path in materials science. Zeng Fanguang, who is about to enter his sixties, has another wish: "to bring out the team, to make the microbeam electron gun realize industrial application, and to realize the innovation of the whole chain of materials, devices and equipment as soon as possible."

What is the purpose of this gun?

The electron gun Zeng Fanguang mentioned is not a "real gun", but an electron-emitting gun that uses electrons as "bullets". The filament is the "barrel" of this gun, and the electrons will "dance" from here under the control of the electric and magnetic fields. So, where is this gun used specifically?

"Do you know about micro robots at the insect-scale level? They are composed of many complex metal micro parts at the mesoscopic scale (10^-4~10^-6m). Doesn't 'micro parts' sound very small and particularly difficult to manufacture?" Zeng Fanguang asked with a smile.

According to him, at present, my country is heavily dependent on imports for filament materials and filament devices for high-end vacuum electronic equipment, such as scanning electron microscopes, transmission electron microscopes, etc., which poses a potential bottleneck risk.

How can we create centimeter-scale or terrestrial insect-scale robots to conduct inspections, detection, and post-disaster rescue in non-structural or narrow spaces? Zeng Fanguang said that precision metal microstructures or micro parts are one of the prerequisites, especially mesoscale (submicron-submillimeter) tiny metal parts between the macroscale and the microscale.

Through years of research, Zeng Fanguang discovered that among the existing manufacturing technologies, the technology that is most promising to solve this problem is the electron microbeam 3D printing technology that uses a high-energy-density electron microbeam to perform graphic melting of metal micropowders. Based on the structural slice graphic data of the micro-parts, the metal micropowders are graphic melted layer by layer with a high-energy-density electron microbeam, ultimately achieving additive micro-manufacturing of complex metal micro-parts.

"Based on the above considerations and after repeated discussions, our team teachers led students to seek breakthroughs in filament materials, and then promoted innovation in core components through innovation in key materials." Zeng Fanguang said happily, and the microbeam electron gun came into being in this way.

After winning the award, he saw the students in tears

In the 18th "Challenge Cup" National College Students' Extracurricular Academic and Technological Works Competition, Zeng Fanguang and his team guided students to win the first prize with the work "Microbeam Electron Gun for Additive Micromanufacturing of Complex Metal Microparts".

During the competition, there were two things that left a deep impression on Zeng Fanguang.

Existing electron gun filaments mainly use lanthanum hexaboride and tungsten wires, but due to the large size of the emission surface, it is impossible to achieve a small electron beam spot. The team members imagined that if the quasi-macroscopic carbon fiber prepared by the laboratory was used instead, this material has a quasi-macroscopic scale and a hemispherical emission surface with a perfect curvature radius, which just meets the requirements of additive micro-manufacturing.

Zeng Fanguang is good at scientific research, especially in the field of electronic source materials and devices and their applications. He knows the difficulty of the scientific research process and the difficulty of achieving results, and he shares his many years of experience with students.

Under the patient guidance of Zeng Fanguang, through rounds of experiments, the participating team finally used the physical space confinement effect and the controlled variable method to prepare quasi-macroscopic carbon fiber with perfect morphology.

In the summer vacation in Zhengzhou, the temperature was as high as 40℃, and the heat wave was overwhelming, but the team members were doing 1000℃ filament growth experiments in the laboratory. In the end, they achieved the controllable preparation of quasi-macroscopic carbon fiber filament materials, and then completed the development and testing of the microbeam electron gun.

Zeng Fanguang said that when making a microbeam electron gun, students also need to first turn the filament material into a filament device. They need to thread the material, which is much thinner than a hair, into a copper tube with an outer diameter of only 0.3 mm, and then crimp the copper tube to a degree that just forms a reliable electrical connection with the filament material.

"Since this is a brand new device, there are no special tools available on the market and it needs to be operated manually, with the help of microscopes and magnifying glasses. You can imagine how afraid the students were." Zeng Fanguang was filled with heartache when talking about this experience.

With the encouragement and demonstration of Zeng Fanguang and other teachers in the team, the students have mastered the skill of manipulating tiny objects. "Now, most students can complete the production of filament devices independently. This has greatly cultivated their craftsman spirit of striving for excellence and their tenacious will to face challenges. This is progress that cannot be achieved by giving lectures in any number of classes," Zeng Fanguang said with emotion.

From the college competition to the national competition, from Zhenghang to the finals. After the competition, Zeng Fanguang was taking the participating students to study near Guiyang when he heard the news that the entry won the first prize. "Hearing the students' screams and seeing them cheering with tears in their eyes, at that moment, I knew that they had quietly transformed."

Let this "gun" realize industrial application

Talking about the R&D value of the project, Zeng Fanguang said, "Based on the micro-beam electron gun, it is expected to develop an electron beam additive micro-manufacturing system, thereby realizing the additive micro-manufacturing of complex metal micro-parts."

Zeng Fanguang also has a clear vision for the future development of microbeam electron guns. He said: "Next, we will focus on promoting the application research of microbeam electron guns, promote the transformation of microbeam electron guns from laboratory products to industrial applications, and optimize and upgrade product quality and performance."

At the same time, he also hopes to develop a dedicated electron optical system and a dedicated power supply system based on the microbeam electron gun, complete the development of the core components required for micro-nano processing equipment for metal parts as soon as possible, and strive to achieve the leap from materials to devices to equipment as soon as possible.

Training students is still the top priority, and Zeng Fanguang wants to integrate more students into the R&D platform. "Through careful training, more students will become compound innovative talents who not only master material science knowledge but also have the ability to apply vacuum electronic technology, and become rare professional and technical talents in the fields of advanced materials and high-end equipment in related industries in my country." Zeng Fanguang said confidently.