Electron-beam technology

Free electrons in vacuum can be influenced by electric and magnetic fields as to form a fine beam. At the spot of collision of the the beam with the particles of the solid-state matter, most portion of the kinetic energy of electrons is transferred into heat. The main advantage of this method is the possibility of very fast local heating, which can be precisely electronically (computer) controlled. The high concentration of power in a small volume of matter, which can be reached in this way results in very fast increase of temperature in the spot of impact causing the melting or even evaporation of any material, depending on working conditions. This makes the electron beam an excellent tool in many applications.

Electron beam melting

Any material can be melted by an electron beam in vacuum. This source of heat is absolutely clean, as well as the vacuum environment, so the purest materials can be produced in electron beam vacuum furnaces. For the production or refinement of rare and refractory metals the vacuum furnaces are of smaller volume, but for steels large furnaces with capacity in metric tons and electron beam power of megawatts are operated in industrialized countries.

Electron beam welding

The above mentioned specific advantages of electron beam heating find the widest use in welding applications. Since the beginning of electron beam welding in industrial scale (end of 1950es) a countless number of electron beam welders with working vacuum chambers volume ranging from a few liters up to hundreds cubic meters, provided with electron guns with the power up to 100 kW have been designed and are used world wide.

Electron beam surface treatment

The modern electron beam welders are usually provided with computer controlled deflection system, which can position the beam very fast and accurate over the selected area of the work-piece surface. Thanks to the high speed of heating, only a thin surface layer of the material is influenced, e.g. for "hardened", annealing, tempering, texturing,etc.

Electron beam additive manufacturing

Additive manufacturing is the process of joining materials to make objects from 3D model data, usually by melting powder material layer upon layer. Melting in vacuum by a computer controlled scanning electron beam is very advantageous. Electron beam direct manufacturing (DM) is the first commercially-available, large-scale, fully-programmable means of achieving near net shape parts.

Electron beam machining

Electron-beam machining is a process where high-velocity electrons concentrated into a narrow beam with very high planar power density in the focus cross-section are directed toward the work piece, creating heat and vaporizing the material. Electron beam machining can be used for very accurate cutting or boring of a wide variety of metals. Surface finish is better and kerf width is narrower than those for other thermal cutting processes, but because the equipment acquisition costs are very high, the use of this technology is therefore limited economically.

Electron beam lithography

Electron lithograph is a device in which a very fine electron beam is used to create micro-structures in the resist that can subsequently be transferred to the substrate material, often by etching. It was developed for manufacturing integrated circuits, and is also used for creating nanotechnology architectures. Electron beams with diameter ranging from 2 up to hundreds nano meters, are used in electron lithographs.

The form of maskless lithography has found wide usage in photomask-making used in photolithography, low-volume production of semiconductor components, and research & development. The electron lithograph is also used to produce Computer Generated Holograms (CGH).

Referencies:

• Schultz, H.: Electron beam welding, Abington Publishing
• Von Dobeneck, D.: Electron Beam Welding – Examples of 30 Years of Job-Shop Experience
• WWW.ebt.isibrno: Electron beam welding (in Czech and/or English)
• Visser, A.: Werkstofabtrag Durch Elektronen-und Photonenstrahlen; Verlag<Technische Rundschau>,Blaue Reihe, Heft 104