19.2.1 Electron Beam Gun 19.2.2 Power Supply 19.2.3 The Electron Beam Machining Systems 19.3
Process Parameters
19.4
Process Capabilities
19.5
Application Examples
19.6
Process Summary
19.7
References
19.1 PROCESS PRINCIPLES Electron beam machining (EBM) is a thermal material removal process that utilizes a focused beam of high-velocity electrons to perform high-speed drilling and cutting. Just as in electron beam welding (Chap. 18),
material-heating action is achieved when high-velocity electrons strike the work piece. Upon impact, the kinetic energy of the electrons is converted into the heat necessary for the 19.2.2 Power Supply
The high-voltage power supply used for EBM systems generates voltages of up to 150 kv to accelerate the electrons. The most powerful electron beam machining systems are capable of delivering enough power to operate guns at average power levels of up to 12 kw. Individual pulse energy can reach 120 joules/pulse. To avoid the possibility of arcing and short circuits, the high-voltage sections of the power supply are submerged in an insulating dielectric oil. AB power supply variables, such as the accelerating current, focus current, pulse duration, and others, are controlled by a CNC unit or by a microcomputer. To ensure process repeatability, the process variables are monitored and compared with set-points by the power supply computer. If a discrepancy arises, the operator is alerted.
Figure 19.2 Computer-controlled multi axis EBM system (Source: courtesy, Messer Griesheim GmbH, Puchheim, W. Ger.).
19.2.3 The Electron Beam Machining Systems An EBM system, as shown in Fig. 19.2, has an appearance very similar to an electron beam welding system. A vacuum chamber is required for EBM and should have a volume of at least 1 m3 to minimize the chance of spatter sticking to the chamber walls.
The time necessary to pump the chamber to an operating level of 10-2 mbar is approximately 3 min for each cubic meter of volume. Inside the chamber a positioning system is
The first method uses a much thinner temperature, minimizing magnification and distortion errors . (15 nm) layer of Cr as a hard mask . Thinner layers still In the S-FIL process, a low-viscosity photocurable suppress charging during electron-beam exposure of the monomer (known as the etch barrier) is dispensed onto the template and have the advantage that CD losses during the surface of the substrate . The transparent template is pattern transfer through the Cr are minimized…
THERMAL AND CFD ANALYSIS FOR FINDING HEAT TRANSFER THROUGH AN ANNULAR BEND TUBE FOR VARIOUS NANO FLUIDS ABSTRACT Heat transfer by convection is extremely necessary for several industrial heating and cooling applications. The warmth convection will passively be increased by dynamic flow pure mathematics, boundary conditions or by enhancing fluid thermo physical properties. A mixture mixture of nano-sized particles in an exceedingly base fluid, referred to as nanofluids, staggeringly enhances the…
