Pulsed voltage machining

An efficient method to decrease the machining over-cut involves adding abrasive particles into the electrolyte [133] or the use a pulsed voltage supply. At the same time surface roughness is decreased and can reach values below 1 pm. 

Figure 7.11 Microholes in glass drilled by gravity-feed using a pulsed voltage supply. The main machining parameters are Ton Toff =2 1 and tool-electrode rotation of 500 rpm at 40 V. Reprinted from [136] with the permission of the Journal of Micromechanics and Microengineering.

Models based on Eqn (8.1) have been established to correlate the interaction and higher-order effects of the process parameters i.e., pulse frequency, machining voltage, duty ratio, electrolyte concentration and microtool feed rate, on the MRR and machining accuracy in terms of WOC,... 

Fig. 12.21 shows high aspect ratio nanometer features fabricated by EMM in nickel sheet [33]. The width of parallel lines in the center of the fabricated structure is 90 nm. The EMM parameter settings for nanofabrication by EMM are 2 ns pulse duration, machining voltage of 2.2 V, 10% duty ratio, and... 

Another application is for X-ray security machines. Here, the contrast between different materials is large, so the X-ray intensity is less high, but a high acceleration voltage is needed, as the penetration depth should be large. Thus a number of pulsed X-ray devices have been made, following the early work of Zhou et al. [59 62]. 

V. Kirchner, L. Cagnon, R. Schuster, G. Ertl, Electrochemical machining of stainless steel microelements with ultrashort voltage pulses. Appl. Phys. Lett. 79, 1721-1723, 2001. 

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