Electrochemical micromachining pulse

Electrochemical Micromachining with Ultrashort Voltage Pulses... 

FIGURE 2.15. Principle of electrochemical micromachining by short voltage pulses [14], (See color insert.)... 

Electrochemical micromachining (EMM) is anodic dissolution of metal by the electrochemical reaction while very low voltage is applied between the anode and the cathode separated by a very narrow gap preferably less than 50 pm. Pulsed power supply is applied for better localization of current. In the very narrow gap, in addition to electrolyte resistance other resistances that are not so prominent in conventional ECM have much more influence in EMM. Hence, all these resistance factors within the narrow gap are discussed along with the electrical circuit model of EMM. 

J.A. Kenney, G.S. Hwang, W. Shin, Two-dimensional computational model for electrochemical micromachining with ultrashort voltage pulses, Appl. Phys. Lett. 84 (2004) 3774, http //dx.doi.org/10.1063/... 

S. Burkert, H. Schulze, T. Gmelin, M. Leone, The pulse electrochemical micromachining (PECMM)— specifications of the pulse units, Int. J. Mater. Form 2 (2009) 645-648, http //dx.doi.org/10.1007/sl2289-009-0464-2. 

M. Malapati, A. Sarkar, B. Bhattacharyya, Frequency Pulse Period and Duty Factor Effects on Electrochemical Micromachining (EMM), Advanced Materials Research 264-265 (2011) 1334-1339. 

M. Kock, V. Kirchner, R. Schuster, Electrochemical micromachining with ultra short voltage pulses—a versatile method with lithographical precision, Electrochim. Acta 48 (1) (2003) 3213-3219. 

Influence of pulse duration during machining of microtroughs by electrochemical micromachining [32]. 

Sketch of the experimental setup and principle of electrochemical micromachining with ultrashort pulses. RE and CE are abbreviations for reference and counter electrode, respectively. 

Biochemical analysis on nanoliter scale is precisely carried out by micrototal analysis system (pTAS) which consists of microreactors, microfluidic systems, and detectors. Performance of the pTAS depends on micromachined and electrochemically actuated micropump capable of precise dosing of nanoliter amounts of liquids such as reagents, indicators, or calibration fluids [28]. The dosing system is based on the displacement of the liquid from a reservoir which is actuated by gas bubbles produced electrochemically. Electrochemical pump and dosing system consist of a channel structure micro-machined in silicon closed by Pyrex covered with novel metal electrodes. By applying pulsed current to the electrodes, gas bubbles are produced by electrolysis of water. The liquid stored in the meander is driven out into the microchannel structure due to expansion of gas bubbles in the reservoir as shown in Fig. 11.8. 

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