Micro-ECM for production of microsystems with a high aspect ratio

Abstract

The most used processes for production of microsytem components are basically from the semiconductor technology. The material properties of used silicon often don't achieve the demands of for example: microsurgery, biotechnology life science, fluidics or high temperature environment. For microstructuring of highly stressed metals, like stainless and heat resisting steels, cold work tool steels, hot work tool steels and nickel-base-alloys and a variety of metals there is no manufacturingprocess. An interesting possibility for structuring this type of materials are the electrochemical machining processes (ECM). Some new developed ECM-sinking-processes are working with oscillating tool-electrode, to improve shape accuracy. IntroductionIn microsystem technology there are only few technologies and processes for structuring of complex shapes in highly stressed metalls, steel and alloys. An interesting possibility for structuring this type of materials are the processes of electrochemical machining. Electro-chemical-machining (ECM) is the anodic electro-chemical dissolution of metallic materials in an electrolytic medium. Figure 1 shows the principle of electro-chemical dissolution process. The ECM-Process is a well established process in the aviation industry for the production of turbine blades and for placement of cooling air bore holes. These bore holes have diameters between 0.5 and 3.0 mm and an aspect ratio of up to 300:1. Other wellknown applications for the ECM are the EC-deburring-processes, the EC-etching processes and a wide variety of EC-hybrid processes like EC-grinding [1][2][3]7].The process of ECM enables the machining of metallic materials independent of their mechanical properties. This process achieves high material removal rates. In opposite to the Electro-discharge-machining (EDM) process the tool-electrode wear is extremely low and the sub-surface is not damaged. Other advantages of ECM are: -no mechanical contact between tool electrode and workpiece -no burr at the shape -no finishing process -smooth surface -batch processing possibleThe traditionally ECM-processes are working with constant feed rate and constant voltage. Using vibrating tool-electrodes, the ECM-process can be under control. The department of process technology -IMTEK of the University of Freiburg investigates applications and possibilities of ECM die-sinking process with oscillating toolelectrode for microstructuring of highly stressed materials [4]. So we will present some results of our ECM work. ECM die-sinking with vibrating tool-electrodeFor our research we are using a machine-prototype PEM 1360, wich is shown in Fig. 2, of the company PEM, Technologiegesellschaft für elektrochemische Bearbeitung, Dillingen/Saar, Germany. This machine works with vibrating tool-electrode with non-varying frequency of 50 Hz and steady amplitude of 200 lm.The process works in the following principle. The toolelectrode moves in direction of the workpiece superimposed by oscillations. As the tool-electrode and the workpiece approaches, the elect...

Time averaged calculations in pulse electrochemical machining, using a strongly non-linear model

“…Oscillating electrodes [1,5] are sometimes used during ECM. The gap is widened during the off-times of the pulse, and hence a better evacuation of the reaction products is accomplished.…”

Hybrid tooling by a combination of high speed cutting and electrochemical milling with ultrashort voltage pulses

“…Datta and Harris 1997). Different methods have been developed to enhance the accuracy of this technique, especially PEM and PECM (Förster et al 2005;Park et al 2002). Schuster et al invented the technique of the electrochemical milling with ultrashort voltage pulses (ECF, where ECF is the German acronym for Elektrochemisches Fräsen, i.e.…”

A novel pulse shortcut strategy for simulating nano-second pulse electrochemical micro-machining

“…Significant progress has been published regarding research on the experimental side of the electrochemical micromachining (ECMM) [1,7,14,19,20,25]. In the literature concerning numerical simulations, Deconinck [4][5][6] presented a detailed analysis of the DC ECM process, using the Multi-ion Transport and Reaction Model.…”