Electrochemical machining (ECM)

C. Blattert (a), C. Müller (b), H. Reinecke (a),(b)

(a) Hahn-Schickard-Gesellschaft e. V. Institute for Micromachining and Information Technology (HSG-IMIT),Villingen-Schwenningen, Germany
(b) Laboratory for Process Technology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany

Abstract

Piracy and counterfeiting as well as retraceability demands of products such as plastic parts or tablets require new and innovative methods for unique product identification. An opportunity is the placement of microstructured codes in moulding tools. These tools are often made from materials that do not allow for highly precise micromachining by traditional technologies. Electrochemical machining (ECM) is a method for structuring construction materials such as steel or titanium. The current paper presents a new technology for the fabrication of microstructured tool electrodes for electrochemical machining by using highly doped silicon as electrode material. A simple and low priced fabrication of microstructured silicon electrodes with locally isolated areas is demonstrated by using wellestablished silicon processing technologies. Prototypes based on this new tool electrode technology are fabricated. Therewith electrochemical machining of microstructures in stainless steel is successfully demonstrated. Machining gaps down to 10 μm and average surface roughness of 60 nm are achieved. Typical rates of removal between 60 - 240 μm/min are reached. The local isolation of electrode areas advances the machining accuracy.

G. Tosello(a), B. Fillon(b), S. Azcarate(c), A. Schoth(d), L. Mattsson(e), C. Griffiths(f), L. Staemmler(g), P.J. Bolt(h)
a: Technical University of Denmark (DTU), Department of Manufacturing Engineering and Management (IPL), 2800 Kgs. Lyngby, Denmark
b: French Atomic Energy Commission (CEA), Laboratory of Innovation for New Energy Technologies and Nanomaterials (LITEN), 38054 Grenoble, France
c: Tekniker Technological Center, 20600 Eibar, Spain
d: University of Freiburg, Institute of Microsystem Technology (IMTEK), 79110 Freiburg, Germany
e: School of Industrial Technology and Management (KTH), Department of Production Engineering, 100 44 Stockholm, Sweden
f: Cardiff University, Manufacturing Engineering Center (MEC), Cardiff CF 24 3AA, UK
g: Hahn-Schickard-Gesellschaft, Institute for Micro Assembly Technology (HSG-IMAT), 70174 Stuttgart, Germany
h: TNO Science & Industry, 5600 HE Eindhoven, The Nederlands

Abstract

This paper is based on the Division 4 “Processing of Polymers” activities within the 4M NoE “Multi-Material Micro Manufacturing”. To overpass limitations of the current existing micro tooling capabilities, a new generation of micro hybrid tooling technologies for micro replication was developed. A metrological approach was applied to standardize the employed tooling processes (μ-milling, μ-EDM, laser μ-machining, electrochemical μ-milling). The micro tools were then tested with different polymers. The paper provides a comparison of these technologies concerning obtainable feature sizes, surface finishing, and aspect ratios of both micro tools and micro moulded parts.