Electroforming Process and Application to Micro/Macro Manufacturing
ABSTRACT Electroforming is the highly specialised use of electrodeposition for the manufacture of metal parts. This paper describes the process principles and mechanisms of electroforming, outlining its advantages and limitations. A review of modelling and simulation of electroforming and experimental analysis work is also presented. The metals that can be electroformed successfully are copper, nickel, iron or silver, thickness up to 16 mm, dimensional tolerances up to 1 μm, and surface finishes of 0.05 μm Ra. The ability to manufacture complex parts to close tolerances and cost effectively has meant that electroforming has applications both in traditional/macro manufacturing and new micromanufacturing fields. These include tooling; mould making; fabrication of microelectromechanical systems (MEMS) and the combination of lithography, electroforming and plastic moulding in the LIGA process. Applications in micro-optics and medicine are included.
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ABSTRACT: A micro electrochemical milling by layer process is presented in this paper. Because of no tool wear in electrochemical micromachining, a very thin tungsten electrode is used as the tool cathode. By applying ultrashort pulses, dissolution of a workpiece can be restricted to the region very close to the electrode. First, the mathematical model of micro electrochemical milling by layer is established to ensure a good shape precision. Second, the micrometer scale cylindrical electrode is fabricated in situ by electrochemical etching for the production of micro structures. And then, effects of machining parameters on the side gap variation in electrochemical milling process have been studied experimentally. Finally, some 2D micro shapes and 3D complex micro structures with physical dimension of several 10 μm have been obtained.International Journal of Advanced Manufacturing Technology 60(9-12). · 1.78 Impact Factor
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ABSTRACT: The marked increase in demand for miniaturized consumer products in a broad range of potential applications including medical, telecommunication, avionics, biotechnology and electronics is a result of advancements in miniaturization technologies. Consequently, engineering components are being drastically reduced in size. This coupled with the quest for higher quality components, has imposed more stringent requirements on manufacturing processes and materials used to produce micro components. Hence, the development of ultra precision manufacturing processes to fabricate micro-scale features in engineering products has become a focal point of recent academic and industrial research. However, much attention in the area of micro-manufacturing, especially micro-mechanical machining, has been devoted to building miniature machine tools with nanometer positioning resolution and sub-micron accuracy. There is lack of fundamental understanding of mechanical machining at the micro and nano scale. Specifically, basic understanding of chip formation mechanism, cutting forces, size-effect in specific cutting energy, and machined surface integrity in micro and nano scale machining and knowledge of how these process responses differ from those in macro-scale cutting are lacking. In addition, there is a lack of investigations of micro and nano scale cutting of common engineering materials such as aluminum alloys and ferrous materials. This thesis proposes to advance the understanding of machining at the micro and nano scale for common engineering alloys. This will be achieved through a series of systematic micro and nano cutting experiments. The effects of cutting conditions on the machining forces, chip formation and machined surface morphology in simple orthogonal micro-cutting of a ferrous, P20 mold steel (30 HRC), and a non-ferrous structural alloy, aluminum AL7075 (87 HRB), used in the mold making and rapid prototyping industry will be studied. The data will also be compared with data obtained from conventional macro-scale cutting. In addition, the applicability of conventional metal cutting theory to micro and nano cutting test data will be examined. The analysis will provide a better understanding of machining forces, chip formation, and surface generation in micro and nano scale cutting process and how it differs from macro-scale cutting. Lackey, Jack, Committee Member ; Kurfess, Thomas, Committee Member ; Melkote, Shreyes, Committee Chair. Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2005. Includes bibliographical references.
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ABSTRACT: A novel technique of electroforming with orbital moving cathode was carried out for the fabrication of non-rotating thin-walled parts. This technique features a large number of insulating and insoluble hard particles as a real-time polishing to the cathode. When cathode moves, hard particles polish its surface and provide the nickel non-rotating parts with near-mirror finishing. Morphology, microstructure, surface roughness and micro hardness of deposits fabricated by novel method were studied in contrast with the sample produced by traditional electroforming methods. Theoretical analysis and experimental results showed that the novel technique could effectively remove the hydrogen bubbles and nodules, disturb the crystal nucleation, and refine the grains of layer. The mechanical properties were significantly improved over traditional method. The microhardness of the layer was in a uniform distribution ranging from 345 HV to 360 HV. It was confirmed that this technique had practical significance to non-rotating thin-walled parts.Journal of Wuhan University of Technology-Mater Sci Ed 26(5). · 0.48 Impact Factor