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AbstractIn this paper reported are some of the activities of the Laboratory of Manufacturing Technology of the NTUA in manufacturing engineering,focusing onto some recent trends and developments in advanced manufacturing of advanced materials, mainly emphasizing my long-standingGreek–Ukrainian–Russian–Hungarian scientific cooperation, also with international involvement worldwide, in the principal research and veryimportant engineering topics nowadays, from industrial, research and academic point of view: ultraprecision engineering and nanotechnologyand net-shape manufacturing of high-temperature ceramic superconductors.© 2004 Elsevier B.V. All rights reserved.
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Keywords: Ultraprecision; Nanotechnology processing; Manufacturing engineering 46844
1. IntroductionQuality of manufactured parts in forming, metal removalprocessing and net-shape manufacturing is mainly deter-mined by their dimensional and shape accuracy, the surfaceintegrity, and the functional properties of the products. Devel-opment of manufacture engineering is related to the tendencyto miniaturization and is accompanied by the continuous in-creasing of the accuracy of the machined parts, see Fig. 1,reproduced from Ref. [1].The two main trends towards miniaturization of productsare the ultraprecision and the nanotechnology processing.The former is carried out by machine tools with very high ac-curacy, while the latter also employs new advanced methodsthat allow for atom manipulation or the so called “bottom-up”manufacturing, where machine particles are built-up atom byatom. Nanotechnology is therefore defined as the fabricationof devices with atomic or molecular scale precision, but italso includes all devices with size less than 100 nm. On theother hand, by ultraprecision processing, defined are theseprocesses by which the highest possible dimensional accu-racy has been achieved at a given time.The materials that present zero resistant at certain temper-ature above absolute zero are named superconductors and the related phenomenon superconductivity, see Fig. 2, repro-duced from Ref.
[2]. The discovery of high-temperature su-perconductivity in 1986 resulted in very extensive researchwork regarding the discovery and synthesis of high-Tc su-perconducting materials, possessing superconductivity aboveliquid nitrogen boiling point, utilized to many engineeringapplications, from electronic sensors to rotating electricalgenerators and from nanometer-scale thin-films to kilometer-long wires and coils. Therefore, design and net-shape manu-facturing of superconducting components, starting from theinitial synthesized powders, is nowadays of utmost industrialimportance.Some of the activities of the Laboratory of ManufacturingTechnology of the NTUA related to the above mentionedareas of advanced manufacturing are outlined below.2. Micro- and nanoprocessingUltraprecision processing refers to the achievement of di-mensional tolerances of the order of 100 m and surfaceroughness of 10 nm. The dimensions of parts, or elementsof parts, produced may be as small as 1 m and the resolu-tion and repeatability of the machines used are of the orderof 10 nm. These accuracy targets cannot be achieved by sim-ple extension of conventional machining processes, but, also, ∗ Tel.: +30 210 772 3688; fax: +30 210 772 3689.E-mail address: mamalis@central.ntua.gr. new processes are required. Several cutting material removalprocesses, depending on the desired result, are suitable for ul- 0924-0136/$ – see front matter © 2004 Elsevier B.V. All rights reserved.doi:10.1016/j.jmatprotec.2004.07.055 2 A.G. Mamalis / Journal of Materials Processing Technology 161 (2005) 1–9Fig. 1. Taniguchi’s classification [1]. traprecision machining, like drilling of microholes, milling ofgrooves, turning of mirror-like surfaces and micropins, whilstusually, ultraprecision turning is combined with other ultra-precision processes, such as grinding. Typical products of theabove processes are miniaturized machined parts, mirror-likesurfaces or macro-components with ultraprecision finishedsmooth surfaces, see Fig. 3 and Ref. [3]. Other processes arealso used for performing ultraprecision cutting, like EDM,ECM, laser beam machining, ultrasonic machining, micro-punching and injection molding.The original idea for the development of nanotechnologycomes from the area of microelectronics and its applicationsin computer systems. According to this manufacturing con-cept, the smaller the particles are the reduced is their man-ufacturing cost and the higher is their productivity. This hasalready been achieved in the chips industry as it can be seen bycomparing the size and the speeds of computers of the 1980sand today. Nanotechnology is made possible through tech-nological advances made in several disciplines, as demon-strated in the “nanotechnology tree”, see Fig. 4 and Ref.[4].Advancing now from the micrometer domain into thenanometer regime it renders difficulties to use the ultra-precision processes outlined above.