This study deals with development of a new device which can machine long and curved holes. To optimize the shape and arrangement of water channels build in a mold, it is strongly required to establish a curved hole machining method. Therefore, the authors have developed two devices to machine curved holes with electrical discharge machining. The first one is mechatronics equipment which has an electrode, a coil spring, and wires. The second one is based on an in-pipe movable mechanism which has a flexible and long body that tiny wheels are attached to its circumference and an electrode to the top. These devices can achieve fabrication of curved holes and extension of their length, respectively. However, they were not able to fabricate complicatedly curved and long holes. The study aims at development of the in-pipe movable mechanism with controllability of its machining direction by combining two devices mentioned above. From the result of machining experiment with the prototype of the combined device, it is found that it can make a curved hole and will be able to fabricate long and complicated curved holes.

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The Laser-Arc hybrid welding of HSLA-590 steel has been studied using 2.4 kW CO_2 laser and MAG welding. Hybrid welding has a number of process parameters which are laser-arc distance, defocusing distance, laser power, travel speed, arc welding current, arc voltage, shielding gas and its flow rate, welding torch angle, wire diameter and so on. From the parametric study in hybrid welding of high strength low alloy steel, it is concluded in our study that the stable welding can be obtained when the welding parameters are controlled properly. Effects of welding parameters on bead shape and the hardness of weld metal at different welding speed, arc currents, arc voltages at constant laser power of 2kW and argon shielding gas flow rate 20L/min were investigated. The hardness of weld metal of then hybrid welding is lower comparing with those of Laser welding and MAG welding, because the heat input of hybrid welding is more than Laser welding and MAG welding individually under the same welding speed. In addition, a low carbon filler wire was used for decreasing the carbon content of weld metal. That means the hybrid welding is very useful for lowing the MAX. hardness and increase the toughness of welds.

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Direct micro joining with YAG laser beams between copper wire and plate or substrate board was carried out. A contact angle between wire and plate affected peeling strength greatly. And an effect of pulse control was also great and it was good work for control of wire melt behavior. In cases of plate of 200μm and 100μm in thickness, high peeling strength of 4N with little dispersion was obtained in pulse control condition. However, in case of copper substrate board of 70μm in thickness, the strength was poor. Because of few thermal capacity, thermal conditions tended to be changed sensitively by conditions such as contact angle, surface state of wire, accuracy of wire setup and so on.

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Methods of UV laser machining for glass are now highly required. However, cracks generate on glass when the glass is merely irradiated with a laser. One of the solutions is to utilize laser absorbent. In this paper, three kinds of absorbent, i.e. plate-like absorbent, powder absorbent and liquid absorbent, were examined for a groove, a deep hole and a 3D micro channel within glass, respectively. In the experiments, the proper machining conditions were investigated in order to fabricate the microstructure without cracks. As a result, a deep hole and a bending micro channel can be fabricated.

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The processing conditions of DLC using the FIB-CVD method were examined in detail and were optimized. Microstructures and mechanical properties of DLC were also investigated. The deposition experiments with changing processing conditions indicated that the rate-determining steps of the deposition rate were varied by the probe current and heating temperature of phenanthrene. HRTEM and diffraction images showed that the DLC had amorphous structures. Young's modulus and Vickers hardness were in the range of 110-140GPa and 1100-1400HV, respectively. These mechanical properties were obtained similarly even though the deposition conditions were changed in our study.

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Etching characteristics of a silicon surface irradiated by high-energy ion beam against HF are investigated in this study. Specially designed ion irradiation facility, which enables to irradiate high-energy ion beam, is employed. A deep structure with a depth of several hundreds nanometers can be fabricated by utilizing high-energy ion irradiation. The depth of irradiated area can be controlled by adjusting acceleration voltage and ion charge, and it is related to distribution of damaged layer induced by ion irradiation. These results indicate a possibility of application as a novel deep three-dimensional nanofabrication process.

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To achieve rapid patterning of quartz surface, ion beam irradiation using focused ion beam (FIB) and succeeding buffered hydrofluoric acid wet etching of quartz was examined. The etched depths of quartz saturated with increasing of ion dose and the optimum wet etching time was 60s. This process improved surface roughness and fabricated a 34nm depth and 487nm width line pattern using 330nm diameter FIB irradiation.

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We tried the method to increase the peel strength between thin film metals and various substrate materials using saddle Field FAB (Fast Atom Beam) sources. It is notable that the peel strength was increased more than several times for all substrates than those who were not modified by surface activation using FAB irradiation. Highest peel strength was observed at the coupling of Si and metals in both case of Ar irradiation and SF_6 reactive etching by FAB. This surface activation process by FAB is expected as one of the available techniques for pre treatment of the film deposition of electrical.

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Ceramic films are needed in micro-electro-mechanical systems as insulating, piezoelectric and ferroelectric materials. The required film thickness is 1-10μm. This is too thin to machine by polishing or grinding, and too thick to grow by chemical or physical vapor deposition. The present study proposes a new method called powder jet deposition (PJD) for fabricating ceramic films 1-10μm in thickness. Indentation and scratching tests are performed on ceramic films deposited by the PJD method. It is found that the hardness of the films depends on PJD conditions.

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We conducted fabrication process of three-dimensional (3D) mold using spin-on-glass (SOG) material as a positive electron beam (EB) resist and buffered hydrofluoric acid as the developer. The SOG resist depth control was demonstrated by the changing the EB acceleration voltage or the changing the EB dose. In either case, 3D patterning was possible. In particular, nanometer order pitch holes arrays were obtained to optimize EB dose at high voltage acceleration. Using delineated resist patterns as a 3D mold, UV nanoimprint lithography was carried out and nanometer size patterns were faithfully replicated.

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The transfer characteristics of sol-gel photocurable polymer were investigated using nanoimprinting method. This polymer is a kind of thermoplastic polymer which was hardened by exposure of ultraviolet (UV) light. Using this polymer, the release before UV hardened method and the release after UV hardened method were examined. In the case of the release before UV hardened method, micrometer patterns were transferred, but nanometer patterns couldn't replicate. On the other hand, nanometer patterns were successfully obtained using the release after UV hardened method.

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This paper reports on nano surface fabrication of hard-brittle materials by direct imprinting method. Ultra fine structured surfaces were fabricated on soda glass. Specially designed nano indentation tester is used for the experiment. Various structured tools are developed. Imprinted mark and the ultra fine structured are analyzed for geometrical shape and processing characteristics. Also, new functional surfaces about friction properties developed by the nano fabrication process are studied.

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This paper proposes a new micromachining method using multi-axes vibration tool and its application to surface texturing. Firstly, hole machining of quartz glass was carried out to compare the result of single-axis vibration of φ100μm tool with that of multi-axes vibration. It was found that the brittle fracture or chipping was well prevented while improving the surface roughness with multi-axes vibration tool. Secondary, texturing was carried out applying both shallow depth of cut and the lateral feed together with the vibration. It was found that the locus was well copied to the surface.

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This study aims to clarify the effectiveness and the mechanism of the application of vibration on the reduction of plastic flow and the improvement of machined surface in the micro/nano cutting or grinding processes. In this study, the molecular dynamics method has been applied to the analysis of extremely small amplitude and high-frequency vibration assisted cutting processes. In the simulations, the cutting tool and the workpiece are assumed to be rigid diamond and pure aluminum, respectively. In this paper, the effect of the vibration parameters, such as frequency and amplitude on the reduction of plastic flow and cutting forces was mainly clarified.

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A miniaturized six axis vertical machining center with linear positioning resolution of 4nm by 10nm by 10nm, accuracy on the order of 0.3μm, in the height, feed, and cross feed directions is presented. The ranges of axes travel are 4mm by 25mm by 25mm in the height, feed, and cross feed and 20 degrees in the rotational space. An injection mold was made of steel with this machine and plastic microcantilevers were fabricated from polystyrene were 464 to 755μm long, 130μm wide, and only 6-9μm thick.

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It is difficult to polish micro-aspherical molding dies because it is difficult to gather the abrasive grains effectively in a small polishing area. In this study, an electrorheological (ER) fluid assisted polishing method is proposed, in which the workpiece and the micro-tool are used as electrodes in order to gather the abrasive grains around the interface thereof. The relationship between polishing performance and the gap between the two electrodes is investigated and the force acting on the abrasive grains was calculated by FEM. Furthermore, a resin coated polishing tool is developed which prevents the workpiece from being scratched when in contact with the polishing tool.

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Nano/micro grinding of tungsten carbide (WC) mould inserts was performed. A form accuracy of 〜200nm (in PV) and a surface roughness of 〜7nm were achieved. Nanoindentation revealed that small chipping or cracking occurred even at a penetration depth of 38nm, which could hinder the further improvement of surface quality during grinding. It was found that when grinding was conducted at nanometric scale, the microstructure of the work material and the morphology of the WC grains should be taken into account to enable a fully ductile removal.

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Many models have been proposed for simulation of planarization process of patterned Si wafer. In the previous report, an analytical model has been established to incorporate variations in pattern density, step height of an oxide layout, the tool stiffness and in feed scheme. In this paper, we aimed to further improving the accuracy of the simulation via introducing an actual oxide layout. Instead of a rectangular layout, a triangular layout with multi-step height was used for the simulation model to clarify the effect of pattern profile.

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For the final finishing of single crystal Si wafers, unlike the conventional polishing, we have developed a dry fixed-abrasive process by effective use of solid-state reaction between the CeO_2 abrasives and Si. Si is removed in a form of complex cerium-oxygen-silicon when two materials are subject to the conditions of about 0.8 MPa pressure and 15 m/s relative velocity. The fabricated φ300mm Si wafers are examined on both surface and subsurface. The results show no defect or mechanical imperfection being introduced during fabrication, and far better quality than the achievables by CMP.

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