Generally surfaces with nanometer-sized structures provide various functions to materials. For example, a glass surface with nanostructures reduces the surface reflectance of optical elements such as camera lenses. While this kind of dogma-researches about surface functions are matured, researches on processing methods for general industrial production are still few. As one of cost-effective nanofabrication methods, we had reported the phenomenon that coating process of the light-absorbable glass precursor and irradiation process of femtosecond-laser on the surface could fabricate nanostructures on a glass surface. In this paper, for the sake of clarifying the fabrication process, cross-sectional analyses of the fabricated microstructures were conducted. Cross-sectional analyses were conducted step-by-step on irradiation number of the glass precursor and they revealed that the structuring process is consisted of the 3 steps. At first, laser irradiation induces oxidization and shrinking in glass precursor layer. Secondly periodic cracks generate inside glass precursor layer. Finally grown-up cracks peel off the layer over the crack and periodic structure are revealed on left surface. These 3 steps are significantly singular processes in conventional researches about laser-induced periodic surface structuring.

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It is known that the mechanical properties of metals change with the given compressive hydrostatic pressure. However, the mechanism of such phenomenon has not been fully understood, because most experiments have been carried out using polycrystalline materials. In this study, in order to clarify such a mechanism at an atomic-scale, a molecular dynamics simulation of the torsion process on a monocrystalline aluminum was performed under relatively high compressive hydrostatic stresses. In the simulation, influences of the pore defect on mechanical properties and deformation of the workpiece were also examined. As a result, it was confirmed that both the modulus of rigidity and yield shear stress were increased and the generation of dislocations was decreased with increasing the compressive hydrostatic stress irrespective of the presence of defect. However, the increase in the yield shear strain was only observed for the workpiece with a pore defect, and this trend was discussed and verified by using a simple fracture mechanics model.

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In reproducing large-area micro shape by injection molding, one of the biggest problem is that the difference of thermal contraction between the mold material and the resin causes a residual stress in the product, and it becomes difficult to release the product from the mold. In this paper, the authors propose a new method which is called ‘directional solidification method’ for solving the problem. The method can reduce the thermal contraction of the product and the releasing resistance by letting the resin solidify sequentially from one end of the cavity toward the another end. In order to realize the method, the authors developed a mold which can make a temperature gradient, and realized the directional solidification of the resin. Using the mold, we reproduced plate-shape products which has micro shapes on their surfaces under two molding conditions such as uniform temperature and temperature gradient. The experimental results showed that the resistance under temperature gradient was 12% lower than under uniform temperature. Through this experiment, it was confirmed that the directional solidification method improved releasability of the products with micro shapes on their surfaces.

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In this study, flank wear of physical vapor deposition (PVD) coated cutting tools during continuous turning of alloy 718 were investigated. The similar damages were observed on the rake face and the flank face. Incidentally, wear rate of the coating on the flank face was higher than the one of the rake face. The aim of this study is to clarify the wear mechanism of the coating on the flank face. A typical Ni based superalloy (alloy 718) was machined by using TiN coated and uncoated cutting tools. After the cutting test, the damages on the flank face of the cutting tool were observed through scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and transmission electron microscopy (TEM). Enrichment of (Nb,Ti)C was observed on the interface between the coating and adhered material. The (Nb,Ti)C layer was made from strengthening phase in alloy 718. Therefore, the (Nb,Ti)C layer adhered on the flank face might cause the strong abrasive wear on the flank face. Thus, the wear modes of the coating on the flank face were composed of abrasive wear, in addition to adhesive wear and fatigue wear. Corrosive wear by oxidation and diffusion between the work and the coating material was not confirmed. It is indicated that the required coating properties for alloy 718 machining were higher softening-resistance and hardness of the coating than (Nb,Ti)C.

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A new cutting force simulator which calculates discretely uncut chip thickness by referring workpiece voxel model has been developed to predict cutting force in end-milling operation. This cutting force simulator can predict cutting force under the complex change of workpiece shape and the non-uniform contact between cutting edge and workpiece. Additionally, a new methodology to realize adaptive control or feed speed control based on the predicted cutting force is developed by integrating with the digital copy milling system which can generate tool paths in real-time during machining operation. This methodology can revise the tool feed speed based on the cutting force which predicted simultaneously with the real end-milling operation

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In this research, we propose charts of description for analysis of assembly work and the sensing system which has facility of automatic description. Charts of description consist of ”motion procedure chart” and ”trajectory chart for hands and eye-gaze”. ”motion procedure chart” can describe kinds of motion and it time. ”trajectory chart for hands and eye-gaze” can describe trajectories of hands and eye-gaze. The sensing system describes the motion based on mutual interferences of hands and objects. It also describes the eye-gaze estimated by the device which is a work cap equipped with two laser pointers. We evaluated the accuracy of description. As a result, we confirmed that the description success rate of the motion procedure is 83.4% on average. And we confirmed that the error in trajectories of hands is within 20mm beside the error in the trajectories of eye-gaze is within 13.4mm on average.

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The roller screw mechanism is more suitable for high load than the ball screw mechanism, because it has a large contact area and a greater radius of curvature between a roller and a screw shaft. However, it is considered that the rolling mechanism which has large contact surface is easy to get a big slip ratio, and it generally has lower mechanical efficiency. In this study, to improve the mechanical efficiency of the roller screw mechanism, we devised the tapered roller screw mechanism (TRS). The shape of flank face of screw shaft and the surface of rollers of TRS is designed to minimize the slip ratio. As a result of experiment, it was confirmed that the apparent coefficient of friction was 0.0018 at minimum, and the mechanical efficiency was 0.985 at maximum. These results showed that the TRS was comparable to the ball screw mechanism in efficiency.

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Delicate movement with high-precision performance has been required in the field of micro-manipulation driven by microscopic robots, especially cell manipulation. Taking the precise micro-manipulation into account, it needs to avoid the singular configuration of manipulator and the complication of calculation processing. In this paper, a novel macro-micro bilateral control system based on force controller is proposed. By dealing with the interference term caused by a mass fluctuation as a disturbance in modal space, the control structure of high-performance haptic transmission is realized. The validity of the proposed method is confirmed by using the experimental device having a high resolution.

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