Toshiba Machine (Japan)

In ultra-precision machining field, it is gradually increasing a demand to manage both machining efficiency and accuracy. To achieve high machining efficiency, each axis has to move at high speed. Though, it can cause travelling error due to servo delay regarding the acceleration/deceleration after interpolation processing. This makes machining accuracy worse especially in machining of free-form shape. This study proposes a way of tool-path optimization which applies compensation for servo delay to improve machining accuracy and efficiency.

In this paper, we propose cutting-force-estimation method for a ball-screw-driven system using triple inertia model. In many cases, dual-inertia model is applied to describe the dynamic behavior of the ball-screw-driven system. In this paper, triple-inertia model is applied and cutting force was estimated without additional sensors, such as dynamometer. The cutting force observer is designed, regarding the ball-screw-driven system as two input and three output system. Simulation results indicate that the proposed method enables accurate estimation around the resonance frequencies. Experimental results showed that the proposed method could monitor external force without being interrupted by the inertia forces.Nomenclature

The demand for large aperture lenses with high surface quality and form accuracy used for single-lens reflex cameras has been increasing. Generally, large aperture glass lenses are produced by ultra-precision grinding. Considering the increasing global competition, the grinding process has to be improved. However, highly efficient grinding causes worse surface quality, which leads to much polishing and ultimately results in lower form accuracy. Thus in this study, aiming at the realization of highly efficient and precise grinding of glass lenses, cross grinding of optical glass BK7 is carried out. As a first step of the study, the influence of grinding conditions on the surface quality is investigated experimentally.

This paper presents a fabrication process of microscale patterned sapphire substrates (PSSs).The resin mold was fabricated precisely by UV roll-to-roll (RtR) imprinting.Pillar pattern were UV-imprinted on a sapphire wafer by using the mold.PSS were formed on the 2-inch and 4-inch entire wafer areas by BCl 3 -based reactive ion etching.The height and bottom diameter of the conical structure in a 2-inch sapphire wafer were 1.73 μm and 2.67 μm, respectively.

We are advancing the development of a smart fiber using a plastic optical fiber (POF) as a fibrous substrate with micro-electro-mechanical-systems (MEMS) patterned on its surface. We employed hot embossing and thermal nanoimprinting techniques for patterning on the surface of POF, although, no work has so far been reported on the molding characteristic of POF. And moreover, achieving any high quality imprinted patterns on POFs has also proven to be difficult. We have been studying the effect of molding on POFs under various heating temperatures and press depths by sandwitching the POF between patterned face of a mold and a buffer material. When a soft buffer material with its hardness less than that of the polymethyl methacrylate (PMMA) core of a POF fiber was used, a reasonable patterning on the clad layer covering the surface of the POF was achieved without any sign of deformation of PMMA core. On the other hand, when the hardness of a buffer material happened to be equal to, or higher than that of the PMMA core, then deep concave pattern could be processed by purposefully deforming the POF. We successfully transferred a pseudo MEMS pattern with a width of 20 μm on the surface of a 250-μm-diameter POF. Also, under another kind of optimized molding conditions combined with buffer material, we fabricated an arc-shaped weaving guide structure on POF with the weaving guide`s bottom width of 300 μm. The investigation of the molding characteristic of POF by examining any change in the cross-sectional shape is a unique one. The experimental results thus obtained, add significantly to the database for the processing of a fibrous substrate by thermal deformation.

In the emerging fields related to healthcare, energy, and environment, realization of devices on large area flexible sheets is imminent. Weaving e-textile with fibrous devices comprising warp and weft is one of the methods to realize such devices. Especially with a display or with a 2-D matrix sensor, a distortion of image, or error in positional information can occur if these matrices get misaligned. Therefore securing of the matrix becomes necessary. However, in a traditional textile, due to weak binding force in shear direction at the intersection of warp and weft, the displacement of intersection often does take place. So we propose to make a weaving guide in a form of dent structure on the fiber substrate. To realize this strategy, we developed a system to produce such weaving guides onto a fiber with improved productivity. To maintain a constant press force onto the fiber substrate during imprint, and to stabilize deformation volume, we adopted a press force control mechanism. As a result we obtained a stable and uniform deformation of imprinted weaving guides. Finally, to validate the weaving guide, we made two samples using 3×3 fibers, with and without the weaving guides. We saw distinct difference between the two samples.

Step-and-repeat UV nanoimprinting for large-scale nanostructure fabrication under atmospheric pressure was realized using high-viscosity photocurable resin and a simple nanoimprinting system. In step-and-repeat UV nanoimprinting under atmospheric pressure using low-viscosity resin, large-scale nanostructure fabrication is very difficult, due to bubble defects and nonuniformity of the residual layer. To minimize bubble defects and nonuniformity of the residual layer, we focused on the damping effects of photocurable resin viscosity. Fabrication of 165 dies was successfully demonstrated in a130×130 mm2area on an 8 in silicon substrate by step-and-repeat UV nanoimprinting under atmospheric pressure using high-viscosity photocurable resin. Nanostructures with widths and spacing patterns from 80 nm to 3 μm and 200 nm depth were formed using a quartz mold. Bubble defects were not observed, and residual layer uniformity was within 30 nm ±10%. This study reports on simple step-and-repeat UV nanoimprinting under atmospheric pressure using high-viscosity photocurable resin, as a very widely available method for large-scale mass production of nanostructures.