In this paper, we propose a triangular mesh deformation method based on dimensions. By specifying the type of dimensions, the regions defining the dimensions, and the target dimensions, the mesh is automatically deformed so that it satisfies the target dimensions. Mesh deformation is based on space-based deformation using barycentric coordinates. The deformation handle, which consists of a set of triangular prisms, is automatically created by mesh segmentation, simplification and offsetting of simplified mesh. In deformation, the deformation and fixed spaces are assigned to each prism in the handle, and the mesh is deformed by applying affine transformation to the control vertices and space-based deformation to the deformation space.

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Recently, mesh deformation techniques have been intensively studied. Such methods preserve differential properties of the original meshes as possible, fulfilling given constraints. We propose a method of the mesh deformation with kinematic models to control implicit kinematic constraints between handles of the deformation. In this report, we describe the method of extracting kinematic models from geometry and mapping motions of the models to transformations of the handles.

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The uses of mesh models in engineering have increased in recent years, and more powerful techniques of handling mesh models are required. In assembly for mesh models, shape matching and configuration between them are needed. Therefore, we introduce graph-based feature representation to recognize a mesh model on each function side, and propose a method for shape matching and configuration between mesh models. Combinations of local regions which can be matched between given two models are extracted, and configurations between them are determined based on a coordinate transformation.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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A CAM software was developed for machining a broad range of complex shapes making use of the rule of surface texture. CL data is computed for the same shapes using rules of area texture in a narrow range. This CL data corresponds to surface texture during moving and turning mapping allowing the CL data to be obtained without the need to calculate the entire surface. This software is expected to enable textures with regular patterns to be machined accurately.

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[in Japanese]

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We introduce a method for extracting iso-surface from CT data composed of multi-material parts. Most contouring method such as marching cubes assumes that the CT data compose of two materials. However these contouring methods can not be directly applicable for a CT data composed of three materials or more, because of many problems. First is that we need to use n(n-1)/2 iso-value in order to segment a CT data consist of n material. Second is the blurry edges at the junction where more than three materials are adjacent. We propose here a method for segmenting the CT data into its composing materials using a combined method of two well known algorithms in image segmentation, region growing and graph-cut. And we demonstrate the effectiveness of our novel method by constructing high quality polygon models of the segmented parts from CT data.

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[in Japanese]

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[in Japanese]

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This report presents a method for extracting medial voxels from large volumetric models. Our method computes medial voxels by using large distance field computation algorithm presented in previous reports. Although our method is based on Prohaska's medial voxel evaluation method using geodesic distance, we simplfy computation costs by introduincing pseudo geodesic distance (PGD). As PGD computation is completely local, our algorithm becomes sequential algorithm and is good for large data. This report also demonstates results of medial voxel extraction from lagre volumetric models.

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In present CAD systems, there are many operations that are very troublesome, difficult or complex.In this research, a system to automatically learn various operations is developed.CAD users can make various operations easily in the system.

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[in Japanese]

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[in Japanese]

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Methods of extending B-spline surfaces in conventional 3D CAD systems are usually based on linear extrapolation from sequence of control points. These methods do not always result in desired smooth surfaces fulfilling the requirements for exterior automotive parts. A new method of extending B-spline surfaces of degree n which preserves C^n-1 continuity is proposed. The method constructs new surfaces in two stages by introducing a surface with smaller intermediate curvature and a plane surface.

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This paper defines logarithmic curvature graph and logarithmic torsion graph and presents a method for drawing these graphs from free-form curves, such as NURBS or Bezier curves. We clarify the characteristics of these graphs and propose to use them as a curve analysis tool.

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[in Japanese]

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[in Japanese]

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It has been reported that the assistance of ultrasonic vibration to cutting tool produces various effects, such as reduction of cutting force compared with conventional cutting, improvement of the machined surface quality and reduction of tool wear, and so on. However, its mechanism has not been explicated till right now. In this paper, experiments of ultrasonic assisted orthogonal cutting are carried out. Oscillating direction is cutting direction. Influences of cutting parameters on cutting phenomenon are investigated, and characteristics of ultrasonic assisted cutting are compared with conventional cutting.

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[in Japanese]

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In recent years, demand of small size and high accuracy machine part is getting higher. Therefore, the necessity for processing micro hole in high accuracy and high efficiency increases. However conventional drilling has some problems such as insufficiency of tool rigidity and chip removal. In order to solve these problems, ultrasonic vibration assisted micro drilling for difficult-to-machine materials was studied. Ultrasonic vibration decreases cutting force and improves of chip removal. The aim of this study is to confirm the effect of ultrasonic vibration drilling for the difficult-to-machine materials.

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This paper deals with the development of micro compound tool consisting of a micro drill part and an electroplated part with a nominal finishing diameter of 100 μm. The fabricated tools were used in the drilling into stainless steel. In the drilling test, characteristics of the drilling and effects of ultrasonic vibration were investigated.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Recently, surface finishing of die such as a mobile phone mold surface has been carried out by skilled workers and it consumes several days to finish. The aim of this study is to improve productivity of die by mechanization of finishing process using ultrasonic machining. Spherical diamond tools that were truncated on a machine tool were used in experiment to obtain mirror surface finishing of inclined planes. The effects of cutting edge truncation on the grinding surface were studied.

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[in Japanese]

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Microdrilling into silicon was investigated using chemically plated diamond tools. From the viewpoint of tool life helical drilling was most useful among the step drilling, helical drilling and drilling assisted by ultrasonic vibration.

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[in Japanese]

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[in Japanese]

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The purpose of this study is to find out effective parameters for monitoring of cutting process to achieve highly efficient end-milling process of titanium alloy, which is difficult-to-cut material. Cutting tests were carried out in down-cut milling to observe state of chips on cutting edge and to measure width of tool wear land and dynamic cutting forces with increase in cutting speed and cutting length. As a result, it was revealed that width of flank wear land and its rate of increase could be related with length of deposited chips on cutting edge and extremes of dynamic cutting forces.

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In recent years, machining center has been used widely in metal mold manufacturing process because high speed machining by using a small diameter end-mill has been put into practical use. However, in cutting process with an end mill that is a low rigidity, it is very important to estimate the machining error caused by deflection of tool. The purpose of this study is to establish a method of in real time estimating machining errors caused by deflection of end-mill at a cutting point. For this purpose, the growth mechanism of machining errors caused by deflection in ball end-milling was investigated in detail.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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The small diameter tool is used for precision and minute cutting on high speed milling. The tool breaking during cutting with a small-diameter end mill is still problematic in the field of production. This study presents a monitoring technique for the in-process measurement of cutting force and the prediction of tool breakage. This technique is based on the newly developed visualization system with a high-speed CCD camera. The system to monitor the tool behavior from the X axial and Y axial is constructed with two CCD cameras. In this report, the tool behavior was measured with this monitoring system and the characteristic of tool deflection was investigated.

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[in Japanese]

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An impact cutting tester has been developed to investigate ultra high-speed cutting phenomena under various cutting environments. In the tester, a small projectile having a small cutting tool loaded into an acceleration tube is launched to a workpiece set in a chamber. The chip is captured in the projectile. After finishing cutting, the projectile goes forward in a deceleration tube; it is decelerated with a compressed gas; finally it stops in the tube. These tubes and the chamber are completely isolated with the atmosphere. The lengths of the acceleration and deceleration tube are 3m. Maximum pressure of the compressed gas is 1MPa. This report describes the properties of the tester developed and shows several experimental results under high speed and ultra high-speed cutting processes obtained with the tester.

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[in Japanese]

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[in Japanese]

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In our group, we have developed a micro robot composed of an electromagnet and piezo actuators. This micro robot has the height adjustment mechanism with the magnetic leg because this robot has four point contact points with the surface. However, there was observed some problems that reproducibility of operation was decreases by the wear-out of V groove slide mechanism. In this research, we improved the suspension mechanism of the electromagnetic legs by using the parallel leaf springs so that each of the leg can contact with the surface even on the rough .The performance of this newly improved walking mechanism is discussed in the experiment.

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[in Japanese]

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[in Japanese]

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The technique for nano manipulation in SEM (scanning electron microscope) becomes more important due to the demands for the latest nano technology trends. However it is also not easy to implement the precise machines into the small SEM chamber since there are some problems such as the lubrication and electromagnetical disturbances. In our group, the unique small robot driven by the piezo elements that is capable of working even in the vacuum SEM chamber with the nano positioning resolution has been developed. For the practical application in SEM chamber, the micro tilting hemispherical table driven by three piezo elements is also set on the small robot and this layout can allow the SEM operator to observe the target sample with the various view angles. However it is difficult to keep the angle for the micro tilting table, so in this report we are proposing the clamping mechanism that keeps precisely the angle of the micro tilting table, and describing the performance in terms of precise rotation control with θ axis.

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[in Japanese]

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The air spindle is an essential machine element of the ultraprecision machine tool because of its high rotational accuracy and low spindle vibration. The size of works machined on the ultraprecision machine tool become smaller, and the diameter of the tools employed are also be decreased. For obtaining suitable cutting speed with these small tools, the rotational speed of the tool spindle of the machine tool should be increased. As a result, a high-speed air spindle with low vibration should be developed. In the present paper, we propose a new tactics for suppressing the spindle vibration at high rotational speed. An active aerodynamic bearing is incorporated into the air spindle supported by ordinary aerostatic bearings. In this hybrid bearing system, spindle weight and cutting load are basically supported by the aerostatic bearings and the spindle vibration in the high speed range can be controlled by the active aerodynamic bearing. A displacement sensor detects the spindle vibration and according to the detected vibration, a microcomputer controls the wedge angle of the aerodynamic bearing by using a piezoelectric actuator incorporated. The load carrying capacity of the aerodynamic bearing increases as the rotational speed of the spindle, therefore the proposed active aerodynamic bearing is effective in higher rotational speed of the spindle. The concept of designing of the active aerodynamic bearing and some results of experiments obtaining by a test model spindle are reported.

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[in Japanese]

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[in Japanese]

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