The phase transformation of zirconia and the deterioration of ground surface are provided in grinding zirconia/nickel compounds. The present paper describes the influences of these phenomena to the strength of compounds. The bending strength of compounds decreases with an increase of nickel contents. The cracks propagate at the interface between zirconia and nickel in the zirconia-enriched compounds. Monoclinic phase contents increase by phase transformation of zirconia in grinding. However, its increase rate lowers with an increase of nickel contents. The bending strength of compounds increases with more zirconia by phase transformation after grinding, and decreases with more nickel than about 50wt% nickel contents due to large ground surface roughness. The increase of compressive residual stress in zirconia depends on phase transformation derived by grinding, and the residual stress in nickel changes from tensile to compressive accompanying with more contents of nickel.

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In some manual manufacturing processes, the human operator could perform its task well and swiftly, if it could acquire sensory information helpful to the performance effectively. In those situations, high frequency components contained in the sensory information (feedback signal to the operator) must be suppressed, because the operator cannot recognize and respond them. However, the filtering condition suitable for the suppression has never investigated so far. In this research, the cut-off frequency of low pass filter in active visual feedback system has been investigated. The objective manufacturing operation is to make a small-diameter hole onto an aluminum workpiece with a carbide drill. As the visual feedback device, see-through-see-around type head mounted display (HMD) was examined. The feedback information is cutting force and its magnitude is displayed by sector chart on HMD's screen. As the results, from the points of operating efficiency, workload and fatigue of the operators, it is found that the optimum cut-off frequency exists and it is related with operator's response characteristics measured separately.

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This paper deals with an accurate cutting force prediction method of ball end milling in non-horizontal tool movement. A model learning technique is introduced in order to enhance the applicable range of process simulation. Because ball end mill has complex shape of cutting edge, cutting situations vary widely according to the change of tool-workpiece interference region. A model learning based simulation framework is proposed to predict cutting force accurately. A procedure of the model learning is proposed by combining the quasi-Newton method and memory-based learning. The effectiveness of the model learning is demonstrated by making comparisons between experimental data and predicted cutting force.

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Scraping operation is indispensable to make high accuracy machine tools and measuring instruments. Scraping however needs not only highly professional skills but also the ability to make a scraping strategy, such as where and how far to be scraped. In general, it takes long time to master these abilities, and skillful workers are decreasing year by year. Digitalization of the operation and its transplantation into a computer must be a way to conserve the skill. The digitalization has been described a previous paper. This paper deals with the transplantation of scraping into a computer as a scraping simulator which can scrape a surface in a virtual space made in a computer. In this simulator, a series of scraping operation, such as Marking up, Recognizing black bearing and Scraping, can be performed just like a scraping operator. The simulator can be used not only to verify a strategy of scraping but also to train a beginner of scraping operation.

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In this paper, an approach is proposed to apply parallel decision-making systems on the same target, and to identify the cutting state synthetically based on evaluation of the results obtained by the plural subsystems. In the present work, a system was developed having two subsystems to estimate chipping of cutting edges during end milling. The subsystems employ artificial neural networks based on the cutting force signals. The chipping of the cutting edge was well identified for different cases of end milling. It is concluded that the flexibility and the reliability of the monitoring system is much improved by operating the subsystems in parallel as proposed in the present study.

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Outer sleeve raceways of ball bush have edges, which are the junctions between the straight portions and slopes, and the straight portions are only ground by internal grinding machine, but the slopes can not be ground. Therefore premature flaking occurs because of balls recirculation over these edge portions, and hence the life of ball bush is comparatively shorter than expectation or theory. The purpose of this paper is the application of abrasive flow finishing for reformation of outer sleeve race way shape of the ball bush. This needs the development of an abrasive finishing device, for rounding out of the edge portions and also improvement of the surface texture of the raceway. The following conclusion is obtained: (1) The abrasive flow processing can result in rounding out of the edge to a suitable radius. (2) The surface texture of the raceway is also improved from 1.85μm Rz to 0.24μm Rz on an average after the processing.

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This paper deals with a practical servo tuning method for high speed and high acceleration feed drives in the latest NC machine tools. CNC-servo systems in machine tool drives generally have current-velocity-position feedback controls, a feedforward controller and a command generator. Techonological progress in hardware and software makes it possible to implement a high response servo control for commercial feed drives. When feed drives are built in a complicated structure, however, vibration problems tend to occur in practical applications. Particularly vibrations at low frequencies deteriorate the contoing accuracy. In order to search the most adequate combination of CNC-servo parameters, a quick and accurate tuning method is required. This paper proposes a systematic tuning method based on simulation and measurement technology. The effectiveness of the proposed tuning method is validated by a case study involving a commercial machining center.

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Dynamic cutting processes, such as wave removal operation and wave generation operation, were analyzed by elastic-plastic finite element method. Variation of undeformed chip thickness affects chip-forming process. Shear angle varies about 15°in wave removal operation under the conditions of wave length 2.65mm, amplitude 0.075mm and mean depth of cut 0.25mm. On the way of the chip thickness decreases, shear angle drops and the deformation concentrates. Strain distribution shows these phenomena clearly. It was also shown that depth of cut varies sinusoidaly but simulated cutting force waveform is distorted from sin-wave. It is because shear angle varies and the size of deformation area in the shear zone varies correspondingly. Thus the cutting force isn't in proportion to undeformed chip thickness at tool edge.

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The purpose of this study is to minimize affected layer generated by electrolytic grinding which results in deterioration of gloss or decrease of hardness on machined surface. In this paper, a reduction process of affected electrolytic ground layer by a spark-out grinding process without electrolysis, in which electrolytic effect stops just in the moment of stopping infeed of grinding wheel, is experimentally investigated by analyzing characteristics of electrolytic ground surface with a glossiness meter or an ultra micro hardness tester. Main conclusions obtained in this paper are as follows: (1) The depth of affected layer decreasing hardness is nearly 2.5 times as large as that deteriorating gloss, and both depths of affected layer increase with increasing electrolytic voltage. (2) In the case of higher electrolytic voltage, the stock removal in spark-out grinding process without electrolysis is less than the depth of affected layer decreasing hardness generated in steady electrolytic grinding process. So after finish of spark-out grinding, an affected layer decreasing hardness is remained on finished surface on which glossiness is recovered up to that of mechanical ground surface.

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This paper proposes a method which smoothly approximates mesh data for measured points by iterative local procedures. The method calculates fourth divided differences along u and υ parametric lines at each mesh point as a local fairness criterion from the regular mesh of measured data, and modifies the central 9 points using 16 points from 5×5 mesh points around the point with the maximum local fairness criterion so as to make the criterion zero iteratively. It repeats these procedures until the global fairness criterion, which is the sum of the local fairness criteria, does not decrease. For treating boundaries or incomplete mesh points, it modifies several candidate points and selects the mesh point with the minimum global fairness criterion among them. Further, it obtains a smooth mesh when a parametric line is given across which the continuity between mesh points is C ¹ Some examples demonstrate effectiveness of the method for the data with random errors and a few extraordinary large errors.

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A structural design is proposed for a fault tolerant steer-by-wire (SBW) system consisting of a principal and a standby SBW unit together with a manual backup. A fault tree is constructed for a top event, "complete loss of steering". Minimal cut sets are derived accordingly. Operation rules are derived for degraded system states with partial failures before causing a minimal cut set. A transition diagram is depicted to summarize the rules. Low level SBW control rules are also proposed for sensor failures of monitoring vehicle states. Experiments using driving simulator are performed to examine the operation and control rules from a safety point of view, indicating 1) fault tolerant drivability for steady driving including constant radius turns, and 2) potential vehicle unstabilities during unsteady pylon slalom driving when the SBW is switched into a manual steering.

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In solid modeling systems, the stability of Boolean set operations is an important issue. Solid modeling systems that employ floating-point arithmetic tend to be unstable because of inconsistent decisions caused by numerical errors. The use of exact integer arithmetic solves this problem. By using exact integer arithmetic based on totally homogeneous processing, error-free arithmetic is implemented. In this paper, we propose a robust polyhedral solid modeling system. The system employs exact integer arithmetic based on totally homogeneous processing. All of the numerical data of solid models for Boolean set operations are represented in terms of integer representations. Boolean set operations and transformations of solid models are performed in the integer domain. Several examples of Boolean set operations, which are very difficult in floating point arithmetic, are presented to show that our system does not cause failure in such situations. Methods that improve the efficiency of exact integer arithmetic are also presented to avoid the increase of computation time caused by the increase of the data lengths of integers.

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In order to produce three-dimensional models with cemented carbide powders, a free form fabrication method named Layered Compaction Manufacturing (LCM), which is a hybrid process of powder compaction combined with CNC milling in layer-by-layer additive manner, is proposed. Each layer is created by compacting powder with subsequent milling of grooves corresponding to a cross-sectional shape of the designed model. The grooves are filled with paraffin wax as a separator. After being separated according to the grooves, the green model is sintered. The feasibility of the LCM method is evaluated using WC-9mass%Co powder. The shape deformation of the grooves in the compaction processes is less than 0.1 mm. The connecting strength between the layers of the model after sintering is measured by the three-point bending test. It is found that the transverse strength of the sintered products is higher than 2 GPa. A WC-9mass%Co model with inside channels, which has a potential to realize molds and dies with temperature control, is successfully fabricated.

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A master-slave type remote ultrasound diagnostic system was developed. This paper presents its controller. The controller has impedance control capability for the master and slave manipulators' positions. To realize manipulation stability in remote ultrasound diagnostic system, a special motion control law is proposed. The impedance control allows master and slave manipulators to move according to the motion control law, and allows the medical doctor to feel feedback force. Manipulability changes according to the impedance parameters. This paper makes clear the relationship of impedance parameters with manipulability and response speed. Furthermore, the method to determine appropriate impedance parameters is proposed according to observation of diagnostic tasks. Experimental results demonstrate that a medical doctor can perform diagnosis successfully using the proposed system.

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This paper reports the study on winding technology using adaptive control for columnar parts. This system has a CCD line sensor to measure the diameter of the wire and the winding angle during the winding. The carriage and rotating motor are rate-controlled, based on this data. It brings a suitable feed to the diameter and keeps a suitable winding angle during the winding. As a result, this system closely winds any wire adapting to the changes in the diameter automatically. An experimental device of this system has realized complete contact winding for any wire that has a diameter of 80-130 μm. This system is expected to be used for the production of various high precision wound parts.

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Recently, the technological innovation using the extreme ultraviolet wavelength with high brightness of synchrotron radiation is actively advanced. In order to effectively utilize such light, it is important to develop the technology that produces and evaluates the optical element with surface accuracy over the 2 digits compared to conventional visible light. In the conventional interferometer, the aberration between the test surface and the standard reference surface is measured. Therefore, the accuracy of standard surface determines the measurement accuracy. To achieve the absolute measurement accuracy, it is necessary to develop a new interferometer that has inherent very high accuracy. The point diffraction interferometer is based on diffraction, which permits the generation of a perfect spherical wave front by using a circular aperture with a radius comparable to the wavelength of light. The purpose of this study is to examine point diffraction interference system for the profile measurement sensor, which can be also utilized for alignment of the EUV optical system. The optical system is consisted of single-mode optical fiber and the fringe scanning using the laser source of visible light. In this report, the effect of arrangement of optical system, sphericity of wave front, surface quality of optical fiber end surface and diffraction noise of imaging lens system etc., on measurement error was mainly examined.

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