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Development of machine tool according to parts size is required by the downsizing and progress of high precision. A new NC lathe has been developed combining the enough rigidity and space for chip treatment. The active vibration control is applied to suppress the specific vibration mode by using actuators driven by PZT. The effects of vibration control are reported in this paper.

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The contributor to the support stiffness of machine tools is investigated. In this paper, it is assumed that the support stiffness depends on the load on mounts of machine tools because the contact stiffness influences the support stiffness. In this case, even if the number of the mounts of machine tools changes, the total support stiffness in the vertical direction should not change. To verify this hypothesis, it is shown that the natural frequency of the vertical vibration mode is irrelevant to the number of the mounts. Moreover, it is verified that the real contact area is decided by the load and the hardness of the contact surface.

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Both of ground disturbance vibration and drive disturbance vibration must be taken into account to discuss the influence of vibration on the machining accuracy of machine tools. In this paper, the relative vibration between the tool and the workpiece is simulated with a machine tool model including its control system. The model consists of a model of mechanical components and a model of a servo control loop. The mechanical components are modeled with rigid bodies coupled with linear springs. The vibration due to the ground disturbance and drive disturbance is simulated in the time domain.

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Cutting force in drilling of Ti-6Al-4V is discussed in simulation based on a predictive model. In the force model, three-dimensional chip flow is made by piling up the orthogonal cuttings in the planes containing the cutting velocities and the chip flow velocities, where the chip flow direction is determined to minimize the cutting energy. The force model is verified in comparison of the simulated and the measured cutting force. The chip formation is also discussed with the measured cutting force. The effect of strain hardening on the cutting force is considered by the orthogonal cutting data in the force model.

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This paper presents computational results of deep holes evaluated by a measurement unit fixed at the end of a cylindrical long measurement bar. The system consists of a measurement unit for scanning hole wall, laser interferometer for detecting topography of the hole wall and optical device for detecting attitude of the measurement unit. The measurement bar is supported by a pair of skids at the end of the measurement bar as well as a measurement unit is also fixed at the end of the measurement bar which is positioned along a hole center. As a result of computational analysis, it is found that deep-hole with 3m-depth and 63mm-diameter can be measured by the measurement unit with the cylindrical long measurement bar.

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Now, the most of lubrication methods of the ball bearing is grease one. However, the grease cannot participate in lubrication when scattered in a bearing so that fluidity is small in comparison with the lubricating oil. In addition, there is the performance investigation example of grease in itself to date, but there are few data about the behavior. It is possible to contribute to the performance gain of all ball bearings including making of it long-lived greatly if the behavior of grease in it can be clarified. In the present study, I produce the experimental device and can observe behavior of the grease in the bearing. I put a result next. (1) Some characteristics of the behavior of the grease including the scattering of the grease are confirmed. (2) It is confirmed for the connecting of the behavior of the grease , the temperature of a ball bearing and the rotating torque.

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In general, rolling bearings are used in continuous one-way rotation. Additionally, they are used in oscillating site such as a swing arm in a hard disk drive. In the swinging movement for several tens of degree in angle, the rolling elements contact the limited range of race surface. Therefore, fretting is easy to occur at the both ends of the contacting range. Then, lubricant agent and addition agent are applied to prevent the occurrence of fretting. However, in the experiment of swinging movement for small ball bearing, the revolution of the rolling elements could be seen and the fretting did not occur in the small ball bearing. Thus, in this research, the authors considered that fretting could be prevented by changing the contacting range caused by the revolution of rolling elements. Then, experimental analysis on observation of revolution of rolling elements and acceleration technique of the revolution was conducted. Accordingly, the following points were clarified. (1) Giving speed variation between to-motion and from-motion in the swinging movement will bring the revolution into existence. (2) The direction of revolution depends on the frictional condition between the rolling elements and the track surface.

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Ultraprecision machine tool is effective together with the use of CAD/CAM system to generate tool paths. However, CAM systems generally focus on generating NC data. Consequently, operators have to make the process planning by considering the features of machine tools, cutting tools and workpieces. Above all, the setting error may cause interference between the cutting tool and the workpiece and result in the low machining accuracy. Therefore, this study deals with the development of CAPP/CAM system in ultraprecision micromachining to assist operators in setting as next step. The developed system can determine the number of the control axes of the machine tool, and calculate required setting accuracy to prevent tool interference and to maintain the shape error within the size tolerance. From the simulation result, it is found that the CAPP/CAM system is effective to produce microparts accurately.

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We are developing the master-slave manipulator with multiple degrees of freedom, aiming to realize minimally invasive surgery. This system has three characteristics. First, the slave manipulator has 5 degrees of freedom. In order to approach to the deeply seated tumor through a narrow hole, the slave manipulator can flex at the end part to face the gripper to the target and can rotate the closing direction of the gripper at the end of the slave manipulator. Second, the slave manipulator has biaxial force sensor using strain gages fit on the gripper clip of the slave manipulator. Biaxial force means frictional and gripping forces when the slave manipulator grips the target. Third, the system can provide kinesthetic sense information for surgeons. This system uses stepping motor for the miniaturization and the simplification of the system. So, we constructed the kinesthetic sense displaying control system using stepping motor. Experimented test showed that the manipulator can approach flexibly to the target, and the taking out force of a target on the soft material was detected clearly. It also showed that the gripper sensor and our control system provide the operator with the kinesthetic sense.

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