This paper deals with the improvement of positioning accuracy of machine table by real-time compensation of thermal elongation of ball-screw. During operation the temperature distribution at fifteen positions of the hollow ball-screw is measured and input into the personal computer by the optical telemeter system developed. Based upon the increase of the temperature distribution and the present position of machine table obtained from CNC controller, the thermal elongation of the ball-screw between the thrust support bearing and the ball-screw nut of machine table is estimated by the PC. The estimated value is fed from the PC to CNC controller as the compensation value, and the origin shift of the machine coordinate is immediately executed. These measurement and control are repeatedly executed during operation, and the real-time compensation is realized. Machine table position is measured by a laser displacement measurement system. It is clarified that the positioning accuracy of -7.1∼ +0.3μm is realized over 555mm length under the table speed not greater than 18m/min.

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In CO₂ laser scribe processing of glass, an initial crack on the start edge of the glass is indispensable. When carrying out laser cross scribe, there is no initial crack on the edge of the first scribed line. However, the second scribe progresses across the first scribed line. In this research, in order to clarify the phenomena of laser cross scribe, the laser irradiation experiments were carried out at various velocities of the second scribing. Using the same conditions as the experiments, three-dimensional thermal stress analyses were conducted by a finite element method. As a result, two kinds of forms were found in the progresses of the second scribe. One is a form that the first scribed crack surfaces are bonded by strong compression at high temperature in the heating area during the second scribing. The other is a form that the tensile stress in the cooling area which makes the second scribe progress is transmitted by the frictional force generated in the first scribed crack surface. Consequently the second scribe progresses across the first scribed line although there is no initial crack on the edge of the first scribed line.

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The ultra-smoothness grinding method based on the new concept, which can finish to almost the same smoothness formed by polishing method, in the previous research, is developed as the countermeasure answering the recently strong requirement about high efficiency production of high quality components. The surface roughness of cemented carbide tool formed by the method using the #140 diamond wheel is cleared to attain about 30nm(Rz) or 5nm(Ra). First of all, in the report, the ultra-smoothness grinding of various kinds of fine ceramics, a glass, a cemented carbide and a die steel is ascertained possible. Furthermore the influence of wheel speed on the surface roughness is investigated. The deterioration of surface roughness depends on the increase of micro-cracks in case of silicon carbide ceramic and of the grinding groove roughness in case of cemented carbide, respectively. The surface roughness becomes worse for higher wheel speed. At wheel speed of 75m/s, however, the surface roughness of silicon carbide ceramic becomes about 80nm(Rz).

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This paper describes the influence of electrolytically-oxidized water of dilute NaCl solution on the surface of copper alloy for lead frame. Electrolytically-oxidized water is different from HCl solution, and that doesn't have any bad influence on the human body and the environment. If electrolytically-oxidized water can be applied to surface treatment of the lead frame, the environmental load can reduce. Almost, by the immersion experiment, it clarified the etching operation of electrolytically-oxidized water to the copper alloy for the lead frame. As the results, the etching speed of electrolytically-oxidized water is big compared with HCl solution. Next, by the surface analysis of the test pieces, it made the influence of the electrolytically-oxidized water on the chemical composition of the surface of the copper alloy for the lead frame clear. That is, when using electrolytically-oxidized water, the oxide film in the surface of Cu-Ni alloy doesn't change but the Cu-Fe alloy oxide film becomes thick. The study indicates the electrolytically-oxidized water can be applied to the oxide film removal of Cu-Ni alloy and the wash of the Cu-Fe alloy surface.

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Dentists and dental hygienists remove dental calculus using a cutting tool called dental scaler. The evaluation of sharpness of dental scalers requires skill which depends on sensory examination. The aim of this research is to evaluate the sharpness of scalers objectively by estimating optical reflection images of blades rotated in two directions. For taking photos of blades at various angles using CCD camera, the scaler to be inspected was fixed on a turn table driven by a stepping motor. In this research, the angle of a scaler fixture on the turn table was also changed by a RC servo motor. As a result, the optical reflection patterns of the cutting edge could be obtained more precisely than before. Next, an image processing method was examined for calculating the area and the length of optical reflection patterns of the cutting edge from the photos obtained from various angles. And the relation between these values and the sensory evaluated values was examined using multiple regression analysis. As a result, it was confirmed that this method can evaluate the sharpness of scalers objectively and precisely. And it was also confirmed that the angle of the scaler fixture is also an important factor for this evaluation method as well as the angle of the scaler.

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Polypropylene/vapor grown carbon nanofiber (PP/VGCF) composite films produced by uniaxial extrusion and sheet drawing process were developed for some functional micro devices. In addition, V-groove micro/nanoimprint performance of the films was examined. VGCFs of the films were highly orientated in drawing direction when VGCFs of 10-30 wt% were added. Tensile strength, Young's modulus, thermal conductivity, storage modulus and loss tangent of the films increased with increasing VGCF content, although these properties in transverse direction of the composite films were smaller than those in drawing direction. Good transcription performance was achieved in the composite films with VGCF more than10wt%. If heated to 130° C lower than melting point of PP, filling rate on transcription attained to 100% under compression stress of 25-125 MPa. In this case, orientation of the films hardly influenced the transcription performance. The good transcription performance was caused by (1) micro dimension and high flexibility of VGCF, (2) increased thermal conductivity, (3) decreased thermal expansion and (4) increased loss tangent by VGCF addition.

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In order to predict cutting forces and chip formation in milling with a ball end mill for various tool paths, inclination of the workpiece surface and of the tool axis, a cutting model proposed in previous paper is extended to the milling process in which both cutting edges of the sphere and cylindrical portions engage with the workpiece. In the cutting model, elemental chip at any point on the cutting edge is described by simple shear plane oblique cutting model, and the condition of side-curl of the chip is considered. In this paper, cutting edge configurations, inclination and normal rake angles at the sphere and cylindrical portions are discussed. Geometric quantities such as contact region between the cutting edge and the workpiece surface, and undeformed chip thickness along the cutting edge in milling for the tool moving upward or downward on the inclined surface are analyzed, and variation of these geometric quantities with tool rotational angle are also discussed. Three components of the cutting force and chip formation such as chip flow angle, radius of side-curl of the chip and chip form are predicted by using developed cutting model and energy method. The preliminary examination shows that there is the large difference in cutting forces and the chip formation for the tool moving upward or downward on the inclined surface.

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A new three-axis FTS system has been developed for ulrtaprecision machining. The 3-axis FTS unit can drive the cutting tool freely in the space by controlling the motion of the three piezoelectric actuators arranged along the three axes of the orthogonal coordinates. In this report, high-speed machining of dies and molds of micro structural array for optical devices has been studied by employing high speed 3-axis motion of the FTS unit. The transient motion error of the machining stage equipped with the work is also compensated with use of the FTS while the work is fed to the machining area in the step and repeat manner. The dies for a micro-prism array and a micro-lens array could be machined by using the developed FTS machining system at high speed.

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This paper describes a three-axis displacement sensor, which can detect displacements in the XYZ-directions simultaneously. In this sensor, positive and negative first-order diffracted beams from a scale two-axis grid and a reference two-axis grid interfere with each other. Displacement in each direction can be calculated from the interference signals. A prototype sensor is developed based on the proposed principle and basic performances of the sensor are evaluated. The interpolation errors of sensor outputs are within ±1 %. The nonlinear error components in the short range along the XYZ directions are ±100 nm, ±100 nm, ±5 nm respectively. 5 nm step motions can be detected in all the three axes.

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In the field of precision measurement and positioning, an active anti-vibration apparatus is the necessary equipment to realize the low vibration environment. However, there was a problem that the position fluctuation of isolated table was generated due to the pressure fluctuation of supplied air. Then, in order to suppress the position fluctuation, a feedforward method using the detected signal of supplied air pressure was previously proposed. In the steady state, the fluctuation of isolated table was sufficiently suppressed using the feedforward compensation. However, a new problem, such that the fluctuation of isolated table is generated due to the switching of feedforward compensator, occurs. To overcome this problem, in this paper, the feedforward compensator is firstly reconstructed for easily parameter tuning. Next, the soft switching is introduced to moderate the fluctuation of isolated table due to the ON/OFF feedforward switching. Furthermore, the feedforward based on the difference detection of supplied air signal is proposed to realize perfect suppression. Finally, using the real air type anti-vibration apparatus, remarkable experimental results are shown.

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As requirements for processing and observing nanometer order sized structure are increasing, significance of electron beam systems such as SEM, TEM and EB machine tools is rising. To make the best use of these systems, they should be incorporated with devices that can position their work pieces or specimens very precisely. In addition to this precision, high or ultrahigh vacuum compatibility and nonmagnetism are required of those positioners that are installed in the specimen chamber of such electron beam systems. To realize such devices, the authors are developing an ultrasonic motor that can operate keeping ultrahigh vacuum condition of the chamber in which it is installed. In this paper, friction material at stator-rotor interface is discussed. Several plastics and ceramics were tested as candidates of rotor surface in preliminary experiments, and stainless steel SUS304 and zirconia ceramic were selected as materials of stator and rotor surface. After 48 hours bakeout treatment at 200°C, gas pressure in a vacuum chamber on which the motor is installed decreased to 2.0×10^-8Pa. When the motor operation was initiated, the gas pressure rose up to higher 10^-7Pa and gradually decreased and reached an ultrahigh vacuum range of 8×10^-8Pa after 3hours of operation.

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Casting defects in die casting materials are known as starting points of fatigue fractures. Therefore investigating their presence, sizes, and distributions are important for lifetime predictions of casting materials. In this paper, the size and the shape of casting defects inside aluminum die casting alloy were investigated by an automated three-dimensional information acquisition system based on consecutive precision milling and cross-sectional image recording. The main results obtained are as follows: (1) Two-dimensional color cross-sectional images were consecutively recorded in 4×4×5 μm resolution for 20×14×20 mm aluminum die casting specimen. (2) Casting defects were distinguishable in those images, and the regions of casting defects were extracted, and over 5000 individual regions were three-dimensionally reconstructed. (3) 90% of those regions were near sphere and relatively small in diameter (<100μm).

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This paper describes a 3-axes angle sensor based on laser autocollimation for simultaneous measurement of small tilt angles about X, Y and Z-axes. The sensor consists of a laser diode as the light source and quadrant photodiodes (QPDs) as the optical position-sensing device. Differing from a conventional 2-axis autocollimator, the sensor uses a diffractive grating as the target mirror. It is verified that the sensitivity of the sensor in the θ_x (rolling) direction is determined by the pitch of the diffractive grating and the diameter of the laser beam. The sensitivities in the θ_y (pitching) and the θ_z (yawing) direction are determined by the wavelength and the beam diameter of the laser beam. It is confirmed that the resolution of θ_x is about 0.2 arc-seconds, and those of θ_y and θ_z are about 0.02 arc-seconds. Optical design and experimental results are presented.

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Precision instrument has maximum permissible vibration in the field of precision positioning. An anti-vibration apparatus has been widely used to restrain floor vibration in this field. In order to avoid the deformation of main body supported by air springs and to eliminate air spring stiffness, the control system of anti-vibration apparatus having the positive feedback using differential signal of relative position was previously proposed. However disturbance suppression characteristic of conventional system is not well because the differential operation increases high frequency sensor noises. Therefore, the positive feedback using integrated signal of relative acceleration is proposed. This system has the elimination function of air spring stiffness and good disturbance suppression characteristic. Then, this paper firstly explains the elimination function of air spring stiffness in this system. Secondly, the disturbance suppression characteristics of this system are compared with that of conventional system. Finally, the problem of implementation due to the high-gain feedback is explained.

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