It is desirable in the moiré topographic method as well as in the ordinary moire method that the fringe patterns with narrow fringe widths can be obtained, so that a high accuracy in the measurement of interfringe-spacings is secured. In the case of the ordinary moiré method, it is known that the use of grids with different widths between bright and dark parts is an effective means for this purpose. In this paper, an approximate theory for the sharpening of fringe widths for the grid illuminating method, which is a typical moiré topographic method, is derived from that proposed previously for the ordinary moiré method. Besides, an another modified theory of that proposed by S. Yokozeki et al. is presented. In case that the grids with considerably large pitches are used, it is verified that the authors' theory may serve as a criterion for estimating the fringe widths.

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Differences of stock removal on lapped or polished work surfaces consisting of two kind of brittle materials were investigated and theoretical equations of the stock removal difference were obtained, taking into account the existence of abrasives between work and lap faces, and the elastic deformation of the polisher, respectively. Based upon the equations, the tendencies of the stock removal difference are estimated under several conditions. They are found to be in good agreement with those of experimental values. In order to reduce stock removal differences in lapping or polishing, it is more effective to use materials with a similar stock removal rate, and to decrease the area of larger stock removal material, if possible. Moreover, it is advisable to employ a polisher with lower elasticity.

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A lattice disordering of the surface of single crystal silicon due to ion bombardment of Ar⁺ was investigated by the high energy electron diffraction method, with the incident angle of 1.7° and 2.8°. By this measuring system, the degree of disorders of the sputter-machined surface layer of Si single crystal in the depth of 50 Å and 30 Å has been determined, under the working conditions of the ion energy ranging from 0.2 keV to 1.5 keV and the incident angle of ion ranging from 0° to 75°. Moreover, the recovery of lattice disorder of sputtermachined surface layer of Si single crystal by means of the isochronal thermal annealing has been also confirmed by the same method. From the above experiments, the following conclusions are obtained.
(1) The layers of sputter-machined surface of Si single crystal workpiece are highly disordered like amorphous, under the working conditions of ion energy ranging from 0.2 keV to 1.5 keV for the vertical ion incident angle.
(2) Under the working conditions of ion incident angle larger than 60°, using the ion beam with a lower energy under 300 eV, the surface of the workpiece is not disordered. Therefore, a sputter-machined surface of Si single crystal with highly ordered structure can be obtained under this working condition.
(3) The recovery of disorder of sputter-machined surface is completed by the heat-treatment of workpiece under isochronal annealing for 1 hour at 800°C. However, it is not clear whether this recovery of lattice point or the dispersion of interstitially located argon atoms from the surface to the outside.

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This paper proposes an index of the stochastic estimation in assembly, "the probability of success in assembly", which is computed as a function of the distribution of disturbances to the assembly operation and of the characteristics in the machine structure, and presents its applications. In order to estimate a plug insertion process by an assembly machine with elastic structure, the positioning error, the angle error of parts and the clearance between parts are chosen as the disturbances. Its application gives these merits as follows: (1) As the probability of success estimates the accuracy of positioning or chucking "quantitatively", the unreasonable requirement of accuracy can be eliminated from the design of machines. (2) To estimate the availability of the equipments without constructing and driving them actually allows the frequent replacement of machines, that is eagerly required in small batch production system. (3) As the index of the accuracy of part dimensions, the probability of success can decide whether the matching assembly should be adopted or not and benefit the total manufacturing system.

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The dynamic responses to the sinusoidal displacement of a vertical repelling force system with cylindrical type rare-earth magnets are investigated. The analysis is made under an assumption that the repelling force is inversely proportional to the n-th power of the center distance between the two magnets and is expressed by a series in powers of the relative displacement of the magnets. The results from the numerical calculation and the experiment are concluded as follows:
(1) When the mass is suspended by a repelling force of the magnet on its bottom face, the response curve shows composite characteristics; i. e., the curve changes its form gradually from the soft spring character to the hard spring one with the growth of the amplitude, and the unstable regions are found on both sides of the back-bone curve in the case of subharmonic resonance.
(2) When the mass is interposed between the repelling forces on top and bottom, the response curve takes the hard spring characteristics and the shorter the distance between the fixed magnets, the more remarkable its tendency becomes.
(3) The neutral line of the vibration shifts to the upward direction by a definite degree depending upon the amplitude as well as the unsymmetricity of the repelling forces acting on the vibrating mass.

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As the present standard of gears is specified from the view point of a processor, the accuracy grade of the standard scarcely corresponds with the performance of the gears. In this paper the way of selecting the accuracy grade of a tangential tooth-to-tooth composite error is studied on the gears which are subject only to a light load or used in the measuring instruments, and in the range in which the meshing frequency is lower than one-eighth of the natural frequency of a pair of gears. As a result, the way of selecting the accuracy grade, by which the accuracy grade corresponds well with the vibration with tooth separation of gears, is offered and made sure by some experiments. Moreover the followings are made sure, that is, the ratio 1.4 between the accuracy grades is reasonable, and the smaller division of module and of pitch diameter are better than the present division from the view point that the amplitude of the vibration with tooth separation becomes two times or one-second times as large.

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The roller gear cam mechanism is often used as the mechanism transferring the parts intermittently. But when it is driven at a high speed, a residual vibration occurs at its camdwell mode and it prevents from exact positioning. It has become clear by the experiments that it is caused mainly by the backlash existing in input and output axis, by the contact stiffness of cam and the roller of follower which varies with its contact position, and by the change of rotational velocity in input axis. In order to reduce the residual vibration, it is very effective to set a magnetic brake at the cam follower and control the brake torque switching the electric current. It is proved by the experiments that it is sufficient to diminish the residual vibration to brake on the cam follower just before the cam-dwell mode for only a few mili-seconds. For the design of high speed indexing mechanism, the relationship is presented between the capacity of the magnetic brake, the inertia of the cam follower, the contact stiffness of the cam, and the stiffness of the axes.

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Kohji, ONO;Tsutomu, SHIMAMUNE;Teruhisa, YAMAMOTOIn order to account for the effects of mechanical cutting action and electrochemical dissolution on the peripheral electrolytic grinding process, the removing mechanism of work material is theoretically analysed. And also, the influence of operating conditions on the mechanism is investigated experimentally. The following results are clarified.
(1) There exist two parts of region in the electrolytic grinding contact zone; the one is the co-operative region of mechanical cutting and chemical dissolution, and the other is the region of the pure chemical electrolysis.
(2) The position of boundary line of the above two regions varies with the operating condition in electrolytic grinding. The boundary depth of cut, that is the height from the bottom of grinding wheel to the boundary line, decreases at the inverse square of the work feed rate and does not depend on the setting depth of cut.
(3) The boundary depth of cut above mentioned plays an important role in electrolytic grinding process. The amount of over-cut, the chemical proportion of material removed and Faraday's current in the electrolytic grinding can be derived theoretically using the boundary depth of cut as an intermediary parameter.

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In this paper, a method of estimating for the material damping of a beam which is machine element in machine structures is reported. There are many studies of the material damping, but as they leave inertia force out of consideration, the material damping cannot be estimated at the higher mode of vibration. Then, a method of estimating for the material damping on consideration of the mode of vibration is suggested in this paper. First, a program is presented by which the material damping is obtained. Second, the material damping is estimated a clamped-free beam, a hinged-hinged beam and a free-free beam, and the material damping of clamped-free beam is confirmed by experiment. In regard to three types of beam, it becomes clear that the relationship between loss factor and stress amplitude is independent of the mode of vibration and the values of loss factor in practice is in the range from O.001 to O.005.

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In the preceding paper, it has been shown that the instantaneous relative position of a grinding wheel and a workpiece can be controlled accurately and the profile error due to the thermal deformation of the workpiece can be corrected, by making use of the elastic deformation of the surface grinding machine, which is equipped with a hydraulic servo mechanism and an auxiliary cam. In the present paper, a new technique is presented. In this technique, even if the thermal deformation of the workpiece varies during grinding, the correction of the profile error can be performed automatically, in accordance with the amount of the actual thermal deformation of the workpiece. The thermal deformation of the workpiece is detected in process of grinding by using a wire strain gauge type or a differential transformer type pickup. The detected signal deforms the grinding machine slightly through an electro-hydraulic servo mechanism, until the relative displacement between the wheel and the workpiece cancels the profile error due to the thermal deformation of the workpiece. In this way, the effect of wheel sharpness variations, stock removal variations, workpiece hardness variations, variations of cooling condition during grinding are eliminated from the thermal profile error problem and the straightness of finished workpieces within 1 μm for 60 mm length can be easily attained.

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From the viewpoint that the main difficulty in improving the grinding wheel essentially is the uncertainty of cutting-edge conditions on the operating surface of the grinding wheel, this paper addresses itself to the question of what the ideal grinding tool is. For this purpose, a new grinder which can be set to operate under the cutting-edge conditions required was developed, and an ideal grinding tool model was proposed. Following this model, the experiment of plunge grinding was conducted by changing rake angles, successing cutting-edge spacings and contact widths of cutting-edge systematically. The relations between cutting-edge conditions and grinding forces as well as wears of cutting-edge were examined. Based on the experimental results obtained, the effects of cutting-edge conditions on grinding performance has been discussed.

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[in Japanese]

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[in Japanese]

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