The subspace iteration method is the most effective method for large scale eigenvalue analysis. In this report, problems that have some thousands of degrees of freedom are solved by the subspace iteration method. Details about CPU time for computation and other parameters are discussed and shown in a table for convenience of comparison. On the other hand Nagamatu et al. presented the component mode synthesis. The calculation time of their method is almost equal to that of the subspace iteration method.

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An attempt is made to formulate the finite element reanalysis to cope with the change of vibration eigenvalues and eigenvectors. The methodology is based upon iterative solution of the nonlinear, coupled equations with respect to the change of the eigen pairs. Use is made of the normalization condition of the eigenvectors. Two methods are proposed for the solution, and the first one requires less CPU time while the second is versatile enough to chase complicated change of the eigen pair. The numerical examples show the validity of the proposed reanalysis methods in regard to the vibration of portal frames which are subjected to so large structural modification in terms of the mass density and the modulus of elasticity that the eigenvector is changed markedly.

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In the previous report, the design method of the dynamic absorbers for suppressing the vibration of multi-degree of freedom systems was established. This paper shows that resonances of Γ-shaped structures with 90°angles are reduced effectively by using dual dynamic absorbers with this design method. First, each vibration mode of this structure is analyzed in order to find a suitable setting point for each dynamic absorber for controlling each mode, and the equivalent masses at its setting points. The structure has three vibration modes which are able to suppress the frequency range of DC to 200 Hz. Thus three dual dynamic absorbers are designed against them, after preparing the complex transfer matrix representation of the dual dynamic absorbers. Next the vibration controlling effect of the structure with three dual dynamic absorbers set is confirmed theoretically by the transfer matrix method. The effectiveness of the design method is demonstrated experimentally.

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This report presents the effect of Coulomb friction combined with viscous damping in the main system, to which a viscous-damped dynamic vibration absorber is attached. The main system is subjected to harmonic base excitation, and in the analysis, a similar process is used to that explained in the previous report. The conclusions are : -(1) The numerical results of the analytical solution coincide very well with those of digital simulation. (2) Coulomb friction coexisting with the viscous damping in the main system, with a dynamic vibration absorber tuned so as to suppress the resonant response of the system in considering only viscous damping, reduces the maximum amplitudes of the main mass. The features of two equi-height maximums in the resonance curve vanish. (3) Since conventional expressions for the optimum tuning of the absorber do not fit in this case, other new empirical formulae are recommended.

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This paper presents a method for identifying the vibration source in a multiple input system where the input sources may be coherent with each other. Using multi-dimensional spectral analysis, it was found that the biggest part of the vibration source was generated by the cylinder pressure in the gasoline engine. This analysis is modelled as a multiple input/single output system when the vibration generating system of the gasoline engine is very complicated. In this analysis the concept of residual spectral analysis and the partial coherence function have been applied. Finally, the overall levels for acceleration on the part of cylinder block obtained by multi-dimensional spectral analysis are compared with those measured and calculated by the frequency response function approach. The experimental results have shown good agreement with the calculated results by this method when the input sources are strongly coherent with each other.

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Interesting features, connected with fluid-elastic vibration of tube bundles in a cross flow, have been reported in many papers. Most of the experiments were done for single-phase (liquid or air) flow. This paper presents an experimental investigation on vibrations of a row of five circular tubes with P/D =1.33, subjected to single-phase water and two-phase (air-water) cross flow. Experiments covered mass-damping parameters from 0.9 to 5 by changing the damping ratio. Experimental results show differences in characteristics of vibration response between those for pure water and two-phase flows. Depending on conditions specified by mass-damping parameters, void fraction and reduced flow velocity, air bubbles contained in the flow destabilize the vibrations of the row of tubes or they suppress the vibrations. Further, critical flow velocity for two-phase flow induced fluid-elastic vibration has been made clear for mass-damping parameters ranging from 0.9 to 5.

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There are many papers which deal with the vibrations of a geared-rotor system, but there are few which consider coupled lateral and torsional vibration. However, an analysis of the coupled vibration is important for reducing vibratios. This paper presents the experimental results of the vibrations of the geared-rotor system constructed by a pair of spur gears, and the results are compared with the theoretical results obtained form analysis of the coupled lateral and torsional vibration. In the response of angular acceleration in the gears, there are some resonant peaks caused by excitation relating to the mesh frequency. Also, some other resonances apear in the response of the lateral and torsional vibrations caused by mesh frequency excitation. These experimental results qualitatively coincide with the theoretical ones obtained from the analysis of the coupled vibration. Moreover, the tooth profile modification acts effectively on the vibrations of the geared-rotor system.

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The engine-clutch-manual transmission system of an automobile is modelled by a forced torsional vibration system of two degrees of freedom including two nonlinear terms, namely clearance and friction. In the derivation of the analytical solution, the friction term is linearized based upon the approximate solution of motion. The conclusions are as follows. 1) It is shown analytically and is confirmed by experiments and computer simulations that the continuous relative slip motion occurs when the friction is small. 2) The sum of torque impulse per cycle of the forced motion becomes large in the system with small friction when the system approaches resonance, but it remains almost unchanged in the system with large friction. 3) The sum of torque impulse is not affected by the size of clearance when the friction is small.

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In order to calculate the pressure pulsations generated in pipelines in frequency domain, it is necessary to linearize the nonlinear damping element |q|q, under the condition that the flow q througth it is periodic in time, but not sinusoidal. It is the authors' idea for the equivalent linearization in such cases, that two coefficients should be determined, one for the steady flow and the other for the fluctuating flow. To show the idea to be reasonable for the present problem, the responses of pressure pulsation in the case of a simple system are calculated by applying several flow input, using three schemes based on this idea. the results obtained by the schemes are all in good agreement with those by Runge-Kutta-Gill method, which confirms this idea to be correct.

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In part 1, it is reported that the method of digital simulation, which is equivalent to analog simulation because of taking the dynamic interaction between reciprocating compressors and the piping systems into consideration is proposed, and that the comparisons between the calculations and experimental data measured in an air intake type reciprocating compressor and the single piping show that accurate predictions can be made using digital simulation. This Part 2 reports the summary of the field work which is carried out so as to investigate the applicability of the digital simulation method to plant design. The results of the comparisons between the calculations and data measured in the reciprocating compressors and the piping systems in an actual gas-treating plant show good agreement ; and the adequacy of the digital simulation method is reconfirmed.

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One method of analyzing pressure pulsations is to use an analog simulation which can consider the interaction between a compressor and the attached piping. Conventional digital pulsation analyses, in which suction/discharge gas flow is one-sidedly applied as a forcing function, do not consider the interaction effects. This paper describes new digital simulation methods which can account for a compressor-piping interaction. In these methods, non-return valves and the stroke of the valves of compressors are expressed by nonlinear damping and nonlinear stiffness respectively. The dynamic equation of the total system is constructed by assembling the characteristic equations of each element using the finite element method. This governing equation is integrated time historically using the Newmark-β method ; and then the flow rate and pressure variation are obtained. By using the above methods, the following three types of digital simulations were carried out for a compressor-piping model : (1) conventional digital simulation (2) new digital simulation equivalent to the analog simulation (3) new digital simulation including the valve dynamics. From these calculations, it is demonstrated that this present method has the same capability as the analog simulation. Furthermore, it is shown that this new method can deal with more detailed interactions by considering the valve dynamics, which is difficult to account for in the analog simulation.

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In the previous paper the non-stationary response of an elastic circular cylindrical tank partially filled with liquid to lateral earthquake excitation was investigated by modeling the earthquake acceleration as an amplitude modulated non-white random process. In the present paper the differential equation governing the displacement of the tank wall is solved directly and the results obtained are compared with those by Galerkin's method reported previously. A fairly good agreement is found between the previous and the present results.

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This research aimed to develop a technique to suppress a liquid sloshing vibration in a tank by injecting air bubbles in a microcomputer controlled manner. Using a rectangular tank 800 mm long, 150 mm wide, and 500 mm high, installed on an oil-hydraulic controlled shaking table, sloshing was excited by sinusoidal motion of the table and air was injected at each corner of the test tank. The timing and duration of air injection were controlled by a microcomputer using pressure signal caused by sloshing. Experiments showed that the most effective timing of air injection was at the instance when the sloshing wave was ascending form the lowest position to the equibrium one, and a small amount of air, equivalent to 1 to 3 % of water contained in the tank, was sufficient to suppress the sloshing. A scale-up test showed similar effectiveness on reducing sloshing. An argorithm for controlling air injection timing and duration was developed using knowledge obtained from the experiments.

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A nonlinear Building Block Approach, abbreviated as NLBBA, was developed to evaluate the frequency response characteristic of the structures with nonlinearity, like hard springs, clearance and others, which are general in the actual system. The method presented in the previous paper to evaluate the frequency response function for the nonlinear multi-degrees-of-freedom system was combined with the linear BBA. The method made it possible to evaluate the frequency response function by simplifying the complicated actual nonlinear system. The effectiveness of the method was verified by the analysis of a beam supported by nonlinear springs. The comparison with the time historical analysis showed that using the proposed method is possible to save the computation time by about 1/3000 that of the conventional method. The method was also applied to the dynamic behavior of the main spindle of a machine tool. A clearance of 1 micron meter between the shaft and bearing which is empirically known in practice was introduced. The characteristics obtained by the analysis showed good agreement with that by experience.

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A car-vibration analyzing system was developed for the maintenance of the riding quality of railway vehicles. This system, composed of a 16 channel FFT signal processor and a thermal printer, has a software program which evaluates car-vibration and riding quality. And it can process simultaneously 8 lateral vibration channels and 8 vertical vibration ones at maximum. The principal evaluation index is the Riding Quality Level L_T which is a newly proposed index fundamentally based on ISO Standard 2631. L_T is calculated form the power spectrum density of car-body acceleration analyzed by the FFT signal processor. The output data are divided into the following 3 groups and are displayed on a CRT. (1) Data for judging riding quality (2) Data for indicating improvement in performance (3) Data for predicting transition of vibration and riding quality in increase of running distance.

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In the previous report, a new method which detects sound sources with high accuracy using a hemispherical hologram was discussed. However, it does not hold for all sound sources. To make highly accurate acoustical holography applicable to all sound sources, methods using a rectangular parallelepiped, a hemicylindrical and a plane hologram were discussed. Firstly, reconstruction formulae for these methods were deduced. Secondly, to test the validity of the formulae and the characteristics of these methods, a numerical calculation was carried out. Consequently the validity of these formulae was confirmed and it was shown that it is suitable to use a hemispherical or a rectangular parallelepiped hologram for statinary sound sources and a hemicylindrical hologram for sound sources which move linearly with constant velocity. Finally, examples of the application to actual sound sources were shown.

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Communication satellites are tending to use multi-beam antennas and narrower shaped antenna beams. The antennas have to be oriented accurately toward their ground targets. Accordingly, antenna pointing mechanisms (APM) are indispensable for multi-beam antennas. This paper describes the design and development of a new pointing mechanism. The mechanism construction and APM system performance are documented. The advantages of this APM are the simplicity and the high accuracy due to its extremely reliable nonlubricated direct drive.

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A program system for simulating hydraulic control systems is developed, being written in BASIC for personal computers. Various graphic functions supported by a personal computer were applied to the program system so that the simulation could be made graphically on the display. The simulation for a given control system can be accomplished straightforwardly only by drawing or constructing the corresponding block diagram on the display. The simulated time responses are compared with the measured responses of hydraulic servosystem.

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This paper is concerned with an analytical study of the dynamics of a plunger-type pneumatic pressure control valve, already proposed by the authors, which maintains a constant secondary pressure lower than the primary pressure, in spite of the change of the primary pressure of the fluctuation of the load connected with this valve. At first, the dynamics of the secondary pressure and the plunger movement, caused by changes of the primary pressure and the load, is analyzed by means of the state variables method. Furthermore, for improvement of responsibility, the conditions for adjusting system parameters are found through the root locus method. Next, the sensitivity analysis is applied to the investigation of the influences of parameter variations on the dynamics of the control valve. By means of simulation studies of sensitivity functions, we have shown which parameters are really significant and also which are not. Throughout these analytical and simulation studies, guidelines for improving the performance of a plunger-type pressure control valve are obtained.

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In this paper we describe the simulation of an automatic deceleration control which depends on the feed back system of the air brake in an electric-car. The desired value of deceleration is made using the characteristic relation between veclocity and the adhesive coefficient. The calculation for the simulation is performed with an express electric-car train, and the results are compared with the experimental results under the same conditions. It is shown that the calculated results agree with the experimental results qualitatively well and that the simulation is available for analysis of the deceleration control. With improved simulation we have obtained the brake distances in the case of four kinds of maximum velocities, e.g. 36.1 m/s.

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Based on a previous paper, an attitude control method of the Vroid is dealt with here, under some conditions, so that some of the modules should satisfy the constraints for the robotic shape and attitude, since it is sometimes required that mobile robots must carry something and/or liquid containers in a restricted moving mode. The assumptions are that (i) the Vroid has six degrees-of-freedom, including the freedoms of the rotational joint of the first link and the moving wheels, which were not treated in the previous paper ; (ii) the central link must be kept in the horizontal position as a constraint, which yields five degrees-of-freedom in Vroid ; (iii) Vroid moves along a slope. The problem is formulated as a linear programming problem minimizing the total applied moments at joints, subjected to constraints. Then the proposed control method gives a solutions for the control sequence of the Vroid for various terrains.

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A precise analysis has been made on the crowing method of the type 3 worm gear. Firstly the calculation method, which is used to find the amount of clearance between the thread surface of the worm and the modified tooth surface of the wheel in this crowing method, is obtained. This clearance is defined to be taken in the direction of the circumference of the wheel and is calculated along the characteristic curve between the thread surface of the worm and the wheel tooth surface. Then the design process for the hob, which cuts the modified wheel tooth surface so as to satisfy the given amount of clearance, is clarified by the using this calculation method. Theories in this analysis are verified by applying the calculation method and the design process to numerical examples of the type 3 worm gear. This calculation method and the design process are easily practicable for manufacturing engineers.

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For the study on the vibration of a gear pair having an inclination or a deviation, the relation between the load and the approach of a gear pair in tooth end bearing have been investigated by applying Sneddon's solution to the contact problem, which the finite elastic roller was pressed to the plane with same width of the roller, and by considering the effect of free end. Furthermore, the proposed calculation method has been confirmed experimentally by measuring the approach of the small taper roller pressed to the plane with an electric micrometer. The results indicated that the approach in tooth end bearing was larger than in normal bearing, and was in proportion to the load squared, and the stiffness was provided with the stiffness in the normal bearing and the load.

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The present paper deals with an analysis of the kinematics and geometry of the tooth engagement of a wave gear drive comprising a rigid gear and a flexible gear in a wave-like motion such as a circular spline and a flexspline in Harmonic Drive. The analysis is carried out in a plane mechanism. From the analysis of the motion of the rigid gear and the flexible gear, the shapes of the rolling contact plates which move together with each tooth are derived, assuming that the tooth of the flexible gear is rigid, although the tooth groove is flexible, and that the pitch the teeth on the unstrechable neutral line of the flexible gear is constant. Then the tooth profiles of both gears are determined, according to the theory of gear mechanism that the common tooth normal at the meshing point passes through the momentary contact point of the rolling contact plates. As an example, a theoretical new tooth profile of the flexible gear in meshing with involute profile internal rigid gear is obtained.

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The behaviour of tooth mesh frequency sound radiated from a tooth mesh point of a spur gear pair was investigated to see how it is generated. After examining the effect of bottom clearance, torque and material (steel or nylon) upon the radiation, the sound proved to be an aerodynamic sound ; i.e., the sound is born from the pumping action of the clearance between meshing teeth, under high speed conditions. Especially in the direction of the exit side of meshing, the radiation is prominent, with a feature of ""level trough"", which occurs due to the existence of two sorts of sounds having the phase difference of 180° nearby the meshing point. It has become also clear that the aerodynamic sound can not necessary be reduced by increasing clearance, after an analogical consideration on the fluctuation of the flow rate of a gear pump.

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The purpose of these investigations was to measure the bulk and its sorrounding temperatures of helical involute gears operating under grease and oil bath lubrication conditions. The gear testing machine used for the tests was a closed power circuit type. All tests were made with pairs of 28 and 32-tooth gears of 2.5-module, 20-deg normal pressure angle, 25-deg helix angle of carbon steel material and HRC55∼56 hardness. The value of the loading force was changed from P_n = 0.0 to 336 kN/m in steps and the value of pitch line velocity was also changed from V_p = 1.59 to 6.19 m/s. The effects of quantities of the lubricant were also investigated experimentally. Results obtained for various greases were compared with the various oil bath lubrications.

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The purpose of this paper is to measure the lubricant stirring loss and study its behavior in a gear box. The gear sets are made with spur gears having a 2.0 module, and with the number of teeth being Z₁/Z₂ =28/52. The lubricant used are two greases made form NLGI 0 and 000 gear oil. The stirring loss and lubricant behavior are examined in relation to the velocity V_p, quantities of lubricants, temperature and the face width. The loading force is no load. The results are summarized as follows : (1) the harder grease has a tendency to show channeling, and the softer grease produces churning. (2) the stirring torque of the grease lubrication is much larger than that of the oil lubrication. (3) the stirring torques of both the grease and oil lubrication are evaluated as functions of (v·V_p).

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This paper describes the wear mechanism of power transmission plastic gears when considering the principal factor for local wear. The experiments were made to find out variations in tooth profile for the total number of rotations. In addition, the local temperature of these meshing possessions was calculated. The amount of local wear agrees with the variations in local temperature in a low load condition. In a high load condition, abnormal wear is found, and that does not always agree with this, but these local possessions of wear are thought to be due to the relation between the calculated value of the depth of the wear trace and that of teeth deflection. The results provided present some data for the design and use of plastic gears.

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A plastic gear tooth greatly deflects because of low mechanical strength. This causes a delay in rotation to the mating driven gear (steel gear) and allows the root of the tooth of the plastic gear to be scooped out by the addendum edge of the steel gear when the succeeding teeth mesh with each other. We have already proposed several methods to prevent this. Apart from these methods, however, we have worked out a way to avoid using a plastic gear made from low friction coefficient materials. We have manufactured gear from two types of low friction coefficient materials of nylon obtained by charging super high molecular polyethylene and synthetic wax, and performed an operation test and studied its effect.

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It is difficult to perfectly predict the fatigue strength of a bolt in joints at the stage of strength design, since many factors influence the load on the bolt. This study treats the possibility of preventing the fatigue fracture of a bolt by detecting the fatigue crack at the thread root at an early stage by means of the ultrasonic flaw detector. A method is discussed in which the crack is initiated at the bolt thread root near the top surface of the nut in the mating threads by shortening the bolt pitch slightly against the nut pitch. By using this method, it is hoped to lengthen the period from the detection of the crack to the fracture. From the results of fatigue tests, it is clarified that the pitch modification is effective in the case of 0.6% pitch difference and of relatively low mean stress.

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Ceramic is a better material than metal to use in the corrosive environment or at an elevated temperature. But ceramic is very brittle. Therefore the combined use of ceramic and metal is needed. A simple and sufficiently strong joining technique between ceramic and metal is essential in that case. We thought that shrink fit is one of the most available techniques, compared with welding, diffusion bonding brazing. In the previous work, we made clear that the existence of surface roughness reduced the strength of the shrink fit experimentally and theoretically. But we didn't change the sizes of the specimens in that work. It is thought that the degrees of the reduction of the strength will vary with the size of the outer diameter of the shaft, although the surface roughnesses are the same. In this paper, the experiments were carried out to obtain the strengths of the shrink fits of various sizes of specimens. And we investigated how the strengths of the shrink fits were reduced by the relationship between the surface roughness and the sizes of the specimens, experimentally and theoretically.

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First, a new method is presented for synthesizing the Watt six-link mechanism which has two prismatic and five revolute pairs as a force-displacement transformer, by applying the five precision-point method to the input-output relation in which the moment of the weights of the links except the pendulum is approximated as a constant, and attaching an additional weight to the pendulum, which corrects the error due to the mass of the links. Second, a self-indicating scale of the pendulum-type is composed of the synthesized mechanism so that the ratio of the range of the output displacement to the maximum length of the links is 0.335 and the maximum structural error is 1/15 400 and a linear-rotary motion trans-former using a rack and pinion whose axis is supported by two circular plates overlapped each other crosswise. Then the linearity of 1/1000 and the reproducibility of 1/4000 are confirmed experimentally.

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We have reported a mechanism whereby a short pipe inserted into a vibrating vertical rod climbs step by step with the yawing motion caused by the vibration. Using the mechanism, a kind of linear stepping motor has been developed and is reported in the present paper. An oscillator made of two side plates is used as a stator in the motor. The yawing motion is given by the cyclic change of magnets which are attached to the side plates. Calculated step widths coincide with experimental ones, when frictional forces between the rail and the oscillator are esimated correctly. The reproducibility of the step width depends chiefly on the frictional forces. When the frictional conditions are carefully arranged, , the average step widths are reproduced with an accuracy of ±1μm.

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A linear stepping motor is constructed by a rotor, which is made of electro magnet cylinders fixed at each of the four corners of a rectangular plate, and a rail with flat sides. The plate is placed on the rail and each pair of cylinders are alligned to both sides of the rail. When these pairs and diagonal pairs are magnetized in order, the rotor moves stepwisely along the rail. Step reproducibility and load capacity are investigated under some different frictional conditions. A small frictional coefficient between the plate and the rail and a large frictional force between the rail and the cylinders produce good results. Under some good conditions the step width can be reproduced with an accuracy of ±1μm. The load capacity is improved remakably in comparison with that in the first report.

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As reported in the previous paper, a synthesis of a planar adjustable 9-link mechanism was carried out, as a practical example of an automatic conveying machine which generates an L-path. It has been found that the driving system of the above mentioned which is constructed of an analog computer, induction motor, magnetic power clutch and brake is so complicated that the system has made a response worse ; and that positioning errors of the machine hand at the edge points of the path have increased. In this paper, a 12-link adjustable mechanism is proposed, which is made by joining a 4-link mechanism to the input link of the above 9-link mechanism for the purpose of making the crank motion uniform in one direction and simplifying the electric controllor of the driving system. Moreover, an optimum distributed mass and moment of inertia of the input link is determined so as to minimize the input torque ; and the dynamic characteristics of the machine are investigated theoretically and experimentally. As a result, the velocity response and the positioning accuracy of the machine hand at the edge points of the path have been improved greatly.

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Pressure distribution has been measured and analyzed to clarify the fundamental characteristics of ""continuous oil-film"" formed in transparent journal bearings, into which oil in general use is supplied. The results are as follows : (1) Sommerfeld's distribution for perfect oil-film is approximately observed only under limited conditions : low eccentricity and low speed. Measured pressure mostly shows quasi-Sommerfeld's distribution, which is characterized by downstream shift of pressure profile and underdevelopment of pressure trough compared with Sommerfeld's distribution. (2) Calculated pressure, taking account of compression and expansion of fine bubbles in a lubricant, shows qualitative agreement with experimental data. This would suggest that the behavior of bubbles constitutes the characteristics of continuous oil-film and remain to be further studied.

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The repulsive magnetic bearings using the diamagnetism of a superconductor are expected in cryogenic engineering, because superconducting bearings can support cryogenic rotors and devices without any mechanical contacts and control and control units at low temperature. However, superconducting bearings have not been developed in industrial applications, since the supporting mechanism and the performance of the bearings have not been analyzed in detail. This paper reports the experiment of Niobium thrust bearings and FEM analysis of magnetic field. The experimental data show a good agreement with the results of numerical calculation upto the field higher than H_cl. Judging form analysis of the results, we guess that the load capacity of superconducting bearings is restricted by H_c2 and J_c.

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Offset bending techniques are widely used in the field of sheet bending processes. The deformation behaviors of offset bending have not been experimentally or theoretically investigated. This paper deals with the change of sheet length (apparent elongation) which consists of the pure stretch of the sheet and feigned contraction by the loose fit of the bent sheet in molding dies. The experiments show that the apparent elongations have minus values in case of thin sheets or deviations form inclined lines in case of thick sheets. The explanations of these results are as follows : The pure stretch may linearly increase with sheet thickness. The loose fit in dies depends on the die configuration and flexural rigidity of the materials. These factors are mutually affected but can be evaluated by the elementary calculations reducing in order of sheet thickness. It is noted that the slip of the sheet form the clamped part is not ignored.

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A new sensor to detect stress and temperature in plastic working has been developed. Installed in a die' this sensor can detect both pressure and frictional stress acting on the same point of die surface. Moreover, it can detect surface temperature at the same time. This sensor is designed to detect pressure from 0 to 300 MPa and frictional stress from 0 to 150 MPa. The principle of detecting 3-dimensional stresses is the deformation of parallel plate structure. Surface temperature is calculated from the two temperatures detected by thermocouples at different points from the surface. This sensor is named Die-sensor. Examples of measurement are shown, and applications of this sensor is discussed.

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Nickel-iron base superalloy (Inconel 718) is used extensively for various high-strength, high-temperature components of aircraft engines. However, it is extremely difficult to machine. In this study, creep feed grinding with continuous dressing is applied to grind Inconel 718. Through the experiments it is confirmed that this new machining method is very efficient for difficult-to-machine materials such as Inconel 718, i.e., the productivity and the machining accuracy are markedly improved.

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Failure of a cutting tool is one of the largest troubles in the automated machining system. Therefore several methods have been proposed, so far to detect the cutting tool failure. However, most of them, have some problems from the viewpoint of the practical application. In this study, an acoustic emission sensor is used to detect the cutting tool failure, and a monitoring system which has high reliability is proposed. Failures of the single-point as well as multipoint cutting tool are successfully detected with the monitoring system developed in this study.

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The whirling vibration of the drill when beginning the drilling of a workpiece with a pilot hole, is theoretically examined. It becomes clear that the whirling is a regenerative chatter vibration which is caused by the regenerative effect at the major cutting edge and the frictional force occurring due to the interference between the flank surface of the major cutting edge and the workpiece surface. As the amplitude and the vibration speed of the drill are restricted by the characteristic of the frictional force, remarkable vibration waves are observed. It is also found that the frequency of the whirling vibration is considerably lower than the natural frequency of the system, and that the odd number polygon is produced by the regenerative effect.

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This paper presents data for estimating the production efficiency of automatic assembling lines, with calculations and considerations for numerical examples. The efficiency of assembling lines is influenced by the trouble rate, the recovery time and the buffer capacity of each assembling station. Calculations and considerations are performed for various of those factors by use of the method proposed previously. The main results reported in this paper are as follows : (1) The efficiency increases with buffer capacity in b₁₂/R_i < 2.0 (b₁₂ ; buffer capacity, R_i ; a multiple of the cycle time) and takes approximately a constant value in b₁₂/R_i >2.0. (2) As the number of stations increases, the effect of the capacity increases. (3) The efficiency takes maximum value at the same trouble rate and recovery time in each stations.

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This paper describes the result of an experimental study on the comparison between the learning of the job enlargement system and of the flow line system. The theory of the selection of an economical work system is proposed. It is composed of get-and-place time, the number of station's the ratio of line balance loss, the initial cycle-time and the learning coefficient of both systems. Both systems based on the theory can be evaluated with the productivity ; and the availability of the theory is examined by an experiment. As a result, it is clarified that the theory is available for practical use.

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