[in Japanese]

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[in Japanese]

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A new vibrating device which consisted of a specially modified Hook's universal joint and other parts was made for this study. The device used in this study was of simple design and can be easily attached to the spindle shaft of any drilling machine. One of the other merits of this vibrating device is its low cost. The drill was rotated at a constant speed and at the same time, vibrated in axial direction twice per revolution of the spindle. The effective rake angle, the effective clearance angle and the cutting ratio varied periodically. The range of the variations near the center of the drill was remarkable. The above phenomena probably lowered the rigidity and exhaust resistance of the chip, and likely extended the drill life.

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The evaluation of single abrasive grains has attracted considerable attention in grinding industry. In the previous research the fly milling chipping characteristic has been extensively studied on various tough grain types using several work materials. In the present study the same chipping test has been made on several friable grain types such as 57 A, 38 A, and diamond, etc. Special interest was concerned with the differences in chipping fracture pattern between the 57 A and 2 A grains, and the 38 A and WA grains. The effects of cutting speed or grinding fluid on chipping performance were also discussed. The 38 A grain was seen to fracture more frequently than the WA grain, but the chipping height was less for the 38 A grain than for the WA grain, while the 57 A grain fractured more frequently than the 2 A grain. The diamond grain has the highest resistance to chipping fracture, but when fractured this grain type gives a high chipping height. Grinding fluid was shown to promote the chipping fracture of grain.

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Previously, the characteristics of the lapping process were discussed, and as a linear model of the surface form generation in the lapping, a vector differential equation was examined. This equation is used here to predict the change in surface form. The convergency to flat surfaces in the lapping is not always true, because such a process is not necessarily wellbehaved in that sense. In order to qualify the process for the convergency, it is discussed, applying the theory of dynamic programming, how to construct the lapping or to determine the pair of workpieces and the lapped distance at each stage of the process as a deterministic multistage decision problem. Thus it is shown that the process of three stages is rather fundamental or of the least number of stages for any initial surface forms. Some effects of lapping conditions are also investigated in connection with the construction of the lapping.

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A method is proposed for gathering the machining informations from the field engineers, instead of from the practical cutting tests, and calculating data files for EXAPT Systems from these informations. The gathered data are punched onto cards and sorted into a Master File after checking errors by a computer. The data in the Master File are plotted into graphs by a X-Y plotter and the trends of the gathered data are examined. It is revealed that the trends of data concerning EXAPT 1 coincide with the System's model, and that the material files and the machining file can be calculated. On the other hand, the trends of data concerning EXAPT 2 (turning) do not always agree with the System's cutting model, but the material files for EXAPT 2 can be created in the following way; 1) introduction of a model of constant feed rate values, irrespective of depth of cut, and 2) as for the model for obtaining cutting speed, calculating from gathered data only important values, and obtaining the others from the standard files. Cutting tests of turning using the material file based on the gathered data are successfully performed.

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An idea of the optimum design of the monitoring system in automated manufacturing is proposed in the paper. The machine system such as a machine tool or an automated manufacturing system is first represented by the flow diagrams of motion, in which a failure in the machine is considered as open or short of a flow path. Next the kinds of the sensors to detect the state of motion and the locations for the sensors to be possibly installed are examined. Analysis of the flow diagrams leads to formulation of the signal matrices of the sensors corresponding to each failure and to determination of the layout of the sensors necessary to identify the type and the location of each failure. Lastly, the optimum layout of the sensors is selected of these sets of the sensors by considering the cost of system operation and the reliability of the sensors.

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Several ways to find the temperature in the grinding wheel in process of grinding have been attempted. In this paper, the temperature distributions in the grinding wheel and the heat flux flowing into the grinding wheel are obtained in surface grinding, by a new method consisting of an experiment and a numerical analysis by means of finite difference equation. That method is characterized by follows: the temperature measurement during only one pass of grinding is required to obtain the temperature distribution in the grinding wheel, the error of temperature caused by existence of a thermocouple is cancelled, and the temperature in the thinner layer below the peripheral surface of grinding wheel is obtained by the finer grid system. And the examination with the numerical analysis explains that a thermometer has unnegligible influence on measured temperature in the grinding wheel.

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For internal gears the measurement of accuracy, such as pitch and profile, is rather difficult and it has not been widely used in gear shops. Some weakness of the usual profile measurement methods has made clear, and the newly developed gear measuring system with 3-coordinates measuring machine and micro computer is applied to the internal gears, which were manufactured by the several manufacturing methods. Not only the individual errors but also the angular transmission errors of these gears have been obtained. It should be remarked that the deformation of gear blank plays a large role in internal gear accuracy, and the careful treatment in the machining and heat treatment of gear blank is necessary for the production of internal gears.

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The paper presents a characteristic equation of crater wear of carbide tool in high speed metal machining, which is derived from a model of adhesive wear and a simple analysis with regarding the wear as a thermally activated process. The equation obtained involves not only the effect of temperature on tool-face but also the effects of normal stress and sliding distance as well. By measuring the distribution of the stress, the temperature, the chip sliding speed and the wear rate along tool-face in high speed, orthogonal cutting of carbon steel, it is verified experimentally that the equation holds well regardless of rake angle, feed and cutting speed. It is further stressed that the effect of the normal stress on tool-face appears to be essential for better understanding of crater wear.

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This paper presents an outline of the experiments as well as the theories on some new ideas for reducing undesirable mechanical vibrations. A Hall-element is used as a non-contact sensor under the magnetic field of a strong permanent magnet attached to the vibrating body. The voltage output of the Hall-element is supplied to an operation circuit in order to modify and amplify the vibration signal into some desired form of damping force, which is fed back to the original vibrating body through a flat coil type electro-magnetic device. The following four kinds of damping are tested in the experiments: (1) Integrated force of vibration displacement, (2) force proportional to the vibration displacement with opposite sign, (3) Coulomb's type damping, and (4) the square damping whose amplitude is proportional to that of the vibration. The experiments and the calculations showed the good coincidence and proved effectiveness of vibration control.

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In the orthogonal cutting of aluminium, there occurs the overcutting beyond the depth of cut without built-up edge in a certain cutting condition. In this paper, the orthogonal cutting of some soft metals (They are the metals having low yield strength and high ductility.) was conducted and the situation of overcutting was observed. Moreover the overcutting phenomenon was discussed from a view point of the mechanical properties of work material. Some results obtained in this paper are as follows:
(1) The thickness of overcut chip is proportional to the frictional force between the chip and rake face and inversely proportional to the hardness of the chip.
(2) The depth of overcutting is proportional to the vertical component of the frictional force and inversely proportional to the hardness of work material.
(3) In case of the occurrence of overcutting, the following conditions are satisfied. That is, the chip is restrained of its flow intensely and the work material having the work hardening property is soft.

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In this paper, the probability distribution for the pitch of ground surface roughness is considered both theoretically and experimentally by a statistical method. Results obtained are as follows: (1) The probability density function and the mean value of the pitch of ground surface roughness are analysed theoretically by a statistical method. And the relation between the mean value of pitch and the mean value or the standard deviation of ground surface roughness is derived. (2) The influences of the distribution for the position of grain cutting edge, the distribution for the tip angle of grain cutting edge, the elastic displacement of grain cutting edge and the number of spark-out on the distribution for the pitch of ground surface roughness are obtained by Monte Carlo simulation. Furthermore, the mean value of pitch is calculated from the power spectrum of ground surface roughness curve obtained by Monte Carlo simulation. (3) A few experiments are performed, and the validity of the authors' theoretical analysis is confirmed.

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