[in Japanese]

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This paper presents a method for measuring a complex elastic modulus by holography, particularly in ultrasonic frequency range. This method uses the characteristics of amplitude distributions in longitudinal vibration of viscoelastic beam while the previously reported method uses those in transverse. The dynamic elastic modulus E' can be determined from the formulas for E' and positions of maximum (or minimum) amplitudes, unlike in the previous transverse vibration method where it was graphically. The loss tangent can be obtainedby measuring the amplitude ratio like in the previous method but independently of the vibration mode in this longitudinal vibration method. This theory is confirmed by the experiment about epoxy resin using a ferrite vibrator and a step horn. In this experiment the frequency is restricted to the resonant one of the vibrator, while arbitrary in the previous method. However, by this method the higher loss tangent can be measured than by the usual one not using holography, it can be checked whether the specimen vibrates normally and it is easy to vibrate specimen.

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A system is established to analyze and evaluate three-dimensional human body motions, which is applied to analyze simple loading and unloading operations. A three-dimensional model of human body consisting of seventeen equivalent rigid cylinders is proposed and the equations of motion are derived. A sequence of loading and unloading motion in both the frontal and the sagittal planes were taken simultaneously employing a 16 mm movie camera with use of a life-size mirror placed in front of the subject. The three-dimensional information of the motion is taken into a minicomputer via a graphic tablet. The threedimensional computer graphics are utilized to display the motion patterns of the operation, the loci of the body center of gravity and the correlations of the angles among the major body joints for detailed analysis of the operation. The forces and torques acting at individual joints are also estimated for quantitative examinations of the motion by solving the equations of motion based on the motion data.

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A software and hardware system developed for forecasting onsets of chatter vibrations by analyzing preprocessed sound mean square frequencies in processes of cutting operations and for retreating a tool at onsets of chatter, is described, together with experimental results of practicabilities of the system. In this system, cutting starts are detected by using amplitudes of accelerationsignals and conditions of calculations, especially a sampling rate and a maximum forecast lead time, are adequately selected to prevent false forecasts of chatter causedby signal variations other than chatter indications. The chatter indications are grasped by using the sound mean square frequencies calculated by an analogue circuit including an AGC. It is revealed by actually forecasting chatter onsets (sampling rate; 20 Hz, maximum forecast lead; 0. 3 s) in turning operations that the realistic chatter onsets can be forecasted by errors within about ±0. 1 s and the chatter vibrations are avoided by controlling a tool located by a pulse motor. The practicability of the real time forecasting system of chatter vibrations is confirmed as the result of the study.

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Optical reflectance method is studied for surface roughness measurement. In order to measure the intensity of the light reflected by a surface at a fixed distance, here employed is an instrument named 'optomicrometer', which is originally used to measure the vertical displacement of a surface. Also discussed is the relation between the relative intensity of reflected light and the surface roughness parameters. The optical wave theory shows that a surface is classified into one of four models according to whether it is rough or smooth and whether its finish is one-directional or equidirectional lay and that the reflected light intensity : is determined by its mean deviation for a smooth surface and by its mean slope for a rough one. Experiments are carried out with various kinds of finished surfaces of which the arithmetical mean deviation ranges from 0.02 to 2.1μm. The results support the theory as well as the proposed method so that the usefulness of optical reflectance method is certified.

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Real time monitoring of working processes is one of the most important technical problems for unmanned operation of machine tools. Especially, real time detection of chipping is required to minimize the damage from it because it happens accidentally and the prediction is not easy. In this report, a method for real time detection of chipping is presented as an application of correlation method which is one of pattern recognition's. Sequential data in cutting force are compared with a standard chipping pattern described with numerical data which is previously assumed. The pattern resemblance and pattern magnitude are calculated at each sampling time. The results show a spike-formed rising at the time point of chipping occurrence. Chipping is detected by checking the height of this spike. Examples that chipping pattern is extracted from cutting force data of facing are showed.

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The critical pressure which corresponds to the breaking stress of the grinding stone has been suggested to have a specific value for the composition of grinding stone (kinds of abrasive grain and bond, percentage of grain, bond and pore, and grain size). However the critical pressure on a superfinishing stone may be decreased for the grinding conditions, because the alternating stress would generate in the cutting edges which is vibrated.Then in this paper, the wear characteristics on superfinishing stone are considered. As the results, it has become evident that the magnitude of alternating stress, i. e. the stress amplitude on the cutting edges is dependent upon the coefficient based on the maximum inclination angle of superfinishing. Therefore, this coefficient is called as the coefficient of stress amplitude in this paper. And it is described that the critical pressure of the stone under the alternating stress can be expressed quantitatively as the function of the coefficient of stress amplitude.

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This study deals with the characteristics of tool behavior in reaming hole, using standard type, carbide-tipped reamers under high cutting speed. When the cutting lips enter into the workpiece, chatter vibrations are excited with so large amplitude that the unevenness in hole profile at the entrance section can be observed, and frequently chipping and spalling of tool tips occurs. These vibrations measured contains frequency components relating to the number of teeth (Z), which are near the natural frequency of spindle-tool system. The entrance geometry in the workpiece have a great influence on the tool behavior. Chatter vibrations can be avoided in reaming chamfered hole with smaller angles (æ<45°) at the entrance portion than the approach angle (λ=45°) of the cutting lips. Increasing the stability in reaming and controlling the direction of chip flow are very important for high speed reaming with carbide-tipped reamers.

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For evaluation of the sharpness of cutting edges on the working face of grinding wheel, the friction test between the wheel face and a Teflon plate is shown to be a very simple and practical method : The wheel faces which have dull cutting edges and, accordingly, require high specific grinding force indicate low coefficient of friction in this test, and vice versa. Then, this test can tell the time for redressing as well as the adequacies of the dressing tool and dressing conditions.

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This paper describes development and trial production of a new balancing equipment for grinding wheels, which consist of a balancing table to measure unbalanced direction and moment, and a balancing weight shift device to adjust them. The outline and the characteristics of that are as follows : (1) Balancing table : A grinding wheel is supported by a steeel ball horizontally. By this method, unbalanced direction and moment can bemeasured quantitatively at the same time. (2) Balancing weight shift device : One ring shaped weight is shifted to X or Y direction by feed screw. Based on the balancing weight travels, unbalanced moment can be adjusted quantitatively and accurately. (3) New balancing equipment has merits in accurate adjustment and efficient operation compared with conventional balancing equipments. Therefore, this will be a useful device for grinding wheels balancement.

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The cutting mechanism, changing in process of finishing, is theoretically analyzed by assuming the stick as a tool having a long cutting edge, and consequently the cutting depth of a stick d is derived.dis composed of the cutting condition term and the measured term of changing speed of workpiece radius. This value is influenced by the cutting characteristics, that is, glazing, crushing or breaking of cutting edges, and decrease in ascending order. Moreover, the evaluating value d_i is offered to express the severity of cutting condition, in which the infeed rate is substituted for the measured term of d. When the specific cutting force k_s derived from d is applied to experimental results, it is revealed that k_s and its changing type depend strongly on the three cutting characteristics as previously stated. k_sin constant pressure honing is lower than that in constant infeed one, and this is resulting from the difference of applying method of infeed. Comparing the value of k_s with those in other operations, in breaking condition of cutting edges, it is not so different from that in abrasive belt grinding, but in glazing condition, it is larger than that in wheel grinding.

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A dynamic stiffness simulator which can set reliably both the static and dynamic stiffnesses between wheel and workpiece in wide range was designed. Utilizing this simulator, the effects of the stiffness upon the sparkout time and stability limit of chatter vibration are clarified experimentally. That is, the minimum amount of static stiffness, which is required to give the proper interval of sparkout grinding under the condition as to utilize the specified motor power fully, is experimentally obtained. Secondly, the minimum amount of dynamic stiffness, with particular interest in damping ratio, which is enough to make the operation free from any chatter vibration, is decided experimentally under the above condition. From these test results, the propriety of stiffness determination method developed in the previous paper is evaluated to be practical.

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Recently, creep feed grinding has become of major interest due to its high productivity. Effective application of grinding fluid is, however, more difficult than in the case of conventional grinding because of its long contact length between wheel and workpiece, so that thermal damage of the ground surface becomes a problem. The purpose of this study is to improve the application of grinding fluid. For that purpose it is necessary to clarify the state of grinding fluid in the arc of contact between wheel and workpiece. In this paper some workpiece models of creep feed grinding were made. Using these models velocity of the air flow along the ground groove near the point where the wheel begins to contact with the workpiece is measured. Furthermore, effect of various factors on the state of grinding fluid in the arc of contact are experimentally investigated introducing the equivalent thickness of grinding fluid.

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