This paper deals with cutting mechanism at inside corner by a square end mill. The results are as follows. (1) Cutting mechanism of corner cut by end mill is analysed geometrically. And calculating procedures of actual radial depth of cut and cutting area are shown at inside corner. (2) New cutting method is presented that commands a looped cutter path during corner cut. The method suppresses rapid increase of radial depth of cut and cutting area. (3) Optimum diameter of end mill and loop radius of cutter path are calculated. Under the cutting condition, these values are 17 mm and 1.5 mm respectively. (4) It is shown by cutting tests that working accuracy is improved remarkably by the new method at inside corner.

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It is generally known that machined surface roughness can be improved with the increase of cut distance just after start of cutting on diamond turning of an Al-Mg alloy. Even for the diamond tool, the tool wear increases as cut distance. In this paper, the effect of the tool wear growth on machined surface roughness was examined on the turning experiments of an Al-Mg alloy. The following results were obtained. (1) Tears generated on the side cutting edge of a straight tool deteriorate machined surface roughness at a positive tool setting angle. But tears decrease as tool wear growth. (2) It is clear that the machined surface roughness has a strong correlation with the cutting edge recession of the tool wear. (3) A residual stock removal is generated at a cutting edge recession distance of more than 0.3 μm. Since the residual stock removal distance is cut off by the trailing end cutting edge, the machined surface roughness is improved after some cut distance.

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This paper deals with the ultrasonic screw vibration tapping for aluminium and its alloy. Cutting torque, chip geometry and female thread shape were investigated and the following results were obtained. In the case of pure aluminium tapping, the torque ratio (i. e. vibration tapping torque/conventional tapping torque) was about 1/2 in dry tapping, about 1/10 in tapping with machine oil and about 1/15 in tapping with kerosene. In addition, the chip geometry became very long and thin, and cross section of female thread was sharp trapezoid geometry. The clearance between female screw and tap in the vibration tapping was almost equal to that of conventional tapping. Effect of vibration tapping was recognized remarkably for the difficult machining aluminium (A 1050), but slightly for the machinable wrought aluminium alloy (A 2017-T 3).

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V-profile groove grinding process of fine ceramics with a formed metal-bond diamond wheel is experimentally investigated, analyzing initial profile of formed wheel, wheel wear, stock removal, grinding force, number of cutting edges on working wheel surface and so on, comparing with those in grinding metals with WA vitrified-bond wheel. Main results obtained are as follows : (1) Initial profile of formed metal-bond diamond wheel is expressed by an isosceles triangle whose top is rounded like that of WA wheel, but the tip radius of diamond wheel is much larger than that of WA wheel. (2) The number of cutting edges on working wheel surface is approximately constant and is not affected by different positions along wheel width and different angles of formed wheel, which is different from that in WA wheel. (3) The ratio of wheel wear to grinding length in steady wear region is decided only by initial cutting depth and is not affected by different positions along wheel width and different angles of formed wheel.

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The protrusion height of abrasive grains in a metal bonded diamond wheel plays an important role in grinding performance. For example, the protrusion height too small causes loading easily and an increase of grinding force markedly, but the too large one causes attritious wear and releasing of cutting edges frequently. However the precise measuring method adapted to the protrusion height has not been developed. In this paper, a new 3-dimensional measuring technique [3 D method] is developed by using SEM stereo pairs. And then the effect of the protrusion height in a diamond wheel which is trued and dressed with a GC cup-truer is investigated experimentally on grinding performance of Si₃N₄ ceramics. The main results obtained are as follows : (1) After truing and dressing, abrasive grains protrude above the flat base of metal bond and are followed with bond-tails, the protrusion height approximates to a normal distribution. (2) Grinding force grows monotonously with an increase of grinding passes. (3) The optimum protrusion height is discussed by means of variations of grinding force, finished surface roughness and wheel wear with an increase of primary protrusion height.

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Residual flexibility which represents the influence of vibration modes in higher frequency range, takes an important role in structural modification simulation for more accuracy. The paper describes how to determine these residual flexibilities based on measured frequency response functions after curve fitting process for modal parameter extraction. Further a new method is proposed to correct these residual flexibilities and applied to mathematical models and to actual structures in order to show the effectiveness.

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In order to realize a CAD system, a design model, a control method of a design process, and a reprentation method of design knowledge for the design model must be concreted. The previous paper describes a boundary factor model as the design model and the Petri net as the control method. This paper reports on the representation method of the design knowledge for the design model. A new representation method, “Object and Operation Dualism”, is adopted for the design model. Object and Operation express designing know how, formulations, programs, tables, and so on. And, Object and Operation together become an information flow moving through machine units. It is regarded that a set of Object and Operation builds up the machine unit. The Petri net method controls the information flow. Object and Operation are coded in a similar way to a frame representation here. Examples show how Object and Operation are built in the design model for the description of the design knowledge, and how they are controlled by the Petri net.

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Eleven operations on a set of two-dimensional domains are defined to grasp and handle clearly the varied types of collision problems in process planning of NC-lathe operations. One of the most essential concepts for the solution of dynamic collision problems is “Interference Domain” determined by a work-contour and a tool-contour. When the tip of the tool is located in the interference domain, the tool must collide against the workpiece. Using inversion and envelope operations, an algorithm named “Inversed Template Method” is presented to compute an interference contour easily from complicated contours of work and tool. A computer program is coded as a set of subroutines executing the operations by which several typical collision problems in lathe operations are solved to show the effectiveness of the domain operations.

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In the past few years one of the authors has proposed the 4×4 determinant method to deal with many types of interference problems in a unified way. The paper proposes an efficient computing technique based on the method. In the 4×4 determinant method almost all of geometric computations are carried out by only computing 4×4 determinants and testing these signs. By recording some kinds of data calculated repetitively we can perform geometric computations efficiently. In the present paper the 4×4 determinant theories are reviewed briefly. Then attention is mainly focused to the efficient computing technique based on the 4×4 determinant method. Test results of some simple cases in ray-tracing hidden surface elimination problems are shown and a generalization of the technique is discussed. The technique described speeds up various geometric processing based on the 4×4 determinant method by eliminating computational duplications.

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The membrane touch panel is gradually becoming more popular and it is necessary that the optimum design based on theoretical analysis is used for developing the high reliable touch panel. In this paper, the touch force needed for the sheets of membrane touch panel to come into contact with a finger, P₀, is analyzed theoretically using the model of continuous plate which is supported by array of dot spacers placed at a pitch, and which is uniformly loaded. As a result, it is shown that the numerical solutions calculated by the deflection equation of the continuous plate model approximately agree with the experimental results. It is also clarified that the touch force P₀ depends on the ratio of spacer height to sheet thickness, h/t, the ratio of sheet thickness squared to spacer pitch, t² / a, the ratio of loaded area to spacer pitch and the spacer pitch ratio, and that the touch force P₀ is in direct proportion to both h/ t and (t² / a)². Also, a process of optimum design is suggested.

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This paper presents a mask-wafer gap setting method for X-ray lithography, using dual gratings. The mask gratings and the wafer gratings are arranged at right angles with regard to each other, so that the diffraction light intensity varies only with the mask-wafer gap variation, independently from the lateral displacement. Two pairs of those dual gratings, which consist of different pitch mask gratings and same pitch wafer gratings, were used as gap setting marks. Diffraction light intensity differences ΔI(0, 1)=I₁(0, 1)-I₂(0, 1) from those pairs were used for gap setting signal. In order to avoid the gap setting error caused by the ripples in the signal, the wafer stage was scanned for several microns in the gap direction. During scanning, ΔI and relative displacement of the wafer stage were sampled to calculate the regression line. The mask-wafer gap was set at the point where the regression line became zero. The gap setting point had good agreement with the calculated gap. A wide gap setting range, 0-60 μm, was obtained. Moreover, 0.4 μm(3σ) gap setting repeatability has been achieved.

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A design procedure of ultra precise linear guideway is discussed with respect to its desired material property first and it was clarified that alumina ceramics suit for ultra precise applications because of its high specific rigidity and possibility to finish precisely by lapping operations. Secondary, the surface-restricted-type air bearing is adopted in order to make the bearing stiffness higher with the smaller bearing clearance. A prototype slider was made, the performances of which does not coinside so well with the theory which was reported previously. But the prototype had shown that its stiffness becomes high, up to about 200 N/μm with the bearing area of 200×120 mm. With the help of present report, it is possible to design more accurate and rigid linear guideway which may be applicable to the various engineering fields.

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This paper describes the theoretical and experimental investigation on strict comparison of non-repeatable radial vibrations (NRRV) between time and frequency domains. The statistical characteristics of NRRV are revealed by analyzing amplitude distributions of both asynchronous and synchronous vibration components in frequency domain. As a result of this study, it is found that the main part of NRRV is composed of asynchronous components in almost all spindles. The amplitudes of some asynchronous components are varying randomly and can be approximately expressed by Rayleigh distribution function. It is also found that the synchronous vibrations include also non-repeatable components. The variance of NRRV in time domain is shown theoretically and experimentally to be equal to the total power of asynchronous components and varying components of synchronous ones. From this relation, the cause of tracking error can be analyzed quantitatively in frequency domain.

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A wafer-surface flattening technique has been developed to improve patterning accuracy of VLSI fabrication systems. The technique is especially applicable to X-ray exposure systems. This paper presents the wafer-surface flattening method, including a wafer deforming chuck and its operating system, as well as an evaluation of the system accuracy. The wafer deforming chuck is designed so that a wafer held onto an elastically deformable plate by vacuum suction is flattened by controlling the heights of piezoelectric actuators underneath the deformable plate based on flatness error measured by an electrostatic displacement detector. A unique open loop voltage control method to improve wafer flattening accuracy by eliminating the displacement error due to hysteresis in the piezoelectric actuators is also discussed. The experimental results show this method is capable of flattening a wafer-surface to within ±0.5 μm of a perfect plane, independent of wafer size.

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A heart surface mapping is used to display the heart surface excitation propagation. The heart surface mapping draws the conduction equitime lines on the measured heart surface potentials, which is essential for identifying abnormal portion in the heart arrhythmia. It is also useful for the analysis of the arrhythmia mechanism associated with the abnormalities of the intracardiac propagation of excitation. However, most of the present mapping systems are very timeconsuming for drawing the heart surface mapping. We developed the new heart surface mapping display system with the features : (1) twelve heart surface potentials are measured simultaneously at one heart beat, and (2) the heart surface mapping can be displayed in real time. The satisfactory mapping results by several dog experiments were obtained for each of normal and abnormal heart conditions. Especially, the mapping results for the ventricular tachycardia induced by the extrastimulus indicates that the origin of ventricular tachycardia is detectable by use of this system.

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The distance measuring sensor proposed has a lens system based on an astronomical telescope type with the fixed distance between lens L₁ and L₂ to the sum of focal lengths, f₁+f₂. Through the optical system, an object point P_s (r_s, θ_s, Z_s1) in the object space which is measured from the front focal point F₁₁ of L₁ is converted linearly into a real inverted image point P_r(r_r, θ_r, Z_r2) measured from the rear focal point F₂₂ of L₂ in the image space ; that is {(f₂/f₁)r_s, θ_s + π, - (f₂/f₁)²Z_s1}. In order to know Z_s1 of the laser beam spot on an object Z_r2 is to be detected, then the sensor has 1-D CCD placed horizontally so that it makes the pixel line in alignment with the optical axis, as is the case of the laser beam axis. The problem is what aspects of image formation occurs on such an unusual horizontal plane, when a laser beam spot on the object has a finite size of diameter under other conditions such as distance Z_s1, object surface orientation, misalignment of CCD and so on. The paper discusses this problem, examining through spot diagrams and illumination intensity distributions of the image formed by optical computing, by means of ray-tracing method and by applying a multi-point-source model to the beam spot. As conclusions, the peak location of computed illumination intensity for the image corresponds to the theoretical whatever height and form of the peak is affected by Z_s1 and object surface orientation, provided that each alignment in the optical system is ideally perfect.

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This paper describes a development of noncontact sudden stopping device by electromagnetic impulsive force. The developed device consists simply of linear motion movement movable side to side, driving coils setted at both ends of moving and driving electric circuit. The action of the device is as follows. The movement is moving at constant velocity and at the point close to coil surface, an electromagnetic impulsive force interactively produced between movement and coil through which huge current flows from capacitor bank by sudden discharge. Experimental results showed that the velocity of movement can rapidly reduced by the force and that by selecting adequately the electric conditions and timing of discharge, the movement could stop without any contact to the coil surface in a very short time and displacement. As an application of the stopping mechanism, electromagnetic press with sudden stopping control was also developed. The performed blanking tests showed expected results ; namely the blanking punch could successfully stop without any contact when blanking operation perfectly performed.

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