[in Japanese]

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[in Japanese]

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This paper describes a new automatic toroidal coil winding technology for hard disk drive (HDD) and video cassette recorder (VCR) magnetic heads, which realizes high speed winding with a simple mechanism. Because the core windows of these magnetic heads are small (0.5 mm square) and the wire to be wound on the core is thin (0.05 mm in diameter), the winding process is difficult to automate. In the new winding method, called Roller Feed Circular (R. F. C.) Toroidal Winding, the wire is fed along a circular wire guide by several pairs of rollers and inserted into the core window. A toroidal coil winding apparatus for HDD and VCR magnetic heads with a high winding speed of 1s/turn has been achieved using this winding method.

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The application of an industrial robot to a scraping operation has been developed. For this purpose, the feature of a manual scraping operation was investigated, and then a scraping unit which simulated manual action was newly designed to adapt to the robot scraping operation. An image processing system with a monochrome CCD camera was used to determine the scraping position on a surface plate. In order to recognise the red lead pattern on the surface plate clearly, an orange or blue color filter was positioned in front of the CCD camera. The robot and the image processing system were controlled by a personal computer, and consequently, the decisions of the scraping position and the scraping action were carried out automatically, except for taking a red lead print on the surface plate. As a result of scraping done by using this system to a cast iron surface plate which was 200 mm square, a surface plate with 6 μm flatness was obtained.

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This paper describes the software structure of the proposed automatic marking system to shorten the set-up time for large castings and forgings. The system mainly consists of two modules ; the first one is to determine the relative position of the required shape into the workpiece, and the second one is to calculate the NC data for the scribing lines. The proposed software system accepts both the workpiece shape data from the developed measuring system and the geometric model of the required shape from the CAD system. Also it adjusts the position and orientation of the geometric model in the workpiece space, makes the stock removal uniform around the workpiece, and generates NC data for the scriber based on these models. Satisfactory results have been confirmed by some tests.

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This paper presents a general method of free-form surface synthesis using only triangular patches with control points and also a method of embedding a triangular patch in a usual spline surface net. Degree of surface patches is two and their connection is in C¹, though their degree may be higher. In the first part, a geometric condition for connection of triangular patches is established : control quadrilaterals which derived from the control points of the constituent patches are a basis for their C¹ connection. Since they are tightly constrained to adjacent ones, local control of shapes are not so easy as spline nets of four-sided patches. To give more freedom in shape control in using triangular patches, an idea of corrective across-boundary tangent vector is introduced in the second part. For practical use and explanation of this method, smooth embedding a triangular patch in a usual spline net is treated. This is an important technique to produce special shapes which appear in rounding parts of vertices of box type shape. Uses of these two methods are shown by several application examples which are not produced from usual spline nets of surface. And also their evaluation of connection of quality is examined by contour line patterns.

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A new automatic operation planning system for NC lathes is developed. Contour of a workpiece and several possible clamping positions are the input data. The domain between contours of a blank-part and a finished-part is divided into subdomains called blocks. The system assigns to each block several single operations or complex operations by which the block can be removed completely with no collisions between workpiece and tools or turrets. A single operation denotes one tool having a setting angle and a feed direction. A complex operation denotes a permutation of single operations which must be applied successively to one block. The correspondence between blocks and operations is transformed into conjunctive normal form in relation to single operations in order to determine a set of a minimum of single operations for the workpiece. NC tape and the indication of a minimum setting length of each tool from turret are generated together with an operation plan. By editing the adaptability values of operations for block patterns, the knowledge and the experience of users can be reflected to the system.

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A mathematical model is introduced into the excitation process of the impulse response testing, and the theoretical analysis is done. Then the control method of the exciting force is proposed and verified with the experimental results. The results obtained are as follows : (1) By applying Hertz's theory of contact in the analysis, the proposed model is valid for evaluating the characteristics of the exciting force exactly, since the simulation can be shown to describe the experimental results qualitatively and quantitatively. (2) The maximum force can be controlled by the hammer mass, hammer velocity, pad radius and elastic contact coefficient. (3) The duration can be lengthened by the increase of the hammer mass, and shortened by the increase of the hammer velocity, pad radius and elastic contact coefficient. (4) The maximum force and the duration can be controlled more effectively by the hammer velocity and the elastic contact coefficient. (5) The impulse is determined by the hammer velocity and the mass coefficient, and is not affected by the elastic contact conditions. (6) The force ratio (average force / maximum force) can be applied to evaluate the wave form of the exciting force.

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Fringe scanning is introduced to the grating projection system for profiling which has been developed to capture three-dimensional shape of the objective. This revised system can give more dense measuring points and elliminate the influence of the surfacial pattern of the specimen. The final measurement is realized with the error ratio of 0.005 to the covering range. Some discussions are also made on the conventional fringe scanning method using a sinusoidal grating, and a trial with a liquid crystal grating, instead of interference fringes, has proved to be applicable to the fringe scanning method.

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A system is developed and tested for the optical noncontact measurement of displacement which consists of a light source, an objective lens, quadrant patterns and quadrant photodiodes. The principle is based on the detection of contrast variation of projected pattern. In this system one axial method is adopted and such good characteristics are shown as are not influenced by color and inclination of the surface. The dynamic range in the measurement is 150 micrometers with vertical resolution of 1 micrometer. The principle of this method is verified with experimental tests and some applications are tried with good results.

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This paper describes the analytical results and comparison between experiments on the noncontact sudden stopping mechanism of high speed movement by electromagnetic impulsive force. As reported on the 1st report, stopping device of which mechanism simply consists of sliding ram and coils is successfully developed. An electromagnetic impulsive force produced interactively between ram and coil could reduce the ram velocity. Selecting the electric conditions adequately, the ram could stop in a very short time and displacement without any contact. As for the estimation of electromagnetic force, some of theories has been suggested, in this paper the simplified circuit theory which including the influence of secondary circuit (conductive plate of the ram) on the impedance of the primary circuit (coil itself) is taken. The velocity and displacement of the ram can be numerically calculated based on above theory and the results could show the moving mode of the ram actually observed, and the final velocity fairly agrees with the experiments. A stopping control system with the aid of a micro-computer is also developed. This system is made up of sensor of ram motion and data processing circuit. An adequate position from which discharge begins for stopping ram can be calculated based on measured real time data. As the results of experiments performed, the ram stops independent of initial ram velocity within a range of 1 m/s-2 m/s.

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This paper proves that the double points of the coupler curves of planar four-link mechanisms are determined by solving the sixth order equation respect to the angular displacement of the driving link and they are classified into the nodes and the ordinary intersections by using the relative angular displacement between the coupler and driven links. A method for determining the inflection points, the maximum-and minimum-curvature points and the number of rotation of the coupler curves is proposed. According to the numbers of these characteristic points and the number of rotation, the coupler curves are automatically classified into thirty kinds. These curves are illustrated schematically together with their appearance frequencies.

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In some cases, the tooth face of the driven side of rolled gear teeth shifts upward by rolling process and it forms plus pressure angle error. To investigate the formation of the error, the tooth profiles of both driven and follower side and the plastic deformations of the center line of teeth are measured and analysed at several stages in the first cycle of rolling. It is revealed that the tooth is plastically elongated and bent to right and left by the applied load during rolling process, and the plastic elongation and deflection remain at addendum. They cause the pressure angle error. The measurements of profiles, elongation and deflection of teeth after 30 cycles of rolling demonstrate that the pressure angle error of gear finished by roll forming is the results of accumulation of the plastic elongation and deflection at each rolling cycle.

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A contouring EDM consisting of a wire frame electrode, a four-axis-controlled NC ED machine and an automatic programming system “APSET-II” has been developed to improve the productivity of bottom-stopped-machining. This paper deals with a newly developed automatic programming system “APSET-III” which controls the position and attitude of the wire frame electrode in the three-dimensional space. In the APSET-III, electrode shapes are defined in a two-dimensional tool definition co-ordinate system, and the electrode is controlled along drive curves and two directional-vectors. To generate three-dimensional curved surfaces, a six-axis-controlled NC ED machine is needed. To build this method, the authors propose that a two-joint robot arm be attached to the four-axis (X, Y, Z, C) -controlled NC ED machine. The four-axis co-ordinates of the NC ED machine and the rotation angles of the robot arm can be obtained from calculating the drive curves and the two directional-vectors.

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The purpose of this research is to clarify the behavior of ultra-precision diamond machining with an infeed range of approximately 1 to 10nm. The machining behavior and the sharpness of the diamond tool edge were monitored by a cutting noise equipment, the chips checked by observing with a scanning electron microscope (SEM) and the machined surface was observed with an interference microscope. As a result, it was concluded that a mirror-like machine surface is generated at the depth of the machined section which is smaller than the cutting edge radius of a tool. Hence, it is very important to pay close attention to the chip producing behavior. The shear angle was not maintained throughout the chip, as two different shear angles, such as 14 and 17 degrees, were observed. These values were changed by the value of undeformed chip thickness compared with the cutting edge radius. Even during micro infeed ultra-precision diamond machining, the surface temperature of chips during machining is assumed to be rather high, exceeding the melting temperature (approximately 660 deg.) of aluminum alloys.

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In case of grinding by a single abrasive grain for brittle materials, the dynamometer must sense extremely small amount of grinding force. It also must respond to abrupt changes of force at high frequency caused by cracking of ground surface. In this paper, a piezo-electric dynamometer just for grinding by a single abrasive grain was newly developed. From the matching of the position of observed cracks with the output peaks of grinding forces, it was confirmed that the dynamometer satisfied the requirements mentioned above. A new calculation system was proposed for measuring impulsive grinding force from output voltage out of piezo-electric devices. It was applied for a single grain grinding on MgO single crystal. A method of correction for interference between horizontal and vertical components of grining force was also proposed.

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The purpose of this paper is to estimate the fundamental processes of diamond cutting with laser beam. In the experiment, natural single diamonds and polycrystalline diamonds are used. Specifically, the phenomena and figuration of the groove irradiated with YAG laser beam under various conditions, that is, average power, peak power, atmosphere and laser scanning times are discussed. The results are summarized as follows; Diamond is removed by graphitization and vaporization. Graphite which diamond is transformed into is removed by existence of the O₂. Binder of polycrystalline diamond is solidified inside the groove and hardly removed. The groove of which proportion of depth to width is 10 to 1, can be obtained in one time irradiation, and the groove of depth to width ratio of more than 20 to 1 can be obtained in 9 times irradiation. Finally, extending the groove width, 3 mm thickness diamond can be cut.

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Surfaces of die steels for die casting were markedly damaged by the repetition of heating and cooling. Heat checking and erosion in the die surfaces were generated and they deteriorated the life and quality of the die. The effects of shot cycles on the residual stresses in the surfaces of die steels for aluminum die casting have been studied and compared with samples for a simulation test. The residual stress in die and samples were measured using the X-ray residual stress method. The stresses before testing in the die and sample surfaces were large compression stresses which are considered to be caused by the surface polishing. Then the stresses on the die changed rapidly to tensile stress with increasing shot cycles up of 100 cycles. However, each stress change curve of the samples showed no change after a few shot cycles.Inflection points in the stress change curves corresponded to crack initiation and unchanged states agree with crack growth, respectively. It was also found that the stress in the die falls to zero at about 100000 shot cycles. The phenomenon can be attributed to the saturation of crack propagation in the die surfaces and resultant release from the stress.

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This paper deals with the bond removal process in the dressing of resin bond CBN wheel by means of WA stick method. The bond removal process was investigated by observing the wheel surface, and measuring the topography of wheel surface with profilometer and processing graphically the results by computer. The bond removal is considered to be mainly caused by the rolling and cutting operation of the loose WA grains cut by CBN wheel. The bond removal rate changes with the location on the wheel surface. As the result, the depth of chip-pocket and the cutting edge spacings on the wheel surface become unevenly with the location on the wheel surface. A number of shallow and narrow grooves made with the constant interval in the spindle axial direction on the wheel surface reduces the uneven magnitude of the depth of chip-pocket and the cutting edge spacings.

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A new internal finishing process applying a rotating magnetic field generated by electromagnetic coils is created and its finishing apparatus is developed of a non-ferromagnetic tubing, in which a magnetic finishing tool newly developed is rotated by the magnetic action force along the internal surface of a tubing. By this new process, the internal surfaces of the various tubings are finished easy such as a long tubing of about 5m in length or a curved tubing, which are unable to rotate at high speed. From the experimental results, it is found that (1) the new magnetic finishing tool using a permanent magnet is suitable for high speed rotation along the internal surface of a tubing, (2) a magnetic finishing tool is rotated smoothly at the same frequency as a rotating magnetic field, and (3) the surface roughness of 5.2μmRmax before finishing is improved to the value of 0.6μmRmax in the finishing experiment of a brass tubing using the magnetic finishing tool sticked an abrasive belt on its surface.

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The elastic deformation of slicing blade, which is an important factor for elucidation of the outer-blade slicing mechanism, is discussed. This deformation is measured by using strain gauges, and analytical as well as experimental considerations are given for the effect of asymmetric wear of blade onto the deformation. Moreover, attritious wear of grain cutting edges on the blade side is observed. The results are obtained as follows. (1) The deformation extends over the contact area of blade with the workpiece. (2) The deformation is kept until the blade passes through the workpieces cut off, because the blade side is in contact with them. (3) The more asymmetric wear in the cross section of the blade brings the larger deformation, and makes the cutting accuracy lower. (4) The deformation causes the elastic contact between the side face of the blade and the work, which encourages the glazing wear of cutting edges.

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