This paper describes a non-contact type automatic wheel balancer which is operated by photo signals. It consists of driving mechanisms for balancing weights, actuators, power sources, control circuits and photo transistors. The photo transistors receive signals from the photo diodes which are set on a wheel cover. Thus, the rotating balancer can be operated under non-contact condition. Using this balancer, vibration amplitude on a wheel head of a surface grinder can be reduced to less than 0.05 μm in any cases.
It is important to establish a form of the knowledge representation system when we construct an intelligent manufacturing system. A knowledge representation system which compensates for errors of models by experiences has been developed. based on a combination of fuzzy inference and theoretical model methods like equations. simulation and so on. It has been applied in a case study to compensate and to predict for chatter vibration in an operation plan for turning. This paper describes a conception of the knowledge representation for compensating errors of models by experiences and the system to predict, for stability boundary of chatter vibration.
In order to understand the engineering mechanism of a semicircular canal of the living organisms and to set up the similar angular motion sensor, this paper deals with the dynamical analysis concerning a torus tube-liquid model which has a valve in the flow line, combining the theories of momentum of fluid flow, distortion or dislocation of the value, and spatial link motion of a dynamic sensing system. The sensing mechanism of the system is possible to express as a differential equation of the linear vibration type which senses angular acceleration under a large radius of the tube and a large spring coefficient of the valve. The leakage of fluid around the valve increases apparently both the spring coefficient of the valve and fluid friction.
This paper describes an alignment technique applied to wafer stepper for sub-micron lithography. To obtain an alignment signal, a heterodyne interferometer is used. The detection plane is located at the conjugate position on the wafer surface to reduce an error caused by the tilt of wafer surface. Sensitibity of 8 nm is obtained stably with this system. In addition, a software method is applied to compensate the detection errors caused mainly by the differences of a complex amplitude refractive ratio between parallel and perpendicular electric vectors to the plane of incidence. With this alignment system, overlay accuracy of 0.07 μm (3σ) is obtained using target marks etched directly on silicate. Even when the target marks on the wafers have relatively rough surfaces, high overlay accuracy is obtained by introducing the software compensating method. For example, overlay accracy of 0.08 μm (3σ) is obtained using wafers overcoated with grained aluminium layer.
A new optical-heterodyne interferometry alignment technique with diffraction gratings is developed for quarter micron X-ray lithography. To obtain detection accuracy as good as a few tens of nanometers, a phase signal is utilized instead of a conventional intensity signal. The relative lateral displacement between mask and wafer is detected by measuring the phase difference between heterodyne beat signals generated by projecting two laser beams from + 1st-order and -1st-order diffraction directions on the mask and wafer grating marks. The displacement signal is not influenced by gap variation using symmetric optics. A lateral displacement detection resolution better than 10 nm is obtained by the experimental alignment setup. Using this optical-heterodyne interferometry alignment method, a stepper is developed for synchrotron X-ray lithography. Alignment servo control is established by combining a 4-channel alignment system with highly accurate stages. The total overlay accuracies of ±0.07 μm (3σ) are achieved.
As an estimation method of vibration of a pair of spur gears due to the tooth profile error, the Linear Approximated Formula (Abbreviate with LAF) between the each resonance component of vibration and the each harmonic component of the tooth profile error, has been proposed. In this report, for improving the accuracy of approximation, The authors obtained the each coefficient of LAF by the method of least square in 5 dimensional space, which consists of the each resonance component amplitude of vibration and the each harmonic component amplitude of error. Specially, when the total amplitude of error is smaller than 0.6xs, the authors found each resonance component of vibration can also be approximated as linear function of each harmonic component of the error. The authors obtained the LAF in case of some contact ratio though the total amplitude of error is any value. The authors applied the LAF to estimate the vibration of gears with error. The estimated results agreed with the detailed-calculated results better than that of the 1st report.
A position sensing technique by using the light diffracted from a small circular grating is proposed. The circular grating is attached to the surface of the object as a reference for the measurement (reference point). The grating is irradiated by laser light and the elliptical pattern generated by diffraction is measured by a CCD image sensor. By processing the diffraction pattern, the distance from the detector to the reference point is obtained. In addition, it is possible to derive the three dimensional position of the reference point and the inclination of the work surface. The experiments were carried out by using a circular grating of 20, μm pitch and 0.6 mm diameter. The accuracies of the measurements are also discussed.
A hybrid bearing is proposed for high speed machine tool spindle. The bearing composed of two angular contact ball bearings in a series arrangement and has a middle race between double column rolling elements besides the inner and outer race. The third race rotates with keeping a balance of the inner and outer bearing's friction. The spindle rotates at the speed of the sum of the inner and outer bearing's speed. The friction torque of the proposed bearing is less than a conventional bearing's one. But the simulation showed that the bearing has an effective speed range due to the retainer speed and the centrifugal force of the balls. At the critical speed, the friction torque of the bearing coincides with a conventional bearing's one. The critical speed can be rised by use of ceramics balls or small steel balls and an optimum lubricant system. A preliminary experiment of the proposed bearing showed that the final temperature rise of outer race is three degrees C only at 10000 rpm. The experimental critical spindle speed was about 8000 rpm against theoretical 17500 rpm.
The impulse response test method is widely adopted as one of the most practical methods at present for dynamic analysis of complex machine tool structures. In most of cases, the impulsive hammering is carried out with human hand. As a result of this, the magnitude and the direction of excitation force are varied, which causes poor accuracy of dynamic analysis of structures, especially when non-linearity exists in the structure. Besides, it is pointed out that the adjustment of the magnitude and the duration of the impulsive force is difficult in manual excitation. In order to overcome such defects, an impulsive hammering device is developed here which can control the magnitude and duration of the impulsive force with good repeatability. The device consists basically of two masses connected by a coil spring and is driven by an air cylinder. It was proved by experiments that accurate and repeatable frequency responses are obtained by the device developed. The effect of structural non-linearity in impulsive response testing is also analyzed experimentally.
The friction drive has merits that it is able to move the table very unnoisily and fast and that it has a simple structure. In the last report a short settling time could be obtained, but this method was not practical because it was necessary to know the traction characteristics, the moved mass and the frictional resistance of the guide way. In this report, the followings are described ; (1) The DC servomotor and the linear measuring device used in the last report were replaced by the DD motor and the laser measuring system to get higher positioning accuracy. (2) The PTP velocity control for the table movement during the process was newly developed when the traction characteristics and the others were unknown. (3) This velocity control and the mechanical improvement carried the suhnticron positioning accuracy and the same settling time as the result of the last report. (1) The simulation using the kinematic equation clarified the mechanical system movement.
In precision grinding of normal sintered fine ceramics of silicon carbide, silicon nitride and alumina, the effects of grinding conditions on the ground surface aspects and the removal mechanism of these materials are investigated experimentally. As the results, the following facts are clarified. (1) When the cutting area of an abrasive grain or wheel speed is reduced, the proportion of brittle fracture area on the ground surface decreases and so surface roughness becomes small. (2) The surface roughness depends strongly on the trace of brittle fracture. (3) As the cutting area of an abrasive grain becomes small, the removal mechanism of materials changes to plastic deformation type from brittle fracture type. (4) The lower wheel speed is, the larger the critical cutting area which material removal of an abrasive grain is caused by plastic deformation becomes. The value of silicon carbide is larger than the value of silicon nitride.
This paper describes the interaction force (adhesive force) based on the atomic force between clean metal (Cu, Ag or Au) surfaces in ultra high vacuum. The interaction force required to separate the contact between the tip and the flat plane is theoretically estimated by the atomic force based on the chemical bond and Hertz's contact theory. In a theoretical analysis, it is assumed that interaction force between clean surfaces can initiate plastic deformation even with zero applied load. This analysis also takes into account of the dislocation density and the size of shear stress field in the contact zone. The interaction force between the tip having radius of 5-25 μm and the flat plane was measured with an electorobalance in ultra high vacuum. At the same time, the contact area was measured by the electrical resistance of contact region. The results of measurement suggested that interaction force alone could initiate plastic deformation. The interfacial energy of Cu was 3.15 J/m2 given by the relation between the measured interaction force and the contact area. The value of measured interfacial energy agreed well with that of atomistically calculated 4.20 J/m2 by considering chemical bonds. Therefore, this suggested that the chemical bond (metallic bond) was induced at the interface.
In order to develop the film formation method, highly charging, pulverizing and accelerating behavior of agglomerated ultra-fine carbon particles was studied by evaluating the charging values of particles extracted from a film-growth region which consists of plane parallelelectrodes held at high DC voltage in a vacuum of 1×10-4 Torr. As for the particle behavior, the following results are obtained (1) in the applied electric field lower than 1 MV/m, particle charging can be made only by conduction mechanism at facing electrode surfaces, which leads to a reciprocating motion of particle between the electrodes. (2) As the applied field is increased, negatively charged particles which start from cathode are U-turned to the cathode due to yielding of electron emission and the consequent charge-polarity inversion and may be subjected to sequential hopping motion nearby cathode. (3) Initially agglomerated particles can be separated into nearly-individual ones through the above motion. This signifies that such refined agglomerates may attain a subsonic velocity of material and should be deposited in film-like form on cathode corresponding to substrate.
Electroplated and vitrified bonded diamond grinding wheels with unique structure were newly developed which have slots/segments and cooling holes in the wheel working surface for creep feed grinding of ceramic materials. Silicon nitride was ground with 64% of the grinding power required with a conventional wheel. Wear flats of diamond grits on the leading edge and trailing edge of the cutting segments were observed. Residual stresses of the ground surface of ceramics were measured by the X-ray diffraction method. Aluminum reinforced alumina was slightly easier to grind than alumina, but its surface finish was 150% as rough as that of alumina. Carbon fiber reinforced silicon nitride was ground with 44% of the grinding power required for silicon nitride, in the case when the grinding direction was normal to the fibers, but its surface roughness increased by 130% compared with that for silicon nitride. When the grinding direction was longitudinal, the grinding power was 10%, but the surface roughness increased by a factor of four. Specific energy for grinding ceramic composites with the newly developed wheel does not increase with increasing wheel depth of cut up to 8 mm.
This report deals with the newly developed stick-aided loose abrasive dressing method (SLAD method), in which loose abrasives are added to the contact area between CBN wheel and WA stick. The SLAD method is applied to both the normal wheels and the wheels having grooves, which promote the bond removal action in dressing. In point of dressing speed, uniformity of bond removal rate and density of cutting edge distribution, the SLAD method is superior to the WA stick dressing method (WASD method), especially much more effective with a little finer grains of both loose and stick abrasives compared with the chip pocket to be generated. The SLAD method with fine grains is thus applicable to normal wheels with no grooves as well as grooved wheels.
This paper presents a laser patterning technique which was developed for a high power solar cell with a through-Hole contact (THC), a new type structure. The performance for THC submodules is estimated by the numerical simulation based on a distributed equivalent circuit model. It is found that a 10% increase in the maximum output power can be expected using this structure. In order to form this THC structure, optical and three-dimensional thermal analysis of multi-layer structures was performed to determine the selective scribing conditions for each layer of the THC structure. It was found that each layer of the THC structure could be selectively scribed without any significant damage to the electric performances around the holes.
In order to make clear the surface generation process in grinding, successive cutting grooves with a shaped diamond cutting edge is experimentally investigated from the three dimensional viewpoint, analyzing cutting force, groove profile, the amount of pile up, real interference area, residual stock and so on. The basic relations for describing the surface generation curve are first obtained by the experimental analysis. Then the simulation of surface generation curve is carried out. Main conclusions obtained are as follows ; (1) Normal cutting force is closely related to the real interference area. (2) Elastic displacement due to system stiffness is expressed as a linearly delayed function of normal cutting force. (3) Surface generation curve estimated by the simulation is well coincident with experimental one.
This paper describes fabrication of aspheric mirrors for an X-ray microprobe which is available on a scanning X-ray microscopy and a local area X-ray analysis. A new X-ray microprobe optics, which improves spherical aberration of spherical mirrors optics (Kirkpatrick-Baez optics), is constructed by a pair of elliptic cylinder mirrors. Elliptic cylinder mirrors are fabricated by a numerically controlled diamond flycutting machine where tool cutting depth is dynamically controlled synchronizing to tool rotational angle. These mirrors have achieved a contour accuracy of 0.05μm and a surface roughness of 1 nm which satisfies hard X-ray reflecting conditions. A focused X-ray spot of 4.2 × 5.5 μm was obtained at a wavelength of 2.0 Å using synchrotron radiation from the KEK Photon Factory 2.5 GeV storage ring.