In this study, we aim to develop innovative stirring technology (electric field non-contact stirring technique (E.N.S.)) applied abrasive control technique with AC electric field. This technique allows for stirring without contact by applying AC electric field to droplets. We examined observation of fundamental behavior and inside behavior for droplet by AC electric field and investigated the feature of electric field non-contact stirring technique as parameter frequency and voltage, quantitatively. As a result, we found that there is no increase in the droplet temperature, and the motion speed of particles in droplet was accelerated by this stirring technology. This E.N.S was developed to the medical field and medical equipment was developed.

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It is known that the yield stress and ductility of many kinds of metals increase under a high compressive hydrostatic pressure. A part of the authors have developed a cutting tool equipped with a jig for locally supplying a hydrostatic pressure in the vicinity of cutting point to reduce the plastic deformation, and it is proved that such a cutting tool is advantageous to reduce burr formation. In this report, a molecular dynamics simulation of torsion process of aluminum was performed in order to clarify the reduction mechanism of plastic deformation under such a relatively high compressive pressure. As a result, it is clarified that the modulus of rigidity and critical shear stress are increased irrespective of the presence of pore defect.

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On the turning operations, the thrust force causes flexural deformation of the work-piece and adversely affects machining accuracy. Minimization of the thrust force is desirable to attain high dimensional precision in the turning operations. In this study, we proposed the equations of predicting the cutting force to decide the conditions of thrust-force-free turning theoretically. We named them modified equations. The modified equations was applicable to a conditions of low feed rate even if size effect occurred. The calculation accuracy and applicable conditions of the equations was confirmed. In order to further improve the calculation accuracy, the models of the projected area of cut was changed and the discretized modified equations were proposed.

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We describe a technique to improve diamond cutting tools used in nanometer- and micrometer-scale machining and formed via focused-ion-beam (FIB) micromachining. Although FIB irradiation is an effective means of fabricating arbitrary miniature shapes in diamond cutting tools, FIB irradiation induces a non-diamond phase, as well as Ga ion implantation, in the irradiated area. This adversely affects the performance of the ultra-precision machining process, especially in terms of tool life and the quality of the machined surface. To eliminate the affected layer, we applied heat-treatment techniques and investigated the optimum thermal profiles. A temperature of 500℃ applied to the cutting tool provided optimal machining of nickel phosphorus. The tool life was significantly improved, and a tool life similar to that of a non-irradiated diamond tool was obtained. The quality of the machined surface was also improved markedly owing to superior tool wear and adhesion resistance.

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This study presents the micro-/nano-structure machining of hardened steel by means of elliptical vibration cutting equipped with the ultra-precision amplitude control sculpturing method. Machining performance of the amplitude control sculpturing method is investigated, and the limitation in nano-scale machining is explored. In this method, machinable part geometry is essentially restricted by vibration/machining conditions and tool geometry. In addition, a considerable error between the amplitude command and the envelope of the tool trajectory is generated when the slope of the machining part geometry becomes steep. To overcome this error, a compensation method for the amplitude control command is proposed. In order to clarify the machining performance of the proposed technology, experimental investigations are conducted. By applying the proposed method, highly accurate machining of the sinusoidal sweep structure is attained with a machining error of less than 20 nm. The proposed sculpturing method is subsequently applied to the machining of a three-dimensional grid surface, which verifies the feasibility of the proposed amplitude control sculpturing method.

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It is required to solve the problem that micro undulation on the optical lens surface causes distorted shape at imaging. Surface integrity on the lens mold, it is classified roughly low spatial frequency is form error, high is roughness, and middle is undulation. In this study, power spectral density of various geometric waves on lens mold profile was evaluated and examined the effect of micro undulation on imaging.

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This paper reports a result of cutting an acrylic workpiece to form a convex nonaxisymmetric surface, using a round tip diamond tool and a ultraprecision lathe with 3-axis simultaneous control. The maximum and minimum sags of the surface differ by 0.1 mm, which requires the tool to travel back-and-forth in synchrony with the workpiece rotation. Tool overshoots after changing directions left bulges and dents on the finished surface, resulting in a form deviation of 4 μm (P-V). Excluding these particular points, the form deviation was within 1 μm (P-V) and the surface roughness was about 90 nm (P-V).

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Neutron analysis technique using neutron focusing mirrors are highly demanded for basic researches of high tensile strength steel sheets, proteins and polymer materials. Although we proposed a new fabricating method of multi-segmented neutron focusing mirrors using metal substrates, it was difficult to measure surface profile precisely. This paper reports a development of non-contact fast speed on-machine measurement probe in order to measure the fabricated mirror profile and results of the profile measurement of super mirrors deposited on polished substrates.

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In this study, a rotation and revolution type polishing (RRP) method is proposed. With this method, the shape of the polishing tool can be stably maintained, and the surface roughness can be uniformly generated by the polishing velocity distribution in the polished area. This paper discusses the principles of the RRP method, along with the results of simulation of the polishing tool shape. It is also investigated the grinding stone finishing characteristics by a developed RRP unit. The fundamental finishing characteristics with this type RRP unit had been confirmed.

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Large reflecting mirrors are used for X-ray telescope in the astronomical space. The large thin mirrors are produced by molding with diamond turned and polished molds made of electroless nickel. The electroless nickel is amorphous material and can be machined to mirror surface. In order to machine more precisely, it is important decrease the tool wear. In this study, the thin electroless nickel and electro nickel are diamond-turned to evaluate the tool wear and machining accuracies. In the experiments, the nickels are single-point diamond turned and the tool wear ratio and the surface roughness were evaluated quantitatively.

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Dynamic characteristics of guideways influence on not only motion accuracy of feed drives but also stability of regenerative chatter vibration which deteriorates productive efficiency of machine tools. This paper describes the influence of the frictional hysteretic behavior in pre-rolling region on dynamic characteristics of the rolling guideway which is widely used in machine tools. The numerical analysis by using the friction model is conducted. The simple friction model based on Masing rule is constructed to identify the inherent factor which affects to the dynamic characteristics of the rolling guideway. The hysteretic behavior generates the harmonic and super harmonic resonances in the frequency response, and causes the excitation force dependency of the frequency response. The tendency of this excitation force dependency varies only with the change rate of friction in the pre-rolling region. If the change rate of friction was large, the harmonic resonance frequency would be high. Also the compliance at the harmonic resonance increases monotony in accordance with increasing the excitation force amplitude. Finally, the experiment with the roller guideway is conducted to prove the validity of the numerical analysis.

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In plasma spray coating, it turned out that ingredient change of Sb-Cu-Sn alloy by evaporation of a low boiling point ingredient occurs. The optimal ingredient was obtained by adjusting materials beforehand. Furthermore, high adhesion was obtained by the structure modification from heat treatment for the coating, and it was suitable for a tribological use.

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Rolling bearings, which are widely used to support rotating shafts for several industrial machineries, are based on tribology. Tribology is the science and technology of interacting surfaces in relative motion and of related subjects and practices and it is an engineering field that deals with friction, wear, and lubrication etc. In this paper, elasto-hydrodynamic lubrication (EHL), which is the basis of lubrication theory of rolling bearings, are explained with a focus on an introduction to an application of tribology in high efficiency technology for tapered roller bearings that are used in many automotive applications.

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Recently, in Lundberg-Palmgren theory pertaining to the rating life and load rating of rolling bearings, it was found that a P-S-N (Probabilistic Stress-life) curve for the structural fatigue has not been established and an imperfect product law of probabilities without a minimum life in the Weibull life theory has been applied considering as the Weibull slope depends on the strength of materials. Therefore, the Lundberg-Palmgren theory has included various questions. In accordance with the published rolling bearing theories since the Lundberg-Palmgren era till present these questions are summarized. Further, the P-S-N curve and size effect as well as their application principles are discussed.

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Recently, various precision parts are produced by ultra-precision machining. For the ultra-precision machining, the precise rotation accuracy, high-bearing stiffness and thermal stability are required to the spindle of the ultra-precision machine tool. Thus, the water driven spindle was developed in previous research. This spindle has the rotor driven mechanism by water flow and has water hydrostatic bearings. However, in the case of actual ultra-precision machining, the rotational speed changes under the influence of cutting forces. This degrades the surface quality of the workpiece. In order to solve this problem, the mathematical model of the water driven spindle is developed and the rotational speed control system is proposed. Effectiveness of this proposed rotational speed control system was verified by simulation tests.

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Machining accuracy of ultra-precision machine tools relies on the performances of its spindle. In particular, high bearing stiffness is important to minimize the displacement due to cutting forces. For this reason, the high stiffness water hydrostatic spindle was developed and its hydrostatic bearing was designed to achieve the stiffness of 1000 N/μm. However, the measured result of its bearing stiffness is lower than the design value. This may be caused by a change in the bearing gap due to deformation of the spindle by water pressure. Thus, this study proposes the design method to introduce the suitable gap size based on a consideration of the spindle deformation due to the water pressure. As the results of this study, it is confirmed that the modified gap of the spindle can achieve objective bearing stiffness. This paper describes measured result of the bearing stiffness with the modified gap of the spindle.

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A high stiff rotary grinding machine for 450mm Si wafer has been designed and developed. In order to improve a stiffness of the machine, rotary and axial feed motion was built in a grinding spindle. As the result, we can reduce the number of component parts and successfully developed high stiffness grinding machine.

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It is known that a micro-scale texture on surface improves wettability and friction. The micro-scale texture generated by ultra-precision machining process achieves high accuracy and repeatability. In this study, in order to construct micro structure and form a shape by milling at the same time for reduction in a lead time, a non-contact positioning system driven by a giant magnetostrictive element (GME) was proposed. In this positioning system, the GME drives positioner as an actuator and estimates its displacement as a sensor simultaneously. Furthermore, by using estimated displacement for feedback control, hysteresis of GME can be compensated. Therefore, This positioning system can be driven with noncontact and without additional displacement sensor, and installed to the rotational tool. Through the experiment, it is confirmed that the developed positioning system achieves high resolution and hysteresis compensation by self-sensing function.

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Although the measurement of rotational accuracy for ball bearing is described in JIS B 1515, specific measuring techniques and measuring conditions are not mentioned. The authors have studied on the measuring conditions for rotational accuracy and clarified that the rotational speed had an effect on the rotational accuracy. For the users of bearings, it is very helpful to know the rotational accuracy of bearing in real operating speed. On the one hand, to quicken the rotational speed, a larger force will be required to fix the bearing. However, when the gripping force of chuck is large in the measurement, the track surface will be transformed and this has the potential to become different to the primary rotational accuracy of the bearing. Thus, in this research, the authors analyzed the deformation of track surface of inner ring in gripping the inner ring from inside by a chuck using FEM(Finite Element Method). Then, the gripping technique and the gripping force were examined not to have an influence on rotational accuracy in high-speed rotational measurement.

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A lathe is one of the most popular model in the machine tool, and it is used everywhere. CNC lathes aim less labor reduction, high efficiency and high accuracy by automatically generating the relative motion between the work piece and cutting tool by the NC program. However, their accuracy had not been valued more than milling machine (machining center). In this report, in order to recognize the motion accuracy of original CNC lathes again, the ball bar circular motion tests were performed and reported. At the same time, the structure of the feed drive system was reviewed in order to understand the test result of the circular test.

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Silicon carbide is expected as a material for power devices in the next generation. The superior processing technique is important in order to utilize the high performance of silicon carbide. The laser processing is useful method for micro-machining of silicon carbide. However, it is reported that the laser induced plasma has a great influence on machining characteristics. Therefore, the observation of the flow field around drilled hole and the debris behavior on silicon carbide by the 4th harmonic of Nd:YAG laser were experimentally investigated in the viewpoints of the surrounding gas pressure conditions. Moreover, the surface integrity of silicon carbide by the 4th harmonic of Nd:YAG laser was discussed by the observation of the plasma on the specimen surface.

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Poly-crystalline silicon wafers sliced by a wire saw have surface damage such as saw marks and microcracks, and subsurface defects such as lateral cracks, amorphous layers, and residual stresses. In this study, a pulsed Nd:YAG laser was used to recover the surface and subsurface damages in the wire sawed poly-crystalline silicon wafers. Changes in the surface topography and subsurface integrity were investigated by laser probe surface profilometer, laser Raman spectroscopy and scanning electron microscopy. The possibility of crystalline structure reconstruction and surface smoothing by the proposed laser recovery method has been demonstrated. The findings from this study may be used to reduce production cost and improve product quality of silicon-based solar cells.

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We present a numerical and experimental study on the microdrilling of glass with UV laser pulses with the repetition rates from 1 kHz to 20 kHz. Pulse repetition frequency dependency on ablation threshold at the surface of the glass was discussed experimentally and numerically. It was confirmed that the pulse repetition rate influenced heat accumulation and temperature of illuminated area changed.

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In dental treatment, many methods of treatment using laser beam were supposed. However, the effects on oral tissues by laser beam irradiation have not investigated yet. In this study, surface temperature of human dentin during CO_2 laser beam irradiation was measured and alteration mechanism of oral tissue was investigated. As a result, carbonization of dentin surface by CO_2 laser beam irradiation occurred at over 250℃ and evaporation occurred at over 1200℃. Additionally, evaporation volume increased with increasing the surface temperature.

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This study deals with advanced mold obtained by additive manufacturing system. It is known that porosity occurs inside of the shaped form fabricated by powder based additive manufacturing system if the energy density is low. Also, it is predicted that the formed porosity is connected from the upper to the bottom surface of the shaped form. Its permeability is under controlled by adjusting the occurrence of the porosity so as to produce molds with an air vent structure. In this report, laser irradiance conditions such as laser power, scan speed, laser scan pattern and laser layer pattern are considered so as to investigate the effect of porosity occurrence and try to control the phenomenon.

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We have been studying the new complex three-dimensional microfabrication method which has the micrometer-order resolution. When titanium dioxide, the photocatalyst is exposed to UV beam in the metal ion solution, the metal ion is reduced to metal simple substance by photocatalyst. And if UV beam is focused in the solution in which metal ion and TiO_2 particles are scattered, metal deposite at the vicinity of beam waist. Therefore, scanning the beam waist in the solution, the microstructure is fabricated on the track of beam waist. In this report, we investigate the property and the flexibility of this method by fabricating line, sin-curve and lattice structure.

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In additive manufacturing process, when the consolidation condition of metal powder is not suitable, the squeezing blade for depositing the metal powder strikes to the consolidated structure due to the decrease of surface quality on the consolidated structure. In this study, the surface of consolidated structure is evaluated by the acceleration measurement during additive manufacturing process. As a result, the output waveform of the acceleration was found to be correlated with the surface properties of consolidated structure.

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There is a great demand for the development of welding techniques to join thin stainless sheets with the reduction of size and weight of the electronic components. In this study, we searched for butt welding conditions of SUS304 0.2mm thickness using a fiber laser and then found the welding conditions which have no burn through and complete penetration. As a result of investigating the joint properties, tensile tests indicated good joint properties of the welded sheets, as evidenced from the strength of approximately 90% when compared with the base metal and ductile fracture as same as the base metal. We found that the shield gas is appropriate way to supply and prevent from oxidation of welded sheets. However, we could not obtain the reproducibility of welding as evidenced from apparent dispersion in strength under the same conditions.

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Glass materials are widely used in many products such as optical components and semiconductor devices. In these products, precision joining technologies of glass are required to manufacture small and complicated shapes. The laser welding method can joint glasses without an intermediate layer. However, the absorption of laser energy started by nonlinear phenomenon at a focusing point with an ultra-short pulsed laser, and the change of temperature is influenced by the focusing condition. Therefore in this study, effects of focusing condition of laser beam on micro-welding characteristics of glass were experimentally investigated. The usage of object lens with the spherical aberration correction could create a large molten area even at the same pulse energy. It was clarified that an optical system with the spherical aberration correction led to stabilizing the shape of molten area, which resulted in higher breaking load of weld joint at the same pulse energy.

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We can only form straight hole in a material by the conventional method, drilling and laser machining etc. First aim of this study is to develop 3D laser drilling method of acrylic resin. The feature of the method is using a steel ball and a laser beam. The steel ball was on acrylic resin board and heat by laser beam in an experiment. When acrylic resin was melt by the heat ball, the ball entered into the resin board and pass it through. Furthermore, we moved or rotated the acrylic resin board during the laser 3D drilling. As a result, we were able to accomplished 3D laser drilling of acrylic resin. On the other hand, Second aim of this study is to develop inner machining method of acrylic resin. We developed a new one in this paper. The feature is using Ultra-short pulsed laser processing and thermal process. A lot of micro crack were formed in a acrylic resin by the focused laser. Then, in thermal process, we found out a lot of micro crack were continued and expanded 3D space.

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Cutting test and analytical prediction based on regenerative chatter theory are the methods to analyze the stability of machine tool chatter. However, the testing procedure is complex and work material is wasted, and prediction is based on fixed machine dynamics in frequency domain. In this paper, occurrence of regenerative chatter is examined by using an electromagnetic loading device. In the test, spindle displacement is feedback to the loading device with a process model.

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The spindle with double face contact nose has come into wide use to make high the accuracy and speed of the machine tool spindle system. The weak point of the tool holding system of this spindle system is that the damping performance is low, although the static stiffness is high. Therefore the dynamic stiffness of the system has been improved by the tool shank. However, the cost of this system is high, since the each of the tool shanks must have a mechanism to generate the high damping characteristic. In this paper, to resolve this problem, we consider the special mechanism incorporated in the spindle to make the damping high without making the static stiffness low. The following results were obtained. (1)We could propose a simple mechanism with disk spring inserted into the bottom of the tapered hole of the spindle. (2) The damping can be improved by the proposed mechanism keeping the static stiffness nearly constant.

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Location of support points has a great influence on the vibration characteristics of machine tools in low frequency. A method for increasing the lowest natural frequency of a machine tool is proposed. For the verification of this method, the natural frequency of a machine tool was measured with different numbers of supports. As expected in the model of the stiffness of support, the measurement result shows that the machine has higher lowest natural frequency with greater numbers of supports. In addition, the residual vibration caused by the Z axis feed drive was also reduced at the same time.

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A vibration due to the interaction of feed drive systems with the machine tool structure has a great influence on the relative position between tool and workpiece. In this study, a state space equation model of NC machine tool which considers the vibration of the machine tool structure is proposed. This model also considers the torsion vibration of the bed, friction and vibration of feed drive mechanism of each axis based on analyzed vibration mode of the machine. Procedure of parameter determination is also proposed. Frequency response and vibration mode, feedback position, table position and the relative position between table and head are simulated and compared with the actual ones. As the results, it is confirmed that the proposed model can adequately predict the vibration mode and circular trajectories.

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The motion accuracy evaluation method of five-axis machining centers is not fixed enough though their demand has increased now. The discussion about the ISO standard concerning the accuracy test method of five-axis machining centers started in 2006. In the discussion, the cone frustum cutting test in NAS979 is improved as five-axis simultaneous interpolation motion described in ISO10791-7 "Accuracy of a finished test piece", and similar test using a ball bar is also described in ISO10791-6 "Accuracy of interpolation motion test". These two standards are scheduled to be issued as International Standards in 2015. In this report, The evaluation methods and problems of interpolation motion accuracy test simulating the cone frustum cutting that described in ISO10791-6 are considered.

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Five-axis machining centers accuracy analysis is done by cone frustum cutting test. Five-axis machining center's geometrical movement is solved by using form-shaping-function. In this research, I was verified what is the relationship between half apex angle and inclination angle of cone frustum would affect the five-axis machining center's each axis. C-axis showed characteristic movement when half apex angle and inclination angle are equal. It is found from the analyzed results that movement of each axis of the five-axis machining center is changed by the magnitude relation of half apex angle and inclination angle.

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This study paid attention to the quadrant projection of the rotary axis which has a big influence on the machining surface in the simultaneous 5-axis machining. This paper presents research on new measurement movement to divide the quadrant projection of a rotary axis and the linear axes into by moving two rotary axes at the same time. And the characteristic of the quadrant projection was confirmed by comparing the machining result with the result of a measurement. Then, we examined a method to reduce the influence that the quadrant projection gave to a machining surface using the characteristic. The effectiveness was inspected by machining.

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A new CNC Lathe with tandem tables driven by linear motors has been developed to machine the non-axisymmetric curved surface by turning. To realize this machining, the high speed motion is a key factor for the X-axis table. The linear motor is equipped to drive the tables with the acceleration of more than 10G. In this motion, as the inertial force cannot be ignored, the tandem is applied to cancel this inertia force. In this report, the fundamental specification of the developed CNC lathe is introduced and the effects of canceling the inertia force by the tandem tables' motions are evaluated.

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This study is aim to establish of the drilling method for achieve high quality, high efficiency and long life in order to drill the through-hole with diameter of 1 mm to the glass plate using an electroplated diamond tool. In previous studies, we succeeded the development of the tool which is satisfied with the hole quality and the drilling efficiency. This report investigated the cause of the drilling force increases with increasing of the drilling hole in order to extend the length of the devised tool life. The result is shown below. The cause of the increasing of the drilling force was abrasion of the abrasive grain. The grain abrasion was suppressed by the improvement of the drilling condition, and the tool life was long.

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This paper deals with the wear characteristics of grinding wheel on spiral ultrasonic assisted grinding of sapphire wafer. The spiral ultrasonic assisted grinding (SUAG) using vitrified diamond grinding wheel have been carried out and sequential changes of the wheel working surface topography have been observed during grinding process using a scanning electron microscope with four electron probes (3D-SEM). The obtain results show that the wheel wear in SUAG process is reduced compared with conventional grinding (CG) process. Especially, these results are closely related that a maintaining of good wheel surface in SUAG is demonstrated based on quantitative evaluation using number of grain cutting edges.

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Form accuracy and smooth surface is required in precision grinding. And the form accuracy and surface roughness are improved year by year. However, the more the surface roughness becomes smooth, the more the grinding marks become remarkable. The grinding mark deteriorates the uniformity of ground surface. In this study, relationship between the uniformity of non-axisymmetric aspherical ground surface and grinding condition is analyzed theoretically. As a result, it is found that there are optimum grinding conditions.

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PCD is expected to apply to a wear part or a sliding part because PCD has superior mechanical properties. Therefore, high efficiency and high quality method of processing PCD is required. The authors proposed the high-speed constant-pressure grinding that is processing method to increase the grinding wheel speed with constant-pressure cutting. In this study, the grinding experiments were conducted using a vitrified bond diamond grinding wheel and metal bond diamond grinding wheel. In this report, the effects of bonding material on the grinding characteristics of PCD and including the effect of grinding heat is described.

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In internal grinding with the high aspect ratio wheel to grind a deep hole, the shape error of the ground workpiece increases due to the elastic deformation of the grinding wheel. In this study, we experimentally analyze the shape error of the ground workpiece. The shape error of the workpiece is estimated by integrating the measured wheel wear and the elastic deformation calculated from the measured normal grinding force with a piezo force censor. It is confirmed that the shape error of the ground workpiece can be estimated with considering the elastic deformation of the grinding wheel and the wheel wear.

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In the lapping of sintered SiC with diamond slurry, many scratches are generated to the directions at random. The surface texture of SiC depends on its mechanical functions. When the motion of workpieces is controlled in the mutual lapping, the unidirectional texture generated on the lapped surface having the special characteristics. Most evaluations of machined surface are carried out based on some surface roughness parameters except Angular Spectrum in ISO25178. The new evaluation of finished surface of SiC by lapping is proposed based on the surface topography in this study. As a result, the proposed evaluation method of surface has correlation with a surface function rather than practical geometric evaluation parameters.

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The micro patterning on cylindrical surface is conventionally carried out by the electrochemical machining, the chemical etching, the cutting and so on. However, there exist some problems in machining dimensional errors and tool lives. On the other hands, blasting is expected as one of micro fabrication methods and progress to apply for machining of hard and brittle materials. The purpose of this study is to develop the micro blasting technique for patterning of micro herringbone grooves on cylindrical parts. Then, machining characteristics in blasting of rotating workpieces are experimentally investigated, analyzing the stock removals, the burr heights and the groove shapes. In addition, micro herring-bone grooves are patterned on spindle surfaces by blasting and the performance of herring-bone bearing is investigated.

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This study proposes a new polishing method using MCF (magnetic compound fluid) slurry for ultra-precision and high-efficiency finishing of sapphire wafer. A semi-fixed abrasive tool called "MCF wheel" was in practice produced by putting MCF slurry on the outer surface of ring-shaped permanent magnets. In this paper, polishing experiments using MCF wheel have been carried out and sequential change of polishing temperature have been measured by infrared thermography during polishing. The obtained results indicated that the polishing temperature are closely related to the wheel working life in terms of the surface roughness and the material removal rate.

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It takes a lot of time to process the single crystal sapphire substrates for LED, because it is hard process material and its diameter trend becomes larger for productivity improvement. Therefore we have attempted to develop the novel processing technologies that enhance the process ability of sapphire substrates. In this paper, we described the results pertaining to the evaluation of the novel lapping process for sapphire substrates. It was confirmed applied AC electric field lead to enhanced removal rate, and the surface roughness was improvement.

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It takes a lot of time to process the single crystal sapphire substrates for LED, because it is hard process material and its diameter trend becomes larger for productivity improvement. Therefore we have attempted to develop the novel processing technologies that enhance the process ability of sapphire substrates. This paper describes the results pertaining to the evaluation of sapphire substrates polishing. It was confirmed the applied AC electric field leads to enhance removal rate, while the surface roughness was comparable.

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It was clarified that the internal magnetic abrasive finishing process of a bent tube using the magnetic particles is effective. However, it is difficult to finish internal surfaces of thick bent tubes, because magnetic force (finishing force) weakens when the thickness of tube becomes thick. In this research, the internal magnetic abrasive finishing process of a bent tube using the magnetic tool is proposed. And the experimental device and the magnetic machining tool with flexibility were developed. Moreover, the finishing experiment of a bent tube was carried out and the usefulness of this processing method was examined.

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The material removal mechanisms on the SiO_2-CMP have been studied to develop new slurries and polishing pads for the advanced ULSI devices. We focus on the chemical reacted layer at the surface of SiO_2 film because formation of the layer is effected by pH of the slurry. Relationship between the MRR (Material removal rate) and chemical reacted layer was suggested by the results of the CMP tests and SEM observations at various pH conditions from 7.5 to 12.5. The size of the SiO_2 fine particles increase as the higher pH reason because the surface of the SiO_2 fine particles might be changed during the CMP. In our report, we discuss the material removal mechanism based on the experimental result of the SEM observation on the SiO_2 fine particles.

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