In late years, sapphire single crystals have been applied in optical flats, windows, filters, covers for electric cells, lenses, as well as substrates for LED. In the production process such as the LED, fixed-abrasive multi-wire saw is often used to get a sapphire wafer efficiency. And in this process, sapphire ingot have been demanded a slicing accuracy. Fixed-abrasive multi-wire sawing process has been classified by using a resinated diamond wire saw or an electroplated diamond wire saw. In this paper, we report the case of slicing sapphire ingot (2inch, 3inch) with electroplated diamond wire, and introduce their high slicing performances.

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A new device which can supply coolant from center hole of grinding wheel to a grinding point utilizing the spindle through supply system of machining center was developed. Thin plates of steel were tested, and temperature field observed from the back side of the grinding point and surface finish was evaluated. Measured temperature using this device was lower than the case with the conventional outer coolant supply. On the machined surface, there was a very few affected layer using this devise.

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The cam is one of the automotive engine parts. As for material of cam, FCD700 is used. It is spheroidal graphite cast iron. As for spheroidal graphite cast iron, high mechanical strength and high toughness is more excellent than gray iron. Its shape is an oval, and it has the circular arc portion and the straight line portion. Generally, the cam is ground in finish machining. However, when those two portion are ground, residual stress and cutting resistance become problems. In this study, the high speed grinding of cam material was carried out step by step grinding, and residual stress and cutting resistance were measured.

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Alumina-Zirconia composite ceramic has some excellent properties as wear resistance and fracture toughness. However, this material is hard to grind with high efficiency or high grinding ratio. In this paper, experiments are carried out to establish the total high efficiently grinding including truing and dressing conditions. The main results obtained are as follows: (1) It's easy to true a grinding wheel using proposed method, but cutting edges are flatten. Therefore, high normal grinding force happened and increased rapidly with an increase of accumulative removal volume of ceramic. (2) Dressing process is necessary to remove the flatten cutting edges and bonds. And, it is clear that the optimum dressing condition exists. (3) Grinding at higher stroke speed exhibits lower grinding force and higher grinding ratio.

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Micro ball end milling is an established process for manufacturing of three-dimensional and micro components. For high-precision machining of fine shape, it is important to clarify the form of micro ball end mill cutting edge wear. In this study, using an end mill, cutting experiments were carried out of hardened steel. Cutting experiments were conducted by varying rotation speed of spindle, and cutting edge wear were evaluated. As a result, it was found that there are suitable rotation speed of spindle to reduce cutting edge wear.

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This paper describes the influence of the radial depth of cut on the characteristics of the finished surface roughness in the micro end milling for die steel. The experiment was conducted by using end mills of 1mm or less in diameter, and examined the relationship between the cutting force and finished surface roughness under various depth of cut. It is found that cutting force altered in direction the surface roughness is significantly increased when cutting depth become more than tool radius.

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Co-Cr-Mo alloy is one of the most difficult-to-cut materials because of its higher strength at high temperature. Co-Cr-Mo alloy have been used in wide variety of industrial fields, and have begun to apply artificial joints in recent years. Although widely used, the cutting characteristics and the machined surface properties have yet been studied enough. The cutting characteristics and machined surface properties have been investigated with several cutting conditions in this study.

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A new simple method for evaluation of adhesion in cutting is proposed. Instantaneous directions of the chip flow and coefficients of friction are calculated from the dynamic cutting force. Adhesion in cutting is evaluated by the adhesion index which is the multiply of the deviation of the directions and the coefficients. We also conducted turning tests of a Ti-6Al-4V alloy bar with cemented carbide tools and evaluated their wear. The deviation of the chip flow direction and the instantaneous frictional coefficient in intermittent cutting was about twice as large as in continuous cutting. The tool wear rate had the correlation with the adhesion index in a low cutting-speed range.

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Characteristics of brittle fracture on tungsten carbide in the milling process are discussed. Milling tests are performed with different roughness of multi-crystal diamond coated tungsten carbide ball endmills (R0.5) to observe the effect of cutting edge roughness on brittle cracking. In milling tests, the surface profiles are changed with roughness of diamond coat and surface roughness growth with roughness of the diamond coat. It is conclued that the tool edge roughness affects on the brittle cracking.

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In this study, cemented carbides which had different Co contents were cut with the PCD tool and the cBN tool, and tool wear was investigated. The main results obtained are as follows: (1) In turning with the PCD tool, the more the Co contents of work material increases, the more tool wear increases. (2) In turning with the cBN tool, the more the Co contents of work material increases, the more tool wear decreases. (3) The tool wear in cutting of the cemented carbides with the PCD tool progressed with cutting of the binder between WC particle and Co. (4) The tool wear progress in cutting of the cemented carbides contained large Co contents with the PCD tool was similar to one with the cBN tool.

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This study deals with cutting properties of titanium materials in milling by an end mill with small diameter. Titanium is well-known as a difficult-to-cut material in conventional cutting. However, the cutting properties are not sufficiently made clear when the micro end mill less than diameter of 1 mm is used In this study, mainly the tool wear and the cutting force in micro end milling of Ti-6Al-4V have been experimentally investigated. As the results, it was found that the tool wear growth was not much when the cutting speed was changed to 200 m/min from 50 m/min. Furthermore, the cutting force was decreased at high cutting speed and in wet cutting.

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Titaniunm alloy is mostly processed by cutting, but it is difficult to machining because of its mechanical properties. Tool life in cutting of Ti-6Al-4V alloy can be extended by mist cutting method, that is, Minimum Quantity of Lubricant. In this study, cutting of Ti-6Al-4V alloy by Air-Blow cutting method and improved cutting tool life.

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Micro cuttings of sapphire are presented to finish crack-free surfaces in scratching and milling. The indentation tests were conducted to measure the critical stress, at which cracks initiate and propagate in subsurface. Then, the cutting processes of r crystal plane are discussed with measuring the cutting forces and observing the surface finishes. The cutting process depends on the cutting direction for r crystal plane and anisotropy is observed in the critical depth of cut for finishing crack-free surface. The critical depth in the cutting direction toward a-axis is much larger than that of perpendicular cutting direction. The surface finishes on a, c and r planes are compared in milling with the inclined cutter at 45 deg in the feed direction. Although the surface finish on r crystal plane is better than other planes, the removed chip is adhered on the surface in cutting with the water supply. The surface finished is improved in milling with lubrication.

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In this study, the machinability of fire-resistant magnesium alloy was investigated in orthogonal cutting and turning. The main results obtained are as follows: (1) Saw tooth chip and crack type chip were generated in orthogonal cutting. And the surface roughness became worse when the crack type chip was generated. (2) In turning, both principal force and feed force didn't decrease and kept almost steady value even if the cutting speed increased.(3) Under this experimental condition, the surface roughness didn't become worse in turning with PCD tool and cemented carbide tool even if depth of cut increased.

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CFRP (Carbon Fiber Reinforced Plastic) has higher specific strength, modulus of elasticity and so on. CFRP is, however, well known as difficult-to-cut material which has very strong physical and mechanical characteristics. Drilling technique of combined material which are CFRP, Aluminum alloy and titanium alloy is currently carried out in aviation and automobile industries. In this research, we tried to make high accuracy drilling process by helical movement method of cutting tools on the CFRP-aluminum alloy and -titanium alloy plates. DLC-coated cemented-carbide ball-nose end mill is suitable to drill out the CFRP-aluminum alloy plate. It is possible to make drill holes on the CFRP-titanium alloy plate by same cutting conditions which are cutting speed of 50m/min and revolution speed of 600mm/min with DLC-coated tool.

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Optimization of cutting conditions is expected to have a big effect of reduction the cost of aircraft parts. Because aircraft parts are generally produced by cutting of difficult-to-cut materials such as titanium alloy 6-4. We adopted Taguchi method to the production with optimizing the combination of the cutting conditions and the cutting tool geometry. As a result, the cutting amount increased 5 times as that of manufacturer recommendations. In addition, we could keep the cutting quality during the process. These results indicated clearly the reduction of tool and processing cost.

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Generally, wet cutting which supplies a lot of cutting fluid is adopted as cutting of the titanium alloy used at the parts for medical equipment or airplane. When near-dry cutting is used as this processing, it will be easy to cause tool damage and stock removal rate and machining accuracy will worsen. So, in this study, it is target at clarification and development of the reduction method of the generating mechanism of the cutting-edge fracture in cylindrical cutting of titanium alloy. This pepper examined the basic examination result of the cutting performance, such as a cutting force, a coefficient of friction on a rake face and tool wear when using Wet cutting and MQL(Minimum Quantity Lubrication) cutting of the Ti-6l-4V material with a cemented carbide.

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Recently, the demand is great for the environmental friendliness and the improvement of fuel efficiency in the automobile industry. Therefore, it is indispensable to make parts more lightly and compactly. To make these parts thinner and more complexity, the usage of extreme-low-carbon steel suitable for the plastic forming has increased. Especially, SAPH370 that has 32% or more elongation rate is the most difficult material to control chips in our products. The chip curl diameter and its thickness are important factors of the chip controllability. But, the relationship with the cutting conditions has not been clearly. So, to improve the chip controllability in lathe cutting of SAPH370, we studied the influence of the cutting conditions on the chip curl diameter and its thickness.

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The nickel-based super heat resisting alloys including Inconel 718 are used for the part of aircraft engine and gas turbine due to their corrosion resistance and the excellent mechanical properties at high temperature. However, these materials are well-known difficult-to-cut materials. Because the usage of the heat-resistant alloy increases in aircraft industry and energy industry, effective cutting technologies are demanded. We propose innovative machining technologies for these metals by using small size ball-nosed end mills under condition of high speed rotating and high speed feed rate. In this paper, we wish to report on the results of high speed milling for nickel-based super heat resisting alloys.

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Relative displacements between tool and workpiece (e.g. chatter vibrations) shorten tool life and deteriorate machining accuracy. These vibrations are determined with cutting forces and static or dynamic compliance of cutting tools, a workpiece or machine tools. In these values, static or dynamic compliance of a workpiece has a feature to change during a machining process. Thus, we propose an algorithm to generate a material removal process which considers dynamic compliance and natural frequencies of workpiece by using FEM (Finite Element Method) and eigenvalue analysis. The generated material removal process is compared with a conventional material removal process by executing a numerical experiment. The result shows that the generated material removal process can decrease dynamic compliance of workpiece during a machining process.

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Generally, it is inevitable problem that processing accuracy decreases after workpiece position is changed. And this workpiece attachment error affects the accuracy of final shape. Therefore, exact and careful operations to change the workpiece position is required of operators. The purpose of this research is to construct the system that improves the efficiency of the operations by combining laser displacement sensor to 3 axis NC machine tool. After workpiece position is changed, 3D shape data of the part that has already been processed is obtained by laser displacement sensor, and workpiece attachment error is detected by matching the data to target shape. Next, the coordinate of NC code is transformed to correct the attachment error and feed back to following processing. In this research the system was constructed and a 3D model was processed with the system. And workpiece attachment error was evaluated.

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In this study, we develop a new method for bonding electronic boards of highly integrated semiconductors. As layering technology for high integration of semiconductor silicon substrate, it is necessary to give fine ditch to thermosetting resin. In this study, a small 3+2-axis NC machining has been developed, and its origin detection method based on non-contact measure and a method to correct tool path on the machine ware developed. By cutting the resin to change the angle of the tool and observing the shape of the fine ditch produced, we found the best tool angle to generate a ditch.

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This study describes a new machining strategy to make regularly aligned micro dimples by a micro ball-end milling process employing a patch division milling technique which can make well aligned cutter marks on the machined surface. First the curved surface which was formed by triangle pyramid employing the method of triangle pyramid patch division milling technique which can substitute for the method of machined surface patch division milling technique is described. Then, it is shown that regularly aligned micro dimples on the triangle pyramids (accumulated truncated triangle pyramid) can be successfully formed.

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The micro-channel chip (micro total analysis system) attracts attention in the medical field. Generally, the photo lithography technology used in a semiconductor manufacture process is used as the manufacture method of a micro-channel chip die. However, there are many manufacturing processes like fabrication of a mask, the photo-resist application to a substrate, expensive facility of a clean room etc. So, this study examined how to form a fine groove by cutting with a micro endmill. This report examined experimentally the processing conditions which should be developed. As a result, relation between cutting conditions and form accuracy, surface roughness of fine groove, were clarified.

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Ball end mill is widely used in machining the die which has the three-dimensional shape. In ball end milling, cutting speed varies at each position of cutting edge. In addition, interference state between tool and workpiece varies every moment during machining. Thus a cutting phenomenon in ball end milling is so complicated to explain tool failures. This study attempts to make clear the tool failure mechanisms of ball end mill. In this paper, generation mechanisms of tool failures were discussed on basis of experimental results. As a result, it was found out that large-scale chipping always occurred at tool life and that cutting speed has a large effect on the chipping.

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In a contour parallel toolpath used often in die machining/ part machining, a hollow-shaped machining error tends to appear at the overlapping part of tool entry and exit. In this study, we suggest the modification method of the tool exit in order to reduce such a hollow-shaped machining error. By an experiment, it is shown that a machining error is decreased compared with a conventional tool but it is still not sufficiently small by this method.

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It is necessary to develop a high-aspect-ratio microdrill method with a diameter of 0.2mm and a depth of 4mm (aspect ratio 20) that can be applied to the fuel injection nozzle of gas turbine. In this study, the drilling conditions from viewpoints of thrust force and tool wear for the austenitic stainless steel are determined. The effects of ultrasonic vibration cutting of the microdrill are verified to measure tool wear.

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The paper presents an analytical model of the tool wear prediction in drilling. The flank wear progress on the end of the lips, which finish the surface in the hole, is predicted with the cutting force and the temperature. The wear characteristic equation is applied to the tool wear prediction with determining the stress and the temperature distribution on the flank wear land. The tool wear tests are conducted to verify the analytical prediction with the wear model.

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Effects of external hydrostatic pressure on machining property of glasses are reported in this paper. Orthogonal cutting tests of soda-glass and quartz glass were conducted using a specially designed high pressure machining tester. It was found from the experiments that hydrostatic pressure exhibited similar effects on the critical depth of cut both for soda glass and quartz glass. However, its effect on roughness of finished surface in ductile manner machining were different for these glasses. The roughness of soda glass did not depend on hydrostatic pressure, but that of quartz glass became smoother when hydrostatic pressure was applied. Also, hydrostatic pressure affected the specific cutting force of soda glass, whereas it did not affect that of quartz glass.

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The demand for usage of ductile cast iron is increasing. Because ductile cast iron is superior to gray cast iron in mechanical properties. Previous studies show using a CBN tool makes high-speed cutting possible in gray cast iron. But in ductile cast iron, high-efficiency cannot be achieved because of excessive flank wear. Thus, in this study, it aimed at clarifying the wear factor of the CBN tool in high-speed cutting of ductile cast iron. In our previous report, it found out that the wear produced in ductile cast iron was accumulation of small chipping. Also, it was clarified that the wear mechanism was subject to a mechanical factor, because the wear position and size on cutting edge changed by tool engagement and disengagement conditions. Then, in this paper, the effect of tool material property on tool wear during high cutting speed was examined. As the result of experiments, it was found out that it was possible to decrease the chipping using the CBN tool with high transverse-rupture strength.

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This study describes scanning probe microscope(SPM) analysis of cBN thin films with a magnetically enhanced plasma ion plating (MEP-IP) method. The structure of films was investigated by means of XRD. SPM was observed in the current mode. As a result, the current distribution of the film where cBN exists together had the difference of the contrast corresponding to the ruggedness on the surface, and, on the other hand, didn't had the difference of the contrast for the film where cBN is not included.

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This study aims to investigate the formation mechanism of Belag and the adhesion situation to the tool. After brief cutting times, formation area was observed by TEM. Belag prevent direct contact to tool without reactive zone at a short time within 10 second. In this study, the effect the voltage on Belag formation was investigate using by constant voltage power supply. consequently, the tool wear was suppressed by impressing it in same discretion of the current as the thermal electromotive force.

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In these days, there are increasing demands for high precision and high efficiency machining in the industry of optical parts. The purpose of this research is the speed-up of shaping with a single crystal diamond tool. In order to investigate the effect of cutting speed on cutting errors, a cutting experiment is conducted under several cutting speeds. As a result, periodic cutting errors appear on workpiece surface in cutting speeds above 10m/min. The pitch of the error does not depend on the cutting speed. In order to investigate the cause of cutting errors, the tool motion is compared with the workpiece profile. The pitch of the cutting error corresponds to that of a periodic component in the tool motion. The pitch of the cutting error increases when a lubricant is used.

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Multi-tasking machine has milling capability and turning capability. Therefore, Multi-tasking machine has become widely used in order to enhance productivity. Especially, 5 axis multi-tasking machine is applied to multiple faces machining in single setup and contouring thanks to rotary axis. This paper presents a method of high efficiency front face grooving by using 5 axis multi-tasking machine. The method aims to generate high aspect ratio groove on the face with inclining the cutting tool. We carried out the front face grooving on the nickel base alloy with ceramic insert at the cutting speed of 1000m/min. From the result, the metal removal rate attains 150cc/min.

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In order to achieve flexible machining operations, a system called Digital Copy Milling (DCM) was developed in our previous studies. The DCM is the original concept to achieve the direct milling operation, which does not require any NC program to perform machining operations, and has functions to change cutting parameters for adaptive machining process control and cutting trouble avoidance. In this study, Voxel representation of removal volume is introduced to enhance the functions of the DCM. The property of Voxels can be utilized for the tool feed speed and posture control.

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The chatter vibration excited during machining process deteriorates quality of workpiece surfaces, and accelerates tool wear. In addition, it often takes long time to find chatter-free cutting conditions. Therefore, a new control system is developed in the present research for searching the optimum spindle speed at which chatter stability is maximized. The developed system detects the chatter vibration that occurs during machining process using a vibration sensor, and then optimizes the spindle speed automatically in real time. This report presents an overview and an application of the developed system.

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Quadrant glitches are one of the causes debased the machining accuracy in NC machine tools because those leave streaky marks on the machined surfaces. In this study, a compensation method of quadrant glitch by using friction force estimated from command values is proposed. When the circular trajectories are precisely observed, it is found that the amount of the preload in the ball screw affect the height and shape of quadrant glitch curves at low feed speed. In this study, a method for compensating two peaks observed in quadrant glitch curves due to the change of contact points between balls and groove of a ball screw is proposed. It is confirmed that the developed compensator can decrease the quadrant glitch in a wide feed speed range through simulation and experiment. Thus, the proposed compensator can correct the quadrant glitches in high accuracy.

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In this study, we analyzed it about the motion error of High precision MC. We used a simulation model and the measurement result of the machine for analysis. High precision MC has the friction-less drive system that combined a hydro static guide way with linear motor drive. In addition, the motion error measured the relative displacement on the X-Y plane between the spindle-table by a grid encoder and we used the Offset-Path Method to do and calculated it. As a result. 1. In a diamond-shaped command trajectory, a motion error to produce by the dynamic-characteristic difference between the axis was confirmed at the corner. 2. We confirmed a motion error at the corner part like the experiment results by simulation. In the case of the velocity-loop proportional gain setting that synchronized the difference in dynamic-characteristic difference, the motion error to be caused by the difference in dynamic characteristics was not seen.

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The multi-points vibration measurements at a bearing support for a ball screw and a ball screw driving mechanism and a moving table by laser displacement meter and an accelerometer have been applied to evaluate the vibration source of machine tool. The vibration of each measured point gives important characteristics of the table motion. Both FEM analysis and FFT of the motion are applied to detect the week points of the driving mechanism. Based on this, the distributions of the acceleration amplitude at the ball screw, table behavior at the table motion in each frequency element are evaluated along with the axial direction. In this report, an experiment method is introduced and experiment results are reported.

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The static rigidity of a rotating spindle in the radial direction is investigated in this research. A magnetic loading device (magnet loader) generates the electromagnetic force and attracts a dummy tool attached to the spindle. However, the eddy current is generated in the dummy tool with the spindle rotation and reduces the attractive force at high spindle speed. Based on the FEM analysis, the designed tool was manufactured and tested. The test result shows that the designed tool successfully reduces the eddy current and recovers the attractive force. By using the magnet loader and the dummy tool, the spindle rigidity can be measured when the spindle rotates with a speed up to 12,000min^<-1>.

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This paper proposes a method for the identification of geometric deviations in five-axis machining centers by measurement method based on workpiece coordinate frame. The ball bar system is used as a measurement instrument. In this method, one rotary axis and two linear axes are simultaneously controlled and the sensitive direction of the ball bar is kept constant in X, Y or Z direction of the machine coordinate accordingly. In our previous measurement methods, the sensitive direction of the ball bar is kept constant in radial, tangential or axial. The identification of geometric deviations was conducted through simulation. From the simulated results, it is found that every deviation can be estimated. However the identification accuracy of the method is less than that of the measurement method proposed previously.

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The machining test of cone-frustum specified in NAS 979 is only one method to evaluate the machining accuracy of five-axis machining centers. This paper analyzes the influence of the apex angle, inclination angle and center position of the cone frustum on the moving range and feed velocity of five axes when the cone-frustum is machined under simultaneous five-axis control. When the center of the cone moves along the X direction it gives a singular condition that the X-axis or Z-axis does not move. The offset along the Y direction gives larger moving range of liner axes and independent reversal points in every axis. The larger apex angle gives the less influence on motion trajectories of the A-axis. Therefore, it is recommended to move the center position of cone frustum along the Y direction.

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The machining accuracy of workpieces mounted on the tilting rotary table is affected by the accuracy of axes of rotation. It is, therefore, important to evaluate the rotational accuracy of the rotary table. Simultaneous there-axis motions are conducted for measuring the motion accuracy of five-axis machining centers by using a ball-bar and an R-test instrument. When measuring the three-axis motion including a rotary axis, the ball-bar has to be rearranged according to its sensitive direction, and the detected values with the R-test instrument have to be transformed into the orthogonal coordinates system. To avoid these drawbacks, in this study, a device named the 3D-probe and the measuring method are proposed. The 3D-probe can detect three sensitive directions at once and do not need to transfer the coordinates.

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In this research, we analyze the manufacturing process by Life Cycle Assessment (LCA). In the present report, the cutting methods are investigated to reduce the environmental impact of 5 axis control machine tool by measuring the power consumption. As a conclusion, cutting force and frictional force are greatly related to the increase in the power consumption of a machine tool. It is especially important to consider the frictional force.

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The paper introduces the concept of the machine tool motion compensation control system when the two dimensional planar motion of the machine is assumed to be detected by high precision two dimensional position sensor system. Also paper describes design study on the machine tool system equipped with two dimensional plane scale sensor system. The study includes the fundamental principle of dynamic identification on the two dimensional motion repeatability when the machine is equipped with two dimensional position sensor, which allows real time two dimensional compensation control for highly accurate machine motion.

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In recent years, cost competition is getting intense, and shortening of cycle time is further more demanded for machine tools. In this paper, we propose the new spindle synchronization control method which is able to shorten acceleration and deceleration time. This proposed method can control acceleration and deceleration movement automatically so that the electric current of each motor does not exceed each limit. We have confirmed by an experiment using two spindle motors that the proposed method could shorten acceleration and deceleration time in comparison with a conventional method.

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Cylindrical grinding machines are typical machine tools for the final finishing process which produce high accurate and value-added products. However the universal method of measurement and evaluation for their thermal displacement has not been established. Therefore, in this study, we propose a measurement and evaluation method of the thermal displacement of the cylindrical grinding machines with rotation of the grinding wheel and make a device on an experimental basis based on the proposition and examine their validity. As the result of this study, it is made clear that the method proposed by us can measure and evaluate accurately and simultaneously 5 thermal displacements of the cylindrical grinding machines, that is, 3 translational deviations and 2 angular deviations.

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An increase in frictional heat due to increases in rotational speed and feed rate causes the thermal deformation of machine tools, resulting in a decrease in machining accuracy. To establish a method for reducing the thermally induced machining errors of machine tools, recently the authors have proposed a method to estimate the heat flux acting upon a machine tool body by solving inverse problems. By using the quasi-steady state temperature rises of the body, the heat flux at the heat source was estimated with sufficient accuracy for practical use. To improve the estimation accuracy of the heat flux, the effects of both the number of temperature measurement points and their positions on the accuracy were examined with the orthogonal arrangement of the temperature evaluation points. S/N ratios and factorial effects at each temperature measurement points were evaluated by the optimum solutions of heat flux estimations. These values are useful for an index in determining a layout of temperature sensors to estimate the heat values at heat sources.

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The linear roller guide used in this study has a very narrow gap between the carriage and the top surface of the guide rail, as compared to conventional types, in order to investigate the friction characteristics of the thin film of lubricants and the influence of friction on the dynamic behavior of the feed drive system. In the measurement of friction force, several kinds of greases with different viscosities are filled into the narrow gap. It is found that the viscous friction measured in the linear roller guides is largely affected by the grease filled in the gap. This paper proposes a mathematical model for a feed drive system by taking into account the friction characteristics of the linear roller guide. To confirm the validity of the proposed model, step responses under various conditions were measured and simulated. As the results, it was confirmed that the proposed model can express the actual behaviors.

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The Weibull distribution function which was postulated by W. Weibull in Sweden in 1939, has been applied to the statistical data treatment for static and dynamic strength of materials. This distribution function has a requirement to be used for the strength of material under uniformly stress, that is the reliability function ln(1/R) is proportional to the stressed volume which is constituted by the probability product law for small elements in the material. However, for actually applied equal stressed field, this stressed volume can be transformed to a stressed area or stressed line or stressed point. This study reports the theoretical method of evaluation of 90% rating stress or load for a test specimen using the three-parameter Weibull distribution function. As a result, the prediction of static strength and fatigue life for the test specimen having arbitrary size, specified stress and reliability can be performed and further it will be found that a linkage between structural fatigue and rolling contact fatigue could be obtained theoretically.

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