This paper presents the improvement of design efficiency of machine tool structure in the conceptual and basic design stage. An interactive system has been developed for designing machine tool structure in this study. The key point in the interactive system is that a set of beam elements are assumed to compose the total structure of machine tool because it is easy to analyze the static, dynamic and thermal features. In this interactive system, a conversion procedure also has been developed. By using this conversion procedure, the selected beam structure of machine tool can be converted to an actual structure, completing conceptual and basic design. Consequently, using the interactive system allow, designers can complete the machine tool structure design in a shorter time with higher efficiency. The goal of the interactive system is to assist designers to quantitatively and quickly select a superior machine tool structure.

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Nonisothermal glass molding press (NGMP) was proposed to fabricate aspherical lenses, and its characteristics were studied by both experiments and finite element method (FEM) simulations in comparison with the traditional isothermal glass molding press (IGMP). The cycle time, form accuracy, surface roughness, stress/strain distributions of the aspherical lenses made by IGMP and NGMP were examined and compared. Experimental results and simulation results show that NGMP is an effective way to improve the molding efficiency and prolong the service life of the molding dies.

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Multi-tasking machine tools are very useful to manufacture complicated workpiece efficiently. However, it is very difficult to generate NC data when an operator uses multi-tasking machine tools. Currently, there are some CAM systems for multi-tasking machine tools. However, there are such problems as the manual allocation of parts to generate tool paths, the difficulty of self-interference recognition without a simulator, and so on. Therefore, this study deals with the development of CAM system which can recognize part configurations, calculate tool paths automatically for turning and milling operations, and sort them in machining order, based on 3-D CAD data of workpieces.

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In design processes, a product shape is defined on a CAD system, and design analysis and evaluation are performed on a CAE system. When modification of the design shape is required as a result of design evaluation, the design shape is modified using the CAD system and the analysis and evaluation processes using the CAE system are repeated. In the analysis of a design shape with the CAE system, mesh data is generated using the form data constructed by the CAD system. Whenever design shape is to be modified using the CAD system, mesh data must be regenerated. The quality of mesh data greatly influences analysis accuracy, and high quality mesh data requires considerable time and cost to generate. The purpose of the study is to propose a novel digital engineering method for design evaluation using a CAE system and to confirm the effectiveness of the method. The proposed method enables designers to modify designs using mesh data and to automatically transform the mesh data to the CAD data, to minimize the cost and time for regenerating mesh data after design modification. A basic system was also developed to confirm the usefulness of the proposed method.

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Significant enhancement of hardness characteristics was achieved through the Frictional Stir Burnishing (FSB) process. The enhanced region was generated by the FSB process where the thickness and hardness were approximately 200 µm and 900 HV, respectively, under the conditions of spindle speed of 10000 min^-1, a feed rate of 200 mm/min and a processing load of 750 N. The processing temperature was approximately 600∼750 °C under compressive stress condition. Although this temperature is lower than A₃ transform point (normally 780 °C), it is known that A₃ transform point decreases under the compressive stress condition. And after the tool passed, the temperature dropped rapidly. This process can be assumed to be the same as a quenching process. However, the obtained hardness value is harder than that of the regular quenched material. When the processing load was 500 N, extremely hard regions over 1000 HV were obtained. In this case, it is thought that the material was not transformed into martensite. It can be concluded that the severe stirring process of FSB caused the grain refinement.

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An increase in frictional heat due to the increase in rotational speed and feed rate causes thermal deformation of machine tools, resulting in a decrease in machining accuracy. To establish a method for reducing thermally induced machining errors of machine tools, a method has been proposed to estimate the heat flux acting upon a machine tool body by solving inverse problems. Experiments were carried out with the cross slide of a machine tool. Using the heat flux estimated at the heat source, the temperature rise of the body in a steady state could be obtained with sufficient accuracy. Effects of both the number of evaluating and measuring points of the temperature on the estimation accuracy were also examined experimentally. More accurate estimation of the heat flux requires that the number and position of both temperature measurement points and candidates for heat sources are selected considering how the machine tool is actually operated.

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This paper presents nano mechanical removal processing of a potassium niobate nanosheet with an atomic force microscope (AFM). In particular, we examined the control processing method for the direction of the nanosheet surface in order to attain a high precision groove machining of a bilayer nanosheet. As a result, by the machining direction taking into account machining anisotropy and the machining load W that balance machining accuracy and machining stability, a machined groove with a maximum width of 28nm and a very sharp edge of a bilayer nanosheet was attained.

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Precision micro-machining without cracks and with a narrow heat affected zone is highly required for the effective use of high-performance material. For this purpose, it is expected that the higher harmonics of Nd:YAG laser could perform the precision micro-machining by its high photon energy. However, even using harmonics of Nd:YAG laser, the heat affected zone is inevitable due to the plasma generation. In order to reduce the influence of plasma, it is important to understand the generation mechanism of plasma. Therefore, the laser induced plasma was observed by the high-speed shutter camera, and the influence of laser wavelength on machining characteristics was investigated.

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A pulsed Nd:YAG laser and a continuous diode laser were spatially superposed for higher absorption of laser beam to aluminum alloy. 12-20% increase in the bead width and 15-30% increase in the weld depth could be obtained by the superposition of continuous diode laser and pulsed Nd:YAG laser. Moreover, the unsteady thermal analysis with a key-hole effect indicated that the temperature of specimen surface with a continuous diode laser could be kept approximately 300K higher than that without a continuous diode laser. Therefore, it was clarified that the bead width and depth would increase greatly due to higher absorption of Nd:YAG laser to aluminum alloy by the superposition of a continuous diode laser.

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An accurate analytical model for regenerative chatter vibration in plunge cutting is proposed. Effects of the cross transfer function and the cutting force ratio on chatter stability are considered in the proposed model. Equivalent transfer function is defined, which is useful to understand those effects on chatter stability. Basic plunge cutting experiments were conducted to verify the proposed model. Although the critical widths of cut in the CW and CCW rotation processes were significantly different from each other in the experiment, even when the other conditions were the same, chatter stability limits were predicted accurately by the proposed model as compared with the conventional model.

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The passive forces acting against the drive force are phenomena that influence dynamical properties and precision of linear axes equipped with feed drives. Covers are one of important sources of passive forces in machine tools. The paper describes virtual evaluation of cover passive forces using the cover complex model. The model is able to compute interaction between flexible cover segments and sealing wiper. The result is deformation of cover segments and wipers which is used together with measured friction coefficient for computation of cover total passive force. This resulting passive force is dependent on cover position. Comparison of computational results and measurement on the real cover is presented in the paper.

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This paper proposes a new method for correction of tool run-out on a machine tool using a laser. The shank part of the tool attached on the machine spindle is irradiated with the laser beam. The thermal stress caused by laser irradiation at the irradiated part can make a very small deformation. First, the deformation patterns based on the thermal stress are shown. Second, experiments are carried out in order to investigate the influences of laser irradiation conditions on the deformation. Finally, a few case studies are performed using a cutting tool and succeeded in reducing the tool run-out to sub-microns.

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This research proposes a two-layered model for dynamic supply chain management considering transportation constraint. The model provides a method for suppliers to estimate suitable prices and delivery times of products based on not only production schedules but also transportation plans in consideration of constraints about shipping times and loading capacities for transportation. A prototype of dynamic supply chain simulation system was developed and some computational experiments were carried out in order to verify the effectiveness of the model. The prototype system is available to determine suitable shipping times and loading capacities of transportation vehicles.

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Most machining tools are controlled by numerical control (NC) programs in order to achieve unmanned machining operations with high precision and improved productivity. However, all the movements of the machining tool are predetermined, and all instructions coded in the NC program are performed sequentially. Therefore, since the cutting process is not adaptable during unmanned machining, the cutting conditions should be set conservatively to avoid cutting difficulties. In this study, machining strategies for adapting the cutting process during a milling operation to avoid tool breakage and to stabilize cutting load have been integrated into an autonomous NC machining tool developed under the Digital Copy Milling (DCM) concept for generating a tool path in real time. In machining strategies, feed speed, radial and axial depths of cut are adapted according to cutting load detected from load cells in the machining table. Successful endmilling experiments verified the effectiveness of the developed machining strategy.

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Polydimethylsiloxane (PDMS) is difficult to machine by conventional cutting process because of its low elasticity and high adhesion. We proposed the cryogenic micromachining method assisted by liquid nitrogen cooling for direct fabrication of 3D micro channels on PDMS substrate in short time. In this paper, the cryogenic cutting mechanism is clarified through some verification experiments. Moreover, Pre-Deformation-assisted Cryogenic Micromachining (PDCM) method is also proposed for fabricating the unique shapes of channels and its validity is evaluated experimentally. The results of cutting tests show that 3D unique micro channels can be processed precisely and rapidly on PDMS.

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Small-sized structures of diamond-like carbon (DLC) deposited by FIB-CVD contain microscopic non-uniformity in their mechanical properties. This is mainly due to the structures containing Ga implanted by Ga ion irradiation during deposition [1]. In the application of DLC nanostructures to mechanical devices, the non-uniform properties cause difficulties in designing nanomechanical devices. To establish a modeling method for nanomechanical device design, the precise mechanical properties of DLC pillars were evaluated. For the property characterization, several techniques, such as transmission electron microscopy, ion implantation simulation, and density measurement by vibration, were examined. Then, an analysis model for finite element method-based design of dynamic characteristics was developed.

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Intelligent machine tools require the functions of high-accurate process monitoring and adaptive control to fit the optimum process condition in each workpieces. For realizing these functions, the various techniques to monitor the cutting process and control it using additional sensors have been proposed and widely studied. Authors propose the sensorless cutting force control method using parallel disturbance observer. The performance of our proposed method is evaluated through simulation and experiments using a linear motor driving table.

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An analytical force model is presented to simulate the cutting force and the chip flow direction in the drilling process. Three dimensional chip flow is interpreted as a piling up of the orthogonal cuttings in the planes containing the cutting velocities and the chip flow velocities. The chip flow direction is determined to minimize the cutting energy. The simulation is performed to discuss the effect of the lip geometry on burr formation at the backside of the plate. Burr formation is associated with the thrust and the chip flow direction. The curved lips drill is examined to reduce the thrust and control the chip flow with the orientation and the curvature of the lips. The counterclockwise orientation with the small curvature is effective in reducing burr formation in the simulation. A drill is designed to have the counterclockwise curved shapes on the straight lips. The designed lips flow the chip upward to avoid the chip clogging in the steady process. Then, the curved shape at the end of the lips control the chip flow toward the radial direction of the tool to reduce burr formation with the thrust around the end of cut.

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Precision motion control technology has been widely used in high accuracy applications such as advanced scientific instruments and semiconductor fabrication equipment. In particular, the nano-motion control system with multiple degrees of freedom positioning in large travel ranges has been required in the field of precision engineering. In order to realize such a system, it is necessary and indispensable to develop a planar motion table system based on a new design concept. This paper presents a newly developed X-Y planar nano-motion table system with large travel ranges. This system is composed of a fine motion table and a coarse motion mechanism. The fine motion table is supported by porous aerostatic bearings and driven by voice coil motors with a laser interferometer feedback in a perfect non-contact condition. In addition, the table is driven at the center of gravity during the X-Y planar motion. The coarse motion mechanism has the frame structure with the coils of voice coil motors for the fine motion table. In order to enlarge the table travel ranges, the coarse motion mechanism follows the fine table motion. Performance evaluation results confirm that the developed table system has a remarkable performance which includes nanometer positioning capability over large travel ranges.

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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) has been developed for the measurement. The magnet loader, which has coils and iron cores, 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. In order to understand the magnetic flux and eddy current in the dummy tool, the electromagnetic field analysis by FEM was carried out. Grooves on the attraction surface of the dummy tool were designed to cut the eddy current flow. The dimension of the groove were decided based on the FEM analysis, and the designed tool were 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 grooved tool, the spindle rigidity can be measured when the spindle rotates with a speed up to 10,000 min^-1.

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This paper presents a system for measuring micro holes that makes use of an optical fiber probe. The optical fiber probe is deflected when it comes into contact with a hole surface, and this deflection is measured optically. For this research, the optical fiber probe is fabricated by using an acid etch technique and its characteristics in the process of displacement detection are described. The effects of surface force are then evaluated. The diameter of the optical fiber probe sphere at the tip of the probe is calibrated by using a 1mm gage block, and the effect of the probe sphere diameter is compensated for measurement of the roughness standard specimen. As a result, it is confirmed that the accuracy after compensation of the roughness standard specimen as measured by the measuring system corresponds well to that of the surface roughness tester in both shape and value, demonstrating the utility of this means of calibration.

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This paper describes the development of a high-performance vitrified bonded cBN grinding wheel using a new type of ultrafine-crystalline cBN (cBN-U) abrasive grain. Surface plunge grinding experiments using a vitrified wheel made of the cBN-U grains with a mesh size of #80/100 were carried out, and the wheel’s grinding performance was compared with those of cBN vitrified wheels made of representative conventional monocrystalline and polycrystalline cBN abrasive grains. This new cBN-U abrasive grain was found to possess a higher fracture strength than these conventional cBN grains. Therefore, the cBN-U wheel exhibits a higher grinding ratio and longer grinding wheel life than conventional cBN wheels.

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Nanometer-scale machining experiments on fused quartz surfaces have been performed using an atomic force microscope combined with a two-axis capacitive force/displacement transducer. The minimum normal force f_nP required to reproducibly form a groove was about 4.7 µN. The minimum critical normal force f_nR, tangential force f_tR and groove depth d_gR when the material removal process began were found to be 33.7 µN, 18.7 µN, and 4.3 nm, respectively. Changes in the swelling ratio R_s and the ratio of force components at the critical normal force f_nR can be used to detect a critical condition when the material deformation behavior changes from plastic deformation to material removal.

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There is a strong need for a fine three-dimensional metal patterning technique for fabricating next-generation devices such as patterned media and plasmon photonic and nano-scale electrodes. In addition, flexible and transparent electronic devices on plastic substrates are desired for wearable devices and flexible thin-film displays. Therefore, a technique for patterning metals onto plastic substrates is required. Nanotransfer printing (nTP) has received much attention recently because of its high throughput and high resolution compared to inkjet printing. However, it is difficult to create sub-100 nm metal patterns using nTP because the PDMS stamp is deformed by transfer pressure. Therefore, we have developed a technique for transferring three-dimensional metal patterns onto a polyethylene terephthalate (PET) substrate by nanoimprint lithography using a metal oxide release layer. The three-dimensional nanoimprint mold was fabricated by control of acceleration voltage electron beam lithography (CAV-EBL) with spin-on-glass (SOG). As a result, three-dimensional metal nano patterns were obtained using a metal oxide release layer. Moreover, the metal moth-eye structure, which has a very high aspect ratio, was transferred onto a PET substrate by applying our process to the moth-eye structure on glassy carbon.

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Polymer materials are widely used in various applications nowadays because of their fine characteristics, light weight, easy to use for mass production, etc. In this study, authors tried to construct a 3-dimensional laser fabrication system which can make freely designed shape by controlling the scanning speed of laser beam. At first, characteristics of KrF excimer laser ablation process to PMMA were studied as preliminary research. In this step, from the results of theoretical simulations and actual machining experiments, it was found that the machining depth was proportional to pulse number of laser irradiation. Therefore, when laser frequency is constant, the pulse number and machining depth can be controlled by feed rate of laser beam on the surface of target materials. Based on this concept, a 3-dimensional fabrication system was constructed. It can machine free-formed surfaces of PMMA making use of ablation process by controlling feed speed of the beam. Finally, some primitive shapes were actually machined by the system. From evaluation of these shapes, the availability of proposed concept and the system were confirmed.

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The joints in machine tools influence greatly the static, dynamic and thermal characteristics of the machines. Then the many researches on them have been carried out. Under these conditions, the authors have established the quantitative measurement method of contact stiffness of the joint with same material combination considering the real contact area, since the real contact area is far smaller than the nominal contact area. In this research, we propose the new measurement method of contact stiffness of the joint with different material combination expanding the former method we developed and its validity is considered. In consequence, the following results are obtained. 1) The measurement method applicable to the joint with various material combinations is established using inserted specimens. 2) The real contact area of the joint with different material combination can be accurately measured considering the reflected level of ultrasonic wave at the real contact area of the joint. 3) The contact stiffness of the joint with different material combination can be treated as the series coupling of the each contact stiffness constructing the joint. 4) The contact stiffness of the joint and each contact stiffness of the contact springs constructing the joint can be measured by the proposed method.

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This study deals with the development of a new CAD/CAM system for fabricating holes whose cross sections change variously. The cross sections of machined holes are generally constant. The limitations in the shapes of holes that can be machined make obstacles in the design stage of industrial products. A new device that utilizes electrical discharge machining has been developed that can create holes with various cross sections to solve this problem. However, it has been impossible to put the device into practical use since there has been no software that has enabled the designed shapes to be easily machined. Therefore, we aimed at developing a new CAD/CAM system for machining the beforehand designed holes with changing cross sections by using the device. As the first step in developing the CAD/CAM system, the post processor in the CAM system is formulated in this paper.

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This paper describes the influences of anisotropy found in the elastic modulus of monocrystalline silicon wafers on the measurement accuracy of the three-point-support inverting method which can measure the warp and thickness of thin large panels simultaneously. Deflection due to gravity depends on the crystal orientation relative to the positions of the three-point-supports. Thus the deviation of actual crystal orientation from the direction indicated by the notch fabricated on the wafer causes measurement errors. Numerical analysis of the deflection confirmed that the uncertainty of thickness measurement increases from 0.168µm to 0.524µm due to this measurement error. In addition, experimental results showed that the rotation of crystal orientation relative to the three-point-supports is effective for preventing wafer vibration excited by disturbance vibration because the resonance frequency of wafers can be changed. Thus, surface shape measurement accuracy was improved by preventing resonant vibration during measurement.

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A special coolant system called ‘Ion-shot coolant system’ which consists of an electrolytic liquid and a nano carbon additive was developed. A series of experimental studies had been conducted to understand the effects of the coolant in micro cutting of two steel materials with different carbon content, a high carbon chromium steel (SUJ-2) and a pre-hardened mold steel (SUS420J-2) using a diamond tool. Significant improvement of the diamond tool wear was observed while cutting ferrous materials. Additional benefits of the ion-shot coolant system were discussed in this paper.

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