Solid freeform fabrication (SFF) is one of the techniques in direct metal parts fabrication in manufacturing technology. Currently there are limited in the choice of metal powder based materials in rapid prototyping. The most common used materials for bone replacement are stainless steel, cobalt-chromium alloys and nickel titanium. This paper discussed on the development of titanium-based mixture which is suitable for freeform fabrication by inkjet 3D printer. This research is aimed to formulate the suitable titanium-based powder using in mini inkjet printer. The specimen will heated in the furnace about 80% from the melting point temperature of titanium. Based on result obtained, it found that binder content in the composition should be lower than 20% for successful fabrication of titanium samples by 3DP technique. This is reported that the sintering process was increase 20% of the surface roughness and 40% of hardness value of the samples. The influences of adhesive binder content on the physical and mechanical properties of the fabricated parts, before and after sintering process has been obtained in order to achieve best quality of parts.

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The purpose of this study is to develop a convenient and precise method to detect distance between small-diameter endmill and work surface based on image processing. A non-contact method using a CCD camera and a thin reflection mirror was proposed in this study to detect the distance without any skills. The CCD images were subjected to three steps of digital image processing. The first step was an image thresholding. The second step was a Laplacian edge detection and the third step was a pattern recognition of the edges. As a result an equation was derived for the distance on the image and the actual distance between the endmill and workpiece.

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A micro-probe based on laser trapping is proposed for the micro-probe system of a nano-coordinate measuring machine. This study focused on the "shadow effect," which is the case wherein a partial beam for laser trapping is shaded by the specimen. A radially polarized beam was introduced to improve laser shading. As a result, the trapping efficiency was increased by 3.2 times. This high-efficient laser trapping made it possible for the proposed probe to measure the vertical surface under the shadow effect. The advantage of using radial polarization was confirmed via a measurement of the micro-groove profile.

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This paper proposes an estimation method for wear of ball screw and support bearing is proposed. In order to develop the estimation methods, special ball screws and support bearings with larger clearance are installed into a feed drive system, and the worn characteristics are investigated. In the estimation method which proposed based on the investigations, sine wave motions under various frequency are commanded into the feed drive system, and quantity of wears can be estimated based on amplitude of feed backed positions and current. It is experimentally clarified that the proposed estimation method can estimate the amount of the wear accurately.

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The demand of more accurate and durable edge shape has increased for high performance cutlery and medical operation tools. However, conventional surface modifications associated with high temperature, such as nitriding occasionally cause the sharp edge to deform. A spattering is effective to improve the durability of the edge shape but thick layer is necessary for high wear resistance, which causes larger radius of the edge. In this study, an applicability of low temperature plasma nitriding to the edge shape was experimentally investigated. It was clarified that the surface hardness increased even with low temperature processing less than 600K. Also, the cutting performance could be kept when the low temperature plasma nitriding is applied to razor blade.

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This paper carried out MQL end milling of an aluminum alloy and investigated the effects of humidified air and lubricants prepared by oxygen-including compounds on the cutting performance. As a result, humid air supply demonstrated the better cutting performance than dry air supply. Among the lubricant esters, an ester with lower kinetic viscosity showed the superior cutting performance probably because of the smaller heat of evaporation and had the advantage in easier vapor lubrication. On the other hand, the lubricating ability of alcohols was found to be greatly influenced by their molecular structures rather than kinetic viscosity.

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In this paper, we consider a plastic limit design problem of truss structures whose objective is to minimize the number of accepted bars. We formulate it as a MIP (Mixed Integer Programming) problem. We also conduct numerical experiments to examine the presented MIP formulation. Test instances generated from a given ground structure are exactly solved by GLPK (GNU Linear Programming Kit), which is one of well-known open source softwares solving MIP and LP (Linear Programming) problems. We report the results on the test instances which show different solutions from ones obtained by solving a typical truss design problem of minimizing the total volume.

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A system for measurement and error compensation of high precision machine tools is being developed. This system involves a sub-nanometer precision, holographic, two-dimensional laser scale, as well as custom developed software. Currently the software allows for measurements to be taken and recorded, with that data being used to develop error maps and compensated NC code. The software will also include the ability to dynamically update the error map. Experiments have been carried out to verify the usefulness of this system, and results show significant error reductions.

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This paper presents an efficient and automated scheme to calibrate error motions of rotary axes on a five-axis machining center by using the R-test. During a five-axis measurement cycle, the R-test sensors nest measures the three-dimensional displacement of a sphere attached to the spindle relative to the machine table. This paper demonstrates intuitive, graphical presentation of R-test measurements to understand how error motions of rotary table changes in three-dimensional space depending on the swiveling angle. The separation of the influence of linear axis error motions, particularly squareness errors of linear axes, from the R-test measurement is also discussed.

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In this research, Micro Nano Form Rolling method was developed. This method is expected for structuring micro cyclic structure. Micro cyclic structuring experiment was carried out to pure aluminum using roller tool with microscale and nanoscale cyclic structure, and relationship between processing conditions and the transcribing behavior was investigated. As a result, microscale and nanoscale cyclic structure was successfully transcribed to pure aluminum. Moreover, it was found that relationship between load and the transcribing behavior at Micro Form Rolling, and it was confirmed that relationship between load, surface roughness of roller tool and the transcribing behavior at Nano Form Rolling.

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Vibration signals used for abnormality detection in machine health monitoring (MHM) are non-stationary in nature. Wavelet packet transform is extensively used in the literature for comprehensive analysis of non-stationary vibration signal but these techniques work only for a specific application lacking in some generalized methodology for selecting appropriate wavelet decomposition level and nodes for optimal performance. This study proposes a framework for inchoate fault detection by selecting the optimal wavelet decomposition level and nodes, named Optimally Parameterized Wavelet Packet Transform (OPWPT). OPWPT uses support vector machine to build the fault diagnostic model. Results in comparison with the existing schemes validate that OPWPT enhances the fault detection accuracy significantly in case of incipient faults when vibration signatures are very weak and overall signal to noise ratio is very poor.

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The purpose of this research is to produce micro parts reinforced by unidirectional short fibers using laser photolithography. Ferromagnetic short fibers are added to a liquid photopolymer and a magnetic field is then applied to the liquid photopolymer, aligning the axes of the short fibers along the magnetic field direction. Then, the photopolymer is solidified by UV laser irradiation in a desired shape. Solidified photopolymers containing the unidirectional short fibers are layered until the desired height is obtained. The surfaces of the solidified layers are observed and the possibility of a reinforcing effect between the layers is examined.

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A continuous diode laser was superposed on a pulsed Nd:YAG laser in aluminum welding because of its high efficient absorptivity to aluminum alloy, and effects of diode laser on the crack generation were investigated. The superposition of continuous diode laser would keep the specimen at the high temperature after the Nd:YAG laser pulse, and the temperature of irradiated area could be decreased gradually, which led to the gentle stress distribution. Therefore, it was clarified that cracks on the surface in a pulsed Nd:YAG laser welding of aluminum alloy could be decreased by the superposition of continuous diode laser.

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The application of laser beam processing has been expected in the field of semiconductor devices because of its flexible cutting line and narrow kerf width. However, the deterioration of cutting quality would occur due to the thermal damage, since the laser beam processing is mainly thermal process. Therefore, the laser dicing method by the superposition of fiber laser and SHG:YAG laser was proposed to perform the high-quality processing. The smaller kerf width could be achieved by controlling the time delay between both laser pulses, and the synchronized laser pulses led to the smaller heat affected zone.

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In this study, the machining characteristics and the removal mechanism in EDM for one directional CFRP was discussed in order to investigate the influence of carbon fiber direction to machining direction and to attain high performance EDM. Then EDM characteristics with two different combinations of machining direction and carbon fiber direction were compared. Experimental results clarified that the material removal mechanism in the EDM for one directional CFRP when the machining direction is perpendicular to the fiber direction is different from that in parallel machining. Therefore, efficient EDM for CFRP is possible by selecting appropriate machining direction to fiber direction.

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Unsteady heat conduction analysis was carried out in order to clarify the surface temperature of workpiece in the EB polishing process. In the analysis model, the electron beam penetration into the workpiece surface and the material structure for cemented tungsten carbide were considered. The temperature changes of surface layer for ceramics, cemented carbide, and stainless steel were analyzed. Moreover, the analyzed results were verified with experimental results, such as observations of the EB polished surfaces. The FEM model built in this study could precisely predict the temperature changes for each material in EB polishing.

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Roller nano imprint (RNI) process is expected as a key technology that realizes a cheap and high through-put nano fabrication process. RNI is a kind of a rolling process that replicates nano structures of a mold to a work material. Development of nano structure mold is therefore essential for development of RNI technology. In this paper, development of a nano-structure foil mold made of TiN and Ni is reported. The foil mold is applied for the RNI experiments. It is shown that RNI modifies optical reflectance of work material. Application of RNI to nano dot array fabrication is studied also.

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Micro-machining employing micro-tools several tens of micrometers in diameter has attracted attention as a new machining technology that adds high value to various fields including optoelectronics, medical science, etc. In order to perform the machine work with sufficient accuracy, the position of the micro-tool tip must be detected accurately. In the case in which the gap between the tip of a micro-tool and a workpiece is approximately 1μm, the light intensity varies sharply with gap distance. The degrees of precision obtained in sets of repetitive measurements performed for position detection using the sharp variation in light intensity were σ≦0.048μm.

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In recent year researchers and industries are trying to reduce the delamination factor when drilling of carbon fiber reinforced plastic (CFRP). Tool geometry design and process parameters were the main factors in the previous investigation. In particular, this work studies the influence of torsional vibration drilling of CFRP in terms of thrust force, surface roughness and delamination factor of the exit hole. In this experiment, a constant cutting speed of 20 m/min and feed rates of 0.01, 0.025 and 0.05 mm/rev were employed. Two types of drill point geometry were used for the entire tests. The results show that the application of torsional vibration drilling tends to reduced the thrust force and delamination for both drills. However, the value of surface roughness is slightly higher than without torsional vibration drilling.

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A prototype-rotary creaser was experimentally applied to an AB double-wall corrugated board to reveal creasing characteristics of the corrugated board and mechanical factors on failures of its height wise crease. From this work, the followings were obtained. (1) There are appropriate combinations of pre-creaser gap and main-creaser gap for restricting the occurrence of failures of an inside liner; (2) The pre-stage creasing for crushing corrugated medium was severely necessary for reducing the failures of the inside liner and performing the high precise position of bending. (3) Dependency of water content and feed velocity on the failures of the inside liner was revealed.

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The effects of laser wavelength and intensity distribution on the removal characteristics of TCO films were experimentally investigated. The top-hat laser beam required the higher pulse energy rather than Gaussian laser beam to perform an acceptable scribed groove. The region of laser fluence to obtain an acceptable groove became wider in the case of top-hat laser beam compared with Gaussian laser beam, and the longer wavelength would lead to the wider acceptable fluence region. The burr height at the edge of groove could be reduced by the top-hat laser beam and the shorter laser wavelength.

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Electroplated diamond tools with superior proportional limit and wear resistance are developed for grinding hard and brittle materials. Application of Ni-coated diamond abrasives is effective for high-speed manufacturing of electroplated grinding tools. However, the sharpness of the grinding tool decreases because nickel membrane was attached on the surface of abrasives. The phenomenon of abrasives aggregation is also serious. In this study, we developed partially Ni-coated diamond abrasives. The production method of the partially Ni-coated abrasives was described and the effect of application of the abrasives was investigated. As the results, the problems with using Ni-coated abrasives or non-coated abrasives could be solved and the grindability of electroplated tools was improved.

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The productivity of deep hole drilling is greatly improved in recent years, where the long twist drill with the high pressure coolant supply has been used. The problems of this system are revealed such as the excess consumption of electric power, and the dispose of the large quantities of waste coolant. To solve these problems, MQL drilling becomes practical and now widely used in many Japanese automobile factories. In this research, the process improvement technology for MQL drilling is proposed. Excellent tool life was achieved by using mixed gases as the mist carrier instead of the conventional compressed air. The results of drilling experiment shows the increasing drill-life and the increasing thrust force during drilling. The cutting force and chip thickness analysis suggest the novel tribological conditions derive from atmosphere.

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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 orthogonal 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. From the simulated results, it is found that every deviation can be estimated. However, the identification accuracy of this method is affected by installation error of the table side socket.

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This paper aims to evaluate the sustainability performance of machining operation of through-hardening steel, AISI 52100, taking into account the impact of the material removal process in its various aspects. Experiments were performed for dry and cryogenic cutting conditions using chamfered cubic boron nitride (CBN) tool inserts at varying cutting conditions (cutting speed and feed rate). Cutting forces, mechanical powers, tool wear, white layer thickness, surface roughness and residual stresses were investigated in order to evaluate the effects of extreme in-process cooling on the machined surface. The results indicate that cryogenic cooling has the potential to be used for surface integrity enhancement for improved product life and more sustainable functional performance.

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In this study, the effect of the interlaminar shear strength by SPWC method was evaluated. Cylindrical CFRP laminas were made by conventional DRY method means winding on aluminum liner at room temperature, and made by combined SPWC method and DRY method means winding on heated aluminum liner at some temperatures. And interlaminar shear strength and volume fractions were measured. As a result, the interlaminar shear strength by conventional DRY method indicated about constant value as any winding tensions. And the interlaminar shear strength by SPWC method at 40℃ indicated higher values. But the interlaminar shear strength by SPWC DRY method at 80℃ with high winding tension decreased remarkably.

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Currently CAD/CAM systems have become more and more common in automated manufacturing to enhance the accuracy and efficiency of machining process. However, currently the CAM programming is still a labor-intensive task. How to analyze the shapes of the products, and how to identify a specific machining operation are mainly relied on the experience the CAM programmer. Therefore, the feature extraction system, which analyses the shape of 3D-model instead of CAM users, was developed in this research. This research enables CAM user who is lack of machining knowledge to generate more effective machining path. Moreover, corresponding machining methods can be automatically carried out to each manufacturing feature by utilizing developed system together with the existing CAM system.

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In this study, we propose a joint model to analyze the dynamic characteristics of joints with FEM analysis. The model can set the spring and damping elements between a pair of nodes on the joint interface in the jointed structure and can change their number and location in vertical and tangential directions. As a result, the procedure of identification of dynamic characteristic parameters of joints is considered with the joint model. It was found out that the exact boundary condition of the joint could be set and the possibility of exact identification of dynamic characteristics of the joints was shown.

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We investigate the wear characteristics of single crystal diamonds by experimentation of wear between single crystal diamonds and optical glass (BK7). This study's purpose is to examine the cause of diamond tool wear that occurs during glass cutting. The wear volume of diamond increases with the normal load and friction velocity. We also analyzed the friction surfaces of diamond and BK7 using Raman spectroscopy. Graphite was detected from the friction area of BK7; no diamond material was detected leading to a conclusion that the diamond changed into graphite resulting in wear.

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In this research, new algorithm for evaluation of real contact area (RCA) from direct observed image under high load condition was proposed. At first, experimental equipment which was suitable for high load condition was developed. It was available for observation by both optical and ultrasonic method. Then the RCA was obtained from optically observed image by edge detection technique. After that the validity of the optical method was checked by comparing with another system based on analysis of ultrasonic reflection analysis under the same contact conditions. As a result, it has been found that the optical method and the ultrasonic method have similar tendency and close values in low load condition. From the experimental result, it was proved that proposed algorithm was effective and appropriate.

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This paper describes a design guideline of multi-axis alignment stage for micro-objects, which have a size in the order of 100 micro meters, by using a board stage that is vibrated in the natural frequencies of various vibration modes. Since it is difficult to grip and to manipulate micro-objects, a simple and reliable method is desired. It is shown that the design concept and guideline to realize this stage. Beside the theoretical representation, an example stage is designed for aligning micro-objects. It was also analyzed by FEM simulation. In addition, the designed vibration stage was fabricated using a stainless steel thin plate. Experimental results were discussed with both the theoretical results from the design guideline and the simulation results.

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To generate optimal machining information, a machining database and operation planning algorithm have to be customized for an actual machine tool based on knowledge of a skilled planner. In this paper, a method to update a machining database from NC data is proposed. The database is updated by adding machining information extracted from NC data based on tool path analysis. A method to generate a database oriented planning algorithm from the machining database based on a decision tree method is also proposed. Machining strategy, cutting tool and cutting conditions are determined based on the algorithm and k nearest neighbor method.

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In this paper, a flexible circular saw is applied to curved line cutting of a plate. In this process, the circular saw is deflected like a bowl by pushing the center of the circular saw on the circular rest. The curved line can be cut by the bowl-like-deflection. The deflection of flexible circular saw is analyzed by FEM. As a result, it is shown that the flexible circular saw is able to cut curved line without interaction between saw body and machined surface. In addition, suitable slit shapes in the saw body were proposed from the viewpoint of deflection curvature and vibration mode.

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The use of microchannel chips (micro total analysis systems) have recently gained attention in the medical field. The photolithography technology used in semiconductor manufacturing is generally used to manufacture microchannel chip dies. However, this technology requires many processes, such as mask fabrication and the application of photoresist to a substrate, as well as expensive clean room facilities. In light of this, this study examines ways to form a fine groove using a micro end mill. This study experimentally examines the processing conditions that need to be developed, and as a result, we formulate selection guidelines for cutting conditions through which burring can be reduced.

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In this research, an arc welding technology has been applied to melt the metal, and the fabrication system for three dimensional metallic parts, direct metal lamination using arc discharge, has been developed. In this paper, residual stress in the shell structure fabricated by this direct metal rapid lamination and the deformation after the finishing process are investigated. As a result, it is clarified that heat input, cooling rate and height of the laminated modeling object are the governing parameters of the mechanism of residual stress formation. Dimension accuracy after the finishing process is influenced by the deformation caused by the residual stress release and the stiffness of the laminated modeling object.

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Cutting point temperature and tool wears during a driven rotary tool was examined in this paper. Dry and MQL tests of stainless steel (SUS304) were carried out. We measured the cutting point temperature by using tool-work-thermocouple method and tool wears of rake face and flank face by using microscope. Then, the cutting speed was varied from 100m/min to 500m/min. Cutting point temperature tends to increase with the increase of cutting speed. At high speed cutting (500m/min), cutting point temperature was over 1200℃ in non-rotation tool. However, by using driven rotary cutting, cutting point temperature was decreased to 1000℃. In addition, by using driven rotary cutting with MQL, cutting point temperature was decreased to 900℃. In rotary cutting, cutting fluid can be delivered to tool-chip and tool-workpiece interfaces. The magnitude of tool wears almost corresponds to the cutting point temperature.

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The accuracy of workpieces machined on the tilting rotary tables of five-axis machining centers depends on the accuracy of the axis of rotation. A 3D probe was developed to measure the accuracy of the axis of rotation under simultaneous three-axis motion to avoid the inconvenience of existing measurement instruments. This paper proposes a measurement method for the parallelism error between the sensitive directions and the movement directions of the linear axes. In addition, this paper proposes a correction method using a rotational matrix consisting of the measured parallelism errors and a display method to show the motion errors of the axis of rotation as an application of the 3D probe.

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In an internal grinding, the stiffness of wheel spindle is not so high because of its small diameter. So the elastic deformation of wheel spindle becomes large. In this reason, the dimensional accuracy of workpiece worsens in internal grinding with a high aspect-ratio. To solve this problem, in this study, the shape of the grinding wheel is modified by the single crystal diamond tool. A grinding test with the formed wheel is carried out and the shape of the workpiece is measured. It is conformed that the shape error of the workpiece ground with the formed wheel is significantly improved.

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In order to control microstructures in metallic materials precisely, we develop a new approach to control the metallic microstructures by using the nano plastic forming which can apply precise strain into the material and exact heat treatment. In this study, we investigate the statically recyrstallized microstructure in a single crystal copper formed by the nano plastic forming. The results show that dislocation cell and subgrain structure are generated by the forming. Furthermore, we can find that the nucleation and growth of the recrystallized grains are occurred from the deformed microstructures.

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For the efficiency of machining of high-precision parts, their on-machine measurement plays a very important role. Laser displacement sensors enable high speed measurement with cost effectiveness. However, laser displacement sensors are potentially subject to several measurement errors. In this paper, the measurement error of a diffuse-reflection-type laser displacement sensor is analyzed for profile measurement. To this end, multi-reflection error is predicted by a simple beam tracking simulation. Based on the simulation result, the measurement range of a laser displacement sensor is tuned narrower to reduce multi-reflection error. Then, measurement errors were evaluated.

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In recent years, efficient production by use of CAD/CAM systems draws attention in terms of the increase in products with high-variety low-volume. Finish cutting by square end mill is more efficient than that by ball end mill. Thus, the study deals with the proposal of new tool path generation method for five-axis controlled machining with square end mill by considering the cusp height and the machined volume. The method allows to determine the interference-free position and posture of end mill. As a result, it is found that the system developed in the study enables to decrease the machining time.

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In this paper, we investigate the applicability of electrical discharge machining (EDM) to carbon fiber reinforced plastics (CFRP) and the effects of short-circuiting on machining in order to discuss material removal in EDM of CFRP. Sinking EDM using deionized water as the machining liquid and wire EDM of CFRP were carried out. The relationship between the short-circuiting ratio and material removal rate was investigated. In addition, the potential drop and temperature of short-circuiting carbon fibers were estimated with a simple model. Experimental results show that sinking EDM and wire EDM of CFRP can be realized. It is found that short-circuiting by carbon fibers contributes to the material removal in EDM of CFRP.

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In orthopaedic surgeries involving bone excision, processing damage and excision accuracy strongly influence the postoperative results. Thermal damage from cutting heat causes necrosis of bone cells and should ideally be avoided. In this study, we propose a cutting tool with two types of cutting edges that avoids tissue damage by decreasing cutting force and temperature. By controlling the generation of brittle cracks and finishing the surface with small depth of cut, it is expected that the processing energy can decrease and the precise surface will be also obtained with our method.

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This paper has proposed novel micro-structuring process of CNTs on desired positions by the help of silica particles. In this process, CNTs are previously adsorbed on the silica particles (1μm diameter), and then the CNT-adsorbed particles are self-assembled on a patterned substrate by dip coating. The authors employ both dry and wet processes for CNT-adsorption, in which they are based on chemical vapor deposition (CVD) and electrostatic interaction, respectively. Then CNT-adsorbed particles are self-assembled on a hydrophilic/hydrophobic-patterned substrate. The particles are self-assembled on only the hydrophilic regions. This process allows CNTs to be patterned on a desired position.

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Fabrication of micromechanical structure using self-assembled particles was proposed. Patterned substrate is drawn up from a suspension containing polystyrene (PS) particles, which have a diameter of 1μm. The particles are autonomously assembled on only the hydrophilic regions. These particles are thermally adhered to each other by annealing at 200 degrees centigrade. The underlying SiO_2 layer is dissolved by chemical etching of HF solution. Some line parts of PS particles forms micro-cantilevers successfully. The length and width of micro-cantilever is about 300μm and 50μm, respectively. These results indicate that this process is utilized for fabricating micro-cantilever sensor.

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Feed drive mechanisms are essential components for machine tools, which drive the table system and spindle to fulfill the machining process. The performances of the feed drive mechanism influence the capability of machine tools. In the study, a conceptual design assistance system has been presented, where all of the components of machine tools including feed drive mechanisms are approximated by beam elements. Since the analysis time is short, design engineers can select a suitable structure quickly on the basis of analysis results. Therefore, the system can support engineers efficiently to determine the suitable machine tool structure in the early design stage with consideration of feed drive mechanism.

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A method for replicating snow crystals using a light-curing resin was proposed and the 3D reproduction of a snow crystal by stereolithography was conducted. It was found that a UV light irradiation density greater than 0.2 mW/cm^2 was required to complete the light-hardening reaction within 15 min when polyene/polythiol resin (NOA81) was used as the light-curing resin, and the temperature rise of NOA81 at 0.2 mW/cm^2 was 5 ℃. This means that the initial temperature of NOA81 should be -5 ℃ or lower when the replication is performed under these conditions.

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A cutting force prediction is very important to improve a machining error and a surface property, and to avoid a chatter vibration. A cutting process simulator based on a cutting force model for ball end mill operations has been developed so far. This paper describes a new approach to determine cutting coefficients, which are indispensable to predict the cutting force, for the cutting force model of ball end mills. A feasibility of the proposed method of the cutting coefficients determination is demonstrated in this paper.

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In electrical discharge machining (EDM), the complex discharge phenomena occurring in the gap are difficult to be clarified, and remain to be studied. In this study, light intensities radiated from the plasma which are considered to reflect the material removal behavior were measured under different machining conditions, and simulation was conducted in order to clarify the machining phenomena occurring in the EDM gap. It was found that plasma expanded in a rapid speed within extremely short period of time right after dielectric breakdown and remained constant with the diameter of about 20um after that.

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We are given an undirected complete graph G=(V,E) and a set Q of n transfer requests. Each transfer request i∈Q is characterized by a starting vertex s_i∈V, a destination t_i∈V, a handling time h_i, and the number q_i of staff members to be dispatched for serving the transfer request. A symmetric travel time w(u,v)=w(v,u) is associated with each edge e=(u,v)∈E, and the edge-weight function w satisfies the triangle inequality. Every vehicle is initially situated at a specified home location v_0∈V, and returns to the home after serving at most b transfer requests. We refer to integer b as the serving capacity of the vehicles. The tour time of a vehicle must not exceed a given upper limit l_<max>. For each vehicle, the maximum of the number q_i of staff members among the assigned transfer requests are dispatched. The objective is to minimize the total number of dispatched staff members for serving all n transfer requests. In this paper, we show that the vehicle scheduling problem can be solved in polynomial time if the serving capacity is two.

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