In fluid dynamic bearings operated under mixed lubrication condition, the surface roughness and shape of the sliding surfaces change due to wear in the contact zone, resulting in changes in bearing characteristics over time. In this study, we developed to predict changes in bearing properties over time due to wear. Specifically, a coupled simulation of solid contact analysis considering roughness and shape change due to wear and fluid lubrication analysis based on the solution of the Reynolds equation were conducted. In addition, the effects of roughness and shape change on bearing characteristics in a plane-tilted bearing are discussed, focusing on the instability of the system.

This paper describes that the film formation and shear properties in MAC lubricant were investigated in order to understand the lubrication mechanism under the full-starved conditions. In the tests, a point contacted sliding-rolling tests were conducted, and the film thickness was measured by the optical interferometry method. The results showed that under full-flooded conditions the film thickness decreased with the slide to roll ratio, and that the shear stress increased with the slip ratio. It was also shown that under full-starved conditions the film thickness decreased with time while the wear was not caused in the test duration. In addition, the shear stress from 15 s after the start did not depend on the shear rate and was almost same value corresponded to 18 MPa. These results suggest that the shear properties under full-starved conditions was identical to that in the solidification film.

There is a growing need for grease-free boom extensions on actual cranes. The problem with implementing a greaseless design is that the friction of the sliding parts increases, which can cause material wear. One way to solve this problem is to apply a special coating to the material surface. In this presentation, we will report on the analysis and evaluation of the friction properties of resin sliding material and high tensile strength steel material with various coatings used in crane boom sections using a 3-pin on disc frictional apparatus.

In the arm telescopic mechanism of construction cranes, intermittent vibration may occur due to the frictional characteristics of the sliding parts. This makes it difficult to position the crane with high accuracy in a short period of time, which can hinder high efficiency of crane operation. In this study, as a first step to investigate the cause of this problem and how to suppress it, we analyzed the friction characteristics of a plastic sliding part and high-tensile steel in a 3-pin-on-disk friction test under grease lubrication at various loadings and sliding speeds. The effects of the surface temperature of the materials were also evaluated.

In the telescopic mechanism of construction cranes, intermittent vibrations arising from the frictional characteristics of the sliding components during telescoping operations have become problematic, hindering the arm's high-efficiency functionality and precise positioning. This study aims to elucidate the causes of this vibration phenomenon and explore potential mitigation strategies. To this end, we developed an inclined friction and vibration characteristic analysis apparatus, simulating the operational conditions of an actual crane arm's telescopic mechanism. The results of analyzing and evaluating friction and vibration characteristics under various conditions are reported herein. The analysis revealed that within the scope of this study, higher contact pressures resulted in lower dynamic friction coefficients. Conversely, higher contact pressures and sliding velocities led to larger differences between static and dynamic friction coefficients, creating conditions conducive to increased vibration. Consequently, an increase in vibration was observed.

Conventional bearing materials use lead-bronze (Cu-Sn-Pb) bearing alloys, but Pb content is restricted due to environmental protection and human health concerns. Therefore, we are focusing on sulfide as an alternative material. Sulfides are not toxic like Pb and have the advantage of being available at low cost. Therefore, research is being conducted to use sulfide dispersed bronze as a maintenance-free bearing by uniformly dispersing sulfide in a Cu-Sn alloy. In this study, the difference in strength between vacuum-sintered and reduction-sintered sulfide dispersed bronze, the effect of sintering on the sulfides, and the state of the sulfides are analyzed.

This report deals with a method for comprehending real contact situation by measuring complex refractive index in contact surface. For the contact surface where spherical samples were pressed against a glass plane, the distribution of complex refractive index was measured experimentally and was estimated by Hertz contact theory and the optical model which considered the multiple reflection inside the gap between surfaces and the surface roughness layer. For the BK7 glass lens sample in air or water, the estimated values considering both the surface roughness layer and the gap were closer to the measured values than those considering only the gap. From the above, the optical model that considers surface roughness layer and gap is expected to improve the accuracy of real contact area discrimination within the contact surface.

It has been reported that alkyl diphenyl ether (ADE) exhibits excellent wear resistance and does not decompose unless nascent surface is exposed. However, under extreme contact conditions, decomposition of ADE was observed when the sliding surfaces wore down. This study aims to extend the period of nascent surface exposure by introducing sulfur into the chemical structure. Using Q-mass, the tribochemical decomposition properties of ADE and monoalkylphenoxathiin (MAPT) were investigated. While ADE began to decompose after a sliding distance of 10 km, MAPT did not show decomposition until approximately 30 km, indicating a threefold increase in induction period due to sulfur introduction. This result suggests that the formation of a tribofilm composed of iron sulfide, arising from the chemical reaction of sulfur at active sites, imparts superior wear resistance. Additionally, the gaseous hydrocarbon generation observed with ADE was not seen with MAPT. The likely cause is the high reactivity of sulfur, which leads to catalyst poisoning of the active sites on nascent surface, thereby inhibiting the tribochemical decomposition of the lubricant.

Carbon-based hard coatings are expected as surface treatments for mechanical materials due to their high hardness.炭素 However, to maintain low friction in the atmosphere, it is necessary to suppress oxidation caused by atmospheric oxygen and protect the graphite structure, which is believed to exhibit low friction. In this study, Group 5 elements were introduced into the coatings to protect the graphite structure, and the potential for wear resistance and maintaining low friction through the oxidation and reduction reactions of the Group 5 elements was investigated. Vanadium, niobium, and tantalum were used as Group 5 elements, and ta-C coating, which contain a high proportion of sp³ structure as the carbon structure, were used. The average friction coefficient of the ta-C:Ta coating, which had tantalum introduced into the coating, was approximately 0.043 in air, the lowest among other coating, followed by ta-C:Nb with approximately 0.067.

Graphite-like carbon films are formed as tribofilms when polyphenylether lubricants are rubbed. To investigate the formation mechanism of graphite-like carbon films, tetraphenyl ether (5P4E) oil was irradiated with electron beams and the structural changes were analyzed by Raman spectroscopy. As a result, it was found that a component with a graphite structure was formed in the 5P4E oil. Finally, it was estimated that the triboelectrons generated by friction are captured by the polyphenyl ether molecules, resulting in the formation of graphite-like carbon as tribofilms.

Gas nitrocarburizing is widely used for surface modification of steel parts because it is effective in improving wear resistance, fatigue strength, seizure resistance, and corrosion resistance of steel, and the heat treatment strain is minimal. However, the gas nitrocarburizing process has various problems, such as the long treatment time and the use of ammonia gas. In this study, we developed an atmospheric-pressure plasma jet nitrocarburizing process, which has short treatment time, low environmental load, and easy partial treatment. As a research method uses an atmospheric pressure plasma jet device and uses nitrogen, argon, and methane as the operating gases. Plasma was generated and the plasma spectrum was analyzed simultaneously with the nitrocarburizing process. As a result, luminescence due to N₂, CH, and C₂ was observed. The surface hardness of the nitrocarburized sample increased by 1.2 to 1.6 times compared to the untreated sample after 30 minutes of treatment time, and the hardened layer was 50 μm.

Surface activated bonding (SAB) is a technique that involves irradiating surfaces with an inert gas as a fast atom beam (FAB) in a vacuum to remove oxide films and adsorption layers, thereby activating the surfaces and enabling bonding at low pressure. This technique allows for the bonding of dissimilar materials and piezoelectric crystals. Recent research has developed an evaluation method for the irradiation performance of FAB sources using plasma simulation to enhance the irradiation performance for large-diameter Si wafers. However, this method is only applicable when the FAB source is directly facing the wafer, necessitating an investigation into the effects of oblique placement in actual bonding scenarios. In this study, simulations and experiments were conducted to investigate the effects of oblique placement.

Surface activated bonding is a technology used in semiconductor manufacturing. This technology enables wafers to be bonded directly at room temperature by irradiating them with a fast atom beam. The fast atom beam removes oxides and contaminants from the wafer, thereby activating the surface. A device that emits a fast atom beam is called a fast atom beam source, which generates the beam using plasma from a carbon electrode. However, after several hundred uses, carbon particles are emitted from the electrode surface. These carbon particles cause voids at the wafer bonding interface. In a previous study, a method for in-process quantitative evaluation of carbon particle emissions was proposed. However, hundreds of experiments and measurements were performed manually in the previous study, resulting in widely varying data accuracy. Therefore, in this study, we developed the methods used in previous study and automated all experiments and measurements. The operation of the fast atom beam source and the measurement of particles were automated using “LabVIEW” software. Particle measurement includes photography with a camera and image processing. By automating these processes, the frequency and reliability of measurement improved compared to previous methods. As a result, it was confirmed that particles begin to be emitted after approximately 400 uses, and then continue to be emitted at a constant rate. This behavior is consistent with what has been empirically recorded in mass production sites, confirming the effectiveness of this study.

Surface-activated bonding, also known as room-temperature bonding, uses fast atom beam sources to create high-performance substrates. This technique is used to bond substrates with different coefficients of thermal expansion, such as those in surface acoustic wave filters substrates for next-generation (5G and 6G) communications. This bonding technique is also expected to be utilized for three-dimensional wafer stacking of semiconductors in the future. According to previous studies, it has been confirmed that the irradiation performance of a conventional fast atom beam source can be improved by applying a bidirectional magnetic field. However, a quantitative evaluation of particle emission suppression has not yet been achieved. In this study, we evaluated the quantitative lifetime of the bidirectional magnetic field-applied fast atom beam source, which had not been quantitatively evaluated before by measuring particle emissions from a fast atom beam source in-process. The experimental results confirmed that the lifetime of the bidirectional magnetic field-applied fast atom beam source is at least 1.5 times longer than that of the conventional saddle-field type fast atom beam source. This result indicates that applying of bidirectional magnetic fields to fast atom beam sources is an effective means to suppress particle emission.

We performed friction force distribution measurements to elucidate the lubrication characteristics on micro and nano groove patterns under lubrication. First, we fabricated a lens probe cantilever with a deflection sensitivity of 0.11 mV/nm. The plate specimen was prepared on a Si plate through anisotropic etching, multilayer film deposition, and polishing, resulting in the formation of microgroove patterns and a nanostripe structure on its surface. The cantilever enabled us to observe the meniscus and to calculate the adhesion force as 0.38 mN. From the friction force distribution image, the location of the microgroove patterns was identified under a constant sliding speed condition. It was found that the friction force was lower at the microgrooves than on the ridges. The transition from the mixed lubrication region to the fluid lubrication region was observed at a sliding speed of 100 μm/s. Comparing the average friction force between the nanostripe structure and the microgroove patterns, the friction force of the nanostripe structure was lower at almost all sliding speeds.

Recently, incorporating supercritical fluids into the systems is becoming popular when envisioning the next generation thermal systems. Especially, using supercritical CO₂ as working fluid to further improve the efficiency of power generation systems is getting a lot of attention. However, this power generation systems may cause unstable CO₂ flow, because of CO₂ phase transition heated under supercritical pressure. According to Ambrosini, There are two types of unstable flow: Ledinegg Instability and Density wave oscillation Instability. In this paper, to realize safe power generation systems using supercritical CO₂, we conducted a survey of CO₂ flow in a heated tube under supercritical pressure based on Ambrosini’s stability map and one-dimensional analysis by using Modelica language. Thus, we derived heating situations that CO₂ flow can cause Ledinegg Instability and Density wave oscillation Instability due to heating CO₂ in a tube under supercritical pressure. In addition, we plan to conduct tests on actual equipment based on the heating conditions obtained in this analysis.

This paper describes the prediction model of the heat transfer performance of a heat sink from the viewpoint of 1DCAE for a heat transfer enhancement technology that combines pulsating flow and a heat sink, which is expected to be a next-generation heat transfer enhancement technology. The modified pulsation Strouhal number proposed by the authors was used to construct the prediction model. The target of the prediction model is a pin-fin heat sink, which is widely used as a heat transfer enhancement device and is assumed to have three pin fins arranged in a row. This paper discusses the modeling of heat transfer phenomena on the downstream surface of a heating element, where heat transfer enhancement by pulsating flow is prominent, as a foothold for the model construction. The heat transfer performance of the heat sink was evaluated using the Nusselt number. As a result, the heat transfer performance of the entire heat sink was predicted with an error of less than 5.5% compared to the Nusselt number obtained by 3D thermo-fluid analysis. Predicting the heat transfer performance for different pin fin locations and modeling the heat transfer phenomena that follow the time variation of the flow velocity are future issues.

In the process of simulating the printing process using thermal heads, challenges arise due to the necessity of computations across a wide scale that include minute heat-generating elements, the requirement for three-dimensional analysis that considers the influence of close channels, and the complication of media movement. These factors complicate rapid computation using heat conduction calculations, such as the Finite Element Method (FEM), and also pose challenges for modeling with 1DCAE in general heat conduction scenarios. In this study, we have developed a method that incorporates a surrogate model, which is constructed using Recurrent Neural Networks (RNN) trained with results from FEM computations, into the heat conduction calculations performed by 1DCAE. This approach enables rapid computation while addressing the challenges.

It is generally known that wheel flats tend to occur when the coefficient of friction between wheel and rail is small. However, the specific conditions under which wheel flats occur have not been clarified so far, since they tend to occur randomly. This paper proposes a method for evaluating wheel flat shape generated during braking of railway vehicles. Firstly, we developed a one-way coupled analysis method which combines vehicle dynamics analysis using commercial software, SIMPACK, and wheel/rail friction heat analysis under wheel-stick conditions. Secondly, the tangential longitudinal stress was calculated from the tangential contact force and contact ellipse calculated by SIMPACK, and the tangential yield stress of wheel steel is obtained from high-temperature tensile tests. Furthermore, the equilibrium conditions of the tangential stress and yield stress corresponding to the contact surface temperature are calculated as the contact ellipse of wheel/rail is gradually expanded, and its final shape is defined as the wheel flat shape. Finally, the validity of our proposed method is confirmed by comparing the results obtained by our proposed method with the measurement results for commercial vehicles.

The authors are researching with the aim of establishing a numerical analysis method capable of evaluating vehicle behavior up to after the derailment of a vehicle during earthquakes. In this paper, to develop the analysis method, we proposed a method to sequentially update the characteristic directions of primary and secondary suspensions in accordance with the rotational motion of the vehicle. Furthermore, we use the proposed method to study the influence of the rotation of these suspensions by sinusoidal excitation. The result shows that the influence on the derailment limit is not significant.

Electronic devices used in environments with extreme temperature and humidity changes, such as automotive ECU, have problems with corrosion and short-circuits due to condensation. Generally, potting and desiccants are used to prevent condensation. However, the mechanism of condensation has not been understood because it is difficult to perform experiments under operating conditions. Therefore, we considered to elucidate the mechanism using simulation. In this study, we investigated the effects of temperature and humidity on condensation by simulating an automotive ECU model. As a result, we understood the mechanism of condensation during operation, and found the possibility to apply to thermal design.

In this study, we constructed a simple state space model of a multicopter with a flexible frame, and compared it with an experiment on the attitude angle response when a step input was applied. To simplify the model, we targeted a two-dimensional one-axis rotational motion model fixed to the frame, and constructed a state space model with the frame as a simple cantilever beam. The state space model was constructed separately on the left and right sides of the rotation axis, and the rotation torque of the entire beam was calculated by adding up the left and right rotational torques. From the experimental results of the attitude angle when a step input was applied, it was found that the attitude angle of the flexible frame vibrated more greatly compared to a rigid frame. Vibration was confirmed in both the conventional rigid body model and the state space model of the constructed flexible frame. Although differences were observed in the amplitude and frequency of vibration, the state space model of the flexible frame showed higher vibration accuracy than the conventional rigid body model.

Wheel loaders are used to scoop up earth and sand generated at construction sites and load it onto dump trucks. If the amount of earth and sand scooped up is larger than the weight limit of the dump truck, the amount of earth and sand must be fine-tuned before being loaded into the dump truck inefficiently. Therefore, our laboratory has been studying methods to control the amount of earth and sand while scooping it up. However, the method proposed in previous studies required a traction force so large that it was impossible to realize. To solve this problem, we newly proposed with traction force control method. The new traction force control method was based on the actual movement of a wheel loader. Then, we proposed an earthwork volume control method. The new control method is expected to be able to control the amount of earthwork volume with an accuracy of less than 1% error. To prevent changes in earth and sand properties due to weather conditions, numerical simulations were used in this study.

In physical modeling using 1D simulation, when it is necessary to calculate the area or length of a moving curved object that changes over time, it is common to divide it in the length direction and discretize it. It increases the computational cost. Based on the radar mechanism, this study proposes a method that discretizes a moving curved object by repeatedly scanning a specified range. It avoids the deterioration of accuracy while suppressing the increase in computational cost. We verify the effectiveness of the method through a simple application example and discuss the issues.

In recent years, emission regulations have become stricter in order to strengthen environmental protection. To assess environmental impact more accurately, there has been a shift from WLTP tests using chassis dynamometers to Real Driving Emission (RDE) tests, which measure exhaust emissions and fuel consumption during actual on-road driving. The aim of this study is to reproduce the RDE test by simulating the real road driving conditions of a series hybrid vehicle. First, a driving test was conducted to measure the acceleration and deceleration patterns of a human driver, and fuel consumption was calculated. Next, a simulated road with undulations was created using GSI map data and 3D scene creation software for driving simulations. Furthermore, a real traffic light schedule was introduced as a scenario. In addition, a driver model was developed to control braking according to the signal color. The acceleration and deceleration data used in the simulations were obtained from driving tests. The fuel consumption calculated by the simulation differed by about 13% from the values obtained from the driving tests. It was therefore accepted that the RDE test could be reproduced on a computer by improving the accuracy of the vehicle and driver models.

The Free Piston Engine Linear Generator is expected to be a highly efficient power generation. However, it’s developing know-how is less established compared to conventional engines, and design knowledge is limited. Therefore, 1DCAE was used to optimize the specifications of intake and exhaust paths for maximize torque. In this optimization, five search algorithms were used: GA, Simplex, AGA, CMA-ES, and Bayesian. Their analysis duration and convergence were compared each other’s to evaluate their effectiveness. As a result, Simplex was considered the most effective algorithm for this optimization.

Gas circuit breakers (GCBs) are commonly used equipment in transmission and distribution systems. GCBs are designed to protect the system from over voltage and over current. Conducting operations with damaged GCBs can cause expansion of failure parts and delay their restoration, therefore diagnostic methods for GCBs are essential to ensure a stable power supply. In this study, a one-dimensional computer aided engineering (1D-CAE) model was used to generate pseudo sensor data under different conditions. A multiclass classifier based on shapelets, which are waveform patterns discovered by machine learning, was developed, and generated sensor data was used for training and test. The results showed that the proposed method can accurately classify the location of anomalies in GCBs and provide explanations based on shapelets.

Metalworkingfluids (MWFs) are industrial lubricants used in the processing of materials such as metals, with purposes of lubrication and chip removal. They prevent the overheating and degradation of workpieces, reduce tool wear and friction, and contribute to improved production efficiency and quality. MWFs which require a wide range of performance characteristics are created by blending various raw materials. The formulation adjustment of MWF is so sensitive that even a minor change may occur the stability issues. Because these adjustments impact product performance, they require careful handling. The objective of this study was to explored improving the efficiency of the MWFs development process by applying machine learning-based experimental design. Machine learning models to predict two key physical properties of MWFs: product stability and antifoaming were constructed with four ensemble learning algorithms: Random Forest, Gradient Boosting, LightGBM, and XGBoost. Based on the predictions from these models, evaluating 20 proposal formulations from the models, two samples in the proposal achieved all goals. Furthermore, the one of the two samples showed the best antifoaming index in all training samples.

The substantial heat generated during the grinding of titanium alloy workpieces poses challenges for heat dissipation, leading to surface damage and reduced machining accuracy. This study investigated heat diffusion during dry grinding of titanium alloy. Stationary heat source and grinding experiments were conducted on the Ti-6Al-4V specimen, with copper specimen serving as a control group. The grinding temperature of Ti-6Al-4V specimen is more affected by the feed rate than normal material, while it is similarly affected by the grinding depth and is minor by wheel speed. The temperature fluctuation was utilized to illustrate the degree of heat penetration. The results indicate that the heat is concentrated in the shallow layer of the Ti-6Al-4V workpiece, while the deep layers are less affected by the motion of the grinding wheel, exhibiting behavior similar to that of being heated by a constant heat source. The heat diffusion pattern during grinding in Ti-6Al-4V specimens was analyzed.

Swiss-type automatic lathe is used for machining small and complex shaped parts. Since it has many axes to realize machining of complex shaped parts, it is assumed that there are many geometric errors between axes. However, there are no studies of organizing geometric errors on Swiss-type automatic lathe and modeling. In this paper, geometric errors that exist in a Swiss-type automatic lathe are summarized, and a mathematical model which represents the tool tip position in workpiece coordinate system considering geometric errors is developed. Machining tests to evaluate influence of the geometric errors and their simulations are carried out. The tests are groove machining tests by a ball-end mill with simultaneous multi-axis motions. Accuracy evaluation tests by using a reference sphere and LVDT are also developed. Actual measurement tests and simulations are compared to confirm the correctness of the developed model. It is confirmed that the developed mathematical model can correctly represents influence of the geometric errors in both of the machining and measurement tests.

From the machining center (MC) user’s point of view, the authors have developed a practical approach to simulate the motion trajectory of a cutter path produced by the NC acceleration/deceleration processing and position servo control for a target MC. Corresponding to normal machining conditions, the approach can provide very accurate evaluation results for the motion error of a circular arc interpolation cutter path. However, in the case of a path including small arc segments with very high feed rate, there are some areas where the simulation results of the tool path trajectory do not match the measured ones due to the unique NC cutting modes of the target MC. In this study, we confirm and quantitatively evaluate the limit condition values for each cutting mode through experiments, and then introduce a simple and convenient operation into the simulation approach to consider the effects of the cutting modes on cutter path motion trajectory. The effectiveness of proposed operation is sufficiently demonstrated by the verification experiments.

In recent years, with the shift to electric vehicles, gear systems are required to be quieter. However, small waviness errors on the gear tooth can cause noise and vibration. Since it is difficult to completely prevent the generation of microscopic waviness due to changes in machining conditions during the gear grinding process, the tooth surface is measured by sampling inspection to eliminate defective gears that contain microscopic waviness. However, it is difficult for existing tooth surface measurement methods to achieve the high accuracy and high speed required to detect defective gears in total inspection. In this study, a high-precision and high-speed tooth surface inspection method based on angular information is investigated. Angular information of the surface gradient can be used as a more sensitive indicator than displacement in the measurement of micro displacement because it represents the rate of change of the geometry. In this study, an angle probe that can measure the angle of the surface gradient is placed on the tangent line of the gear's base circle, and the tooth surface gradient is measured while the gear is rotating. We measured gears using a reflected illumination telecentric optical system as an angle probe and attempted to detect the waviness of the tooth profile.

The purpose of this research is to propose a physical mock-up technology at the upstream design stage that enables usability evaluation by testing the shape and structure of products based on various ideas with human touch and feeling, and acquiring digital data related to their operation. This paper explains the author’s new physical mock-up technology that combines an infrared motion capture device with a visible light absorbing and infrared transmitting filter on a three-dimensional object made of a thin transparent plastic sheet.

Motion in industrial products contributes to both functional and aesthetic qualities, and stimulates user curiosity and interest, thereby encouraging the formation of attachment to the product. In this study, we deduced that the optimal prediction error from typical motion leads to interest, and that fluctuations in prediction error arouse curiosity. Using the free energy principle, a unifying principle of the brain, we formulated that fluctuations in prediction error encourage curiosity and decreases in prediction error arouse interest. We also developed a system to generate motion by controlling prediction error, and experimentally confirmed that the evaluation of interest is convex upward with respect to prediction error and that fluctuations in prediction error increase curiosity.

When the circular economy is realized in the near future, the requirements for product design maust change drastically as a fundamental shift in the social structure is anticipated. Therefore, it is necessary to discuss the way that product design should be by forecasting technological and social trends, and backcasting from a possible or ideal vision of the future. This paper argues the issues of product design related to the circular economy. In order to discuss product design methods based on the assumption of product circulation, we formulate an optimal design problem that takes into account equipment performance and replacement cycles. The results of a case study of a residential air conditioner show that the design specifications are different from those of conventional products under the assumption that they can be recovered and replaced at the optimal timing, and design solutions that achieves highly efficient operation despite rapid deterioration are derived. In addition, scenario studies on the level of remanufacturing and other regeneration technologies provide insight into the development goals of these technologies.

In the manufacturing field, adding value and reducing environmental impact are required. This study aims to develop cutting technology for creating highly functional surfaces while machining a desired shape to consolidate and reduce the surface treatment process, which emits a significant environmental burden. Specifically, we make a surface with an intended uneven shape by cutting marks, improving its functionality.

In this study, we created surfaces with square cutting marks of three different sizes by ball end mills with 10 mm, 5 mm, and 2 mm diameters. To evaluate the functionality of those machined surfaces, the gloss and the static contact angle of water were measured. The gloss level varied with the size of the cutting marks, although there was no proportional relationship between the size and the gloss level. Observation of the static contact angle of water from the tool feed direction showed that the contact angle increased with smaller cutting marks.

Low-frequency vibration cutting is a machining method that breaks up chips. The intermittency of the cutting process is considered to affect the performance of cooling and lubrication. The authors have reported that maintaining the intermittency of the process improves tool wear. However, the effect of the machining atmosphere on wear has not been analysed in terms of cooling, lubrication and chip break-up. In this study, the effects of various machining atmospheres on tool life were experimentally evaluated, considering that the suppression of cutting temperature and efficient chip break-up are effective in reducing tool wear by making effective use of the intermittency of the low-frequency vibration cutting process.

We aimed to machine grooves without chipping on SiC substrates using a PCD blade. In this study, three types of water supply methods, dry processing, water processing, and coated water processing were compared and evaluated each other. The evaluation methods were performed by the groove surface condition of the SiC substrate, grinding resistance, and the temperature at the side of the blade. These results indicate that coated water processing is the best way to cool down the blade surface and to eliminate cutting chips from the groove.

This research has developed a fiber conditioner that can grind more uniformly and finer than conventional types of conditioners used to maintain the surface condition of polishing pads in the semiconductor CMP process. Evaluation of the cut rate and measurement of chips showed that the fiber conditioner can grind more finely than conventional types. In addition, evaluation of the conditioner's flutter using an AE sensor and removal rate revealed that it can condition the entire polishing pad more uniformly than the conventional type.

A method using a convolutional neural network (CNN) to predict and correct inaccuracies in incremental forming. By training the CNN with height data of truncated cone shapes, the network can generate more accurate tool paths reducing errors in forming height, wall angle, initial diameter, shear droop height and gap volume. Three models were created with resolutions of 50×50 pixels, 100×100 pixels and 200×200 pixels for training data. The results demonstrated that the CNN significantly improved forming accuracy, with the 100x100 pixel model achieving optimal performance. This model showed the best balance between computational efficiency and detail resolution, achieving a height matching rate of 75.351%, an angle error of 0.852%, an initial diameter accuracy of 91.426%, and reducing gap volume and shear droop height by 39.359% and 23.386% respectively. The findings highlight the potential of CNNs in improving the precision of incremental forming, suggesting further research into complex shapes.

This paper presents an application of a developed convolutional neural network (CNN) to improve the forming accuracy of polygonal pyramids and spherical segments in incremental forming. The developed CNN was trained using height data converted into CSV files, generating new tool paths for forming. Three models were created with resolutions of 50×50 pixels, 100×100 pixels and 200×200 pixels for training data. The research method involved comparing the traditional and CNN-generated forming processes, focusing on parameters which include wall angle, forming height, initial diameter, gap volume, and shear droop height. Among the models tested, Model100 generally provided the best results, outperforming traditional methods and other CNN models. Results showed that the CNN approach significantly reduced free surface deformation and springback, leading to more precise shapes. This study highlights the potential of CNNs in improving the incremental forming process, suggesting further application to more complex shapes and the potential for broader industrial adoption.

Polarization effect, as a significant aspect of femtosecond laser-material interactions, on laser drilling has received much attention. However, the polarization effect, especially in vector polarization, on the laser drilling of transparent materials has not been systematically investigated. In this study, we systematically compared the drilling performance and investigated the hole depth evolution process under different polarization via the high-speed pump-probe imaging technologies. This study yields a comprehensive understanding of the polarization effect on ultrafast laser processing and underscores the potential for tailored polarization approaches to enhance manufacturing processes, offering valuable insights for polarization-modulated processing strategies in industrial contexts.

Recently, there have been increasing demands for high resolution and accuracy in laser processing to improve functions of three-dimensional microstructures. In order to satisfy these demands, further development of laser ablation is needed. As a laser processing technique, laser ablation using a photonic nanojet (PNJ) has been developed. In order to improve the accuracy of laser ablation using PNJ, it is necessary to clarify the mechanism. The shock wave generated by ablation propagate through air and reach the microsphere. It is thought that the shock waves can be detected to quantitatively analyze the conditions during processing. Therefore, we consider using the microsphere as a probe to detect the vibration. In this paper, we experimentally demonstrated that shock wave detection is possible during single-shot laser irradiation and discussed the relationship between the amount of processing and shock wave.

People with visual and hearing impairments often experience inconvenience in their daily activities due to the limited information they can obtain from the environment. In particular, they cannot respond to danger signals such as alarms or calls from others, leading to decreased quality of life, such as when exposed to danger. To replace these senses, information presentation devices using cutaneous sensation have been studied, but they are not yet widely used. We have been studying devices that present information using vibrations and electrical stimulation. This report describes these devices and a new cold sensation presentation device prototype.

A robot unit packaged with a flexible plastic film was developed. By packaging the robot with a thin plastic film, waterproofing was achieved at a low cost and using a simple method. This robot can operate underwater and in living areas by being waterproof. This study developed a robot based on the “robot packaging method.” This method is a technology of vacuum packaging a robot and insulating fluid in a film. Since this robot has three links, it can be expected to work as a stand-alone robot. The effects of the film’s length and the amount of liquid on the range of motion of the robot unit in the robot packing method were confirmed through experiments. The experimental results confirmed that in this robot unit, the amount of liquid affects the range of motion. Furthermore, it was shown that the optimal length of the plastic film may change depending on the robot’s shape and the amount of liquid. In this study, the proposed robot is intended to be used for various tasks, and examples of its use as a locomotive robot, a robot hand, and a fish-like robot are shown. In an underwater experiment using a fish-like robot, we confirmed that the robot packing method was waterproof, operated underwater, and achieved movement as a single robot unit, similar to a mobile robot. As for the robot hand, we confirmed changes in the gripping force of the object by changing the hand position.

Recently, the demographic aging and the increase in the people certified for long-term care are social problems. The demand for welfare equipment such as electric wheelchairs is increasing in nursing care sites. Not just conventional electric wheelchairs, there are electric driving unit that convert manual wheelchairs into electric wheelchairs by attaching driving wheels. However, many of these electric driving units are unable to fold when attached. Therefore, they have the problems with ”portability” and ”storability”. We developed an electric driving unit that is usable as an electric wheelchair by replacing both front casters of a manual wheelchair. The folding functionality of the wheelchair is maintained when attached. The electric drive unit consists of the left and right drive unit and the controller unit. The wheelchair is operated by using the joystick and the switchs mounted on the controller unit. As a result, it was confirmed that the wheelchair with electric driving unit is able to perform basic movements such as "going straight", "steering" and "turning" when a person boarded on wheelchair.

Today, aging of population is one of the serious problems of Japanese society. Additionally, the number of senior citizens certified as requiring long-term care is also increasing. Therefore, the number of elderly people who use wheelchairs is predicted to increase. By attaching drive units to a manual wheelchair as needed, the burden on the user and caregiver may be reduced. In this study, compact drive units for a manual wheelchair were produced. The units are designed to be simply attached and removed without disassembling the manual wheelchair. The size and weight of the unit are reduced by dividing them into left and right. The units are attached near the left and right rear wheels of the wheelchair to turn in tight spaces. In this study, it is confirmed that the units are able to attach to a manual wheelchair without disassembly. In addition, it is ascertained that wheelchair with the units are capable of running straight and turning by using the joystick.

During stroller use, there are obstacles on the road, such as bumps and gradients, which pose a risk of accidents due to potential operational errors. Therefore, it is necessary to improve the stroller’s maneuverability and stability to reduce the physical burden on the operator and enhance safety. This study aims to clarify the impact of the camber angle of the stroller’s rear wheels on its maneuverability and stability. The study involved three young male participants and included experiments to measure straight-line performance and assess the muscle burden on the forearm during S-curve driving, investigating the effects of different camber angles. The results showed that straight-line performance was significantly improved at a camber angle of 15° compared to camber angles of 0°, 5°, and 10°. Additionally, the muscle burden on the forearm during S-curve driving decreased as the camber angle increased, with a significant reduction observed at a camber angle of 5°. These findings suggest that adjusting the camber angle of the stroller’s rear wheels can effectively enhance both maneuverability and stability.