The main study objective was to evaluate the influence of the perspective "Internal" (coolant is supplied to the channel inside the indexable insert body) and "Combined" (coolant is supplied to the rake and flank faces through the channel inside the indexable insert body) Cooling Schemes on the temperature of the contact point between the tool and the workpiece, on the heat distribution inside the indexable insert body, and (additionally) on the cutting forces. The contact point temperature and cutting forces were investigated during the non-orthogonal turning of SUS304 Stainless Steel at speeds of 180, 140, and 100 m/min with constant feed and depth of cut. The heat distribution was examined through 2D simulations using DEFORM 2D3D software. The evaluation of the perspective cooling schemes' influence on the selected parameters was performed by comparing the obtained data with the test results of the "traditional" external cooling and dry cutting under similar cutting modes. According to the comparison results, the perspective cooling schemes demonstrated a slight decrease (~3-7%) in the temperature of the contact point between the tool and the workpiece, a significant decrease in the heat distribution (~38-55%) inside the indexable insert body and, in some cases, a decrease of the cutting forces. Based on the study results, the authors confirmed the influence of perspective cooling schemes on the selected parameters and suggested a further positive effect of these schemes' utilization on the cutting tool life.

An investigation is carried out through experiments and numerical calculations for the improvement of the resolution of measuring the pitch deviation of a diffraction scale grating with the diffracted beams. Since the changes in angles of diffraction of the diffracted beams detected by an optical head are utilized to evaluate the pitch deviation in the method, the sensitivity of the optical head directly affects the resolution for measurement of the pitch deviation. Meanwhile, in the previous studies, the resolution of a laser-autocollimation unit in the optical head for the detection of the change in the angle of diffraction of a diffracted beam has been limited to approximately 0.1 arc-second; this has been a bottleneck in increasing the resolution for measurement of the pitch deviation. In this paper, an investigation using a prototype optical head is first conducted in preliminary experiments to clarify the cause of the degradation of the resolution for measurement of the pitch deviation. Numerical calculations are also carried out to confirm the influence of the multiple longitudinal modes (MLM) of a laser beam, which is suggested as the main cause of the degradation of resolution in the results of preliminary experiments. Based on the results of experiments and numerical calculations, an attempt is made to employ a laser beam having a single longitudinal mode (SLM) in the optical head. The pitch deviation of a scale grating with a nominal pitch of 4 μm is measured by a prototype optical head with an SLM laser to verify the improvement of the resolution for measurement of the pitch deviation.

The bone marrow examination is an essential investigation, from diagnosing many hematologic diseases to evaluating the effectiveness of treatment. Evaluation of bone marrow smears in bone marrow examination requires microscopic counting by a clinical laboratory technician. To obtain reliable test results, they must acquire extensive experience and high technical skills. However, this current method limits the number of examinations due to a chronic shortage of human resources. To solve this issue, various studies have been conducted on methods utilizing both deep learning and image processing technology for the automatic classification of blood cells. When incorporating these methods into actual clinical examinations, medical technologists must manually obtain the images of bone marrow smear surface at high magnification utilizing an optical microscope. However, this process significantly consumes time and labor. Thus, the purpose of this study is to develop an automatic imaging system for bone marrow smear surfaces by combining an imaging instrument and a method for determining a focused image. Moreover, based on the results of analyzing the color features of blood cells, this paper proposes a system that generates images suitable for automatic classification of blood cells by extracting individual blood cells utilizing image processing technology such as the watershed algorithm. To validate the effectiveness of the system, we conducted a case study. The results confirmed that the system could automatically obtain images of bone marrow smear surfaces, and 3114 blood cells were successfully extracted from 20 images (155 cells per image). The number of these that could be classified by the technician was 2871 (92.2%).

Automated process planning is one of the means to shorten production lead time, and there have been many previous studies because it is particularly effective for high-mix, low-volume production factories. However, to build a practical automated process planning for organic shapes, it is necessary to consider the computational cost and keep the machining time as short as possible. Therefore, this study proposes an automated process planning system that effectively combines turning, which has good workpiece removal efficiency, and milling, which allows more flexible machining. The system extracts the contour line model and its solid of revolution as point cloud data from the 3D CAD model in STL format, and performs process planning based on these extracted point cloud data, the specified workpiece geometry, and the machining conditions. Furthermore, it automatically generates tool paths and NC programs that consider tool interference. Machining experiments were conducted on a multitasking machine to verify the validity of the automated process planning system proposed in this study. As a result, it was confirmed that the proposed system can perform automated process planning for organic shapes, and is effective in reducing machining time when roughing by turning is applied.

This study proposes a method for extracting the machining region machined by swarf machining and hole drilling from a Standard Triangulated Language (STL) data exported from 3D CAD and automatically generating a tool path. First, a method is proposed for extracting the machining region and obtaining geometric features, such as slope, curved surfaces, holes, and pockets, from the STL data exported from 3D CAD. The STL data uses only triangular mesh data and drops all information, which is necessary for extracting the removal volume for the machining and geometrical characteristics. Then, a half-edge algorithm is proposed that clarifies the connection relationship between planes by integrating triangular meshes of the same plane in a model in STL data and realizes automatic extraction of machining regions through the analysis of shape data. Subsequently, a method is proposed to determine the 5-axis indexing posture and generate a tool path according to the geometrical features of the machining region. A machining experiment was conducted to validate the effectiveness of the proposed method. As a result of the machining experiment, it was confirmed that the tool path automatically generated from the STL data exported from 3D CAD can be machined without any problems and with a practical level of accuracy.

This paper examines the machining accuracy when simultaneously machining pilot holes and threads, and the machining accuracy when machining threads after pilot hole drilling. To verify them, cutting forces were measured in the tool rotation coordinate system using a wireless holder. To examine the influence of the machining area of the tool bottom edge machining the pilot hole, three patterns of pilot hole diameters (φ0 mm, 7.0 mm, and 8.5 mm) were used. The results showed that when the pilot hole diameter is φ0 mm, the cutting force in the plane direction does not increase significantly compared to the case with a pilot hole due to the offset effect of the cutting forces generated by the facing cutting edges when machining the bottom edge. Therefore, if chip entrapment can be prevented, it is highly possible to omit the pilot hole, improve machining efficiency, and maintain machining accuracy. It was also found that tool vibration could be reduced. However, when the pilot hole diameter is Φ0, the load in the tool axis direction increases. Therefore, it was also found that machine rigidity and tool life must be considered due to the increased load during machining. These results are summarized in this paper.

This study investigates the effects of ultrasonic vibration-assisted drilling with a 0.3 mm diameter drill on engagement behavior and hole dimensions. The study addresses the increasing demand for small-diameter deep drilling in fuel injectors and medical instrument applications. The proposed “suitable ultrasonic vibration-assisted drilling” method is introduced to optimize small-diameter deep drilling processes. The chisel-walking phenomenon in conventional drilling is a challenge addressed in this study, and ultrasonic vibration-assisted drilling was explored as a potential solution. At first, the engagement behavior observation experiment was conducted. Circularity improved significantly when ultrasonic vibration amplitudes exceeded 4 μm, with a corresponding improvement in position deviation at amplitudes of 10 μm. In the condition of ultrasonic vibration amplitude was 4 μm_p-p, and spindle speed of 500 and 1,000 min^-1, the circularity dramatically improved, almost 0 μm. The chip removal volume in this condition was 53.07 μm³ on one period of ultrasonic vibration. From comparing the chip removal volume with other experimental conditions, the engagement behavior can be improved by reducing the chip removal volume as much as possible. Based on the engagement behavior observation experiment results, the experimental conditions were applied to the suitable ultrasonic vibration-assisted drilling, and the hole dimensions were measured. During the engagement, the spindle speed, the chip load, and the ultrasonic vibration amplitude were set to 1,000 min^-1, 1 μm/tooth, and 4 μm_p-p, respectively. The variation in the size of the holes was 0.0024 mm compared with 0.0043 mm in conventional drilling. Furthermore, when the ultrasonic vibration amplitude was applied 1 μm_p-p during engagement and deep drilling, the dispersion was further improved to 0.0015 mm. The results show that suitable ultrasonic vibration-assisted drilling suppresses the variation in hole dimensions compared to conventional drilling.

This study developed a voxel-based method to simulate machining error caused by elastic deformation of the tool and workpiece in end milling. The tool and workpiece shapes are represented by a set of cutting edge points and a voxel model, respectively. The cutting force is calculated based on the collision state between the cutting edge points and workpiece voxels. The elastic deformation is analyzed based on tool and workpiece elastic deformation models and the predicted cutting force. The tool deflection is predicted by a composite model of a cantilever beam and spring. In addition, each voxel representing the workpiece is connected to adjacent voxels using beam elements to build a stiffness matrix for the workpiece. The stiffness matrix and the predicted cutting force are used to predict the workpiece deflection. The predicted workpiece deflection is converted to tool distortion, which keeps the geometric relation between the tool and workpiece equivalent. By considering the tool deflection and distortion corresponding to the workpiece deflection, the cutting edge trajectory is simulated. Machining error can be obtained from the predicted cutting edge trajectory. The change in the workpiece shape is represented by removing voxels. The advantages of this method are that re-meshing is not required to update the workpiece shape change and that re-building the stiffness matrix is not time consuming. Additionally, both models to predict the cutting force and the deflection are linked closely to each other based on the voxel model. It is very important to consider the effect of the elastic deformation on the uncut chip thickness calculation in the cutting force prediction. Especially in the cutting of a thin wall, the effect of the elastic deformation on the uncut chip thickness in the cutting force prediction is quite large. The predicted machining error in the cutting operation of a thin wall had good agreement with the measured one in the experimental verification.

Cube-machining test is a possible method for evaluating the accuracy of five-axis machining centers. Although the geometric errors of rotary axes can be evaluated by measuring the height and inclination errors of the machined surfaces, other error sources, such as tool length and profile errors, influence the machining accuracy. Clarifying the factors that influence the machined result is necessary to correctly evaluate the machine tool accuracy based on the cube-machining test results. In this study, the effect of tool path and Z-axis reversal error motion on the cube-machining test accuracy was investigated. Actual machining tests were conducted with three types of the reversal error conditions of Z-axis. The Z-axis reversal error directly affected the results owing to different Z-axis motions for each surface of the workpiece. Based on the investigation, for the machining, a tool path pattern, which can reduce the influence of the Z-axis reversal errors by restricting the motion direction changes of Z-axis for all surfaces, was proposed. According to the Z-axis reversal error test results, the surfaces machined using the proposed tool path were not affected by the reversal error.

In mass production, the tool life of cutting tools is generally controlled by the number of parts to be machined and the machining time, making it difficult to operate each tool to its full life. In addition, it is desirable to avoid tool changes due to tool life during machining in order to avoid an increase in machining setup time. This study proposes a process design and tool path generation method that predicts tool life based on the tool flank wear width as a cumulative value of the contact length between the tool edge and workpiece during machining, and selects tool assignments and machining sequences for machined parts based on the predicted tool life. Based on the contact length corresponding to the defined tool life and the contact length estimated by machining simulation, a tool is selected that can use up as much of the tool life as possible. Since the contact length during machining varies depending on the cutting conditions, this study proposes a method to shorten the machining time by generating tool paths with different cutting conditions to accelerate the progression of tool flank wear and use up the tool to the limit of its service life, even in situations where the tool is conventionally discarded because it cannot be used up to the limit of its life.

Non-step drillings of deep holes with twist drill are required to achieve high production rates in machine shops. However, tool breakage sometimes occurs due to chip clogging in the holes. The surface finish is also deteriorated by chip scratching. These machining troubles are induced by the change in the chip flow accompanied by tool wear progress. This paper discusses the cutting process in drillings of deep holes in terms of the geometrical change in the cutting edge with the tool wear. The chip flows towards the radial direction with the change in the edge shape when the tool wear increases. Then, the chip clogging in the hole induces a large oscillation in the cutting force. The chip flow is also analyzed with the change in the edge shape due to the tool wear by the energy-based force simulation.

The demand for Ni-based alloys, particularly Alloy 718, is increasing in the gas turbine industry due to their high-temperature resistance and chemical stability. However, Alloy 718 is challenging to cut, owing to its susceptibility to work-harden, its high cutting resistance, and its poor thermal conductivity. Ultrasonic elliptical vibration cutting (UEVC) can be performed on steel materials using diamond tools, which is facilitated by elliptical vibration of the tool. This approach helps suppress heat generation at the tool tip and prevents chemical decomposition. In this study, we explored the precision cutting of Alloy 718 using UEVC with planar cutting and a single-crystal diamond flat tool. We achieved a surface roughness Ra of 8.4 nm at a cutting speed of 2.0 mm/s. We compared surface roughness under various conditions, including cutting speeds, the amplitude of elliptical vibration, and cutting depth, to investigate the effect of these parameters on surface roughness. Additionally, we studied the geometry and thickness of chips under these conditions using scanning electron microscopy (SEM) images. Our findings indicated flow-type chip shapes in all conditions, signifying stable ductile-regime cutting. Moreover, tool life was investigated by observing the cutting edge, which exhibited slight wear, maintaining a mirror surface for a cutting distance of approximately 50 m. These findings reveal an effective method for high-precision surface fabrication of Alloy 718, elucidating the cutting mechanism and the feasible cutting distance.

A rotary tungsten inert gas (TIG) torch has been developed to enhance the quality and complexity of fabrications in wire and arc additive manufacturing (WAAM). This study explores the influence of arc length on deposition characteristics within a rotary TIG torch by adjusting the wire feed speed, travel speed, and shielding gas type. The findings reveal that the unique vertical wire feeding mechanism of the rotary TIG torch prevents the wire-feeding position shift typically observed in conventional TIG processes. However, extended arc lengths in the rotary TIG setup tend to induce arc deflection and molten metal scattering due to the employment of a tilted electrode. Specifically, at high wire feed and travel speeds, bead continuity is compromised by molten metal scattering. Conversely, at low travel speeds relative to wire feed speeds, defect-free deposition is achievable across a broad arc length spectrum from 4 to 20 mm using rotary TIG. Furthermore, decreasing the wire feed speed in proportion to the current and increasing the heat input per material input minimizes the contact time between the wire and the molten pool, thus mitigating arc deflection. Employing helium-mixed gas as a shielding gas facilitates defect-free deposition over an extensive range of arc lengths, even under conditions that typically induce humping with pure argon.

Recently, there has been a growing interest in utilizing surface texture to enhance the tribological properties of sliding components. Particularly noteworthy is the application of tool vibration at ultrasonic frequencies for efficiently generating surface textures. This study focuses on generating surface texture on the end surface of a stainless steel disk through ultrasonic assisted turning. The mathematical expression of the theoretical texture configuration, derived from the tool trajectory, is closely aligned with the actual machined surface. A novel geometric analysis was conducted to address the challenge of interference between the finished surface and the flank surface, resulting in a reduction in texture height. This analysis revealed that the texture height error from the theoretical value was limited to within 10%. Ball-on-disk tribological experiments were also performed on the textured surface to assess starting friction phenomena. The findings indicated that surfaces with texture exhibited a more minor fluctuation in the starting friction coefficient compared to those without texture. In summary, this paper explores the efficient generation of surface texture on stainless steel disks using ultrasonic assisted turning. Theoretical configurations were mathematically expressed and aligned well with actual machined surfaces. The study also introduced a novel geometric analysis to address interference-related texture height reduction. Moreover, tribological experiments demonstrated that textured surfaces experienced a more stable starting friction coefficient, highlighting the potential of surface texturing for improving tribological properties in sliding components.

Some nanoscale technologies are being employed without a full understanding of the underlying phenomena. Both static and dynamic observations of nanoparticles are essential for investigating these phenomena. While there are several methods for static observation such as scanning electron microscopy typically in a vacuum environment, however, there are few methods for dynamic observation. One of the dynamic observation methods is to observe nanoparticles using an evanescent field, a unique field that emerges only near the surface being observed. The dynamic observation method has been proposed for measuring the three-dimensional positions of moving nano-particles in liquid using a multi-wavelength evanescent field. However, the absolute height of the nano-particles remains unexplored in this study. Hence, to establish this method, it is necessary to confirm the absolute distance or the height from the surface being observed at the same position by other reference measurement methods. In this paper, an optical resin with a refractive index close to the water was formed as an invisible reference tilt surface that was thinner than 200 nm in height. We also constructed a compact interferometric optical system to utilize optical interferometry that can measure the height of the tilt resin without contact and with nanoscale accuracy. Polystyrene standard nano-particles suspended in water were deposited onto the water-invisible tilt resin and was measured the height at each position on the tilt resin by a multi-wavelength evanescent field. As a result, it was confirmed that the 3D position measurement of particles using multi-wavelength evanescent fields tends to follow the resin surface height well. At the heights under approximately 100 nm, the differences in height were less than 5 nm between multi-wavelength evanescent fields and interferometry measurement, and the precision (2σ) also was approximately 5 nm.

Low-frequency vibration cutting technology can actively generate an intermittent cutting process in which chips are broken up by vibrating the tool in the feed direction synchronized with the spindle rotation. The sinusoidal oscillation superimposed to feed drive motion triggers cutting thickness fluctuations so that air cutting occurs. To attain efficient and practical machining, selection of appropriate conditions for low-frequency vibration cutting is important. From a practical point of view, it is necessary to analyze the cutting process for its effects on tool wear as well as chip breakup. Low-frequency vibration cutting has been reported to reduce average cutting force and average cutting temperature. On the other hand, few studies have analyzed the effect of tool trajectory on the tool life, and thus the mechanism has not been fully clarified. In this study, the effects of low-frequency vibration on the tool life in turning operations were experimentally investigated for carbon steel, stainless steel, and titanium alloys. In low-frequency vibration cutting of ductile materials such as carbon steel and stainless steel, tool damage was significantly improved by designing an intermittent cutting process with large amplitude. On the other hand, the tool life for titanium alloys was deteriorated in low-frequency-vibration cutting. The experimental results indicated that the higher the vibration speed, the faster the tool wear progression in titanium alloy machining. Model-based analysis of the cutting force revealed a characteristic mechanism of the flank wear development that depends on the tool trajectory with low frequency vibration.

Currently, measurement of long and thin objects is done by the contact method. However, some problems such as long measurement time including fixing the gauge and the object to be measured and the effects of buckling and other problems caused by contact loading. Therefore, there is a need for length measurement of long and slender objects in a short time with high accuracy. In this study, we deem that the non-contact spatial frequency filtering method, which has been studied and developed in our laboratory, can satisfy the requirements given in this study. This method adopts the optical configuration of the traditional projection optical system, but removes the transmitted ray and only allows the high-order diffracted rays generated by the edge of the object to be measured to enter the camera under the condition of parallel ray irradiation. At this time, the diffracted ray generated by the edge of the object to be measured will appear as a bright-dark-bright line segment on the camera. And the position with the lowest brightness value in the dark part will be the specific position of the edge of the object to be measured that is illuminated by parallel light. The standard deviation of the results in 30 repeated placement experiments was around 1 micrometer.

This study entails an examination and comparison of features observed in an accelerometer signal obtained from floating-scrap detection during stamping with those obtained using the “center-of-gravity” method, which is conventionally used for anomaly detection via machine learning. The samples are detected using the Mahalanobis–Taguchi system. If using the center-of-gravity method, the unit space that contains normal samples without scraps cannot be separated from the error samples. Based on an estimated threshold for detecting all the error samples, the false-positive rate of the abovementioned method is 0.9 %. In this study, a suitable threshold that allows the system to detect 100 % of the error samples (and no normal samples) is estimated using six features. Detection using the six suggested features is more effective than that using only three features associated with the downward journey of the press slide. Features selected from two different events (i.e., the downward and upward journeys of the press slide) may result in more effective detections than features selected from only one event (i.e., the downward journey). To confirm the effect of tool wear, six experiments based on normal samples are conducted after all error samples are created. The machine-learning method with the suggested features is more insensitive to tool wear than the center-of-gravity method, as the features correspond closely to the size and deformation of a foreign object. Nevertheless, the unit space should be updated as tool wear progresses; otherwise, false positives may occur even when the suggested features are used.