In aim to shorten lead-time of die fabrication, electrical discharge machining is being replaced with cutting. However, when cutting with tools of long extrusion length, achieving necessary accuracy becomes difficult due to chatter and machining remains. Therefore, cutting and measurement are repeated until satisfactory cutting conditions are achieved. Concerning this problem, we have developed a technique that analyzes profile error and surface roughness before machining, by simulating dynamic vibration of the tool. In the simulation, cutting force is calculated through integration of cutting force and edge force. It has been confirmed that taking in account the area where ploughing takes place due to the tool shape, takes a large role especially in deep die mold cutting. Also through the developed time domain simulation, the normal chatter free cutting conditions at around 0 degrees phase shift between the cut, was found to have large profile error. On the other hand, it has been found that at around 180 degrees phase shift, there is a condition where both chatter and profile error are suppressed, enabling high speed machining of deep die mold, without the need to repeat the same process in production, to satisfy the necessary accuracy.

Carbon or Ceramic particles are randomly arranged in conventional functional devices such as fuel cells or Li batteries because they are mainly produced by screen printing or spray coating. Carbon-aligned structures with low tortuosity and larger interface area can possibly improve the performance of such devices because it smoothens mass or proton transfer through membranes and increases active chemical reaction area. The biggest challenge faced while producing a carbon-aligned microstructure is the aggregation of particles, which prevents mold packing. We demonstrated a powder molding method with a centrifugal acceleration varying from 9.8−9.9×10⁴ m/s². Greater centrifugal force increased the ratio of fulfilled particles. Discrete element method simulation was also performed to clarify the interaction between particles. The simulation results are similar to the experimental results, and they indicate that centrifugal acceleration does contribute to mold packing in this method. This study investigated mold packing, which is the first stage of powder molding.

The purpose of this paper is to clarify the influence of tool electrode materials on discharge delay time in electrical discharge machining (EDM). In this study, Copper, brass, and zinc were used as tool electrode materials. Experiments of single pulse discharge were conducted for both polarities, with and without debris particles put in the gap, respectively. The experimental results showed that regardless of the machining polarity and existence of debris particles, under the same machining conditions, the average discharge delay time was longest when using brass as the tool electrode material followed by copper, and shortest using zinc. This tendency agrees with the order in which the work function of electrode material decreases, indicating that under the same machining conditions the discharge delay time is largely affected by the work function of the electrode material. When the debris particles were mixed in the dielectric liquid, the average discharge delay time was significantly short compared with that when debris do not exist in the discharge gap and decreases with the increase of debris concentration. Since the average discharge delay time was decreased to one tenth with the inclusion of debris particles, the effect of work function on the delay time was insignificant and the effect of the debris concentration was decisive.

Counter pressure injection molding is a type of gas-assisted molding technology for preventing the generation of swirl marks by adding N₂ or CO₂ gas at high pressures of 1-15 MPa to the cavity. In this study, using a laser-light-sheet visualization mold, we visualized the movement of gas clouds and the bubble breakage phenomena at the flow front. The resin and gas used were general purpose polystyrene and N₂. First, we confirmed that the generation of gas cloud (as a result of gas condensation) can drastically be suppressed in the conventional injection molding process, even at a very low pressure of 0.7MPa. Secondly, in microcellular foam injection molding using supercritical fluid, the counter pressure method was found to reduce not only the nucleation of voids in the filling core layer and the subsequent fountain flow area, but also gas cloud generation with N₂ even at a low counter pressure of 1.0MPa. These visualization results clarify that low counter pressure is effective for empirically reducing both the gas cloud generation and the voids nucleation in supercritical foam injection molding.

Although the external electrode of multi-layer ceramic capacitor (MLCC) is formed through the burning process after coating the liquid state of Ag paste on the base material of the dielectric ceramics, there is an issue that the coating shape of the film thickness of the external electrode is not uniform enough by the influence of the surface tension. It has been clarified that various changes occur in the physical phenomenon by applying ultrasonic vibration to the liquid, and in the previous report, it was found that this effect could be applied to make the Ag paste an ideal application shape. In this study, we develop a new experimental device by wire blotting method that removes Ag paste by applying ultrasonic vibration to the wire, examine appropriate conditions for making the coating shape thin and uniform, and I showed the solution to the problem of the application shape and the effectiveness to an ideal application shape by the suggestion method.

Compact light detection and ranging (LIDAR) with wide scanning angle is required for the environment monitoring of automobile. We have developed a two-dimensional (2D) laser scanner for the LIDAR system with the horizontal scanning angle of 360 degrees. The scanner is composed of an inclined rolling ellipsoidal reflector equipped with a permanent magnet at the center, a ferromagnetic steel pillar, and six electromagnets. The reflector is attached on top of the pillar by magnetic force; the reflector is translationally-fixed but free in rotational motion. The electromagnets are arranged in a circular pattern under the reflector. Applying current pulses to the electromagnets subsequently, the reflector is rotated by the electromagnetic force. The maximum rotational speed of 85 rps (revolutions per second) was achieved with an elliptical reflector (major axis: 22 mm, minor axis: 18.2 mm, thickness: 0.2 mm) and a permanent magnet (diameter: 4 mm, thickness: 2 mm) at an applied current 28 mA to the electromagnets. We successfully demonstrated 2D laser scan with the horizontal scanning angles of 360 degrees, the vertical scanning angle of 18 degrees, and the rotational speed of 70 rps.

Calibration technology of profile surface roughness (Ra: from 0.2 nm to 100 nm) by using an atomic force microscope with differential laser interferometers (DLI-AFM) has been developed at NMIJ, AIST. Recently, there have been increasing needs for calibration service of surface roughness of sub-nanometer order. In order to realize surface roughness calibration of sub-nanometer order using the DLI-AFM, however, several challenges remain unaddressed, including scanning stability and drift. At present, authors are developing a length-standard-traceable AFM (LST-AFM) to calibrate surface roughness calibration of sub-nanometer order with a small uncertainty. In this LST-AFM, a reference mirror for the z-axis interferometer is mounted on the AFM cantilever probe unit so as to realize more stable surface roughness calibration. An overview of the LST-AFM, stability of temperature and a light source of an AFM optical lever system are reported in this paper.

In the former paper “Study of the Moment of Inertia Ratio of Feed Axes of Machining Centers to Servo Motors (2nd)", the interrelation between the moment of inertia ratio of a machine feed axes to servo motors and actual cutting results by a machining center is studied. However, the actual cutting so often contains many other elements than servo motors such as machine deformation, cutting tools, cutting conditions, etc. With this reason in this 3rd paper the interrelation between the moment of inertia ratio and the machine feed axes movement driven by the servo motors is studied.

Through the same cutting program used in the former paper, the feed axes movement driven by the servo motors is monitored with the specially-designed detection system in this paper. Then the monitored data are converted to the time, precision, and smoothness of the axes movement. The results of this show that the servo motors with relatively low moment of inertia contribute to high cycle movement, while those with relatively high moment of inertia contribute to high precision and smooth movement. These results are consistent with the ones in the former studies.