Shigeomi Koshimizu

Ultrasonic Vibration-Assisted Cutting of Titanium Alloy

Although titanium is a very useful material and becoming more in demand, we are faced with difficulties in machining the material. By applying ultrasonic vibration to the tool tip, interrupted cutting can be applied. Using ultrasonic vibration-assisted cutting of titanium alloy, we succeeded in reducing the cutting force. This technology enables us to improve tool wear and surface roughness of the workpiece. In regards to cutting fluid supply methods, it was found that semi-dry cutting was the most suitable for ultrasonic vibration-assisted cutting of titanium alloy.

Micro-Grooving of Glass Using Small-Diameter Diamond Grindstone with Ultrasonic Vibration

The purpose of this study was to achieve grooving on glass substrates with high levels of efficiency and precision with the use of a diamond grindstone with a small diameter in the range of 1.0-1.8 mm. Mechanical material removal by grinding has high efficiency and enables process control for creating complicated forms, but has a drawback of generating chippings on the processed surface of the brittle glass material. The study gave ultrasonic vibration of 10 μm at 20 kHz in the thrust direction to the rotating small-diameter diamond grindstone in the grinding process, in order to attain high levels of efficiency and precision in micro-grooving of glass. The grooving approach with ultrasonic vibration did create some minor chippings, but succeeded in meeting the target of reducing the average size of chippings around the groove to 0.1 mm or less.

Reduction Method for Residual Stress of Welded Joint Using Two Ultrasonic Vibrations with Different Frequencies

A reduction method of tensile residual stress using two ultrasonic vibrations with different frequencies is proposed. Advantage of the method to using one ultrasonic vibration is examined. Obtained results are summarized as follows. 1. Thick plate is buildup welded using ultrasonic vibration is used during welding in experiment. Residual stress of specimen using one ultrasonic vibration is reduced compared with that without ultrasonic vibration. Residual stress of specimen using two ultrasonic vibrations is reduced compared with that using one ultrasonic vibration. 2. Using two-dimensional model, residual stress is calculated by simulation method. Same results as experiment are obtained.

A Fundamental Study on Differences in Heart Rates During Creative Work and Non-creative Work

We sought to clarify how creative and non-creative work influence R-R intervals. Clearly different patterns of R-R intervals were found between creative and non-creative work, with heart rate quickening during creative work and recovering during subsequent rest periods. The differences between median R-R intervals during creative work were significantly and positively related to feelings of stress, with most coefficients of greater than 0.7 (reaching as high as 0.840; P < 0.001). In contrast, the differences between R-R intervals during non-creative work were not significantly correlated with feelings of stress, and the maximum coefficient did not exceed 0.3. Therefore, it appears that variability of median R-R intervals can be used to effectively predict feelings of stress when people engage in creative work but not when they engage in non-creative work.

Ultrasonic Coring of Glass Disks Using Double Core Tool

Glass disks are used as substrates for the recording media in magnetic disk devices. To mass produce glass disks, a technology is required for machining glass (a material that is difficult to machine) with both high precision and high efficiency. Consequently, this study adopted a method that processes the inner- and outer-diameters simultaneously using a double core tool. In addition, the thrust force in coring process was also reduced using an ultrasonic spindle to apply ultrasonic vibration to the feed direction of the rotating tool. This resulted in high quality machining with less chipping. Furthermore, this study conducted experiments to compare the three methods of stabilizing the stack of glass substrates. As a result, it was found that the method using ultraviolet curable resin was able to limit the chipping to a smaller size.

Study on Micro Blasting of Glass for Micro Channel Forming

The production of a compact chemical reactor called a micro channel device requires a glass microfabrication technique since it involves the formation of a micro channel on the surface of a glass substrate. We propose a direct mask drawing and micro blasting technique, designed to form a micro channel on a glass substrate. This method is suitable for producing a wide variety of patterns in small quantities. In conventional micro blasting the channel formed has a narrow base i.e. “V” shape cross-sections. Using a seesaw table to tilt the glass substrate during blasting, we can produce a wider based channel i.e. “U” shape cross-sections.