Kimiyuki Mitsui

New analytical method for V-block three-point method

The V-block method is a widely accepted method for measuring the roundness of a cylindrical workpiece. However, the complexity of conventional analysis schemes, based on Fourier transformation, makes it difficult to develop specific software programs for analyzing the measured data. Here, a new algorithm developed for the three-point method using inverse matrix calculations is extended to the analysis of the V-block method. The results are compared with the conventional analytical algorithm and the validity of the new method is confirmed.

Miniature tilting mechanism using piezoelectric actuators

A tilting mechanism using piezoelectric actuators which has two rotation degrees of freedom has been developed. The dimensions of the body of the tilting mechanism are 10 mm in diameter and 24 mm in length. We have achieved the following specifications of the tilting mechanism; +/- 20 degree(s) rotational angle in the orthogonal two axes, 30 seconds of the angular resolution, 10 degree(s)/sec of the maximum rotation speed, and 1.75 Nmm of the maximum torque. This paper describes the structure and the experimental results of the linear actuator and the tilting mechanism.

A New Measuring Method for Spindle Error Motion Using a Cube-Corner Prism and Laser Interferometers

A new measuring method for evaluating error motion of the spindle rotation during machining has been developed. In this report we define the principle for a new method and present results of preliminary experiments. A cube corner prism (hereafter CCP) is installed on the axial end of the spindle and laser interferometers are mounted on the optical axes incident onto and reflected from the CCP with a fixed angle of inclination only from the axial direction. Fluctuation of the optical path length generated between the CCP and the laser interferometers by the rotation and displacement of the spindle is detected. The method was verified on an optical bench, and was applied to in-process measuring experiments for the spindle of a surface grinding machine.

Error correction method in radial runout measurements based on laser autocollimation

Radial runout measurement on a spindle, based on laser autocollimation, is susceptible to reflection surface irregularities because an irregularity occurring in the reflected laser beam rotates with the spin of the reflection target. This, study proposes an error correction method for the influences of reflection surface irregularities by applying the three-point method, which separates the radial runout of the spindle and the out-of-roundness of the reference cylinder attached to the spindle by using three displacement sensors. The principle of the proposed method is described, and its validity is confirmed in a computer simulation and experiment.

Acoustic Emission Signals in the Micro-EDM of PCD

The mechanism of fracture in micro-electrical discharge machining (-EDM) processes is related to the discharge pulses energy. This paper investigates the correlation of fractures and discharge pulses energy in the -EDM of polycrystalline diamond (PCD) to the acoustic emission (AE) signals. The evaluation of fracture mechanism was done by measuring the generation and propagation of elastic wave in single discharge pulse by using AE sensor. The results show a strong correlation between fractures and discharge pulses energy to the AE signals and mechanism of material removal in the -EDM processes.

Development of an Optical Measuring Device for Rotation Accuracy of Micro-Spindle —Application to Measurements of a High-Speed Spindle—

It is very difficult to measure the rotation accuracy of miniaturized spindles running at high-speed with a common measuring method which uses capacitive displacement sensors. Therefore the authors have proposed a new optical measuring method using a small reflection sphere as a measurement target. In this paper, the basic principle of the optical measuring method, the configuration of the measuring device and some of the measurement data are shown.

A Circular Profile Measurement Method Using Software Techniques

In industry, disk type products with a highly accurate surface such as silicon wafer and hard disk, are important elements. To measure these surfaces, an interferometer is used. However, this method generally needs a highly accurate reference surface. Another method to obtain the disk surface profile is by a scanning displacement sensor. However, the output of this sensor is influenced by the parasitic motions of the scanning along the reference guide. This article presents novel measurement procedures, a reversal method, an improved reversal method and a multi-prove method, to measure the circular profile on a disk without any references but with high accuracy.

Development of a new displacement-measuring ultrasonic sensor based on astigmatic focus error detection-measuring principle and its demonstration

Conventional ultrasonic displacement-measuring systems normally employ the pulse-echo technique. Resultant resolution capability, however, typically is not suitable for meeting high-dimensional, in-process measurement standards used in cutting and grinding operations. This paper presents a new ultrasonic sensor for displacement measurement based on astigmatic focus error detection. The measuring principle and basic analysis applied in the design method are described in detail, after which the validity of the principle is demonstrated by the results of experimental evaluations.

Material Removal and Fracture Detection in Micro-EDM Processes

The important thing in micro-machining is its accuracy. The Micro-Electrical Discharge Machining (micro-EDM) is a promising method in micro-machining, because (1) the process is independent on the hardness of the workpiece but only depends on its thermal conductivity and melting point and (2) it can be used to machine materials with highly complex geometrical shapes using a simple-shaped tool electrode. However, the process in micro-EDM is not totally well-known, especially related to the formation of discharge pulse energy and the fracture phenomena. In the micro-EDM processes, the formation of discharge pulse energy is a complex phenomenon, since it is related to many parameters such as discharge gap, charge voltage, capacitance, and tool electrode wear. In this paper, the Acoustic Emission (AE) sensor is used to detect the changes of discharge pulse energy during machining of brass using micro-EDM. The results shows that the AE signals can detect and explain the fracture phenomena during the micro-EDM processes.

Study on the Effect of Nano and Micro MoS2 Powder in Micro-Electrical Discharge Machining

The application of powder mixed dielectric to improve the efficiency of electrical discharge machining (EDM) has been acknowledged extensively. However, the study of micro-size powder suspension in micro-EDM field is still limited. In this research, nano and micro size powder of MoS2 were used as catalyst agent. Powder suspension in different size was able to provide significant improvement in material removal rate and surface quality to increase the efficiency in μ- EDM processes.