Kenji Kawata

Prevention Against Adhesion of Contamination to End Surface of Optical Fiber Connectors in Lapping Film Finishing

The end surface of optical fiber connector is finished by using the lapping film with colloidal silica as abrasive in order to obtain fine optical characteristic. However, the adhesion of some contamination to the finished end surface very often occurs. In the practical manufacturing process, after finishing, a cleaning process of wiping with cloth is adopted, which induces higher production costs and generation of scratches. In this study, two new types of lapping films are proposed to overcome the above problem, namely, to prevent the contamination from adhering to the end surface in the finishing process. Then the lapping film with addition of titanium oxide particles and the lapping film utilizing spherical fused silica particles as abrasives were developed. The finishing experiments revealed that the scratch-free end surface quality without contamination could be achieved by using the developed films.

Development of a High-Porosity Fixed-Abrasive Pad Utilizing TiO2 Powders

It is very easy to cause loading on a fixed-abrasive tool in the grinding process of soft metal materials such as aluminum substrates, and this leads to difficulty in the smooth running of the grinding process. Hence, a porous PVA (polyvinyl alcohol) stone is the only fixed-abrasive tool that is generally used until now. However, the PVA stone has some disadvantages that it is easy to be softered because of absorbing water during grinding, and high-density abrasive grains cannot be used due to precipitation in the polymerization process. In this research, a new high-porosity fixed-abrasive pad for grinding aluminum disks was developed. The method proposed to manufacture a high-porosity fixed-abrasive pad while TiO2 ultra-fine powders are added into the pad. This pad made of SiC or Al2O3 abrasive grains not only provided for a loading-free grinding process, but also had a better finishing roughness than PVA stones.

Investigation on Tool Plates for Polymer Particle Assisted Polishing with Oil Dispersion Medium

A polishing pad has been playing a crucial role in conventional mirror polishing though many problems occur such as process instability, polishing non-uniformity and maintaining difficulties etc. Recently, a new mirror polishing method, which uses fine polymer particles, has been proposed and developed for overcoming the problems. At the same time, the feasibility of this new method when using oil as dispersion medium has been certified as well for polishing the materials unstable in water. In this paper, the tool plate, one of the most important elements in the new method, has been investigated to find an optimal type for the new polishing method when using oily slurries. Several kinds of tool plates have been discussed about the polishing characteristics and it is clear that the tool plate must have not only proper roughness and high rigidity, but also good affinity to the slurry. Furthermore a thin elastic layer covering on the surface of a hard tool plate is desirable. In addition, the urethane rubber plate with high hardness and tensile strength is the best one with relatively superior polishing characteristics, endurance and easiness of surface preparing among the discussed plates up to now.

Development of a high-efficient finishing process using abrasives bonded by liquid.

A fine finishing process has been newly developed, in which abrasives bounded by liquid, such as water or oil, are used. The abrasives are densely suspended in the midst of the liquid, so that the number of abrasives working effectively is more than in conventional polishing processes. This makes it possible to obtain a more efficient removal rate and higher accuracy of the surface finish. Since the stiffness supporting the abrasives is tough enough, deterioration of the flatness around the edge of the workpiece would be prevented. A high removal rate was maintained by a self-dressing motion for the abrasives, which could be activated by spraying the bonding liquid. A high removal rate expected for the high finishing pressure and high finishing speed is to be investigated in the future.