スパイラル・ウォータージェットを用いた軟質物の切削

Abstract

High performance spiral water jet cutting system for soft materials such as liver and styrofoam has been developed. With this system, the 7cm-thick liver was cut under the 2.94×106Pa (30kgf/cm2)-4.90×106Pa (50kgf/cm2) water pressure. The kerf was narrower and its surface was smoother than that by conventional system. The motivation behind this study is to clarify water jet cutting performance from the fluid dynamics view point. Alternatively, one would think that materials could be cut by introducing water at high axial velocity. Polymer water jet for converging the jet structure have been trying. But these trials are not satisfactory in its cutting surface condition and its cost performance. The water jet cutting performance is depended on the jet energy transfer efficiency to target material surface. The essential approaches for achieving the high cutting to decrease performance are to increase the water jet momentum and to decrease the chance of collision between the direct and rebounded water jets. These requirement can be responded by spiral system, because the focusing spiral jet with high stability transfers water jet momentum effectively to the materials, and its swirling characteristic decreases the chance of collision of jets. Finally, an approximate solution for normal shear stresses was obtained and the results were compared with the experiments. These superior stress distributions contributed to enhance the performance over a conventional water jet system.