研究課題
Fluid Jet Polishing (FJP) is a finishing process for small and complex workpieces. The benign processing pressure and abrasive size result in slow material removal, but injection of micro-bubbles by cavitation can boost removal up-to 380%. In this research, the removal boost mechanism was investigated.A study of micro-pit formation by collapsing micro-bubbles near the workpiece wall determined that micro-jetting and water hammer pressure are not occuring, so the micro-pit hypothesis was ruled out.A study of workpiece vibration found significant shear forces in the jet impingement zone. After analysis of the correlation between fluid displacement and shear force, the erosion model for FJP was modified with time-averaged fluid vibration terms and verified against experimental removal data.
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In accordance with the original research plan, the process mechanism in micro-bubble assisted FJP could be determined by experimental observations, including high-speed camera observations of micro-bubbles and dynamometer measurements of workpiece vibration to determine the influence of fluid shear (Stage 1 and 2). The standard removal model for FJP was then modified to account for fluid vibrations, and verified against experimental removal data (Stage 3). Therefore, all targets for FY2017 were reached succesfully.In preparation for Stages 4-6 of this project, a more powerful ultrasonic generator and transducer have been purchased, ready for assembly into a second generation ultrasonic FJP nozzle. An industrial robot and associated work frame have also been prepared.
In accordance with the original research plan, Stages 4-6 will be implemented in FY2018.A second generation ultrasonic FJP nozzle will be designed and assembled together with the new ultrasonic generator and transducer (Stage 4). The performance of the new nozzle cavity will be assessed by validation experiments. Material removal rate increase >1000% is expected with this new system.The second generation nozzle will be integrated on the industrial robot, and a post-processor for the python based CAD/CAM system used to operate the robot will be implemented (Stage 5).Finally, the robot integrated system will be used to demonstrate application of micro-bubble assisted FJP on complex freeform shapes, including micro-optics and dental implants (Stage 6).
The small remaining amount of 80 yen could not be spent on a meaningful item. It is thus requested for this amount to be brought forward to the next year.
すべて 2018 2017
すべて 学会発表 (1件) 図書 (1件)
