薄肉円筒工作物の切削加工時に発生する工作物変形型びびり振動

（びびり振動に及ぼす工作物直径の影響）

抄録

Recently, aircraft parts have been lightened for low fuel consumption. However, the parts such as jet engine turbine case reduce heat resistance for thinning. So it has been required thinning with heat resistance material. However, cutting heat resistance workpiece of low stiffness that thinning causes contributes chatter vibration. In this study, the phenomenon of chatter vibration is elucidated and predicted. By chatter vibration measurement in several workpiece, chatter vibration frequency and chatter vibration mode in cutting workpiece were found out. Chatter vibration measurement was practiced with 72 displacement sensors to circumferential direction. It turned out chatter vibration is similar to the natural vibration of workpiece and self-excited vibration, which is caused by coupling two vibrations near the cutting tool position. To confirm the relationship between chatter vibration and natural vibration, natural vibration of several workpiece got. By impact test, workpiece's natural frequency and natural vibration mode were found out. Modal analysis by impact test impacted 72 points of the test piece to circumferential direction. It turned out vibration mode at the lowest natural frequency accord with occurred chatter vibration mode. Vibration mode at the lowest natural frequency depends on workpiece's size. These phenomena are compared with the experiment of the different work of the diameter that reached in the past. It shows a similar tendency. So chatter vibration mode is predicted by vibration mode at the lowest natural frequency found thickness and length that became no dimension at a diameter.