钎杆内孔的液压低频振动扩孔工艺实验

为完全去除中空钢钎杆内孔表面的氧化层和裂纹层的影响,采用深孔扩孔的方式加工钎杆内孔。针对深孔扩孔过程中存在的切屑排出困难、切削温度高、内孔表面加工质量差等问题,利用液压低频振动辅助枪钻对中空钢钎杆进行深孔扩孔,研究振动参数及加工参数对切屑形态、内孔表面质量、切削热的影响。实验结果表明:在转速为500 r/min、进给量为0.1 mm/r条件下,相对于普通扩孔,液压低频振动扩孔可减小切屑尺寸,减少切屑表面锯齿边缘现象,优化内孔加工表面,减少刀痕和划痕,降低加工温度。且当频率为36.7 Hz、振幅为0.58 mm时,切屑尺寸最小,内孔表面划痕最少,加工温度最低;随着进给量在0.80～0.12 mm/r范围内增大,切屑长度变大,内孔表面的刀痕和划痕增多;转速对切屑长度及内孔表面形貌影响较小。

Experiment on hydraulic low frequency vibration reaming process of drill rod inner hole

To completely remove oxide layer and crack layer on the inner surface of the hollow steel drill rod, deep hole reaming was processed on the inner hole of the drill rod. In view of the problems of chip discharge difficulty, high cutting temperature and poor processing quality of the inner hole surface during deep hole reaming, hydraulic low-frequency vibration assisted gun drill was adopted to improve the hole surface quality here. Experiments results showed that compared with the ordinary reaming, the hydraulic low-frequency vibration reaming can reduce the chip size and the jagged edge phenomenon on the chip surface, improve the inner hole machining surface, reduce the tool marks and scratches and the processing temperature under the condition of the speed of 500 r/min and the feed rate of 0.1 mm/r. Furthermore, Furthermore, the minimal clip size with least scratches and lowest processing temperature could be achieved when the frequency reaches 36.7 Hz with vibration amplitude at 0.58 mm. With the increase of the feed rate within the range of 0.80~0.12 mm/r, the length of chip becomes larger, and the tool marks and scratches on the surface of the inner hole increase. The speed has little effect on the chip length and the surface quality of the inner hole.