School of Mechanical and Equipment Engineering, Hebei University of Engineering, Handan, China.
School of Mechanical Engineering, Hebei University of Technology, Tianjin, China.
Proc Inst Mech Eng H. 2023 Apr;237(4):489-501. doi: 10.1177/09544119231157448. Epub 2023 Mar 16.
A temperature exceeding the safety threshold and excessive drilling force occurring during bone drilling may lead to irreversible damage to bone tissue and postoperative complications. Previous studies have shown that vibration-assisted drilling methods could have lower temperatures and drilling forces than those of the conventional drilling method; we hypothesized that the main reason for these reductions stems from the differences in the transient machining processes between conventional and vibration-assisted drilling methods. To investigate these differences, comparative experiments and two-dimensional finite element models were performed and developed. The differences in the transient machining processes were verified by experimentation and clearly exhibited by the finite element models. Compared with the steady cutting process that produced continuous-spiral chips in the conventional drilling method, transient machining in the low-frequency vibration-assisted drilling method was a periodically dynamic cutting-separation process that produced uniform petal chips with specific settings of drilling and vibration parameters. Moreover, the transient machining process in the ultrasonic vibration-assisted drilling method was transformed into a combined action with high-speed impact and negative rake angle cutting processes; this action produced a large proportion of powdery chips. Therefore, it could be concluded that the superposed axial vibration significantly changed the transient machining process and radically changed the mechanical state and thermal environment; these changes were the main reason for the apparent differences in the drilling performance levels.
在骨钻过程中，温度超过安全阈值和过大的钻削力可能导致骨组织的不可逆转损伤和术后并发症。先前的研究表明，振动辅助钻削方法的温度和钻削力可能低于传统钻削方法；我们假设这些降低的主要原因源于传统和振动辅助钻削方法之间的瞬态加工过程的差异。为了研究这些差异，进行了对比实验和二维有限元模型。通过实验验证和有限元模型清楚地展示了瞬态加工过程的差异。与传统钻削方法中产生连续螺旋切屑的稳定切削过程相比，低频振动辅助钻削方法中的瞬态加工是周期性动态切削分离过程，在特定的钻削和振动参数设置下产生均匀的花瓣状切屑。此外，超声振动辅助钻削方法中的瞬态加工过程转变为具有高速冲击和负前角切削过程的组合作用；这种作用产生了很大比例的粉状切屑。因此，可以得出结论，轴向叠加振动显著改变了瞬态加工过程，并从根本上改变了机械状态和热环境；这些变化是钻孔性能水平明显差异的主要原因。
