School of Control and Mechanical Engineering, Tianjin Chengjian University, Tianjin 300384, China.
School of Control and Mechanical Engineering, Tianjin Chengjian University, Tianjin 300384, China.
Med Eng Phys. 2022 May;103:103795. doi: 10.1016/j.medengphy.2022.103795. Epub 2022 Apr 6.
Bone drilling tends to cause mechanical damages and thermal necrosis in the vicinity of the drilled hole, which can deteriorate the surgery quality and patients' recovery. Understanding the cutting forces generation mechanism is crucial in controlling thrust force and bone temperature for optimum tool design. In this study, a novel crescent drill bit featuring an improved positive rake angle distribution was designed to reduce the thrust force and temperature elevation. On this basis, a mechanistic model for predicting thrust force and torque was proposed for drill bits with different geometries (twist drill and crescent drill). The proposed model was established in the polar coordinate system to precisely calculate the curvilinear integral of the crescent cutting edges. Drilling experiments were carried out using two types of drill bit under different cutting conditions and results showed that our proposed model agrees well with the experimental data. The experimental results also demonstrated that our tool design can significantly reduce the thrust force and reduce the bone temperature below the thermal threshold without coolant, providing a clinical option for coolant free drilling.
骨钻通常会在钻孔附近造成机械损伤和热坏死，这会降低手术质量和患者的恢复速度。了解切削力的产生机制对于控制推力和骨温度以实现最佳工具设计至关重要。在这项研究中，设计了一种新型的月牙形钻头，具有改进的正前角分布，以降低推力和温升。在此基础上，提出了一种用于不同几何形状（麻花钻和月牙钻）钻头的预测推力和扭矩的力学模型。所提出的模型是在极坐标系中建立的，以精确计算月牙形切削刃的曲线积分。在不同的切削条件下，使用两种类型的钻头进行了钻孔实验，结果表明，我们提出的模型与实验数据吻合较好。实验结果还表明，我们的工具设计可以显著降低推力，并在不使用冷却剂的情况下将骨温度降低到热阈值以下，为无冷却剂钻孔提供了一种临床选择。
