Drilling is one of the most common procedures in orthopaedic surgery. However, drilling-induced trauma occurs frequently and affects the processing damage and position accuracy of the holes, which strongly influence the postoperative recovery. Therefore, there is an urgent need to design a dedicated drill bit that can satisfy low-trauma requirements such as low cutting force, low temperature, self-centring, and low surface damage during orthopaedic surgery. In this work, a novel three-step drill structure is proposed to modify the cutting conditions at the entrance and exit of drilling, to effectively reduce the mechanical and thermal damages and improve the position accuracy in bone drilling. As the first step drill, a unique tip with thinned web was adopted by considering the drill skidding mechanisms under a non-perpendicular drilling condition. The second step was achieved by using an optimal point angle for balancing the effects of the cutting force and temperature. Moreover, a transition arc design was proposed as the third step to adjust the point angle during the finishing stage for switching the cutting mechanism from ‘fracture & shear crack’ cutting to ‘shear’ cutting in association with a certain range of feeding rates. This could reduce the mechanical and thermal damages to the finished hole surface. Drilling experiments under various process conditions demonstrated that the proposed drill design significantly reduced the drilling force, temperature, and damage and also improved the position accuracy of the holes compared to the conventional drill design. The proposed design provides an effective tool to achieve low-trauma bone drilling in orthopaedic surgery.

钻孔是整形外科中最常见的手术之一。然而，钻孔引起的创伤经常发生并且影响加工损伤和孔的位置精度，这强烈影响术后恢复。因此，迫切需要设计一种能够满足低创伤要求的专用钻头，所述低创伤要求例如是低切削力，低温，自定心以及整形外科手术期间的低表面损伤。在这项工作中，提出了一种新颖的三步钻结构，以修改钻头入口和出口处的切削条件，以有效减少机械和热损伤，并提高骨骼钻头的定位精度。作为第一步钻，考虑了在非垂直钻削条件下的钻头打滑机制，采用了具有稀疏网的独特刀头。第二步是通过使用最佳切角来平衡切削力和温度的影响。此外，提出了过渡弧设计作为第三步，以在精加工阶段调整刀尖角度，以便在一定的进给速度范围内将切削机构从“断裂和剪切裂纹”切削切换到“剪切”切削。这样可以减少对精加工孔表面的机械和热损伤。在各种工艺条件下进行的钻探实验表明，与传统的钻探设计相比，所提出的钻探设计显着降低了钻削力，温度和损伤，并且还提高了孔的定位精度。拟议的设计提供了一种有效的工具，可在整形外科手术中实现低创伤骨钻孔。