Compression plates are widely used in orthopaedic surgeries for internal fixation of fractured femurs. To fix the plate and thus to provide compression to a fracture, the self-tapping bone screws are tightened through predrilled pilot holes of smaller diameter. Preliminary investigation showed that the holes drilled with the inappropriate cutting parameters cause mechanical and thermal damages to the local host bone, which further lead to loosening of internal fixations. In this paper, the mechanistic models to predict the thrust forces and torques during bone drilling were developed, using a 3.20 mm diameter drill bit. As a procedure, the cutting action was investigated at three different regions of the drill point, namely cutting lips, secondary cutting edges and indentation zone. The models employed the analytical approach to account for the drill-bit geometry and cutting parameters, and an empirical approach to account for the material and friction properties. To complete the procedure, calibration experiments were conducted on bovine cortical femurs with two different spindle speeds (1000 and 3000 r/min) and feeds (0.03 and 0.06 mm/rev), and then the specific normal and friction coefficients were determined. The developed mechanistic models were validated with different ranges of parameters (500–3500 r/min speeds, and 0.02–0.07 mm/rev feeds) those commonly involved in manual and robot-assisted surgery. The validation study revealed that the thrust forces predicted using the mechanistic models showed a maximum error of only 5.80%. However, the torques predicted from the mechanistic model found with more error than the thrust forces. The predominant reasons for this under-prediction might because of the extrapolation used to determine the specific cutting pressures, slip-line field applied to the indentation zone instead of compressive fracture, and chip clogging involved during the bone drilling as demonstrated in earlier studies. Despite the deviations, the developed mechanistic models satisfactorily follow the trends of the thrust forces and torques experienced during bone drilling. The outcomes can be used to practice the bone drilling procedure and monitor the effect of process parameters on thrust forces and torques in the in-silico environment before performing actual surgery.

加压钢板广泛用于骨科手术中用于股骨骨折的内固定。为了固定接骨板，从而为骨折提供压力，自攻骨螺钉通过较小直径的预钻导向孔拧紧。初步调查显示，不适当的切削参数钻孔对局部宿主骨造成机械和热损伤，进一步导致内固定松动。在本文中，使用直径为 3.20 毫米的钻头开发了用于预测骨钻孔过程中推力和扭矩的机械模型。作为一个程序，研究了钻尖三个不同区域的切削作用，即切削唇、副切削刃和压痕区。这些模型采用分析方法来考虑钻头几何形状和切削参数，并采用经验方法来考虑材料和摩擦特性。为了完成该程序，在具有两种不同主轴速度（1000 和 3000 r/min）和进给（0.03 和 0.06 mm/rev）的牛皮质股骨上进行了校准实验，然后确定了特定的法向系数和摩擦系数。开发的机械模型在手动和机器人辅助手术中常用的不同参数范围（500-3500 r/min 速度和 0.02-0.07 mm/rev 进给）进行了验证。验证研究表明，使用机械模型预测的推力显示的最大误差仅为 5.80%。然而，从机械模型预测的扭矩发现比推力有更多的误差。这种预测不足的主要原因可能是因为用于确定特定切削压力的外推法、应用于压痕区的滑移线场而不是压缩断裂，以及在早期研究中证明的骨钻孔过程中涉及的切屑堵塞。尽管存在偏差，但开发的机械模型令人满意地遵循了骨钻孔过程中所经历的推力和扭矩的趋势。结果可用于练习骨钻孔程序并监测工艺参数对推力和扭矩的影响 滑移线场应用于压痕区而不是压缩断裂，以及在早期研究中证明的骨钻孔过程中涉及的切屑堵塞。尽管存在偏差，但开发的机械模型令人满意地遵循了骨钻孔过程中所经历的推力和扭矩的趋势。结果可用于练习骨钻孔程序并监测工艺参数对推力和扭矩的影响 滑移线场应用于压痕区而不是压缩断裂，以及在早期研究中证明的骨钻孔过程中涉及的切屑堵塞。尽管存在偏差，但开发的机械模型令人满意地遵循了骨钻孔过程中所经历的推力和扭矩的趋势。结果可用于练习骨钻孔程序并监测工艺参数对推力和扭矩的影响在进行实际手术之前的计算机环境中。