Abstract The carbon fiber reinforced plastic (CFRP) has been widely used in manufacturing industry due to its excellent mechanical and physical properties. Brad drill, as a representative of new-type structural drills, is applied in processing of CFRP. Meantime, rotary ultrasonic drilling (RUD) is regarded as a superior method for machining composite materials, due to its outstanding performance in lowering thrust force and improving processing quality. However, there are few reports about RUD with Brad drill in CFRP drilling. In this study, the theoretical model of thrust force for RUD of CFRP using Brad drill is developed. The dynamic uncut chip thickness and average uncut chip thickness in RUD are obtained based on kinematic characteristics analysis. After that, the structure of Brad drill is analyzed and thrust force of the cutting lip is molded. Then a theoretical model is proposed to predict the thrust force. Finally, pilot experiments are conducted for the model verification. Experimental results show that the trends of thrust force agree well with the thrust force model and the prediction error is less than 10%.

中文翻译：

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Brad钻头对CFRP旋转超声钻削推力的研究

摘要 碳纤维增强塑料（CFRP）以其优异的机械和物理性能在制造业中得到了广泛的应用。布拉德钻头作为新型结构钻头的代表，应用于CFRP的加工。同时，旋转超声钻孔（RUD）因其在降低推力和提高加工质量方面的突出性能而被认为是加工复合材料的优越方法。但是，关于在CFRP钻孔中使用Brad钻头的RUD的报道很少。在这项研究中，开发了使用 Brad 钻头的 CFRP RUD 推力的理论模型。通过运动学特性分析，得到了RUD中的动态未切屑厚度和平均未切屑厚度。之后，分析了Brad钻头的结构，确定了切削唇的推力。然后提出了一个理论模型来预测推力。最后，进行了模型验证的试点实验。实验结果表明，推力趋势与推力模型吻合较好，预测误差小于10%。