Mechanistic approach for prediction of forces in micro-drilling of plain and glass-reinforced epoxy sheets
Mechanistic approach for prediction of forces in micro-drilling of plain and glass-reinforced epoxy sheets
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DOI：
10.1007/s00170-014-6202-z
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发表时间：
2014-08
期刊：
影响因子：
--
通讯作者：
I. Rahamathullah;M. Shunmugam
中科院分区：
文献类型：
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作者：
I. Rahamathullah;M. Shunmugam
航空航天和汽车工业广泛使用塑料和纤维增强塑料制成的部件，这些部件需要进行包括微钻孔在内的微加工操作。文献中报道了各种尝试来研究不同的策略并对微钻孔中的力进行建模，以期产生具有大纵横比的微孔并减少钻头破损。力模型在方法上更多是统计性的而不是机械性的。在目前的工作中，尝试开发普通环氧树脂板微钻孔中的推力和扭矩的机械模型。为此目的，采用了捕获环氧树脂材料的应变率和温度相关屈服强度的材料模型以及加工的基本原理。使用精心策划的全因子实验设计来验证推力和扭矩预测的机械模型。实验是在实验室专门研制的高速微型机床上使用直径0.5mm、三级转速和进给的硬质合金钻头进行的。该材料模型扩展到玻璃增强塑料（GRP），并使用所提出的机械模型预测钻孔力。在普通板材和 GRP 板材的情况下，模型预测都接近实验测量的钻孔力。
Aerospace and automobile industries extensively use components made of plastics and fiber-reinforced plastics which require micro-machining operations including micro-drilling to be carried out. Various attempts are reported in the literature to study different strategies and model the forces in micro-drilling with a view to produce micro-holes having large aspect ratio and to reduce drill breakage. The force models are more statistical than mechanistic in approach. In the present work, an attempt is made to develop mechanistic models of thrust and torque in micro-drilling of plain epoxy sheets. Material model capturing strain rate and temperature-dependent yield strength of epoxy material and basic principles of machining are employed for this purpose. The mechanistic model for prediction of thrust and torque is validated using well-planned full factorial design of experiments. Experiments are carried out using a carbide drill of 0.5-mm diameter with three levels for speed and feed on a high-speed miniature machine tool specially developed at the laboratory. The material model is extended to glass-reinforced plastics (GRP), and drilling forces are predicted using the proposed mechanistic model. In both cases of plain and GRP sheets, the model predictions are close to the experimentally measured drilling forces.