Understanding the influences of drilling parameters on machinability characteristics of NFRCs is of value to both academia and manufacturing industries. The present work investigates drilling-induced delamination and hole quality of fully biodegradable flax/poly(lactic acid) composites in response to cutting speed, feed rate, drill diameter, and drill material. Among various types of drilling-induced damages, exit-ply delamination is found to be the most destructive damage and cutting thrust force is identified as the main reason. The experimental results revealed that thrust force is highly dependent on drilling parameters where feed rate and drill material were found to be the most influential parameter on it. The choice of drill bit in terms of diameter and material has a considerable effect on the machinability. Drilling with HSS drills resulted in nearly 60% lower thrust force and better hole quality compared to that with carbide drills. While the size of delamination damage in the samples drilled at the lowest feed (0.02 mm/rev) sounds to be unrelated to cutting forces, the overall trend confirms that decreasing the value of thrust force leads to lowering delamination damages. Hence, an effective strategy in avoiding such undesirable defects is calculating the critical thrust force below which delamination is negligible. An analytical model is developed based on the theory of virtual work to determine the critical thrust force at delamination onset. Through validating with experimental data, the proposed model agrees better with a more accurate prediction than existing models.

了解钻孔参数对NFRCs可加工性的影响对学术界和制造业都具有价值。本工作研究了响应于切削速度，进给速度，钻头直径和钻头材料的，完全可生物降解的亚麻/聚乳酸复合材料的钻孔诱导的分层和孔质量。在各种类型的钻井引起的损坏中，发现出口板层脱层是最具破坏性的损坏，而切削推力被确定为主要原因。实验结果表明，推力高度依赖于钻削参数，其中进给速度和钻削材料是对其影响最大的参数。在直径和材料方面选择钻头对可加工性具有相当大的影响。与硬质合金钻头相比，HSS钻头的推力降低了近60％，孔质量更好。虽然在最低进给（0.02 mm / rev）下钻取的样品中的分层破坏的大小听起来与切削力无关，但总体趋势证实，减小推力的值可以降低分层破坏。因此，避免这种不希望的缺陷的有效策略是计算临界推力，在该临界推力之下分层可以忽略不计。基于虚拟功理论开发了一种分析模型，以确定分层开始时的临界推力。通过对实验数据进行验证，与现有模型相比，所提出的模型与更准确的预测更吻合。