Iqbal Asif, Zhao Guolong, Zaini Juliana, Gupta Munish Kumar, Jamil Muhammad, He Ning, Nauman Malik Muhammad, Mikolajczyk Tadeusz, Pimenov Danil Yurievich
Faculty of Integrated Technologies, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE 1410, Brunei.
College of Mechanical & Electrical Engineering, Nanjing University of Aeronautics & Astronautics, 29-Yu Dao Street, Nanjing 210016, China.
Materials (Basel). 2021 Feb 8;14(4):795. doi: 10.3390/ma14040795.
Lightweight materials are finding plentiful applications in various engineering sectors due to their high strength-to-weight ratios. Hole-making is an inevitable requirement for their structural applications, which is often marred by thermal damages of the drill causing unacceptable shortening of tool life. Efficient cooling of the tool is a prime requirement for enhancing the process viability. The current work presents a novel technique of cooling only the twist drill between drilling of holes with no effect of the applied cryogenic coolant transferred to the work material. The technique is applied in the drilling of two commonly used high-strength lightweight materials: carbon fibers reinforced polymer (CFRP) and an alloy of titanium (Ti-6Al-4V). The efficacy of the cooling approach is compared with those of conventionally applied continuous cryogenic cooling and no-cooling. The effectiveness is quantified in terms of tool wear, thrust force, hole quality, specific cutting energy, productivity, and consumption of the cryogenic fluid. The experimental work leads to a finding that between-the-holes cryogenic cooling possesses a rich potential in curbing tool wear, reducing thrust force and specific energy consumption, and improving hole quality in drilling of CFRP. Regarding the titanium alloy, it yields a much better surface finish and lesser consumption of specific cutting energy.
轻质材料因其高强度重量比而在各个工程领域得到广泛应用。钻孔是其结构应用中不可避免的要求，但钻孔过程中钻头的热损伤常常会导致刀具寿命不可接受地缩短。对刀具进行有效冷却对于提高加工可行性至关重要。当前的工作提出了一种新颖的技术，即在钻孔之间仅冷却麻花钻，而施加的低温冷却剂不会对工件材料产生影响。该技术应用于两种常用的高强度轻质材料的钻孔：碳纤维增强聚合物（CFRP）和钛合金（Ti-6Al-4V）。将这种冷却方法的效果与传统应用的连续低温冷却和无冷却的效果进行了比较。从刀具磨损、推力、孔质量、比切削能、生产率和低温流体消耗等方面对有效性进行了量化。实验工作得出的一个发现是，孔间低温冷却在抑制CFRP钻孔中的刀具磨损、降低推力和比能耗以及提高孔质量方面具有很大潜力。对于钛合金，它能产生更好的表面光洁度并降低比切削能的消耗。
