MQL Cutting of Difficult-to-Machine Materials with the aids of CAE and Ultrasonic Vibration

为了减少对全球环境的影响，实现制造业的可持续发展，MQL技术已被广泛应用于机械加工过程中，该技术将少量生物可降解油与大量压缩空气一起供应。然而，将MQL技术有效地应用于难加工材料的加工仍然是一个难题。本文从理论和实验两方面对难加工材料的MQL切削技术进行了研究。为此，分别对Inconel 718和碳钢S45C进行了超声振动切削和非超声振动切削的MQL切削实验；研制了精密监测切削温度的刀具；利用计算流体力学通用程序分析了油雾在刀尖周围的流动。在精加工Inconel 718时，优化了压缩空气压力、油耗和刀具涂层材料，在60m /s或更高的切削速度下延长了刀具寿命。开发了控制油雾COD吹气方向的工具。研究发现，这些工具能够减少50- 70%的石油消耗。研究发现，将超声振动应用于MQL切削，特别是在较慢的切削速度下，可以有效地减少弹坑磨损，这在加工直径较小的细长棒材时是不可避免的。利用精确监测切削温度的工具，利用光刻技术在工具上制备薄膜热电偶，然后涂覆硬薄TiN膜。用这些工具测量了车削时的切削温度。对油雾的流动进行了分析，以进行调谐和开槽。在开槽过程中，油雾流动的局部化与油耗的降低有一定的定量关系。

To decrease the impact to the global environment and realize the sustainable development of manufacturing, MQL technology, in which a small amount of bio-degradable oil is supplied with plenty of compressed air, has been widely applied to machining processes. However, it is still difficult to apply MQL technology to machining of difficult-to-machine materials effectively. In this study, MQL cutting technology effective for machining difficult-to-machine materials was investigated from theoretical and experimental viewpoints. For this purpose, MQL cutting experiment of Inconel 718 and carbon steel S45C were conducted with and without ultrasonic vibration cutting ; cutting tools for monitoring cutting temperature precisely were developed ; oil mist flow around tool tip were analyzed using a general purpose code of computational fluid dynamics. In finishing Inconel 718,optimization of the pressure of compressed air, oil consumption, and coating materials of tool increased tool life at relatively high cutting speeds of 60 m/s or more. Tools for controlling the blowing direction of oil mist COD tools were developed. It was found that these tools were able to decrease oil consumption by 50-70 percent. Application of ultrasonic vibration to MQL cutting was found to be effective particularly in decreasing crater wear at slower cutting speeds, which were inevitable in machining a slender bar of smaller diameters. With tools for monitoring cutting temperature precisely, thin film thermocouples were fabricated on the tools using photolithography technology, then were coated with hard and thin TiN film. Cutting temperature in turning was measured with these tools. The flow of oil mist was analyzed for tuning and grooving. In grooving, reduction of oil consumption was related to the localization of the flow of oil mist quantitatively.