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

为了减少对地球环境的影响，实现制造业的可持续发展，MQL技术，其中少量的生物降解油与大量的压缩空气一起供应，已被广泛应用于机械加工过程。然而，将MQL技术有效地应用于难加工材料的加工仍然是困难的。本文从理论和实验两方面研究了难加工材料的MQL切削技术。为此，对Inconel 718和碳钢S45 C进行了超声振动切削和非超声振动切削的MQL切削试验;研制了可精确监控切削温度的刀具;采用通用计算流体力学程序对刀尖油雾流动进行了分析。在精加工Inconel 718时，通过优化压缩空气的压力、油耗和刀具的涂层材料，在60 m/s以上的较高切削速度下延长了刀具寿命。开发了用于控制油雾COD工具吹向的工具。结果发现，这些工具能够减少50- 70%的石油消耗。应用超声波振动MQL切削被认为是有效的，特别是在减少凹坑磨损在较低的切削速度，这是不可避免的加工一个细长杆的直径较小。为了精确监测切削温度，采用光刻技术在刀具上制作薄膜热电偶，并在其上镀上一层坚硬的TiN薄膜。用这些刀具测量了车削时的切削温度。分析了调谐和切槽时油雾的流动情况。在切槽加工中，降低油耗与油雾流动的局部化定量相关。

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.