Micro-Scale Characterization of Machining Interfaces

加工界面代表了在小空间和短时间尺度上发生重要现象学事件的情况。通过将各种光学技术与透明切割工具(如蓝宝石、钻石)的使用相结合，可以通过放大这些事件的长度和时间尺度来直接观察和分析这些事件。拥有可视记录通常会给出正在发生的物理过程的线索，并通常有助于显示“发生了什么和没有发生什么”。在一系列新颖的实验中，将使用光学透明工具、高分辨率光学显微镜、高速、基于CCD的多波长红外线(IR)测温和高速显微摄影来研究沿刀具-芯片-工作界面的接触的性质以及这些接触区域的温度分布。初步观察表明，接触边界条件(例如粘连程度、滑动区等)的完整表征。通过使用这些技术，可以获得这些界面上完整的温度和速度分布的第一张详细地图。探讨了在常规和高速加工条件下的切削速度、刀具几何形状、刀具磨损和刀具涂层等参数对接触条件和界面温度的影响。这些实验代表了先前关于金属低速切割的现场观测工作的自然和有趣的演变。接触边界条件和界面温度分布是验证和改进加工力学模型、控制刀具温度、刀具磨损和加工表面质量以及实现加工过程完全可预测性这一长期追求的目标的关键参数。从技术角度来看，研究结果有望对提高加工过程的效率、使刀具和涂层的设计能够减少磨损和减少加工中流体的使用产生重大影响。

The machining interface represents a situation where important phenomenological events occur over small spatial and short time scales. By combining various optical techniques with the use of transparent cutting tools; e.g., sapphire, diamond, it is possible to directly observe and analyze these events by magnifying their length and time scales. Having a visual record frequently gives clues to the physical processes taking place and is often advantageous in showing "what is and what isn't happening." The nature of contact along the tool-chip-work interfaces, and the temperature distribution at these contact zones, will be studied in a novel series of experiments using optically transparent tools, high-resolution optical microscopy, high-speed, CCD-based, multi-wavelength infra-red (IR) pyrometry and high-speed micro-photography. Preliminary observations show that a complete characterization of the contact boundary conditions (e.g. extent of sticking, sliding zones, etc.) and the first detailed map of the complete temperature and velocity distributions at these interfaces can be achieved with the use of these techniques. The effect of parameters such as cutting speed both in the conventional and high speed machining regime, tool geometry, tool wear, and tool coatings, on the contact conditions and interface temperatures is being explored. The experiments represent a natural and interesting evolution of previous in-situ observational work on the low speed cutting of metals. The contact boundary conditions and the interface temperature distributions are key parameters for validation and refinement of models of the mechanics of machining; for control of tool temperatures, tool wear and work surface quality; and for realizing the long sought after goal of complete predictability of the machining process.From a technological standpoint, the results of the research may be expected to have a major impact in enhancing the efficiency of machining processes, enabling the design of tools and coatings for reducing wear and reducing the application of fluids in machining.