Laser machining fundamentals: micro, nano, atomic and close-to-atomic scales

Abstract

With the rapid development in advanced industries, such as microelectronics and optics sectors, the functional feature size of devises/components has been decreasing from micro to nanometric, and even atomic and close-to-atomic scale (ACS) for higher performance, smaller volume and lower energy consumption. By this time, a great many quantum structures are proposed, with not only an extreme scale of several or even single atom, but also a nearly ideal lattice structure with no material defect. It is almost no doubt that such structures play critical role in the next generation products, which shows an urgent demand for the atomic and close-to-atomic scale manufacturing (ACSM). Laser machining is one of the most important approaches widely used in engineering and scientific research. It is high-efficient and applicable for most kinds of materials. Moreover, the processing scale covers a huge range from millimeters to nanometers, and has already touches the atomic level. Laser-material interaction mechanism, as the foundation of laser machining, determines the machining accuracy and surface quality. It becomes much more sophisticated and dominant with a decrease in processing scale, which is systematically reviewed in this article. In general, the mechanisms of laser-induced material removal are classified into ablation, Coulomb explosion and atomic desorption, with a decrease in the scale from above microns to angstroms. The effects of processing parameters on both fundamental material response and machined surface quality are discussed, as well as theoretical methods to simulate and understand the underlying mechanisms. Examples at nanometric to atomic scale are provided, which demonstrate the capability of laser machining in achieving the ultimate precision and becoming a promising approach to ACSM.

Alloy design for laser powder bed fusion additive manufacturing: a critical review

“…In L-PBF, metallic parts undergo complex thermal cycles [45,46]. Initially, the powders interact with the laser beam and are melted at a fast heating rate.…”

A review on current development of thermophotovoltaic technology in heat recovery

“…The generated ions hit the surface of the target under the action of an electric field and sputter onto the target. In addition to the above methods of depositing thin films, nanoscale patterning is often achieved with methods including reactive ion etching (RIE), focused ion beam (FIB), femtosecond laser direct writing (FLDW), etc [140,141]. The RIE process is a plasma etching technique that adds a directional component to the etching process by using a charge.…”

Design and optimization of fluid lubricated bearings operated with extreme working performances—a comprehensive review

“…Meanwhile, manufacturing errors of the grooves introduce periodic exciting forces that influence the rotational stability. At present, grooves are formed through chemical etching, high precision laser texturing [309], or ultra-precision machining. Typical groove structures are 10-30 µm high.…”