Towards atomic and close-to-atomic scale manufacturing

Human beings have witnessed unprecedented developments since the 1760s using precision tools and manufacturing methods that have led to ever-increasing precision,from millimeter to micrometer,to single nanometer,and to atomic levels.The modes of manufacturing have also advanced from craft-based manufacturing in the Stone,Bronze,and Iron Ages to precisioncontrollable manufacturing using automatic machinery.In the past 30 years,since the invention of the scanning tunneling microscope,humans have become capable of manipulating single atoms,laying the groundwork for the coming era of atomic and close-to-atomic scale manufacturing(ACSM).Close-to-atomic scale manufacturing includes all necessary steps to convert raw materials,components,or parts into products designed to meet the user’s specifications.The processes involved in ACSM are not only atomically precise but also remove,add,or transform work material at the atomic and close-to-atomic scales.This review discusses the history of the development of ACSM and the current state-of-the-art processes to achieve atomically precise and/or atomic-scale manufacturing.Existing and future applications of ACSM in quantum computing,molecular circuitry,and the life and material sciences are also described.To further develop ACSM,it is critical to understand the underlying mechanisms of atomic-scale and atomically precise manufacturing;develop functional devices,materials,and processes for ACSM;and promote high throughput manufacturing.

Advances in micro cutting tool design and fabrication

Microcutting is a precision technology that offers flexible fabrication of microfeatures or complex three-dimensional components with high machining accuracy and superior surface quality.This technology may offer great potential as well as advantageous process capabilities for the machining of hard-to-cut materials,such as tungsten carbide.The geometrical design and dimension of the tool cutting edge is a key factor that determines the size and form accuracy possible in the machined workpiece.Currently,the majority of commercial microtools are scaled-down versions of conventional macrotool designs.This approach does not impart optimal performance due to size effects and associated phenomena.Consequently,in-depth analysis and implementation of microcutting mechanics and fundamentals are required to enable successful industrial adaptation in microtool design and fabrication methods.This paper serves as a review of recent microtool designs,materials,and fabrication methods.Analysis of tool performance is discussed,and new approaches and techniques are examined.Of particular focus is tool wear suppression in the machining of hard materials and associated process parameters,including internal cooling and surface patterning techniques.The review concludes with suggestions for an integrated design and fabrication process chain which can aid industrial microtool manufacture.

On the Three Paradigms of Manufacturing Advancement

Good morning!Before we begin our discussions,I would like to share my thoughts regarding the three paradigms of manufacturing advancement.Since my college days and even earlier,I have been fas-cinated by the concept of a“salon”,a gathering of like-minded people.My interest was rooted in my impression of the Copenhagen group,which organized a salon that allowed everyone to freely express their thoughts on a particular topic.

Recent Progress in Surface Integrity Research and Development

1.Introduction Surface integrity has great significance for the quality and performance of machined components,and has therefore been increasingly recognized by industry.In particular,within certain industries that require high reliability,such as the aerospace industry,surface integrity is one of the most relevant indexes used to evaluate the quality of machined parts.Thus,obtaining updated knowledge on surface integrity is of great interest to both the academic community and industry[1].

Advances in Molecular Electronics:A Brief Review

The field of molecular electronics,also known as moletronics,deals with the assembly of molecular electronic components using molecules as the building blocks.It is an interdisciplinary field that includes physics,chemistry,materials science,and engineering.Moletronics mainly deals with the reduction of size of silicon components.Novel research has been performed in developing electrical-equivalent molecular components.Moletronics has established its influence in electronic and photonic applications,such as conducting polymers,photochromics,organic superconductors,electrochromics,and many more.Since there is a need to reduce the size of the silicon chip,attaining such technology at the molecular level is essential.Although the experimental verification and modeling of molecular devices present a daunting task,vital breakthroughs have been achieved in this field.This article combines an overview of various molecular components,such as molecular transistors,diodes,capacitors,wires,and insulators,with a discussion of the potential applications of different molecules suitable for such components.We emphasize future developments and provide a brief review of different achievements that have been made regarding graphene-based molecular devices.

Precision micro-milling process:state of the art

Micro-milling is a precision manufacturing process with broad applications across the biomedical,electronics,aerospace,and aeronautical industries owing to its versatility,capability,economy,and efficiency in a wide range of materials.In particular,the micro-milling process is highly suitable for very precise and accurate machining of mold prototypes with high aspect ratios in the microdomain,as well as for rapid micro-texturing and micro-patterning,which will have great importance in the near future in bio-implant manufacturing.This is particularly true for machining of typical difficult-to-machine materials commonly found in both the mold and orthopedic implant industries.However,inherent physical process constraints of machining arise as macromilling is scaled down to the microdomain.This leads to some physical phenomena during micromilling such as chip formation,size effect,and process instabilities.These dynamic physical process phenomena are introduced and discussed in detail.It is important to remember that these phenomena have multifactor effects during micro-milling,which must be taken into consideration to maximize the performance of the process.The most recent research on the micro-milling process inputs is discussed in detail from a process output perspective to determine how the process as a whole can be improved.Additionally,newly developed processes that combine conventional micro-milling with other technologies,which have great prospects in reducing the issues related to the physical process phenomena,are also introduced.Finally,the major applications of this versatile precision machining process are discussed with important insights into how the application range may be further broadened.

Magnetohydrodynamic‑based Internal Cooling System for a Ceramic Cutting Tool:Concept Design,Numerical Study,and Experimental Evalidation

The efective removal of the heat generated during mechanical cutting processes is crucial to enhancing tool life and produc-ing workpieces with superior surface fnish.The internal cooling systems used in cutting inserts employ a liquid water-based solvent as the primary medium to transport the excess thermal energy generated during the cutting process.The limitations of this approach are the low thermal conductivity of water and the need for a mechanical input to circulate the coolant around the inner chamber of the cutting tool.In this context,this paper proposes an alternative method in which liquid gallium is used as the coolant in combination with a magnetohydrodynamic(MHD)pump,which avoids the need for an external power source.Using computational fuid dynamics,we created a numerical model of an internal cooling system and then solved it under conditions in which a magnetic feld was applied to the liquid metal.This was followed by a simulation study performed to evaluate the efectiveness of liquid gallium over liquid water.The results of experiments conducted under non-cooling and liquid gallium cooling conditions were analyzed and compared in terms of the tool wear rate.The results showed that after six machining cycles at a cutting speed Vc=250 m min−1,the corner wear VBc rate was 75µm with the coolant of and 48µm with the MHD-based coolant on,representing a decrease of 36%in tool wear.At Vc=900 m min−1,the corner wear VBc rate was 75µm with the coolant of and 246µm with the MHD-based coolant on,representing a decrease of 31%in tool wear.When external cooling using liquid water was added,the results showed at Vc=250 m min−1,the diference between the tool wear rate reduction with the internal liquid gallium coolant relative to the external coolant was 29%.When the cutting speed was increased to Vc=900 m min−1,the diference observed between the internal liquid gallium coolant relative to the external coolant was 16%.The study proves the feasibility of using liquid gallium as a coolant to efectively remove thermal energy through internally fabricated cooling channels in cutting inserts.