制造发展的三个范式:制造发展规律的研究

基于对人类社会发展历史和科学技术发展内在规律的认识,本文详细分析了制造发展的三个范式,论证了原子及近原子尺度制造是制造范式III的核心使能技术。文章回顾了国内外各机构对原子级制造研发规划现状,指出我国目前处于原子级制造技术发展的重要战略机遇期,并从设计、材料、加工和检测等角度分析了原子级制造的技术体系内涵;梳理了原子级表面制造、原子级结构制造、原子级测量与表征等领域的研究进展,呈现了当前具有原子级制造能力的部分代表性技术,包括原子级切削、原子级抛光、电化学加工、等离子体原子级加工技术、原子精准操控以及原子分辨测量与表征技术,并对原子级制造战略规划提出发展建议。

Recent advances in design and preparation of micro diamond cutting tools

Micro diamond tools are indispensable for the efficient machining of microstructured surfaces.The precision in tool manufacturing and cutting performance directly determines the processing quality of components.The manufacturing of high-quality micro diamond tools relies on scientific design methods and appropriate processing techniques.However,there is currently a lack of systematic review on the design and manufacturing methods of micro diamond tools in academia.This study systematically summarizes and analyzes modern manufacturing methods for micro diamond tools,as well as the impact of tool waviness,sharpness,and durability on machining quality.Subsequently,a design method is proposed based on the theory of cutting edge strength distribution to enhance tool waviness,sharpness,and durability.Finally,this paper presents current technical challenges faced by micro diamond tools along with potential future solutions to guide scientists in this field.The aim of this review is to contribute to the further development of the current design and manufacturing processes for micro diamond cutting tools.

Fundamentals of atomic and close-to-atomic scale manufacturing:a review

Atomic and close-to-atomic scale manufacturing(ACSM)represents techniques for manufacturing high-end products in various fields,including future-generation computing,communication,energy,and medical devices and materials.In this paper,the theoretical boundary between ACSM and classical manufacturing is identified after a thorough discussion of quantum mechanics and their effects on manufacturing.The physical origins of atomic interactions and energy beams-matter interactions are revealed from the point view of quantum mechanics.The mechanisms that dominate several key ACSM processes are introduced,and a current numerical study on these processes is reviewed.A comparison of current ACSM processes is performed in terms of dominant interactions,representative processes,resolution and modelling methods.Future fundamental research is proposed for establishing new approaches for modelling ACSM,material selection or preparation and control of manufacturing tools and environments.This paper is by no means comprehensive but provides a starting point for further systematic investigation of ACSM fundamentals to support and accelerate its industrial scale implementation in the near future.

Enhancement of surface wettability via micro-and nanostructures by single point diamond turning

Studies on surface wettability have received tremendous interest due to their potential applications in research and industrial processes. One of the strategies to tune surface wettability is modifying surface topography at micro-and nanoscales. In this research, periodic micro-and nanostructures were patterned on several polymer surfaces by ultra-precision single point diamond turning to investigate the relationships between surface topographies at the micro-and nanoscales and their surface wettability. This research revealed that single-point diamond turning could be used to enhance the wettability of a variety of polymers, including polyvinyl chloride(PVC), polyethylene 1000(PE1000), polypropylene copolymer(PP) and polytetrafluoroethylene(PFTE), which cannot be processed by conventional semiconductor-based manufacturing processes. Materials exhibiting common wettability properties(θ≈ 90°) changed to exhibit "superhydrophobic" behavior(θ > 150°). Compared with the size of the structures, the aspect ratio of the void space between micro-and nanostructures has a strong impact on surface wettability.

3D Cohesive Finite Element Minimum Invasive Surgery Simulation Based on Kelvin‑Voigt Model

Minimally invasive surgery is an important technique used for cytopathological examination.Recently,multiple studies have been conducted on a three-dimensional(3D)puncture simulation model as it can reveal the internal deformation state of the tissue at the micro level.In this study,a viscoelastic constitutive equation suitable for muscle tissue was derived.Additionally,a method was developed to define the fracture characteristics of muscle tissue material during the simulation process.The fracture of the muscle tissue in contact with the puncture needle was simulated using the cohesive zone model and a 3D puncture finite element model was established to analyze the deformation of the muscle tissue.The stress nephogram and reaction force under different parameters were compared and analyzed to study the deformation of the biological soft tissue and guide the actual operation process and reduce pain.

Surface defects incorporated diamond machining of silicon

This paper reports the performance enhancement benefits in diamond turning of the silicon wafer by incorporation of the surface defect machining(SDM)method.The hybrid micromachining methods usually require additional hardware to leverage the added advantage of hybrid technologies such as laser heating,cryogenic cooling,electric pulse or ultrasonic elliptical vibration.The SDM method tested in this paper does not require any such additional baggage and is easy to implement in a sequential micro-machining mode.This paper made use of Raman spectroscopy data,average surface roughness data and imaging data of the cutting chips of silicon for drawing a comparison between conventional single-point diamond turning(SPDT)and SDM while incorporating surface defects in the(i)circumferential and(ii)radial directions.Complementary 3D finite element analysis(FEA)was performed to analyse the cutting forces and the evolution of residual stress on the machined wafer.It was found that the surface defects generated in the circumferential direction with an interspacing of 1 mm revealed the lowest average surface roughness(Ra)of 3.2 nm as opposed to 8 nm Ra obtained through conventional SPDT using the same cutting parameters.The observation of the Raman spectroscopy performed on the cutting chips showed remnants of phase transformation during the micromachining process in all cases.FEA was used to extract quantifiable information about the residual stress as well as the sub-surface integrity and it was discovered that the grooves made in the circumferential direction gave the best machining performance.The information being reported here is expected to provide an avalanche of opportunities in the SPDT area for low-cost machining solution for a range of other nominal hard,brittle materials such as SiC,ZnSe and GaAs as well as hard steels.

Modelling of grinding mechanics:A review

Grinding is one of the most widely used material removal methods at the end of many process chains.Grinding force is related to almost all grinding parameters,which has a great influence on material removal rate,dimensional and shape accuracy,surface and subsurface integrity,thermodynamics,dynamics,wheel durability,and machining system deformation.Considering that grinding force is related to almost all grinding parameters,grinding force can be used to detect grinding wheel wear,energy calculation,chatter suppression,force control and grinding process simulation.Accurate prediction of grinding forces is important for optimizing grinding parameters and the structure of grinding machines and fixtures.Although there are substantial research papers on grinding mechanics,a comprehensive review on the modeling of grinding mechanics is still absent from the literature.To fill this gap,this work reviews and introduces theoretical methods and applications of mechanics in grinding from the aspects of modeling principles,limitations and possible future trendencies.

A Simulated Investigation of Ductile Response of GaAs in Single-Point Diamond Turning and Experimental Validation

In this paper,molecular dynamic(MD)simulation was adopted to study the ductile response of single-crystal GaAs during single-point diamond turning(SPDT).The variations of cutting temperature,coordination number,and cutting forces were revealed through MD simulations.SPDT experiment was also carried out to qualitatively validate MD simulation model from the aspects of normal cutting force.The simulation results show that the fundamental reason for ductile response of GaAs during SPDT is phase transition from a perfect zinc blende structure(GaAs-I)to a rock-salt structure(GaAs-II)under high pressure.Finally,a strong anisotropic machinability of GaAs was also found through MD simulations.

Three-dimensional biofabrication of nanosecond laser micromachined nanofibre meshes for tissue engineered scaffolds

There is a high demand for bespoke grafts to replace damaged or malformed bone and cartilage tissue.Three-dimensional(3D)printing offers a method of fabricating complex anatomical features of clinically relevant sizes.However,the construction of a scaffold to replicate the complex hierarchical structure of natural tissues remains challenging.This paper reports a novel biofabrication method that is capable of creating intricately designed structures of anatomically relevant dimensions.The beneficial properties of the electrospun fibre meshes can finally be realised in 3D rather than the current promising breakthroughs in two-dimensional(2D).The 3D model was created from commercially available computer-aided design software packages in order to slice the model down into many layers of slices,which were arrayed.These 2D slices with each layer of a defined pattern were laser cut,and then successfully assembled with varying thicknesses of 100μm or 200μm.It is demonstrated in this study that this new biofabrication technique can be used to reproduce very complex computer-aided design models into hierarchical constructs with micro and nano resolutions,where the clinically relevant sizes ranging from a simple cube of 20 mm dimension,to a more complex,50 mm-tall human ears were created.In-vitro cell-contact studies were also carried out to investigate the biocompatibility of this hierarchal structure.The cell viability on a micromachined electrospun polylactic-co-glycolic acid fibre mesh slice,where a range of hole diameters from 200μm to 500μm were laser cut in an array where cell confluence values of at least 85%were found at three weeks.Cells were also seeded onto a simpler stacked construct,albeit made with micromachined poly fibre mesh,where cells can be found to migrate through the stack better with collagen as bioadhesives.This new method for biofabricating hierarchical constructs can be further developed for tissue repair applications such as maxillofacial bone injury or nose/ear cartilage replacement in the future.

Smoothed-Particle Hydrodynamics Investigation on Brittle-Ductile Transition of Quartz Glass in Single-Grain Grinding Process

The smoothed-particle hydrodynamics(SPH)method was introduced to simulate the quartz glass grinding process with a single grain under micrp-nano scale.To investigate the mechanism of brittle-ductile transition,such factors as the machin-ing depth,grinding force,maximum equivalent stress,and residual stress were analyzed.The simulation results indicate that quartz glass can be machined in a ductile mode under a certain condition.In this paper,the occurrence and propaga-tion of cracks in quartz glass at different grinding depths(0.1-1μm)are observed,and the critical depth of brittle-ductile transformation is 0.36 pum.At different grinding depths,the grinding force ratio is greater than 1.When the cutting depth is 0.4 um,the crack propagation depth is about 1.2μm,which provides a basis for the prediction of subsurface damage depth.In addition,the correctness of the simulation result was verified by carrying out scratch experiments of varying cutting depth on optical quartz glass.

Atomic-Scale Friction Studies on Single-Crystal Gallium Arsenide Using Atomic Force Microscope and Molecular Dynamics Simulation

This paper provides a fresh perspective and new insights into nanoscale friction by investigating it through molecular dynamics(MD)simulation and atomic force microscope(AFM)nanoscratch experiments.This work considered gallium arsenide,an importantⅢ-Ⅴdirect bandgap semiconductor material residing in the zincblende structure,as a reference sample material due to its growing usage in 5G communication devices.In the simulations,the scratch depth was tested as a variable in the fine range of 0.5-3 nm to understand the behavior of material removal and to gain insights into the nanoscale friction.Scratch force,normal force,and average cutting forces were extracted from the simulation to obtain two scalar quantities,namely,the scratch cutting energy(defined as the work performed to remove a unit volume of material)and the kinetic coefficient of friction(defined as the force ratio).A strong size effect was observed for scratch depths below 2 nm from the MD simulations and about 15 nm from the AFM experiments.A strong quantitative corroboration was obtained between the specific scratch energy determined by the MD simulations and the AFM experiments,and more qualitative corroboration was derived for the pile-up and the kinetic coefficient of friction.This conclusion suggests that the specific scratch energy is insensitive to the tool geometry and the scratch speed used in this investigation.However,the pile-up and kinetic coefficient of friction are dependent on the geometry of the tool tip.

Foreword to the Special Issue on Nanofabrication,Atomic and Close-to-atomic Scale Manufacturing

Nanomanufacturing covers a wide range of manufacturing technologies for enabling nanoscale materials,structures,components,devices,and systems through the manipula-tion and control of matter at the nano-scale.This is pivotal to our economy,as nanoproducts such as nano materials,nanooptics,nanosensors,nanoelectronics,NEMS,etc.,are becoming established in major areas of our daily lives and can already be found across a broad spectrum of application areas,especially in sectors such as autos,appliances,electronics,photonics,food,healthcare,and fitness.

Centre for Precision Manufacturing

The Centre for Precision Manufacturing(CPM)is an internationally leading research centre for advanced manufacturing.The centre researches and develops materials,processes,tools,machinery,and numerical modelling techniques for improving economic and technical performance of materi-als and manufacturing processes with advaneed precision,micro-and nano-manufacturing techniques.CPM is one of the most successful centres in Europe in attracting external funding(over￡40 million)to con duct industry-relevant research.The centre led the EU FP6什agship integrated project MASMICRO,one of the largest-ever funded EU projects in the EU NMP theme(€21.4 million budget and 36 partners from 13 EU countries)which led to a series of new design and manufacturing solutions in dealing with materials,size effects.

Insight into Atomic-Scale Adhesion at the C-Cu Interface During theInitial Stage of Nanoindentation

Adhesion is a common phenomenon in nanomachining which affects processing accuracy and repeatability.As material removal approaches the atomic or close-to-atomic scale,quantum mechanics becomes the dominant principle behind the atomic-level interaction.However,atomic-scale effects cannot be properly described by empirical potential function-based molecular dynamics simulations.This study uses a first-principles method to reveal the atomic-scale adhesion between a diamond tip and a copper slab during initial-stage nanoindentation.Using a simplified tip and slab model,adhesion energy,electronic distribution,and density of states are analyzed based on quantum chemistry calculation.Results show that atomic adhesion is primarily due to the covalent bonding interaction between C and Cu atoms,which can induce structural changes to the diamond tip and copper slab.The effects of tip position and angles on adhesion are further studied through a series of simulations.The results show that adhesion between the tip and slab is sensitive to the lattice structure and a variant in angstroms is enough to cause different adhesion and structural changes.The actual determinants of adhesion can only be the atomic and electronic structures at the tip-slab interface.Bond rotation and breakage are observed during simulation and their effects on adhesion are further discussed.To conclude,the first-principles method is important for the analysis of an atomic-scale interaction system,even if only as an aid to describing adhesion at atomic and electronic scales.