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This article provides a simple and fast method to adjust the wettability and adhesion of aluminum (Al) alloy surfaces after electric discharge machining (EDM). For an Al alloy plate after EDM, without any grinding and polishing, laser treatment was directly performed on the surface to prepare the Al alloy surface with different wettability and adhesion behaviors. Scanning electron microscopy was used to analyze the surface morphologies of the smooth surface, wire-cut surface, and the surface treated with different laser parameters after wire-cut. Then, the chemical composition, contact angle (CA) stability, adhesion and surface bounce behavior of the surfaces processed

In this work, the localized electrochemical micro additive manufacturing technology based on the FluidFM (fluidic force microscope) has been introduced to fabricate micro three-dimensional overhang metal structures at sub-micron resolution. It breaks through the localized deposition previously achieved by micro-anode precision movement, and the micro-injection of the electrolyte is achieved in a stable electric field distribution. The structure of electrochemical facilities has been designed and optimized. More importantly, the local electrochemical deposition process has been analyzed with positive source diffusion, and the mathematical modeling has been revealed in the particle conversion process. A mathematical model is proposed for the species flux under the action of pulsed pressure in an innovatively localized liquid feeding process. Besides, the linear structure, bulk structure, complex structure, and large-area structure of the additive manufacturing are analyzed separately. The experimental diameter of the deposited cylinder structure is linearly fitted. The aspect ratio of the structure is greater than 20, the surface roughness value is between 0.1&ndash, 0.2 &mu, m at the surface of bulk structures, and the abilities are verified for deposition of overhang, hollow complex structures. Moreover, this work verifies the feasibility of 3D overhang array submicron structure additive manufacturing, with the application of pulsed pressure. Furthermore, this technology opens new avenues for the direct fabrication of nano circuit interconnection, tiny sensors, and micro antennas.

The effect of the plating voltage on the surface roughness, morphology, chemical composition and wettability of the Ni coatings was investigated by means of Laser scanning confocal microscopy, scanning electronic microscope, X-ray diffraction, energy-dispersive spectroscopy, and water contact angle measurements. The results indicate that the evolution of surface morphology on Ni coatings prepared by brush-plating depends strongly on the variation of plating voltage. The microstructure characterization shows that the typical hierarchical cauliflower-like structures was formed uniformly on the as-prepared Ni coatings. The combination of the porous morphology and hierarchical cauliflower-like structures plays a crucial role in improving the hydrophobic property. In absence of surface chemical modification, the Ni coatings exhibit an excellent hydrophobicity and have a high contact angle of 141 degree. Based on the Cassie-Baxier models, the relationship of two dimensionless geometrical parameters and the wetting property of the Ni coatings were investigated. It was demonstrated that to obtain the stable Cassie hydrophobic state, the aspect ratio and the water contact angle on the basal surface should be as large as possible and the spacing factor should be limited within a specific range for given aspect ratio and water contact angle on the basal surface.

Reducing the contact time of a water droplet on non-wetting surfaces has great potential in the areas of self-cleaning and anti-icing, and gradually develops into a hot issue in the field of wettability surfaces. However, the existing literature on dynamic behavior of water drops impacting on superhydrophobic surfaces with various structural shapes is insufficient. Inspired by the microstructure of lotus leaf and rice leaf, dual-level and three-level structures on plane and convex surfaces were successfully fabricated by wire electrical discharge machining on aluminum alloy. After spraying hydrophobic nanoparticles on the surfaces, the plane and convex surfaces with dual-level and three-level structures showed good superhydrophobic property. Bouncing dynamics of impact droplets on the superhydrophobic surfaces wereinvestigated, and the results indicated that the contact time of plane superhydrophobic surface with a three-level structure was minimal, which is 60.4% less than the plane superhydrophobic surface with dual-level structure. The effect of the interval S, width D, and height H of the structure on the plane superhydrophobic surface with three-level structure on contact time was evaluated to obtain the best structural parameters for reducing contact time. This research is believed to guide the direction of the structural design of the droplet impinging on solid surfaces.

Despite the success of previous methods for fabricating underwater superoleophobic surfaces, most of the surfaces based on soft materials are prone to collapse and deformation due to their mechanically fragile nature, and they fail to perform their designed functions after the surface materials are damaged in water. In this work, the nanosecond laser-induced oxide coatings on hydrophilic bulk metals are reported which overcomes the limitation and shows the robust underwater superoleophobicity to a mechanical challenge encountered by surfaces deployed in water environment. The results show that the surface materials have the advantage that the underwater superoleophobicity is still preserved after the surfaces are scratched by knife or sandpaper and even completely destroyed because of the hydrophilic property of damaged materials in water. It is important that the results provide a guide for the design of durable underwater superoleophobic surfaces, and the development of superoleophobic materials in many potential applications such as the oil-repellent and the oil/water separation. Additionally, the nanosecond laser technology is simple, cost-effective and suitable for the large-area and mass fabrication of mechanically durable underwater superoleophobic metal materials.

In this study, we developed a simple, low-cost and convenient method to fabricate grid structures of different scales on the surface of 6061 aluminum alloy via laser processing. By changing the line spacing (50, 150, 250, 300 μm) during laser beam irradiation, different sizes of the square-shaped unprocessed surface areas and cross groove structures could be achieved. By adjusting the area ratio between the accumulative microstructure and the unprocessed surface, the adhesion of a water droplet to the surface could be varied from a state of low adhesion (line spacing of 50 or 150 μm) to a state of high adhesion (line spacing of 250 or 300 μm). The results indicated that different surface wettabilities could be obtained on aluminum alloy surfaces through the combination of a crisscross groove structure and unprocessed surface, which together formed a square groove structure. Corrugated protuberances, granular bumps and pit texture were formed on the groove structure. The surface showed excellent superhydrophobic properties. The contact angle was as high as 154.6° and the sliding angle was 6° for a line spacing of 150 μm. In this case, the low adhesion led to a rolling and self-cleaning behavior. For the larger line spacings, the wetting state of the water droplet indicated a high adhesion to the surface and a transition of the Cassie-Baxter state to the Wenzel state. Surfaces with high adhesion are of great significance for water collection and preservation. The approach presented in this study provides a facile, low-cost and efficient method to fabricate superhydrophobic surfaces on all types of metallic materials for commercial applications.

An aluminium alloy surface with a microgroove array was fabricated via laser processing, and exhibited superhydrophobicity. The as-prepared surface showed excellent anti-adhesion properties and potential self-cleaning behaviour. The wettability of the fabricated surface was investigated by measurement of the water contact angle. The surface morphology and chemical composition were characterised by scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. The wettability of the surface was successfully modified from hydrophilicity to superhydrophobicity by the laser processing. The water contact angle was increased to 155°, and the sliding angle reduced to

The fabrication of pure copper microstructures with submicron resolution has found a host of applications, such as 5G communications and highly sensitive detection. The tiny and complex features of these structures can enhance device performance during high-frequency operation. However, manufacturing pure copper microstructures remain challenging. In this paper, we present localized electrochemical deposition micro additive manufacturing (LECD-μAM). This method combines localized electrochemical deposition (LECD) and closed-loop control of atomic force servo technology, which can effectively print helical springs and hollow tubes. We further demonstrate an overall model based on pulsed microfluidics from a hollow cantilever LECD process and closed-loop control of an atomic force servo. The printing state of the micro-helical springs can be assessed by simultaneously detecting the Z-axis displacement and the deflection of the atomic force probe cantilever. The results showed that it took 361 s to print a helical spring with a wire length of 320.11 μm at a deposition rate of 0.887 μm s−1, which can be changed on the fly by simply tuning the extrusion pressure and the applied voltage. Moreover, the in situ nanoindenter was used to measure the compressive mechanical properties of the helical spring. The shear modulus of the helical spring material was about 60.8 GPa, much higher than that of bulk copper (∼44.2 GPa). Additionally, the microscopic morphology and chemical composition of the spring were characterized. These results delineate a new way of fabricating terahertz transmitter components and micro-helical antennas with LECD-μAM technology.

Low frequency noise has strong penetration power and is difficult to be attenuated. In order to solve the problem of low-frequency noise absorption in traditional sound absorbing materials, a coupled structure of coiled-up space core embedded in a porous material (CSPM) is proposed. The coiled-up space core (CSC) structure consists of a folding structure and a labyrinth structure, and a rectangular slot is cut at the top of each structure to allow the sound wave to enter. The resonant sound absorption peak of CSPM is formed in the low frequency range and the sound absorption performance is achieved above 85% at 105 Hz and 90% at 315 Hz. The CSMPs which consists of four different parameters of CSC embedded in the porous layer, and its absorption performance can reach as high as 0.75 from 195 Hz to 600 Hz. The influences of the porosity, flow resistance, tortuous factor of porous materials and parameters of CSC on the sound absorption performance are also investigated. In this work, CSPM is fabricated and its sound absorption performance is tested through an impedance tube for verifying the correctness of the simulation.

Ti6Al4V is often used in the manufacture of biomedical equipment due to its excellent properties such as light weight, high strength and good corrosion resistance in the physiological environment. Therefore, it is very important to form a non-toxic antibacterial surface on Ti6Al4V material. In this paper, a micro-nano manufacturing method of Ti6Al4V antibacterial surface was studied. In this process, the surface was firstly cut by low speed wire electrical discharge machine, and then the cut surface was hydrothermal treated. The antibacterial surface prepared by this process had the characteristics of non-toxic, stable structure, and would not cause bacteria to develop drug resistance. The preparation process is simple, friendly to the environment, and can realize mass production. The influence of different cutting times on the antibacterial surface morphology in the low speed wire electrical discharge machining was studied. The micron-grade surface obtained after three cutting times was of good quality, less molten material and high wear resistance. The influence of two etching agents mixed with different molar ratios on the micro-nano structure of antibacterial surface during hydrothermal treatment was analyzed. When the molar ratio of A and B solution was 14:1, the surface structure of the best size was obtained, and the wear resistance of the micro-nano structure surface was improved compared with the polished surface. The antimicrobial test results show that the surface of the prepared workpiece had obvious antimicrobial properties compared with the surface of the polished part after cultured for 24 h. The bacteriostatic rate of Escherichia coli was 49.55%. Based on the above, the research results of this paper have positive significance for the development of micro-nano antibacterial surface.

The T-shaped groove surface with groove width of 0.3–1.2 mm and groove depth of 0.6–1.5 mm is prepared on the copper surface by using electric spark wire cutting technology, Set up a set of wall temperature measurement, bubble visualization and steady flow heating test bench. Experimental observations of boiling heat transfer of deionized water on different heat transfer surfaces are achieved. The boiling curves of T-shaped surface such as superheat, heat flux and heat transfer coefficient were plotted. The effect of heat transfer area on the heat transfer performance was investigated, and the bubble growth process was studied by using finite element simulation software. The effect of size on heat transfer performance is explained by experiment and simulation. It is found that the influence of groove width on heat transfer performance is greater than that of groove depth, under the reasonable width of the groove, the larger the depth of the groove, the easier it is to reach the required temperature for the vaporized core generation. The optimal size value of T-shaped grooves in this size range is selected, and the surface of T-grooves at different scales is constructed by laser marking technology. The boiling heat transfer performance of four kings of surfaces including smooth surface and laser scanning surface was studied. Studies have shown, heat transfer effect of multi-scale T surface is always the best,1.31 times of single scale surface,2.38 times of smooth surface and 2.83 times of laser scanning surface. The surface with micro structure can effectively promote boiling heat transfer by wire cutting and laser machining.

Micro machining has attracted great attention, and micro components made of hard-to-machine material are broadly applied in aerospace and automobile areas. Laser-assisted machining is an effective machine method for hard-to-machine materials. Combining the laser heating with conventional machining will be benefit for the machinability. In this study, an experimental investigation of laser-assisted micro machining of SiCp/2024Al composites was conducted. The aim of this study is to investigate the machining characteristics of SiCp/2024Al during laser-assisted micro machining (LAMM) in terms of cutting force, surface integrity, chip formation, and tool wear. L16 (type B) Taguchi orthogonal array was designed and the results are analyzed by ANOVA method. It is found that thrust force is the dominant force during experiment compared with main cutting force. There is 27% decrease in thrust force when laser power increased from 0 to 31 W which shows marked effect on cutting force. Adhesion wear and abrasive wear on flank face play a major role during LAMM when continuous chips were produced. The variation of flank wear VB max is calculated by mean value, and the result shows that tool wear decreased 38% when laser power increased to 31 W. The experiment results show that the LAMM is benefit for the surface quality by small cutting depth and high laser power. There is 38% decrease in Ra when 31-W laser power was used compared with conventional machining. In terms of LAMM mechanism, there are two parts involved in. In one side, the material will soften because of high temperature by laser. In the other side, there are numerous aluminum oxide nanoparticles produced in the cutting area during LAMM. The mechanism of nanoparticles functioning, ball bearing effect, mending effect, and tribo-film effect are included in LAMM which affected the tribological behavior.

In this work, the reaction films were generated on the Ti–6Al–4V alloy by means of high-speed wire electrical discharge machining (WEDM-HS) technology in order to improve its microhardness and corrosion resistance. The microhardness was evaluated by using a nanoindentation tester. The corrosion behaviour was studied using measurements of potentiodynamic polarisation and electrochemical impedance spectroscopy. The experimental results showed that the processed alloys presented a higher microhardness than the matrix, and the thicker film on the surface had a greater microhardness. Additionally, the corrosion resistances of the processed alloys were superior, which could have been due to the lower corrosion current densities and the higher impedance values. Furthermore, the corrosion current densities of the processed alloys would decrease with thicker reaction films. This research provides important insights into the surface modification of titanium alloys.

With the continuous exploration of the special morphologies and properties of skin of some animals and plant leaf surfaces in the nature, new hydrophobic surfaces are developed through imitation of the observed surface effects. The aluminum alloy surface which is similar to multi-scale hierarchical structure surface of biomimetic rice leaf can be obtained by combining high speed wire electrical discharge machining (WEDM) method and electric brush-plating technique. The morphological feature was analyzed by scanning electron microscopy (SEM). The surface wettability of the sample was measured at ambient temperature using a contact angle measurement instrument and the SCA20 software by placing a 4 μ L pure distilled water droplet onto the surface of the sample. Three dimensional (3D) profile of the sample surface was obtained through confocal laser scanning microscopy (LSCM). The elemental composition was determined by X-ray diffraction (XRD) analysis in order to determine the phase composition on the sample surface. The regular submillimeter groove ridge structures were processed on the aluminum alloy surfaces by the method of high speed wire electrical discharge machining. And the hierarchical cauliflower-like structures which were consisted of micro-protrusions and submicro-grains were formed on the sample surfaces by electric brush-plating technique. The anisotropic functional surfaces and the superhydrophobic surfaces were achieved by the combination of the regular submillimeter groove ridge structures and hierarchical cauliflower-like structures. The research showed that the regular submillimeter groove ridge structures are similar to the surface morphology on rice leaf, and the hierarchical cauliflower-like structures are similar to the surface morphology on lotus leaf. The results showed that double scale (micro-submicro) microscopic structure obtained by electric brush-plating can play a key role on the hydrophobicity of the surface. The regular submillimeter groove ridge structure obtained by high speed wire electrical discharge machining further enlarged the hydrophobic properties of the direction of parallel groove. The sample surface showed excellent superhydrophobic properties, and the contact angle of the direction of parallel groove could reach up to 151°. The sample surface also showed different hydrophobic properties in the direction of the parallel groove and the direction ofthe vertical groove. Due to the existence of the edge structure make the two directions, and the two directions have different static wettability, which also led to the surface anisotropy. With the changing of electric brush-plating time, the trend of double and multi scale structure surface contact angle had large difference on the sample surface. The sample surface is fabricated without any chemical modification by combining high speed wire electrical discharge machining method with electric brush-plating technique. Although the application of the surface anisotropy and superhydrophobicity were not showed in other places, it is important for animals and plants in the nature. With the deepening of the study, this research will rise to certain guiding significance on the applications of combining the anisotropic functional materials with the superhydrophobic materials.

A robotically assisted catheterization system can obviously reduce the radiation exposure to the surgeon and lesson the fatigue caused by standing for long time in protective clothing. However, effective detection and feedback of proximal force signals is essential to the success of a surgery. This paper presents a compact, cost-effective force-sensing device based on strain gauges, for our team developed slave side, to measure the proximal force signals of the input catheter. A significant advantage is that the proposed sensing device can detect the force signals directly without any mechanical transmission, and this can increase the measurement accuracy of force information. In addition, a haptic interface based on MR fluid is designed to provide a realistic sense of operation according to the force signals from the slave side, so as to improve the safety and success of a surgery. Comparing experimental results from an insertion test and a load cell, show that the average error for force measurement is less than 0.01 N. This research provides important insights into the design of compact, ergonomic, robotic catheter manipulators for intraoperative navigation using effective tactile sensing devices.

The micro-nano composite structure on carbon steel substrate can be fabricated, and the composite structure not only has the property of hydrophobicity, but also has the property of corrosion resistance, which can be fabricated by combining a sandblasting technology and electro-brush plating method. The micro-nano composite structure fabricated by combining methods have been studied by the different preparation technology parameters, and then the different surface morphologies were obtained, at the same time, the different micro surface structures were formed. The parameters of the brush plating voltage plays an important part in this preparation process, so we can select the best parameters by changing the parameters of the brush plating voltage during the preparation process, and after the preparation process, hydrophobic surface has a bigger static contact angle than before, which is up to 149.3°±2.5° without any modification. In this paper, the qualitative and quantitative ananlysis of various properties of the fabricated surface with the composite structure were studied by advanced techniques. The hydrophobic surface morphologies were investigated by means of scanning electron microscope (SEM), and the wettability of the surface were investigated by water contact angle measurements (WCA), the corrosion resistance of the fabricated surface on carbon steel substrate was investigated by potentiodynamic measurements. Through the above analysis, we can get a lot of corresponding results, and the results what we get showed that the micro-nano composite structure that constructed on the surface of carbon steel not only has the property of hydrophobic on the surface, and the hydrophobic surface also has the property of corrosion resistance by combining the technology of sand blasting and electro-brush plating. Moreover, based on potentiodynamic polarization measurement in 3.5 wt% NaCl solution, the average corrosion current density of the sample surface that was fabricated by combining methods on carbon steel substrate is decreased by 1–2 orders of magnitude, and which is also less 1–2 orders of magnitude than the bare carbon steel, and because of that, the corrosion rate is also decreased, and the corrosion electric potential has an ascending tendency because of the average corrosion current density decreased. So its corrosion resistance is improved after this preparation process. It is seen that, through the method that design of combining sandblasting technology and electro-brush plating method constructed on the surface of carbon steel, the micro-nano composite structure was obtained excellent properties which included hydrophobic and corrosion resistance.

A simple method, involving twice electric machining by HS-WEDM and chemical etching, is used to fabricate super-amphiphobic (both super-hydrophobic and super-oleophobic) surfaces on aluminium alloy. The surface morphology of the samples was investigated using scanning electron microscopy and laser scanning confocal microscope. The evaluations of surface oleophobicity were carried out using the contact angles of ethylene glycol, diiodomethane and dodecane. Finally, the experimental result indicated that after the twice electric machining and chemical etching, the micro/nanometre-scale binary rough structure was presented on the sample surfaces, and the resulting sample surfaces produced in this method had super-hydrophobic and lipophilic properties (water contact angle of 155.74°). More importantly, after surface fluorination, the sample surfaces turned to super-amphiphobic surfaces and the biggest contact angles of water and oil were 156.24° and 157.34°, respectively. Therefore, it can be considered that the acquirement of the micro/nanometre-scale rough structures and the reduction of the surface energy are essential requirements to fabricate super-amphiphobic surfaces. The advantages of the present method over the other methods are that the used wire electrical discharge machining can machine most metals, and the processes of surface forming and microstructure fabrication were combined, which saves processing time greatly.

A 51-year-old man presented with non-ST-elevation myocardial infarction due to extrinsic compression of the left main coronary artery (LMCA) caused by a dilated pulmonary artery (PA) with secondary pulmonary hypertension and was successfully treated with surgical intervention including pulmonary angioplasty, atrial septal defect correction, and thromboendarterectomy. Imaging modalities were extremely useful in making the diagnosis and providing follow-up of LMCA compression syndrome in this case. During the follow-up, a sufficient hemodynamic improvement was obtained, without exacerbation of the PA dilatation, resulting in the absence of compression of the LMCA.

Herein, we report for the first time the use of ethanol for the switchable underwater wettability on a rough titanium dioxide (TiO2) surface. The rough TiO2 thin films on the titanium surfaces are fabricated by the high speed wire electrical discharge machining (HS-WEDM) processes, and the resultant surfaces show the switch between underwater superhydrophobicity and oleophobicity via ethanol immersion and dark storage. The underlying mechanism of the switch is depicted, and the result shows that during the ethanol immersion and dark storage, the change of hydroxyl groups leads to the switch. Considering that the use of ethanol is time-saving and low-cost, we anticipate that the use of ethanol will open up a new way of surface wettability change.

In order to achieve superamphiphobic surface of aluminium alloy, a method based on laser-EDM (electrical discharge machining) was proposed. By means of laser etching, the size of the controllable micrometre square column structure could be prepared on the surface of aluminium alloy. Then combined with the electric processing method, the binary micro-nano rough structure was constructed and modified with fluorosilane methanol solution, and the superamphiphobic surface was achieved successfully. The morphology and size of the superamphiphobic surface were observed by scanning electron microscopy and laser confocal microscopy, and the superamphiphobic performance of the surface was detected by video optical contact angle. The results showed that the water contact angle of the surface prepared by laser-EDM was 157.06°. After the modification of fluorosilane methanol solution, the contact angle of the surface to ethylene glycol reached 156.46°. It can be discovered that the acquisition of binary micro-nano rough structure and the decrease of surface energy are important conditions to obtain superamphiphobicity. Compared with the existing methods, laser etching can be a good control surface morphology, and eventually get superamphiphobic surface.

In recent years, titanium alloys have been widely used in aerospace and other fields for their performance advantages. However, its high hardness and brittleness, in particular, low thermal conductivity and strong chemical affinity make titanium alloys become more difficult to process metal materials. Since the aerospace industry requires a large number of high-precision holes, the research on its processing technology has received much attention. According to investigations, the ultrasonic vibration-assisted drilling (UAD) technology is very suitable for drilling hard and brittle materials. In this paper, the variation of cutting force, cutting heat, roughness and hole expansion was investigated by control of processing parameters. Experiments show that cutting force, cutting heat, surface roughness and pore expansion decreased where amplitude is large. Specifically, an increase in spindle speed leads to decrease in cutting force and increase in cutting heat. The surface roughness of the hole generally increases with the increase of the spindle speed. But as the feed increases, the conventional drilling (CD) and the UAD show opposite behaviors. Hole’s surface roughness produced with CD becomes smaller, and UAD becomes larger.

The surface of the titanium alloy was blackened by a nanosecond pulsed laser, and two-dimensional and three-dimensional morphology observations and microstructure reflection measurements were performed by scanning electron microscopy (SEM), laser confocal scanning microscopy (LCSM) and microscopic angular resolution spectrometry (ARM). The effect of laser processing depth on reflectivity was studied by one-way filling scanning method. The results show that under different laser processing times, different microstructures are formed, and as the number of laser processing increases, the reflectivity of light decreases. In the 400–1000 nm band, the reflectance of the sample can be reduced to a minimum of about 1%.

Due to the large reduction in workpiece size and tool size, the quality of the micro-milling surface has a greater impact on the product than that obtained by conventional milling. Since the typical two-dimensional surface roughness parameters can only partially reflect the state of the surface, a three-dimensional surface roughness evaluation system is proposed to characterize the micro-morphology of the micro-milling surface in this paper. The micro-milled surface was simulated by a non-Gaussian surface. We used the two-dimensional empirical mode decomposition algorithm to extract the reference plane of the simulated surface, selected the three-dimensional roughness parameters suitable for the micro-milling surface and established the evaluation system. This paper compared the three-dimensional surface roughness of the simulated surface and the actual machined surface. The results show that the Bidimensional Empirical Mode Decomposition algorithm is suitable for extracting the reference plane of micro-milling three-dimensional surface roughness, and the three-dimensional surface roughness evaluation system can reflect the characteristics of the micro-milled surface more comprehensively.

In the process of ultra-precision machining, the tool-setting accuracy of the micro-milling tool is limited by the tool diameter. The accuracy of tool setting decreases with the decrease of tool diameter, which becomes an important factor for restricting the accuracy of ultra-precision machining. Based on the imaging principle of digital in-line holography, an efficient and non-contacted method for tool setting was proposed for improving the accuracy of tool setting. Aiming at the imaging problem of micro-milling tool, the evaluation function based on wavelet transform was introduced in the process of progressive search, so the optimal reconstructed image was accurately obtained through the autofocusing algorithm. Then the zero-order term and the conjugate image were eliminated via the self-snake diffusion. The tool contour was extracted by Sobel operator, and tool diameter was measured using different methods. Measurement results proved that holographic imaging can meet the requirements of in-position dynamic measurement for micro-milling tools, and also provided an important basis for the accuracy of tool setting.

The hard and brittle nature of Zirconium-based metallic glass (Zr41.2Ti13.8Cu12.5Ni10Be22.5) makes it difficult to meet industrial requirements in mechanical processing. Therefore, the processing performance of WEDM of MG was studied by using the advantages of WEDM to process hard and brittle conductive materials in this paper. The effects of peak current, pulse width and voltage on material removal rate (MRR) and surface roughness (Ra) were investigated by orthogonal experiment. Analysis of variance was employed to analyze the experimental results and obtain the optimal combination of parameters. In addition, machined surface topography was analyzed. The results show that the degree of influence of each process parameter on MRR from high to low is peak current, pulse width and voltage; and the degree of influence on Ra from high to low is pulse width, peak current and voltage. MRR and Ra are proportional to peak current and pulse width. Interestingly, the MRR and Ra do not increase with increasing voltage, but tend to increase first and then decrease. There are craters, microspheres, hard convex edges, droplets and surface microcracks on the surface of the machined workpiece. This study provides a theoretical reference for promoting the research on WEDM of MG.

The T-shaped groove and the square-column microstructure of the aluminum alloy surface were constructed by EDM. It was found that the contact angle of the square column formed by the two processes can reach 147.62°, and the surface of the part exhibits high viscosity at the same time. Successfully achieved the preparation of highly viscous hydrophobic surfaces. At the same time, solutions of different PH were prepared to further characterize the chemical stability of the samples. It is found that the contact angle increases first and then decreases with the increase of PH, and the variation range is about 10°, which indicating that the sample has good chemical stability. Finally, the surface morphology was observed by scanning electron microscopy and the hydrophobic surface wetting mechanism was further analyzed. This paper aims to construct a good, stable functional surface and offer the basic research for subsequent functional observations of other functionalities that may be available.

The aluminum alloy 6061 was used as the substrate, and the hydrophobic surface was prepared by wire cut electrical discharge machining (WEDM), and the superhydrophobic surface was obtained by optimizing the processing size. The condensation performance of the three different wettability surfaces under condensing conditions was observed and the mechanism analysis was carried out. The results show: The condensation performance and wettability of the aluminum alloy surface are directly related. Under the test conditions of the same temperature and humidity, the condensation speed from the fast to the slow is smooth surface, hydrophobic surface and superhydrophobic surface; at the same temperature and humidity change test conditions, the smooth surface has the most condensation, followed by the hydrophobic surface, and the superhydrophobic surface has the least amount of condensation. Through the mechanism analysis, it is found that the surface of the superhydrophobic surface produced a large Laplace pressure, and the micro-nano structure caused the transition of the condensed droplets from Wenzel to Cassie, thereby increasing the anti-condensation effect of the surface.

A method of using an adaptive sliding mode observer to estimate induction motor rotor flux is presented in this paper, in order to improve the robustness of parametric variation in sensorless vector control. The observer obtains rotor flux and speed by constructing a mathematical model on the basis of the state equation in static coordinate system. Furthermore, the stability of the observer is guaranteed by the Lyapunov stability theory which is analyzed in this paper. The simulation in MATLAB/SIMULINK shows that the adaptive sliding mode observer is robust against motor parametric variation in sensorless vector control system by changing the resistances of stator winding and rotor winding. Finally the experiment based on DSP28335 platform verifies that the observer can obtain the rotor flux and speed in sensorless control system, and the algorithm has good robustness when load and given speed changes.

In view of high coefficient of friction and poor wear resistance of titanium alloy, laser processing method is used to form grooves on the surface of titanium alloy, and the grooves surface of titanium alloy is coated with titanium dioxide films to improve the wear resistance of titanium alloy. Friction tests were carried out on three surfaces of titanium alloy respectively in this paper: smooth surface, groove surface, groove surface coated with titanium dioxide films. A comparative analysis of wear depth and morphology different test conditions were conducted accordingly. The experimental results show that titanium alloy groove surface coated with films has the lowest coefficient of friction, produces the shallowest scratch depth and the least wear, Titanium alloy grooves surface coated with films, however, is very slightly different from titanium alloy grooves surface. In addition, titanium alloy grooves surface coated with films has the least increase of oxygen after wear.

International audience; no abstract

In this study, four bionic fish-scale models were extracted and produced based on the microscopic morphology and the arrangement of scales on the body of Sciaenops ocellatus. A simple, quick and low-cost method using laser was introduced for fabricating the bionic fish-scale surface on aluminum (Al) alloy. Under the action of laser beams, the fish-scale morphology with inclined surface was obtained by controlling the density of laser path and processing times. Biomimetic fish-scale surfaces with different sizes were produced through adjusting the four ratios of fish scale graph. Then wettability test was performed on different samples. Our results showed that all the samples were hydrophobic and the sample with 100% zoom ratio demonstrated excellent superhydrophobicity and low adhesion. Furthermore, we tested the drag reduction performance of the sample with zoom ratio of 100%. The experimental results indicated that under different flow conditions, the sample exhibited different performance values in drag reduction, and the drag reduction rate could reach 4.814% under laminar conditions. This study provided a simple method from the perspective of bionics to fabricate a bionic superhydrophobic surface with drag reduction performance, providing positive guidance for the fabrication of underwater drag-reducing surface.

The tool wear is a big problem when machining titanium alloy. If the tool wear law is not mastered well, the machining quality will not be guaranteed. In this paper, the theoretical model of the tool is established, which can understand the spatial dimension model of the tool. At the same time, the tool wear experiment of the most commonly used tool for titanium alloy machining in the manufacturing industry is carried out, and the influence of the tool cutting wear on the cutting process is studied. The experimental analysis shows that the tool produces the chip extrusion stripe when it is worn in the initial stage and normal stage, which is perpendicular to the chip in the outflow direction, the fringe protrusions are parallel, and the contact surface of the chips is relatively flat. When the tool reaches the stage of severe wear, the protrusion stripes perpendicular to the outflow direction of the chips are fluffy, and the stripes are twisted. With the continuous cutting wear time of the tool becoming longer, the cutting force, the residual stress of the machined surface layer and the cutting temperature obtained in each stage gradually increase; with the tool reaching the stage of severe wear, the protrusion stripes are fluffy, and the stripes are twisted The tool wear time gradually increases, and the cutting surface roughness obtained by continuous tool wear decreases first and then increases; the surface quality of the tool in the initial wear stage is relatively obvious and the edge burr is large, while in the normal wear stage, the surface quality of the tool is gradually gentle, but when the tool reaches the severe wear stage, the surface quality of the tool begins to be processed Sharp drop and thick edge burr.

In this work, a method for the fabrication of two- and three-dimensional curved surfaces with robust underwater superoleophobicity is reported for the first time on light alloys (including 5083 Al and TC4 Ti alloys) through the high speed wire electrical discharge machining (HS-WEDM). The surface morphology and compositions were characterized by scanning electron microscope and energy-dispersive X-ray spectrometer. The results showed that rough structures and a layer of oxidization were created on the light alloys by HS-WEDM cutting. The two- and three-dimensional structured curved surfaces after an ethanol immersion exhibited the extreme underwater superoleophobic property with the high oil contact angle and low oil sliding angle. More importantly, the underwater superoleophobic surfaces with the three-dimensional curved features could have many new applications. In order to use the potential functions, the durability of the fabricated samples was tested and the results showed that the samples still exhibited the underwater superoleophobic property after the underwater storage and physical mechanism tests. Additionally, this method is versatile, simple, environment-friendly, and cost-effective.

The interest of this article lies in the proposition of using bionic method to develop a new sound absorber and analyze the efficient of this absorber in a ski cabin. Inspired by the coupling absorption structure of the skin and feather of a typical silent flying bird &#8212 owl, a bionic coupling multi-layer structure model is developed, which is composed of a micro-silt plate, porous fibrous material and a flexible micro-perforated membrane backed with airspace. The finite element simulation method with ACTRAN is applied to calculate the acoustic performance of the multi-layer absorber, the vibration modal of the ski cabin and the sound pressure level (SPL) near the skier's ears before and after pasting the absorber at the flour carpet and seats in the cabin. As expected, the SPL near the ears was significantly reduced after adding sound-absorbing material. Among them, the model 2 and model 5 showed the best sound absorption efficiency and the SPL almost reduced 5 dB. Moreover, it was most effctive for the SPL reduction with full admittance configuration at both the carpet and the seats, and the carpet contribution seems to be predominant.

Titanium alloy has been widely used in the aerospace field due to its advantages of low density, high specific strength and high-temperature resistance. Its scope of application, however, has been narrowed down because of its high reflectivity to light. In order to maximize the potential, it becomes necessary to construct a surface light trapping structure of titanium alloy. Therefore, a simple and tunable method was introduced in this paper to fabricate antireflection microstructures on titanium alloy surface with the superhydrophobicity based on nanosecond laser. By optimizing the laser processing speed parameters, microstructured surfaces with low reflectance over the entire visible wavelength range and near-infrared region (400–1000 nm) can be obtained. Results indicate that when the scanning speed is 100 mm/s, the minimum reflectance in the 900–1000 nm wavelength range is less than 1%, and the total reflectance in the 500–1000 nm wavelength range stabilizes below 6%. In contrast, the surface of conventional titanium alloy absorbs only about 50% of the incident light, and the remaining 50% is reflected. Furthermore, treated surfaces demonstrate effective performance concerning hydrophobicity, with a maximum contact angle of 153.03°. The results show that the nanosecond laser can induce the anti-reflection and super-hydrophobic properties, and improve the absorption capacity of the surface.

At the beginning of the design of a certain type of engine, the dynamic analysis of the left and right valve chamber assembly of the engine is carried out by means of finite element method, and the modal calculation is carried out. The overall stiffness of the cover of the left and right valve chamber is evaluated. The modal frequency and mode of the hood cover are obtained. According to the calculation results, the scheme of the valve chamber cover is optimized. The modal analysis is carried out on the improved normal hood cover, and the final optimal scheme is obtained, which provides a reference for the followup design of the hood chamber cover of the engine. According to it. Compared with the original scheme, the improved scheme of the left valve chamber cover frequency is 1676Hz, which is 6.28% higher than that of the original scheme 1577Hz; the first order mode frequency 1729Hz in the assembly state of the right valve chamber cover is 14.88% higher than that of the original scheme.

This paper primarily analyzed the mechanism of crack propagation in brittle materials micro-grinding, and obtained the empirical formula of the maximum unreformed thickness. Using the grinding rods with diameters of 0.7mm and 1.0mm, the single-factor experiments were carried out, through changing spindle speed, feed speed and depth of cut. We selected different processing parameters to study the general rules that the processing parameters affect the surface quality. The results show that the grinding depth has the most obvious influence on the surface quality, and the surface quality is the best when the grinding depth is 5 μm. The feed speed affects the surface quality secondarily, and the better surface quality can be obtained at 50 mm/min. The effect of spindle speed on surface quality is not obvious, but with the increase of spindle speed, the surface quality first increases and then decreases. We compare the different processing methods in order to study the effect of different processing methods on the surface quality. It can be concluded that in the case of smaller depth of cut, micro- grinding is easier to obtain high-quality machined surface than micro-milling

In this paper, SiCp/2024Al composites was drilled by electrical discharge machining (EDM) to investigate the effect of different electrode cross-section shapes on material removal rate (MRR). The material removal mechanism (MRM) at different discharge energy were also analyzed by changing the electrical parameters. It is found that the MRR of EDM with tube electrode is 5 times greater than that of with cylinder electrode. Electro-erosion debris filled in the discharge gap makes the tool electrode retreat frequently, greatly reducing the MRR. The MRM includes thermal spalling, melting/vaporization and oxidation. The MRM varies with different discharge energy. Thermal spalling is the main MRM at low discharge energy, while melting/evaporation occupies a dominant position in MRM at high discharge energy. Either low or high discharge energy, oxidation always occurs.

Based on the background of engine lightweight and low noise, this paper used the 3D modeling software Pro/E to build the mathematical model of a high speed engine. The finite element mesh was divided by ICEM. The structural vibration of the engine complete machine was calculated by combining finite element theory with multi-body dynamics. By using the Timing Drive and Power Unit in AVL Excite, the multi-input parameter’s coupled calculation of the gas distribution mechanism and crankshaft connecting rod was carried out. External loads such as output torque and gas explosion pressure and internal loads such as piston cylinder sleeve thrust and valve system excitation force were added to the complete machine multi-body dynamics model by means of coupling calculation. In this paper, the vibration response characteristics of the engine complete machine and internal loads were further studied and the main excitation of vibration was combined with the analysis of cloud map and main surface area.

The ultrasonic vibration has increasing implementation in metal machining as an assisted method. It adds high frequency vibration with low amplitude to the workpiece or the cutting tool and it has been verified to have the great potential on cutting force reduction, surface quality improvement, tool wear decrease and so on. This paper applied the ultrasonic vibration to the micro-holes drilling of 30CrNiMo8. In order to identify the performance of the combination, an ultrasonic machine tool with the vibration in the feed direction was designed and assembled. The spindle speed and feed rate and were taken as the controlled variables and a series of experiments were carried out. The results indicated that the ultrasonic assisted micro-holes drilling transformed the drilling process and the mechanism of the chip formation, which noticeably suppressed the exit burrs and ensured the dimensional accuracy and the surface roughness of the micro-holes.

In order to study the regulation of the roughness and micro-morphology of the machined surface with cutting parameters changing, a single factor experiment of micro milling groove was carried out on Si Cp/Al using a 2 edges hard alloy end mill with a diameter of 1 mm (4HCE010025S04). The following conclusions are obtained through the experiment and detection analysis: With the spindle speed n increasing, the roughness of the milling groove surface gradually decreases, the quality of the machined surface becomes better, and the contour of the bottom of the groove is flatter; with the feed rate f increasing, the roughness of the milling groove surface gradually increases, the quality of the machined surface gets worse, and the contour of the bottom of the groove is worse; with the cutting depth ap increasing, the roughness of the milling groove surface is reduced and the quality of the machined surface improved, and the contour of the bottom of the groove becomes more flatter, although the depth does not change obviously.

At the design beginning of a certain type of passenger car, the noise spectrum of the air intake system is analyzed. Firstly, the structure model and acoustic model are established by GEM3D, and then GT-Power was used to analyze the noise of the system and simulate the full load condition of the engine. The sound pressure levels of the third, sixth, ninth, and twelfth order nozzle noise at 1000-6000r/min were respectively calculated and optimized. Comparing the sound pressure levels, the results show that the each order and the total sound pressure levels of the intake system do not exceed the target curve to meet the noise reduction requirements.

The polyurethane foam with different structure was prepared by one-step foaming process, and the acoustic properties of the foam were measured by impedance tube, using sound absorption coefficient as the measure index, the effects of manufacturing temperature, ratio of polyols to MDI and total mass (density) on the acoustic properties of polyurethane were analyzed by experimental optimization design. The test results show that the ratio of polyols to MDI is the most important factor affecting the sound absorption coefficient, and the effect of total mass and manufacturing temperature take the second place, the quadratic order of temperature has a major impact on the average acoustic absorptivity of polyurethane.

To study the temperature of the cylinder block and cylinder head, temperature analysis was carried out for the engine based on FEM. The temperature and convection heat transfer coefficient boundary were obtained by CFD analysis. Then the engine temperature analysis was carried out by the software ANSYS and the accurate temperature field distribution is obtained which provides technical guidance for the performance improvement of each part of the engine.

Vibration-assisted cutting as one of specially typical precision non-conventional machining methods, recently, has aroused lots of scholars and science researchers interests, especially in hard and brittle material cutting with a significant challenge. The objective of present study develops a novel apparatus which combines mechanical and control design, a series of cutting experiments conducted on Al 7075 alloy that defined as one of high strength alloy materials appliance in lots of industries field to investigate the feasibility and reliability of the appliance. In present paper, a mechanical model of vibration- assisted cutting apparatus was designed and than evaluated by off-line test analysis. The novel apparatus can work at below 124 Hz with maximum stroke 27.285µm. Fuzzy PID was preliminary introduced into vibration-assisted cutting apparatus control strategy. Programs were established based on LabVIEW software and then downloaded into NI Compact 9033 controller in order to control vibration-assisted cutting apparatus. By compared with three strategies each other, the tracking error of fuzzy strategy increased 11.2 times that of fuzzy PID, at the same time, PID strategy oscillation amplitude increased 5.3 times that of fuzzy PID. A series of cutting experiments were conducted on the plane and freeform surface deforming. The validity and availability of vibration-assisted cutting apparatus were conducted in experiments.