Surface Smoothing Process Research Articles

A 3D tailored monolithic glass chip for stimulating and recording zebrafish neuronal activity with a commercial light sheet microscope

Microfluidic technology is unrivaled in its ability to apply soluble chemical stimuli with high spatiotemporal precision. Analogous, light–sheet microscopy is unmatched in its ability of low phototoxic but fast volumetric in vivo imaging with single cell resolution. Due to their optical translucency during the larval stages, zebrafish (Danio rerio) are an ideal model to combine both techniques; yet, thus far this required light–sheet microscopes, which were in most cases custom–built and adapted to the available softlithographic chip technology. Our aim was to use a commercial light–sheet microscope to illuminate a microfluidic chip from two opposite lateral directions and to record images with the detection objective placed orthogonally above the chip. Deep tissue penetration can be achieved by superimposing beams from opposite directions to form a single light sheet. But a microfluidic chip that allows a) targeted stimulus application in a closed microenvironment, b) interference–free incoupling of excitation light from two directions and c) outcoupling of fluorescence in the perpendicular direction through an optically perfect cover glass was not known until now. Here, we present a monolithic glass chip with the required plane-parallel sidewalls and cover slide closure at the top, constructed by advanced femtosecond laser ablation, thermal bonding and surface smoothing processes. In addition, the 3D shape of a fish fixator unit was tailored to match the body shape of a zebrafish larva to ensure stable positioning during whole–brain recording. With hydrodynamic focusing a targeted partial exposure of the larva’s head to chemical stimuli and fast position switching (in less than 10 s) was possible. With the capabilities of this unique monolithic glass chip and its up–scalable wafer–level fabrication process, the new NeuroExaminer is prone to become an excellent addition to neurobiology laboratories already equipped with high–quality commercial light sheet microscopes.

Surface smoothing of additively manufactured Ti-6Al-4V alloy by combination of grit blasting and large-area electron beam irradiation

AbstractAdditively manufactured (AMed) titanium products are typically produced by electron beam melting (EBM), since oxidation of titanium alloy surface can be suppressed in vacuum environment. The surface roughness of AMed titanium products becomes more than 200 µm Rz, and the very rough surface would lead to reduction in fatigue strength. Therefore, a post surface finishing process is required. Abrasive blasting is one of the common surface smoothing processes of AMed metal products. Large surface roughness can be decreased, and compressive residual stress can be introduced to the surface. However, there is a limitation to reduction of surface roughness to several µm Rz. On the other hand, it was recently found that AMed metal surface produced by powder bed fusion with laser beam could be smoothed by large-area electron beam (LEB) irradiation. However, it is difficult to smooth surface with large initial surface roughness, and a tensile residual stress may be generated on the surface. In this study, surface smoothing and change in residual stress of AMed titanium alloy (Ti-6Al-4 V) were proposed by combination of grit blasting and LEB irradiation. Surface roughness of AMed Ti-6Al-4 V alloy significantly decreases from 265 to about 2.0 µm Rz by combination of grit blasting and LEB irradiation. Reduction rate of surface roughness by LEB irradiation linearly increases with decreasing mean width of blasted surface. Influence of the mean width on smoothing effect by LEB irradiation can be explained by thermo-fluid analysis. Moreover, tensile residual stress caused by LEB irradiation can be reduced when LEB is irradiated to blasted surface.

Investigation of the Surface Treatment Process of AISI 304 Stainless Steel by Centrifugal Disc Finishing with the Use of an Active Workpiece Holder.

This article presents the results of experimental studies of the centrifugal disc finishing (CDF) process of 304 steel elements with the use of an active workpieces holder, that allows workpieces for additional rotational and oscillation movements. The main aim of the research was to evaluate the mechanism of formation of the surface texture and to assess the intensity and effectiveness of the machining process. It is shown that additional movements of the workpiece significantly affect the formation of the machining traces generated by the elementary phenomena of micro-cutting, scratching, grooving, etc. As a result, these combined and complex interactions lead to the formation of the surface topography of the workpieces. Based on the research results, it can be concluded that the use of an active workpiece holder in the CDF process allows changes in the intensity of the machining process. Moreover, the active holder allows modification of the surface smoothing process. The intensity of the treatment process depends primarily on the location of the workpiece holder in the appropriate energy area of the work charge. On the other hand, the efficiency of the workpiece surface smoothing depends on the parameters of the oscillation and rotational movements of the workpiece mounted in the active holder. The presented research results show that the use of an active holder, enabling rotation and oscillation of the workpiece, may lead to a more effective use of smoothing processes in CDF machines. The analysis of the results shows that the values of the Sdr and Sa parameters are more strongly dependent on the vibration frequency and increase with its increasing frequency. This is undoubtedly the result of the concentration of smoothing marks on the smoothed surface. However, with regard to the rotational speed of the object, this relationship is non-monotonic, and its greatest influence occurs at its intermediate values. It follows that this activity does not have a significant impact on the generation of the number of smoothing marks and the degree of their concentration. The research methodology proposed in the work allows the initial determination of the dependence of the results of the CDF process on the machining parameters, including the parameters of the active holder. This methodology can also be used for machining materials other than AISI 304 steel.

Synergy Effect of Abrasive Blasting and Large-area EB Irradiation on Surface Finishing of AMed Titanium Alloy

Among a broad spectrum of AM technologies, electron beam melting (EBM) is widely applied in AM process for producing titanium alloy parts. In general, AMed metal products have very rough surface of more than 200µmRz, since relatively large beads are arranged on their surface by scanning electron beam. Moreover, surface irregularities such as spatter and cavity are also generated on the surface. Rough surface and surface irregularities would lead to reduction in surface strength and poor appearance. Therefore, post surface finishing processes are required to smooth the surface of AMed metal products. One of the common surface smoothing processes is abrasive blasting. Large surface roughness can be decreased by abrasive blasting, and compressive residual stress can be introduced to the surface. However, there is a limitation to reduction of surface roughness. On the other hand, in large-area electron beam (large-area EB, LEB) irradiation method developed recently, mold steel surface can be finished by melting it in a few minutes. However, it is not easy to smooth surface with large initial surface roughness, and a tensile residual stress may be generated on the surface.In this paper, surface smoothing of AMed titanium alloy by combination of abrasive blasting and large-area EB irradiation was proposed. At first, the AMed titanium alloy surface was blasted to reduce the initial large surface roughness to some extent and change the surface topography. Then, large-area EB was irradiated to the blasted surface. It is made clear that surface roughness significantly decreases when large-area EB is irradiated to the blasted surface with small mean width. Moreover, tensile residual stress generated in large-area EB irradiation can be reduced by abrasive blasting. Therefore, combination of abrasive blasting and large-area EB irradiation is effective for efficient reduction of large surface roughness of AMed titanium alloy.

Investigation on the smoothing of surface spatial frequency errors for borosilicate glass by heat-treatment

The mid-spatial frequency error and high-spatial frequency error on the optical glass component surface limit the development of high-power laser devices. By heat-treatment in wet atmosphere, the surface can be smoothed spontaneously under the action of capillary force, which is positive to improve the quality of optical components. In this paper, the finite element simulation model of the glass surface smoothing process is established based on the level-set method. The factors affecting the smoothing process, such as morphology wavelength and viscosity, are analyzed by simulation. A series of surface smoothing heat-treatment experiments for borosilicate glass were carried out to verify the effectiveness of improvement on surface quality through heat-treatment. Finally, the reasons for the discrepancy between theory and experiment are investigated through the simulation, and the effects of wavelength and the water content in the material are further investigated.

Surface smoothing process for high-performance MgO-based magnetic tunnel junctions

We developed a surface smoothing technique for stacked Ta–B and Co–Fe–B amorphous layers in a magnetic tunnel junction (MTJ) to yield a higher magnetoresistance (MR) ratio and stronger synthetic anti-ferromagnetic (SAF) coupling. The technique yielded an ultra-smooth surface (Ra ∼ 0.1 nm) for both amorphous films and gave rise to atomically flat interfaces at the subsequently deposited layers. Top-pin MTJs fabricated with the technique exhibited superior properties, such as an MR ratio up to 315% and strong SAF coupling exceeding 0.7 erg cm−3. The smoothing process for amorphous layers will be an important for fabricating the MTJs of high-performance spintronics devices.

Super-smooth surface demonstration and the physical mechanism of CO2 laser polishing of fused silica.

This Letter reports on the results of experiments aimed at obtaining high-quality super-smooth surfaces by investigating the laser polishing of fused silica. A maximum reduction in root-mean-square roughness to 0.156nm was achieved, and laser-polished surfaces exhibited virtually no micro-defects or damage. A subsequent analysis using a multi-physics numerical model revealed the underlying physical mechanism of laser polishing of fused silica. The model simulated the surface smoothing process of laser polishing and demonstrated the effects of surface tension, the Marangoni effect, light pressure, and gravity in the process. It was found that the surface tension dominates the surface smoothing process, and it is a critical factor for achieving sub-nanometer micro-roughness of laser polishing of fused silica. Additionally, the model was successfully applied to predict the residual surface roughness of laser polishing.

Self-Smoothening of an Ion-Beam-Sputtered Ag (100) Surface: Evolution of Surface Morphology Using RHEED

The development of the surface morphology and rough-to-smooth transition of the ion beam-sputtered Ag (100) surface was studied using reflection high-energy electron diffraction (RHEED) at two different temperatures. After sputtering, self-evolution of the Ag (100) surface morphology was continuously monitored by the passage from spotty to streaky RHEED patterns. This approach allowed us to follow the qualitative time evolution of the surface morphology of the Ag (100) surface, which underwent a self-transition from a rough-to-smooth surface (3D rough surface to 2D-like smooth surface) within 120 minutes at room temperature (RT) and about 60 minutes at 323 K temperature. Once the saturation in smoothness was reached, no significant changes in surface morphology with time were observed. At temperatures about 323 K, the achieved smoothness value was about 12 pct more than that observed at RT. The surface smoothing process at RT is understood in terms of self-diffusion, nucleation of randomly distributed defects and vacancies, whereas increased surface diffusion due to an increase in temperature leads to a smoother surface.

Analiza aktywności ziaren ściernych w procesie wygładzania foliami ściernymi

In the paper the active of abrasive grains in the films abrasive finishing process was analyzed. The results of the simulation of surface smoothing process were presented. The subject matter of the analysis was a 3IDLF diamond abrasive film.

Investigation of additive manufacturing surface smoothing process

PurposeThe additive manufacturing technologies have been facing an extraordinary growth along the past years. This phenomenon might be correlated with rise of low-cost FDM technologies into the non-professional market segment. In contrast with that, among the main disadvantages found in this sort of equipment are the final object finishing and low mechanical strength. For that reason, the purpose of this paper is to present and characterise a surface treatment which is based on solvent vapour attack and that is also known as smoothing process. In addition, a concise overview about the theory beneath this process is presented besides an experimental study that evaluates the main effects on the mechanical properties of object.Design/methodology/approachTo analyse the benefits of this process, the authors preliminarily investigated the working mechanism that supports such surface treatment. It allowed them to identify and select a proper solvent for each material. The authors have also established that the exposure time repetition numbers (passes) were the main variables, whereas temperature, solvent type, drying time, object direction and object shape were constants. The main object dimensions, surface roughness, absorbed solvent mass and mechanical strength were the main study responses.FindingsAs a result of this work, the peak-peak roughness was reduced in 71 per cent, indicating the potential benefit of this process. On the other hand, excessive solvent exposure implied on relevant dimensional distortions and internal disruptures. It was also possible to see that the vapourised solvent penetrate into the object surface and fused layers and filaments. As consequence, the mechanical strength was also improved.Originality/valueDespite the growth that additive manufacturing market segment has seen along the past years, the finishing and mechanical strength of low-cost equipment still lack for improvements. For that reason, applications like solvent vapour attack or smoothing process new perspectives for this non-professional segment, whereas roughness and mechanical strength are improved after its treatment. As a consequence, it is possible to consider a final object to be obtained directly from low-cost FDM in combination with smoothing process.

Effective 3-D surface modeling for geographic information systems

Abstract. In this work, we propose a dynamic, flexible and interactive urban digital terrain platform with spatial data and query processing capabilities of geographic information systems, multimedia database functionality and graphical modeling infrastructure. A new data element, called Geo-Node, which stores image, spatial data and 3-D CAD objects is developed using an efficient data structure. The system effectively handles data transfer of Geo-Nodes between main memory and secondary storage with an optimized directional replacement policy (DRP) based buffer management scheme. Polyhedron structures are used in digital surface modeling and smoothing process is performed by interpolation. The experimental results show that our framework achieves high performance and works effectively with urban scenes independent from the amount of spatial data and image size. The proposed platform may contribute to the development of various applications such as Web GIS systems based on 3-D graphics standards (e.g., X3-D and VRML) and services which integrate multi-dimensional spatial information and satellite/aerial imagery.

4H-SiC surface structure transitions during crystal growth following bunching in a fast sublimation process

Kinetic Monte Carlo wurtzite structure crystals of 4H-SiC simulations were performed. The first stage of system evolution was the sublimation process which ended when bunched structure appeared. Then the crystal growth started. Vanishing of bunched structure and its transition to the double stepped one was observed on setting the proper parameters during growth up. For high incoming fluxes during growth 2D nucleation happened at wide terraces and surface debunching was blocked. Application of low resulting flux of incoming and out-coming particles have also blocked the surface smoothing process.

Smoothing of SFS Reconstructed Surface Based on Genetic Algorithm

To improve the smoothness of SFS reconstructed surface, a new approach based on genetic algorithm is proposed. First, by analyzing the principle of SFS, the reason for surface error and distortion zone are found. By adding data according to the symmetric and asymmetric principle and B spline, data in the distortion zone are added and the reconstruction of SFS is realized. The evaluation criteria for smoothness of curves and surfaces are given according to the mathematical sense and concurrent level of CAGD/CAD/CAM. The surface smoothing process is turn into two curve smoothing process in two directions. The evaluation criteria is taken as the constraint condition and then the smoothing of SFS reconstructed surface based on the genetic algorithm is realized. The experimental results show that this new approach is an effective way to eliminate the bad points of SFS surface, improve the surface quality so it is a practical method for surface smoothing.

Development of Cup Inner Surface Smoothing Process by Ironing

Ironing process is a normal method to improve the surface quality and thickness precision of a drawn cup. Multi-stage processes that combined drawing and ironing, have been developed to obtain the cups with a each surface quality. However, the ironing process is generally used to outside of the drawn cup, and the trial to improve the inside surface property is not carried out very much. The purpose of this study is to clarify the effect of ironing process on the improvement of the surface quality of multi-stage drawn cup. The effects of the ironing reduction, lubricants and punch shape on the improvement of the inner surface properties are investigated by using a series of experiment. It is found that the inner ironing process is effective to improve the inner surface properties of a drawn cup.

Fundamental Study on Sputter Deposition of Ceramic Film by Large-Area Electron Beam Irradiation

The sputter deposition of ceramic film on metal mold steel surface by large-area electron beam (EB) irradiation was discussed. The large-area EB has high energy density enough to generate plasma above the workpiece surface during the surface smoothing process, which causes the sputtering of target material set near the workpiece surface. The sputter deposition of target material with simultaneous surface melting and resolidification of workpiece surface by large-area EB would improve the adhesion between the deposited film and the workpiece. Short ceramic tube made of alumina or zirconia as a target was put on the substrate surface of steel, and large-area EB was irradiated to the surface. The workpiece surface component and structure after the irradiation were investigated using EDX and XRD analysis, in order to discuss the possibility of large-area EB irradiation as a new coating method.

圧力変動下でのリン脂質に覆われたマイクロバブルの挙動

The shrinking and growth of microbubbles under pressure change are observed with a CCD camera. The influence of gas diffusion on the stability of microbubbles coated by phospholipid is investigated. The microbubbles are made with acoustic liposomes encapsulating phosphate buffer solution and perfluoropropane gas. It is shown that when the ambient liquid pressure increases, the observed microbubbles shrink accompanied with the cyclic surface deforming and smoothing process. The bubble surface smoothing shows that the excess phospholipid layers are removed from the surface, which results in the instantaneous bubble shrinkage. It is also shown that the smaller the initial radius is, the more the growth of microbubbles is reduced. The experiments are compared with the simulations in which the dynamic surface tension and the variation of gas permeation resistance of molecular layers are taken into account. The instantaneous bubble shrinkage in the experiment is simulated successfully with the bubble model in which the instantaneous increase of surface tension due to the reduction of the excess phospholipid layer material is taken into account.

Study on NC Machining Technology for Integral Impeller of Pelton Turbine

Integral production technology of impulse turbine runner effectively prevents phenomenon of bailer broken when generation unit working, and then improving its service life. Based on comprehensive application of vibration inhibition technology and machining optimization path CAD/CAM technology, the high-speed plunge milling process is forwarded in this paper under the condition of big slenderness ratio and be able to present processing vibration. By using matching principle of tool connection point surface smoothing processes and the helix curved surface processing method this process successfully solves the problem of interfering point state complex in finishing plunge milling impulse water turbine whole runner and it achieves high active finish machining by three-axis NC process. This technology has also successfully been used in the power station whole runner manufacturing process in HPE group.

DEVELOPMENT OF A PROTOTYPING SYSTEM FOR CUSTOM-CONTOURED FOAM CUSHION USING THE PRESSURE MAPPING METHOD

For people with limited mobility such as wheelchair users, prevention of pressure sore is an important health care issue. To relieve pressure at buttocks, foam cushion enveloping specific contour matching with an individual's buttocks has commonly been employed. This paper presents a prototyping system that generates custom-contoured foam cushion using the pressure distribution at the buttock–cushion interface. Based on the load–deformation characteristics of the foam material, this pressure distribution is converted into the corresponding deformation of the foam. A surface smoothing process approximates all discrete data points into a bi-cubic surface. ASCII NC codes are then generated for CNC fabrication of the cushion with the desired surface contour. This study integrates commercially available products into a fully automated system and can be readily implemented by seat/wheelchair cushion manufacturers.

Enhancing the quantum efficiency of InGaN green light-emitting diodes by trimethylindium treatment

This work demonstrates the effectiveness of using trimethylindium (TMIn) treatment to improve the luminescence efficiency of InGaN∕GaN quantum wells grown by metal-organic vapor-phase epitaxy. Photoluminescence, x-ray diffraction, atomic force microscopy, and high-resolution transmission electron microscopy indicate that the treatment leads to a smoother InGaN surface and InGaN∕GaN interface with substantial decrease in V-shape defects density, compared to the samples without treatment. Green light-emitting diodes prepared by this method exhibit higher output power than the control device. These improvements are attributed to the surface smoothing process in TMIn ambient, resulting in an abrupt InGaN∕GaN interface.

New Surface Modification Method of Bio-Titanium Alloy by EB Polishing

A new surface modification for bio-titanium alloy products by electron beam (EB) polishing is proposed. In this EB polishing method, high energy density EB can be irradiated without concentrating the beam. Therefore, large-area EB with a maximum diameter of 60mm can be used for instantaneously melting or evaporating metal surface. Experimental results made it clear that surface characteristics, such as repellency, corrosion resistance and coefficient of friction could be improved simultaneously with the surface smoothing in a few minutes under a proper condition. Therefore, EB polishing method has a possibility of high efficient surface smoothing and surface modification process for bio-titanium alloy.