Finishing Process Research Articles

Investigation and optimization of parameters for bidirectional composite vibratory finishing of gears

ABSTRACT To meet the core requirements for uniform and efficient finishing of high-precision gears, a bidirectional composite vibratory finishing (BCVF) process was introduced. The influence of motion parameters (gear rotational speed n, vibration frequency f x and f z , vibration amplitude A x and A z , vibration phase difference ψ), process parameters (media loading height H, gear installation position h), gear parameters and container geometric parameters (cross-sectional shape, size L x × L y ) on the finishing effect was investigated by kinematic analysis and discrete element simulation (DEM). On this basis, the parameters with significant influence were selected and further optimized by gray relational analysis (GRA). Numerical simulations were carried out by orthogonal design, taking the cumulative contact energy and distribution uniformity on gear surface as evaluation indicators for multi-objective optimization. The results indicated that the affecting significance on comprehensive performance was ranked as f x > f z > A x > A z . Besides, the optimal parameter combination was obtained.

Influence of corrosion inhibitors on aging mechanism of epoxy resin coatings for copper 62 alloy in simulated marine environment

Abstract Aiming at the shortcoming that when applied to nonferrous copper 62 surfaces, epoxy coatings are prone to aging in marine environments. In order to extend the service life of copper 62 coatings in marine environments, methods of screening the corrosion inhibitor commonly used in copper 62 alloys and adding it to epoxy organic coatings have been investigated. Tafel polarization test and electrochemical impedance spectroscopy (EIS) were used to study the corrosion inhibition effect of different corrosion inhibitors on copper 62 alloy in simulated marine environment, and the influence of MBI on the damage process and water transport of epoxy coatings was studied by EIS. The results show that 2 mercaptobenzothiazole (MBT) has good corrosion inhibition on copper 62 alloy in marine environment. When the total mass fraction is 0.5 wt%, the corrosion suppression can reach 96.4 %. When MBT is added to the epoxy organic coating at 0.5 wt%, the diffusion coefficient of the coating is as low as 8.35 × 10−11 cm2 s−1, and the failure time of the coating is extended to 1824 h. It has been shown that the addition of MBT can effectively improve the service life of copper 62 alloy/epoxy coatings in marine environments.

Ultrasonic cavitation finishing of 316 L stainless steel using different abrasive particles: A combined SPH simulation and experimental study

Ultrasonic cavitation and its driving effect on abrasive particles have been studied and applied to the surface finishing of 316 L stainless steel. To explore the influence of abrasive characteristic parameters on the surface finishing process, a cavitation-driven single abrasive impact model was established by coupling the smoothed particle hydrodynamics (SPH) method with the finite element method (FEM). The changes in the workpiece surface and the wear of abrasive particles after the impact were analysed, the effects of the abrasive particle size, material and shape were discussed, and the effectiveness of the model was verified through ultrasonic finishing experiments. SiC abrasive particles possessing irregular shape and Al2O3 abrasive particles possessing irregular and spherical shapes were used for comparison. Both simulation and experimental results indicate that the abrasive particle with a high hardness and a spherical shape has better material removal capability. However, the spherical abrasive particles tended to occur large cracks and split into small pieces, which accelerated the wear of the abrasives. In this work, the best finishing result was obtained by using irregularly shaped SiC abrasive particles, and the surface roughness Ra was improved by 12.87 %. This study provides a comprehensive understanding of the material removal process using cavitation-driven abrasives and examines the influence of key characteristics of abrasive particles. These insights are significant for advancing the application and enhancement of this technology in metal surface treatment.

Evolution of mechanical behavior in granular soil during fine particle loss simulated by salt dissolution: Insights from ring shear tests

Fine particle loss in soil is one of the main causes of slope instability and geotechnical structure failure. Loss of fines can cause instability in granular assembles by changing the fabric and microstructure of the sample. However, real-time monitoring of the evolution of mechanical behavior in granular soils during the particle loss process is still poorly explored. This study presents a novel approach by simulating fine particle loss through salt dissolution in ring-shear tests, offering real-time insights into the mechanical evolution of granular soils under realistic stress conditions. Meanwhile, the shear resistance, shear displacement, vertical displacement, salt content, and acoustic emissions were simultaneously recorded. The test results showed that the instability of the sample was triggered by the loss of fine particles. With a gradual loss of fine particles, both the vertical and shear deformations and the void ratio increased. The evolution of shear resistance in the sample can be divided into three stages: stress weakening, then strengthening, and finally recovery to the initial value. We infer that the evolution of shear resistance originated from the collapse and rearrangement of its granular fabric and microstructure. Additional evidence for this hypothesis was provided by high-frequency acoustic emissions (approximately 150 kHz), suggesting buckling of the force chains accompanying the particle loss process. Furthermore, the sample experienced greater shear deformations and stress weakening that developed under a larger initial fine content or a higher normal stress. This finding may provide valuable insights into the mechanical behavior of granular soil during the fine particle loss process.

Recycling B4C grinding waste to fabricate high-performance ceramics by modification treatments and hot pressing

B4C grinding waste, originated from the fine grinding process of sapphire wafers, is discarded without reutilization, which causes environmental pollution and resource waste. This work proposes new methods on recycling B4C grinding waste to fabricate high-performance ceramics by first modification treatments via ball-milling mixing or microwave digestion with sulfuric acid and then hot pressing. The characteristic of B4C grinding waste is studied and Al2O3 is the main impurity. The direct hot pressing of B4C grinding waste is performed and the obtained ceramic is fragile. The large-size and unevenly distributed Al2O3 is verified to cause the fracture according to the structure analysis. Ball-milling mixing can break the Al2O3 agglomerate and make Al2O3 distribute evenly, and microwave digestion with sulfuric acid can remove most Al2O3. The ceramics fabricated via hot pressing with B4C grinding waste treated with ball-milling mixing or microwave digestion show good microstructure and mechanical property. The relative density, hardness, flexural strength and fracture toughness of the ceramics fabricated with grinding waste treated with ball-milling mixing are 98.82%, 32.42 GPa, 439.44 MPa, 4.82 MPam1/2, respectively, higher than those of the ceramics fabricated with grinding waste treated with microwave digestion, which are 98.69%, 29.54 GPa, 368.18 MPa, 4.20 MPam1/2, respectively. This work not only realizes the secondary utilization of waste and avoids pollution, but also provides another way supplying the high-cost B4C powder and ceramic, which has high economic benefits.

Effective Technologies for Finishing and Cleaning Processing: Innovations Based on Screw Rotors

The results of many years of scientific research in the development of machines, installations, and devices for finishing and cleaning processing of machine parts are presented. Typical diagrams of machines based on screw rotors of classes I-IV are included, along with the types of finishing and cleaning operations performed by screw rotors, requirements for the parts being processed, the processing environments, and the composition of solutions used in the finishing and cleaning of components. Additionally, the methodology and calculations for a continuous operation setup designed for finishing and cleaning parts with specified productivity are demonstrated.

Multi-Objective Parameter Optimization of Rotary Screen Coating Process for Structural Plates in Spacecraft

Multi-Objective Parameter Optimization of Rotary Screen Coating Process for Structural Plates in Spacecraft

Ezrin-mediated astrocyte-synapse signaling regulates cognitive function via astrocyte morphological changes in fine processes in male mice

Astrocytes, which actively participate in cognitive processes, have a complex spongiform morphology, highlighted by extensive ramified fine processes that closely enwrap the pre- and post-synaptic compartments, forming tripartite synapses. However, the role of astrocyte morphology in cognitive processes remains incompletely understood and even controversial. The actin-binding protein Ezrin is highly expressed in astrocytes and is a key structural determinant of astrocyte morphology. Here, we found that Ezrin expression and astrocyte fine process volume in the hippocampus of male mice increased after learning but decreased after lipopolysaccharide injection and in a mouse model of postoperative cognitive dysfunction, both of which involved models with impaired cognitive function. Additionally, astrocytic Ezrin knock-out led to significantly decreased astrocytic fine process volumes, decreased astrocyte-neuron proximity, and induced anxiety-like behaviors and cognitive dysfunction. Astrocytic Ezrin deficiency in the hippocampus was achieved by using a microRNA silencing technique delivered by adeno-associated viruses. Down-regulation of Ezrin in hippocampal astrocytes led to disrupted astrocyte-synapse interactions and impaired synaptic functions, including synaptic transmission and synaptic plasticity, which could be rescued by exogenous administration of D-serine. Remarkably, decreased Ezrin expression and reduced astrocyte fine processes volumes were also observed in aged mice with decreased cognitive function. Moreover, overexpression of astrocytic Ezrin increased astrocyte fine process volumes and improved cognitive function in aged mice. Overall, our results indicate Ezrin-mediated astrocyte fine processes integrity shapes astrocyte-synapse signaling contributing to cognitive function.

Elemental composition oriented biomass wastes sorting method towards efficient downstream energy recovery

Biomass wastes (BW) can be used to produce value-added products by multiple energy recovery technologies. However, the actual conversion results are unsatisfactory since heterogeneous feedstocks mixture with different characteristics are hard to optimally recovered in the same fine conversion process. This paper aimed to develop a new method to improve the energy conversion efficiencies, which focused on the rational matching of BW characteristics and demand for highly efficient energy recovery. Accordingly, this paper explored the correlation between BW representative characteristics and energy conversion efficiencies. The results showed that BW types with different characteristics had significant correlation with multiple utilization technologies (P value < 0.05). Existing BW sorting methods based on source/density showed limited promotion on downstream utilization since the large diversity of characteristics within groups. Furthermore, to assist efficient energy conversion of BW, a novel BW sorting mode, different from traditional manual and mechanical sorting methods, was established to achieve the matching between feedstocks and utilization technologies. The chemical properties, containing elemental composition and heating value, were selected as BW sorting criterion. According to new sorting categories, the fuel characteristics, reaction conditions and products performance in terms of its energy conversion process have more significant differences between groups than traditional sorting methods. The energy conversion efficiency can be improved by 10.71% than unsorted as least. The new BW sorting method towards efficient downstream energy recovery has feasibility in industrial applications. The future perspectives were also discussed. This work was helpful to improve the downstream energy utilization.

Study on improving surface integrity for additively manufactured Inconel 718 via high-speed micromilling

ABSTRACT The surface finish required for the application of products to aerospace and defense sectors cannot be produced by additive manufacturing (AM), and hence, a secondary finishing process is required post-additive manufacturing. Consequently, the current study analyses the ability of micromilling to enhance surface integrity for AM Inconel 718. Micromilling has been performed at three different levels of cutting conditions. The force induced during micromilling, surface finish, and top burr width for machined workpieces has been analyzed. A minimum value of 50 nm has been achieved for surface finish post-machining at a feed of 2 µm/flute and a speed of 50,000 rpm. An upmilling strategy has been found to be generating a lower top burr width compared to downmilling with a minimum value of 141 µm. A stability plot has also been constructed for the micromilling of AM Inconel 718 and compared with the stability lobe for wrought Inconel at different cutting speeds.

Experimental investigation of pool boiling on Ti-Cu composite coated surfaces prepared using Electric Discharge Coating

Boiling heat transfer has become a very potent two-phase heat transfer mechanism for cooling high heat-producing devices such as microelectronic devices, fusion reactors or turbine blades. Increasing research has shown that micro/nano-structures on surfaces increase the number of nucleation sites for bubble formation, which ultimately results in a major improvement in boiling performance. This led to studies on developing various coated surfaces in order to generate micro/nano-structures on surfaces. In the current study, microstructured boiling surfaces were prepared using the Electric Discharge Coating (EDC) process. Titanium-copper (Ti-Cu) composite microparticles were coated on copper surface under reverse polarity in the Electric Discharge Machine. Four surfaces were prepared by using current settings of 3 A, 4 A, 5 A and 6 A. It was followed by characterisation of the surfaces which included, wettability analysis, porosity, pore size estimation, mean roughness measurement and elemental analysis, in order to better understand the boiling results on the surfaces. The surfaces formed were hydrophilic in nature, with contact angles varying from 47° to 65°. Pool boiling were performed with the developed surfaces and critical heat flux (CHF) and nucleate boiling heat transfer coefficient (NBHTC) improvement of 37.17 % and 172 % respectively were observed with the best performing surface compared to the bare surface. The best performing surface was also compared with relevant published literature to determine its standing against the present state of the art.

Durability of deterministic textures produced by maskless electrochemical texturing (MECT) during Skin pass cold rolling

Skin pass is a fundamental finishing process to control the sheet roughness in cold metal rolling. The energetic and tribological efficiency of this process can be improved by surface texturing to control the roll surface topography and consequently the final sheet roughness. In this work, deterministic textures were produced on flat segments of skin pass rolls using the maskless electrochemical texturing (MECT) technique. The textures consisted of arrays of circular dimples. After texturing, the specimens were coated either with hard chrome or NiP electroless coatings, aiming to evaluate the ability of electroless NiP coating to protect textures as a potential replacement of the carcinogenic hard chrome coating. The evaluation of the texture durability was carried out via dry reciprocating sliding tests with samples extracted from cold rolling work rolls. The test configuration and conditions were chosen to intensify the wear process in order to evaluate the durability of the textures during skin pass cold rolling. Wear evaluation was also by analyzing changes in roughness parameters. The results indicated that the best tribological performance occurred for the textured surfaces coated with NiP. The average coefficient of friction of the textured surfaces coated with NiP was around 16 % lower than that of the uncoated textures and around 19 % lower than that of textures coated with hard chrome coated. Although the mass loss was negligible in the tests, the analysis of surface topography parameters showed that both hard chrome and electroless NiP coatings acted to decrease the wear of MECT textured surfaces.

Fluidization of fine coal particles in an ultrasound enhanced gas-solid fluidized bed

Coal continues to be one of the most important primary energy sources and is a major contributor to economic growth, especially in the developing world. Coal fines are an unavoidable by-product of coal extraction. Fine coal is classified as waste when it is too difficult or uneconomical to process and thus disposed of into waste ponds. This leads to environmental liability and loss of valuable high-quality product. There have been numerous studies regarding the efficient processing of fine coal particles, to realise the full economic potential whilst reducing the product's environmental risks. Fluidization is commonly used in the processing of powders or fine particles since it enables continuous powder handling and promotes good particulate mixing. However, the fluidization of fine particles is challenging due to the propensity for channelling, clustering and elutriation. Enhanced fluidization methods have been used to overcome these problems. Several methods that have been employed include electric or magnetic fields, mechanical vibrations, centrifugal forces, introduction of foreign particles, the use of microjets and the use of acoustic sound waves. This study considered the use of in-situ ultrasound as a new alternative enhanced fluidization technique. The overall aim of this research project was to quantitatively determine the improvement in the fluidization behaviour of fine coal particles, under the influence of ultrasound. This new technique helped prevent channel formation, and bed cracking, and improvement in fluidization regimes were observed. Decreasing minimum fluidization velocities were observed for increasing ultrasonic intensities, across various bed heights. The addition of the ultrasound correction factor was able to improve the prediction capability of the model that was developed for the minimum fluidization velocity. The reduction in minimum fluidization velocity shows promise for reduced energy consumption, and increased production throughput, of the fine coal particle processing industry. Overall the novel application of ultrasound improved the quality and operability of the fluidization of fine coal particles.

Study on the hydrolysis characteristics of polymeric aluminum chloride forced by fine bubbles and its key factors affecting the efficiency and capacity of forcing hydrolysis

Enhanced coagulation is an important way to remove natural organic matter and reduce disinfection by-products in traditional water treatment processes, in which the micromolecular organic matter that is difficult to be removed during conventional coagulation can be enhanced more conveniently by modulating the dominant Al species in the traditional metal salt coagulants (e.g., polymeric aluminum chloride, PACl). Based on the forcing hydrolysis characteristics of fine bubbles due to the adsorption of hydroxide ions on their surfaces, this study verified the adaptability of the forced PACl hydrolysis by fine bubbles under different operating conditions objectively and comprehensively. The morphological changes of PACl before and after forced hydrolysis by fine bubbles were characterized figuratively, and the evolution of the dominant Al species before and after forced hydrolysis by fine bubbles was reasonably elaborated. The experimental results showed that fine bubbles had the effect of forcing the hydrolysis of PACl with different degrees of alkalinity and modulating the dominant Al species. It was innovatively found that the mass transfer efficiency of the fine bubbles determined their efficiency in forcing PACl hydrolysis (Pearson's r = -0.9423) and the concentration of fine bubbles affected their capacity to force PACl hydrolysis (Pearson's r = 0.8189). At pH = 7 and an air flow rate of 20 mL/min, the DOC concentration of micromolecular organics and the DOC removal efficiency of total organics could be reduced by 0.54 mg/L and enhanced by 12.6 %, respectively, after forced PACl hydrolysis by fine bubbles. While deepening the mechanism of forced PACl hydrolysis by fine bubbles, the above results preliminarily verified the relevance and feasibility of modulating the dominant Al species through forced PACl hydrolysis by fine bubbles to improve the coagulation efficiency, which provided theoretical and data support for the construction of a fine bubble-enhanced coagulation process for drinking water treatment plants.

Unveiling the effect of vacuum heat treatment on HVOF-sprayed high entropy cantor alloy coatings: Microstructure, diffusion behavior and mechanical property

This study explored the effect of vacuum heat treatment on the microstructure and mechanical properties of High-Velocity Oxygen Fuel (HVOF) sprayed Cantor alloy (CoCrFeNiMn) coating. The heat treatment improved the microstructure of the coatings by decreasing the size of the pores. Enhanced diffusion distance at the interface was observed with higher heat treatment temperatures, promoting thorough bonding between the coating and substrate. Besides, recrystallization at high temperatures led to a reduction in grain size and improved uniformity. At 900 °C, the density of geometrically necessary dislocations decreased, while microhardness increased, indicating improved coating integrity and durability. The grain boundary strengthening played a dominant role in the coating heat treated at 900 °C compared to the dislocation strengthening. Therefore, optimizing the heat treatment process for HVOF-sprayed Cantor alloy coatings is essential for reduced defects, achieving sufficient diffusion at the interface, and enhanced coating mechanical properties.

Research on machining technology of stepped boring for intersecting holes in aircraft

Abstract During the assembly process of a large-scale aircraft fuselage, critical bearing areas require the drilling of intersecting holes, which are commonly processed using traditional single-edged reamers by most domestic manufacturers. To improve the efficiency and accuracy of the finishing process for these holes, enhance the quality of the assembly, and further shorten the construction cycle for precision processing, improvements need to be made to traditional single-edge reamer machining methods. This paper proposes a new approach that uses stepped reamers to machine intersecting holes. By setting up an experimental platform to simulate actual processing conditions and optimize processing parameters, the study analyzes and compares the quality and efficiency of traditional reaming and stepped reaming modes. The results show that stepped reaming can improve processing efficiency by 50.6% compared to traditional machining while also reducing human intervention and minimizing quality risks. The findings from this research project can be extended to various aircraft fuselages or wings for precise drilling of intersecting holes, providing significant guidance for efficient and high-quality delivery of aircraft.

Moxa combustion waste and its bio activities on cotton -- a facile and green finishing process towards a sustainable and value adding application for medical textile

Moxa combustion waste and its bio activities on cotton -- a facile and green finishing process towards a sustainable and value adding application for medical textile

Study on the difference of composition between traditional and modern lime used in the restoration of Qufu San Kong Ancient Architectural

In recent years, a decline in the binding strength and frost resistance of lime binder used in the restoration of the Qufu San Kong ancient architectural complex in Shandong Province has been observed, which has significantly affected the quality of restoration. In this study, lime binder samples were collected from the Kuiwen Pavilion roof, limestone samples in the vicinity of the Confucius Temple, and modern industrial quicklime from various provinces in China. Analytical methods including X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy were employed. Results indicate that the local limestone in Qufu contains impurities such as Si or Mg. XRD patterns reveal that the main phase of the Kuiwen Pavilion roof lime binder samples is calcite. Using FTIR and Scanning Electron Microscope- Energy Dispersive Spectrometer (SEM-EDS), the presence of hydrated calcium silicate (C-S-H) gel is identified in the samples. This suggests that the traditional quicklime-production process in Qufu yields a multiphase composite system. Modern industrial quicklime, aged for two months, showed no presence of C-S-H gel in the FTIR spectra and SEM-EDS results, indicating that it is a comparatively pure system primarily comprising CaO. The study suggests that traditional quicklime-production processes typically involve burning limestone with higher Si content, leading to the generation of a significant amount of dicalcium silicate. Additionally, the use of high-ash coal as fuel introduces reactive silicon dioxide into the quicklime product. These factors contribute to the formation of C-S-H gel in hydrated lime. The presence of C-S-H gel enhances lime binder properties such as binding strength and frost resistance. Modern quicklime production, which selects limestone with lower Si content and employs low-ash coal as fuel, aims to minimize or avoid the formation of C-S-H gel in hydrated lime. High-purity CaO quicklime products align with the principles of modern fine processing; however, they compromise the binding strength and durability of lime binder required for traditional architectural restoration.

Development of Electron Beam Physical Vapor Deposition Coating Process for YSZ Material Using Domestic Equipment Technology

Development of Electron Beam Physical Vapor Deposition Coating Process for YSZ Material Using Domestic Equipment Technology

Fabrication of Zinc Oxide Thin Films by Sol-Gel Dip Coating Process

Zinc oxide (ZnO) is a non-toxic material known for its distinctive physical and chemical properties, including a direct band gap energy of 3.37 eV and a large exciton binding energy of 60 meV, which contribute to its significant thermal and chemical stability at room temperature. Due to these characteristics, ZnO plays a critical role in various applications, such as UV light emitters, transparent conducting thin films in electronic devices, gas sensors, piezoelectric materials, transducers, and as a transparent conductive oxide (TCO) layer in thin-film photoelectrochemical cells. Numerous fabrication techniques have been employed to produce ZnO thin films. However, many of these methods require costly equipment, high vacuum environments, and elevated temperatures. In contrast, the sol-gel process stands out as a convenient, cost-effective, and versatile method for ZnO thin film fabrication. It offers advantages such as simplicity, low crystallization temperature, ease of reproducibility, molecular-level homogeneity, and precise compositional control. In this study, ZnO thin films were deposited onto Indium Tin Oxide (ITO) glass substrates using the sol-gel dip coating method, with varying preparative parameters: sol concentrations and annealing temperatures. The resulting samples were characterized using a UV-visible spectrophotometer, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX). The results demonstrated that the unique properties of ZnO thin films are highly dependent on the preparative parameters. Specifically, the band gap energy decreased from 3.25 eV to 3.18 eV with increasing sol concentration and also showed a similar decline with higher annealing temperatures. XRD patterns revealed a smaller full width at half maximum (FWHM) of the most intense peak (002) at higher sol concentrations and annealing temperatures, indicating an increase in crystallite size. FESEM images highlighted distinct morphological changes corresponding to the variations in sol precursor concentration and annealing temperature, while EDX analysis confirmed the formation of highly pure ZnO thin films on ITO glass substrates.