Dry Milling Process Research Articles

Optimizing dry milling of stir-cast and heat-treated AZ80 magnesium alloy using multiple criteria optimization technique: an experimental study.

The primary aspects of this research are to evaluate surface roughness, cutting force, and material removal rate and optimize it with dry milling process parameters for heat-treated and stir-cast AZ80 magnesium alloy. Multiple methodologies are utilized in the research, which includes the Integration of design of experiments-response surface methodology for experimental design with the technique for order of preference by similarity to ideal solution for multi-criteria optimization. In order to evaluate the effect of process parameters on the response, the experimental design manipulates the depth of cut, feed rate, and cutting speed in a systematic manner. An evaluation of the machined surface's quality is conducted via surface roughness measurements. Likewise, insights into the forces exerted during milling can be obtained through continuous monitoring of cutting forces. The calculation of material removal rate is predicated on weight reduction. The interaction between the depth of cut and feed rate has a significant impact on the critical-to-quality characteristics of the alloy, which has contribution percentage greater than 25%. This finding validates that despite the heat-treated alloy having a similar composition to the as-cast alloy (where the closeness coefficient is 0.9843), the optimal process parameters of the former are not applicable to the latter. Nevertheless, the technique used to prepare the specimen has no bearing on the material removal rate, which is a process parameter-specific effect.

Experimental Study on Dry Milling of Stir-Casted and Heat-Treated Mg-Gd-Y-Er Alloy Using TOPSIS

This study examines the dry milling process of a rare-earth-based magnesium alloy, emphasizing the optimization of the milling parameters and their impact on the surface quality, cutting forces, and the rate of material removal. The objective is to improve our comprehension of the milling behavior of the Mg-Gd-Y-Er alloy. The Taguchi technique is adopted to formulate the experimental design. This study methodically investigates the influence of heat treatment (T4 and T6) on milling performance, and the effects of speed, feed rate, and depth of cut. The output variables considered for this investigation are the surface roughness (Ra, Rz, Sa, and Sz), material removal rate (MRR), and cutting force. To optimize the milling parameters and achieve superior outcomes, the multi-objective optimization technique TOPSIS is used. At a feed rate of 150 mm/min, a spindle speed of 1500 rpm, and a depth of cut of 1 mm, the T4-treated sample exhibits a minimum surface roughness value of 0.0305 µm. The highest resultant force values of 96.4416 N and 176.1070 N for 200 °C and 225 °C T6-treated alloys are obtained by combining process parameters such as a spindle speed of 1500 rpm, a feed rate of 50 mm/min, and a depth of cut of 1.5 mm. Furthermore, the maximum closeness coefficient value is achieved by combining a spindle speed of 1000 to 1500 rpm, a feed rate of 150 mm/min, and a depth of cut of 0.5 mm to 1 mm. The closeness coefficient value is significantly influenced by the most significant process parameters, as indicated by the ANOVA results.

Comparative Review on the Production and Purification of Bioethanol from Biomass: A Focus on Corn

In the contemporary era, conventional energy sources like oil, coal, and natural gas overwhelmingly contribute 89.6% to global CO2 emissions, intensifying environmental challenges. Recognizing the urgency of addressing climate concerns, a pivotal shift towards renewable energy, encompassing solar, wind, and biofuels, is crucial for bolstering environmental sustainability. Bioethanol, a globally predominant biofuel, offers a versatile solution, replacing gasoline or integrating into gasoline–ethanol blends while serving as a fundamental building block for various valuable compounds. This review investigates the dynamic landscape of biomass generations, drawing insightful comparisons between the first, second, third, and fourth generations. Amid the drive for sustainability, the deliberate focus on the initial generation of biomass, particularly corn, in bioethanol production is grounded in the current dependence on edible crops. The established utilization of first-generation biomass, exemplified by corn, underscores the necessity for a comprehensive examination of its advantages and challenges, allowing for a nuanced exploration of existing infrastructure and practices. To produce bioethanol from corn feedstock, various milling methods can be employed. Thus, this paper delves into a comparative assessment of dry-milling and wet-milling processes scrutinizing their efficiency, environmental impact, and economic feasibility.

Methodology of Chip Temperature Measurement and Safety Machining Assessment in Dry Rough Milling of Magnesium Alloys Using Different Helix Angle Tools.

This paper presents the methodology of measuring chip temperature in the cutting zone in the rough milling of magnesium alloys. Infrared measurements are taken to determine the effect of variable cutting speed, feed per tooth, and depth of cut on the maximum temperature of chips. Thermal images of chip temperature for a generated collective frame and corresponding histograms are presented. Chip temperatures are presented in numerical terms as median and average values; maximum and minimum values; range; and standard deviation. Box plots are also shown for selected machining conditions. The problems arising during signal recording with a mean emissivity coefficient ε = 0.13, a value which is dedicated during machining magnesium alloys, are discussed in detail. Chip temperatures obtained in the tests do not exceed approx. 420 °C. Therefore, the dry rough milling process carried out with carbide tools with different blade geometries can be considered safe for a wide range of machining parameters. The proposed methodology of chip temperature measurement and result processing is a new and effective approach to safety assessment in the dry milling of magnesium alloys.

Revealing dynamic-mechanical properties of precipitates in a nanostructured thin film using micromechanical spectroscopy

Abstract Nanostructured materials with their remarkable properties are key enablers in many modern applications. For example, industrial dry-milling processes would not be as widely spread without the use of hard, wear-resistant metal nitride coatings to protect the cutting tools. However, improving these nanostructured thin films with regard to dynamical properties is demanding as probing respective parameters of (sub-)micron layers without any substrate influence is still challenging. To extend the scientific toolbox for such spatially confined systems, a novel methodological approach based on resonance peak measurements of a cantilever-transducer system termed micromechanical spectroscopy (µMS) is developed and applied to a Al0.8Cr0.2N model system. The mainly wurtzite type supersaturated Al0.8Cr0.2N system showed precipitation of cubic CrN at grain boundaries and local Cr variations upon annealing at 1050°C. This was accompanied by an increase in the previously unknown damping capability of 63 percent and an increase in Young’s modulus by 36 percent. Impact statement There is a wide variety of applications for nano- to micrometer-sized thin films in today’s engineering technology, from thermal barrier- and wear-resistant coatings in turbines and bearings, over diffusion barriers and heatsinks in microelectronic devices, to optically active layers in lasers or mirrors. The mechanical properties of such thin films are oftentimes governed by their thermal history, leading to either intentional or undesired changes in the microstructure (e.g., the formation of precipitates). While the investigation of such features is usually constricted to static analysis using high-resolution techniques, such as transmission electron microscopy, understanding their impact on dynamic properties of the film remains a challenge. However, these are highly relevant in many engineering applications where cyclic behavior is common, such as high-speed dry milling. In the present work, we investigate the change in mechanical damping capability upon annealing of a 6-µm thin AlCrN film, commonly used in demanding dry-milling applications, using micromechanical spectroscopy (µMS) of cantilever-shaped specimens. After a carefully adjusted heat treatment, the film exhibits the formation of cubic CrN precipitates in an otherwise wurtzite AlCrN matrix, which leads to a previously unknown beneficial increase in damping capability of the film. Graphical abstract

Mechanosynthesis of semiconductor nanocrystalline Cu2ZnSnSe4 for solar cells

Cu2ZnSnSe4 is a promising material that can be used to make low-cost, high-efficiency thin-film solar cells. The present study, we established a simple and efficient approach for producing a single-phase Cu2ZnSnSe4 bulk material from fundamental precursors (Cu, Zn, Sn and Se) using dry ball milling. After every two hours of the dry milling process, X-Ray Diffraction (XRD) and Raman Spectroscopy investigations were carried out to investigate the movement towards single phase Cu2ZnSnSe4 and the concurrent secondary phase depletion. The development of Cu2ZnSnSe4 materials that crystallize in a Kesterite system is shown by the prominent diffraction peaks. The crystalline size of the materials is 10–20 nm and dislocation density is 3.02–3.22 ×1015 lines/m2. UV–Vis spectroscopy was used to investigate the optical properties of the materials. Using transmittance and reflectance data, the linear and nonlinear optical constants of Cu2ZnSnSe4 films were calculated and the bandgap value is 1.6 eV. Hence from these results we can conclude that the above synthesized powder can be used for the development of thin films via thermal or electron beam evaporations on desired substrate and also we can use for various energy harvesting applications as a photoabsorber.

Preparation of argyrodite Li6–2xZnxPS5−xOxCl with improved electrochemical performance and air stability for all-solid-state batteries

The argyrodite Li6PS5Cl (LPSCl) solid electrolyte applied to all-solid-state batteries is gaining increasing attention as an attractive next-generation material, but in humid conditions it causes degradation of battery performance as a result of instability and poor contact with electrodes. In this experiment, LPSCl solid electrolyte was modified by substituting Zn for Li, and O for S through dry ball milling and heat-treatment processing. As evidence of ZnO substitution, X-ray diffraction, Laser-Raman, field emission scanning electron microscopy, nuclear magnetic resonance spectroscopy, and X-ray photoelectron spectroscopy analysis of the synthesized solid electrolyte were performed. The Li5.95Zn0.025PS4.975O0.025Cl (LPSCl-ZnO) solid electrolyte showed a high ionic conductivity at 30 °C. Moreover, it showed a higher critical current density value of 0.55 mA·cm−2 compared to the of 0.3 mA·cm−2 of LPSCl. It also exhibited high compatibility with Li metal as a cathode in cyclic voltammetry and in DC profile. In addition, the H2S gas generated after exposure to 10% humid air was a very low 0.38 cm3·g−1. Notably, an all-solid-state battery assembled with the ZnO-substituted solid electrolyte (x = 0.025) showed a specific capacity of 148.5 mAh·g−1 (0.1 C) and a high capacity retention rate of 99.7%.

Study of chip adhesion behavior in titanium alloy dry milling process based on image extraction technology

Study of chip adhesion behavior in titanium alloy dry milling process based on image extraction technology

Study on machinability and grain deformation of laser cladding manufactured and wrought IN718 alloys in dry milling process

Study on machinability and grain deformation of laser cladding manufactured and wrought IN718 alloys in dry milling process

Synthesis of glass–ceramic Li7−2xZnxP2S8–xOxI oxysulfide solid electrolyte with high chemical stability for all-solid-state lithium batteries

All-solid-state batteries remain problems to be overcome due to the high-temperature heat-treatment process, and the compatibility problem with Li metal as an anode. In this work, Li7P2S8I (LPSI) solid electrolyte with high ionic conductivity is prepared using a high-energy dry ball milling process with a low-temperature (200 °C) heat-treatment process. Then, ZnO are doped with LPSI solid electrolyte, particularly Zn2+ at the Li site and O2− at the S site, by our optimized synthesis process. The ZnO co-doping is confirmed by powder X-ray diffraction, Laser–Raman, field emission scanning electron microscopy, and nuclear magnetic resonance spectroscopy analysis. The ionic conductivity value of the prepared solid electrolytes is measured by electrochemical impedance spectroscopy analysis, and the prepared LPSI and Li6.9Zn0.05P2S7.95O0.05I solid electrolytes exhibit an ionic conductivity of (4.4 and 4.2) mS·cm−1, respectively, at room temperature. To evaluate the electrochemical stability of the prepared solid electrolyte, we perform cyclic voltammetry and galvanostatic discharge/charge voltage profiles analysis. In addition, the fabricated all-solid-state battery exhibits a high specific capacity of 165.4 mAh·g−1 (0.1 C), and a high-capacity retention rate of 95.2 %. Interestingly, ZnO co-doped LPSI solid electrolyte exhibits longer air-stability than the undoped LPSI solid electrolyte in dry air with 10 % humidity.

Facies, Geochemistry, and Ceramic Properties of Corumbataí Formation, Upper Permian of Paraná Basin, and its Application in the Ceramic Industry, Brazil

AbstractThe supply of Corumbataí Formation rocks, which occur widely in the State of São Paulo, Brazil, and are used by Santa Gertrudes Ceramic Cluster, is dwindling and prospecting for new deposits is essential. The current study aimed to map and characterize new reserves of ceramic raw materials which would guarantee mineral and economic sustainability of the important concentration of ceramic-processing capability in that area, and thereby contribute to improving and diversifying the range of products manufactured and to promoting a greater presence in the international market. To achieve the proposed objectives, 16 profiles were sampled and the samples were submitted to granulometric analysis by laser diffraction, and the major elements by inductively coupled plasma-mass spectrometry, and the mineralogical compositions of clay samples were determined by X-ray diffraction and ceramic properties. Six lithofacies were identified and grouped into two facies associations: a lower shoreface association comprising massive siltstone (Sm) and laminated siltstone (Sl); lithofacies, and an upper shoreface association comprising heterolithic sandstone (Sh), lenticular sandstone (Sle), intercalated sandstone/siltstone (Si), and altered siltstone (Sa) lithofacies. The lithofacies of the lower shoreface association were more clayey, flux with a significant presence of illite and microcline, and a more uniform granulometry distribution, which made its classification possible, technologically, as stoneware and semi stoneware. The main application of this material is in the production of coatings through the wet milling process. The lithofacies of the upper shoreface association was sandier, had a refractory presence with kaolinite and montmorillonite, and had a less uniform granulometric distribution; technologically, it can be characterized as porous and semi-porous. The main application of this material is in the production of coatings by the dry milling process. The results obtained by facies analysis combined with the geochemical and ceramic properties of the Corumbataí Formation rocks revealed both vertical and lateral variations of the lithofacies, which influence their properties, behavior, and application as ceramic raw materials.

Effect of Mg and Zn Composition Variations on Surface Characteristics and Flexural Strength of Biodegradable Mg-Zn-Ca Alloys by Powder Metallurgy Method

This study aims to determine the Mg-Zn-Ca alloy's surface characteristics and flexural strength using powder metallurgy methods. The Mg-Zn-Ca alloy was prepared by powder metallurgy method with three composition variations (89Mg-10Zn-1Ca, 93Mg-6Zn-1Ca and 97Mg-2Zn-1Ca). The Mg-Zn-Ca powder alloy was mixed with the dry milling process for 60 minutes. After mixing, the compaction process is carried out with a load of 200 MPa. Then, the sintering process was carried out at a temperature of 500 ℃ and held for 3 hours with a furnace fed with argon gas. The sintering results were characterized by the microstructure of the Mg-Zn-Ca alloy using SEM and XRD. After that, it was carried out to test the flexural strength of the Mg-Zn-Ca alloy. SEM results obtained that the 89Mg-10Zn-1Ca alloy sample has less porosity and a smaller pore diameter compared to the 93Mg-6Zn-1Ca alloy sample and the 97Mg-2Zn-1Ca alloy sample, which has more porosity and has a smaller diameter. Bigger pore. The results from XRD had the highest peak in the 89Mg-10Zn-1Ca alloy sample, seen from a crystalline spectrum of 82.4%. The results of the bending test, the most optimal flexural strength occurred in the 89Mg-10Zn-1Ca alloy sample, which was 0.579 Mpa. The results from XRD had the highest peak that occurred in the 89Mg-10Zn-1Ca alloy sample, seen from a crystalline spectrum of 82.4%. The results of the bending test, the most optimal flexural strength occurred in the 89Mg-10Zn-1Ca alloy sample, which was 0.579 Mpa. The results from XRD had the highest peak in the 89Mg-10Zn-1Ca alloy sample, seen from a crystalline spectrum of 82.4%. The results of the bending test, the most optimal flexural strength occurred in the 89Mg-10Zn-1Ca alloy sample, which was 0.579 Mpa

Optimization of High-speed Dry Milling Process Parameters Based on Improved ELM and Genetic Algorithm

High-speed dry grinding has the characteristics of high processing efficiency and clean environment. The high-speed dry grinding method meets the requirements of the green and efficient development of the national manufacturing industry. However, inappropriate cutting parameters seriously affect the surface quality of the workpiece and cause the workpiece to be scrapped. Therefore, this paper proposed an optimization method based on the combination of the improved extreme learning machine neural network (ELM) for high-speed dry milling surface roughness prediction model and genetic algorithm (GA). The Taguchi orthogonal experiment results show that the surface roughness of high-speed dry milling can be accurately predicted by the improved ELM and thereafter the optimal cutting parameter combination can be determined by GA.

A Comparative Study on the Effect of the Traditional and Industrial Milling on the Nutritional Composition of Sorghum, Pearl Millet and Wheat Flour

Pearl millet, sorghum, wheat is a staple food in India. It is milled into flour by traditional and industrial dry milling processes. This research was conducted to help determine how to improve the nutritional value and acceptability of pearl millet. The traditional milling step has lowers the pH of kernels. The effects of the traditional and industrial “dry milling” processes on the physical and nutritional composition of grain were compared. Regarding comparing the milling processes, was conditioned and decorticated traditionally with a millstone and industrially with an roller mille. The traditional decorticated grain was steeped and sun dried for 24 h before milling, whereas the industrially decorticated grain was roller milled. Proximate analyses were conducted on the samples. The traditionally milled flour was lighter in colour than industrial milled flour. However, it was significantly lower in protein, ash and nutrient contents in comparison to industrial milled flour. This was due to the removal of more pericarp and germ in the traditional process. The industrial dry milling process, therefore, produces flour with a higher nutrient content in terms of protein, fat and minerals. However, the traditional milling process makes the colour of the pearl millet flour lighter, which is probably the reason that it is more acceptable to consumers.

Effectiveness of Tannin Removal by Alkaline Pretreatment on Sorghum Ethanol Production

Sorghum has been proposed as a complement or replacement for corn in ethanol production. One difference between sorghum and corn is the presence of tannins, which may affect enzymatic activity. High-tannin sorghum hybrid XM217 was used to analyze the effect of tannin removal by the alkaline pretreatment of sorghum for ethanol production. A laboratory-scale dry-milling process was used on treated sorghum/corn blends to generate mash that was fermented by Saccharomyces cerevisiae and then compared to a 100% untreated sorghum control. Cellulase was added to a similar set of mash to determine the feasibility of the tannin-removal treatment as a pretreatment method for cellulosic ethanol production. Theoretical ethanol yield increased from 68.2 ± 1.5% to 78.5 ± 2.5% for alkaline-pretreated sorghum vs. untreated sorghum, with a corresponding increase in mean ethanol concentrations from 8.02 ± 0.15 to 9.39 ± 0.26% w/v. The average theoretical ethanol yield increased from 69.8 ± 1.7% to 94.6 ± 1.9% when using cellulase with untreated and treated sorghum. The use of alkaline tannin removal resulted in a significant increase in the theoretical ethanol yield obtained when using 100% sorghum, when compared to the theoretical ethanol yield obtained when using 100% corn. The combination of cellulase and alkaline tannin removal improved the yield of ethanol in all cases compared to the experiments without cellulase.

SWARA-CoCoSo method-based parametric optimization of green dry milling processes

Attaining green environment for various machining processes has now caught the attention of many manufacturing industries. The input parameters involved in those machining processes are mainly responsible for achieving the desired performance as they are directly related to the process outputs. Hence, proper selection of the input process parameters becomes vital for having sustainable machining environment. In this paper, an integrated application of step-wise weight assessment ratio analysis (SWARA) and combined compromise solution (CoCoSo) methods is presented to identify the optimal parametric combinations of two green dry milling processes. In the first example, cutting speed, depth of cut, feed rate and nose radius are treated as the input parameters, while power factor, electric consumption and surface roughness are the responses. On the other hand, in the second example, cutting speed, feed rate, depth of cut and width of cut, and surface roughness, active cutting energy and material removal rate are respectively considered as the input parameters and responses. Instead of considering equal weights, SWARA method assigns relative subjective importance to the responses based on the preference set by the decision-makers, while CoCoSo ranks the experimental trials from the best to the worst. The derived optimal parametric settings are finally analyzed using the developed regression equations. It is observed that SWARA-CoCoSo method outperforms the other popular optimization techniques in identifying the best parametric intermixes for the green dry milling processes for having improved machining performance with minimal environmental effect.

Surface Finish Comparison of Dry and Coolant Fluid High-Speed Milling of JIS SDK61 Mould Steel

This paper investigates the influence of dry high-speed milling on the surface quality of JIS SKD61 hard steel, compared to the conventional coolant fluid method. This research was conducted in a Super MC 500 high-speed CNC milling machine with a Hitachi coated carbide 20mm in diameter. High-speed cutting parameters such as cutting speed V, cutting depth t, and spindle speed S were considered as variants. The experiment was designed based on Taguchi's L9. Surface quality, including Ra and Rq, was measured using the Mitutoyo Surftest SV-210. A mathematical regression model was found for the average values of surface roughness through regression analysis for dry and coolant fluid conditions. The chosen high-speed milling parameters and the respective Ra and Rq values were obtained by ANOVA. The grey relation scores for wet and dry milling surface quality for cut depth, feed rate, and cutting speed were 0.7527, 0.7869, 0.6302, and 0.8167, 0.7199, 0.6040, respectively. The results showed that the feed rate had the greatest influence on the surface quality during the high-speed coolant milling of hardened steel, while the depth of the cut had the greatest influence on the surface quality during the high-speed dry milling process.

Experimental evaluation of surface generation and force time-varying characteristics of curvilinear grooved micro end mills fabricated by EDM

Conventional cutting fluids as coolants and lubricants are being widely used in various machining processes, but these cutting fluids give rise to biological and environmental problems. The advantages of implanting micro texture on macroscopic cutting tools have been proved widely in implementing sustainable machining. But seldom studies focused on preparing micro texture on the surface of micro end mill with diameter less than 1 mm. In this study, an attempt has been made to create curvilinear grooved micro textures on the rear surface of double helical micro end mills with diameter of about 800 μm by electrical discharge machining (EDM) method for lowering specific milling energy and forces. Then, dry micro milling experiments were performed on aluminum alloy material using micro end mills with or without curvilinear grooved micro textures. The surface generated mechanism, force time- varying characteristics, specific milling energy, chip capacity and tool wear form of curvilinear grooved micro end mills in dry micro milling are revealed. Besides, the effects of structural parameters of micro textures and process parameters on specific milling energy and dry micro milling forces are discussed. Experimental results disclosed that the average specific cutting energy involved in dry micro milling process of aluminum alloy material machined by micro end mill with curvilinear grooved micro textures is decreased by 21.35%. The normal and tangential forces are significantly reduced compared to ordinary micro end mill. The voids and stomatal located in micro textures fabricated by EDM method are found to be conductive to store and accommodate some extrusion chips. For micro end mill with curvilinear grooved micro textures, the oxidative wear is more serious but the adhesion wear is slighter than ordinary micro end mill. This research is expected to prepare and optimize micro textured micro end mills suitable for dry micro milling process, which has important theoretical significance and engineering application value.

Effects of grinding time on morphology and collectorless flotation of coal particles

The impact of particle shape and surface properties has been mainly overlooked in the literature for different mineral systems. In this study, to investigate the effects of morphological variations, samples of clean coal particles (−0.212 + 0.075 mm) were used and the flotation experimental in a batch condition (2 L Denver cell) were conducted in the absence of collectors by keeping the particle size constant. Binocular microscopic images were used to determine the shape factors of coal particles. A dry ball milling process was carried out as a function of grinding time (60–960 s) and representative samples were taken for determining both shape and floatability of particles. Further, particle-bubble attachment, zeta potential, roundness, surface roughness values and flotation kinetics were measured. It was indicated that by increasing milling duration from 60 s to 960 s, the roundness and roughness increased from 0.792 to 0.809 and 23 nm to 57 nm, respectively. This led to increasing flotation rate constant from 0.4482 ± 0.02 to 0.4856 ± 0.03 1/min. In addition, the theoretical calculations for energy barrier showed that upon increasing the roughness degree from 0 to 57 nm, the energy barrier significantly decreased from 2.79E-16 to 6.51E-17 J/m2, which also proved our findings from a theoretical point of view. Thus, it was finally concluded that the more the roughness, the higher the flotation kinetics and the lower the energy barrier.

Preparation of Graphene Nanosheets from Graphite Flakes via Shear Assisted Exfoliation

Graphene is one of the most important forms of carbon. Due to its exceptional physical, chemical, and mechanical properties, it’s used in different fields such as electronic, energy storage, and medical applications. Therefore, the production of graphene in large quantities, at a low cost, and high quality, has become critical. Using graphite powder, a few layers of graphene sheets were prepared via a series of mechanical exfoliation methods. the dry ball milling process by the planetary mill was used. Thereafter, the milling was followed by shear force and then supported by ultra-sonication to reach the lowest level of the graphene layers. Morphological properties were examined using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Also, structural characterizations were investigated using Raman spectra and X-ray diffraction measurements (XRD) and (FTIR). Findings presented in this research highlighted that the synthesis method followed was found to have several advantages, including low cost and the ease of producing a few layers of graphene nanosheets. Subsequently, the promising efficiency of the used methodology is important.