Feed Rate Research Articles

Generation of uniform micro-textured structures by two-dimensional modulation fly-cutting

Micro-textured structures are widely applied in the fields of aerospace, military and medical etc. because of their unique properties such as self-cleaning, structural color and antibacterial effects. The traditional fast tool servo technology is believed to be an ideal machining method for the fabrication of micro-textured structures, however, its frequency response is limited by the varied linear velocity along the radial direction of workpieces, which make it difficult to machine uniform micro-textured structures. In this paper, a novel two-dimensional modulation fly-cutting system is developed to machine uniform micro-textured structures. In the machining system, the principal cutting motion is generated by a fly-cutting while a sinusoidal excitation motion as the assistive modulation is generated by a two-dimensional vibration platform. The two-dimensional vibration platform can apply excitation both in the x- and z-directions to the workpiece. By changing the excitation frequency, tool rotation radius and feed rate in X-axis, the corresponding optimal offset angle, length-width ratio and density of micro-textured structures can be obtained. Also, uniform concave-convex micro-textured structures are fabricated further by two-dimensional modulation of the principal cutting motion. According to the experimental results, uniform concave-convex micro-textured structures have good quality, which proves that the present machining method is effective. The present study provides an effective machining method for fabrication of micro-textured structures, and also serves as a reference for the fabrication of other similar micro-textured structures.

Critical state-of-the-art literature review of surface roughness in incremental sheet forming: A comparative analysis

Incremental sheet forming (ISF) is a controlled and die-less forming process that can produce customized products from the sheets layer by layer using the same setup, i.e., forming tools and machine. This novel and emerging forming technique can potentially be useful as a green aspect of manufacturing by reducing the required power and by saving the resources for producing the components of lightweight materials because material is deformed locally during ISF. The surface quality of the formed parts from sheet material affects the aesthetics aspects, stress concentration, fatigue life and their applicability. This review article aims to provide a state-of-the-art review for various aspects and parameters of ISF process that affect the surface roughness significantly by conducting literature survey quantitatively. Furthermore, the techniques of ISF and roles of various parameters responsible for affecting the surface quality of parts have also been explored for providing the critics for existing literature and setting the further guidelines for the researchers. Various instruments used for measuring the surface roughness of parts formed by ISF has also been discussed. Comparative analysis of exiting literature available in the context of various process parameters, ISF hardware, and surface roughness makes this study comprehensive and exhaustive for the researchers to find the gaps and challenges in this field. The relationship of wall angle with other process parameters can be explored in the future to obtain the desired surface quality of a particular material. Significant parameters responsible for the surface quality have also been discussed critically. Further, the new tool paths can be developed for high surface quality and low forming time. A study on the selection of feed rate for various applications and relation with other parameter is also recommended for the future work. The lubricants with additives can further be tested for high surface quality of ISF. Further, significant study on surface roughness is not conducted on hybrid sheet forming and other advanced variants of ISF (like hot forming, friction stir assisted incremental forming, waterjet forming). It is required to develop the comparisons between the different techniques of ISF. Results also showed that majority of researchers used SPIF technique followed by DSIF and hybrid ISF.

SAMP Rao algorithm based minimization of the roughness of milled surface of Ti-6Al-4V

In order to solve optimization problems including machining responses as objectives, this study suggests a parameter-less method called the self-adaptive multi population (SAMP) Rao algorithm that does not rely on metaphors. When machining titanium alloys, achieving a good surface quality is a difficult process. In the current study, an effort has been made to reduce surface roughness during milling Ti-6Al-4V. Response surface methodology (RSM) was used in the experiment design to create a model for surface roughness using cutting parameters as variables. The developed model was tested in additional tests in addition to the primary experiments. It was shown that cutter speed and feed rate had the biggest effects on milled roughness, whereas depth of cut had very little of an impact. The model’s quality is demonstrated by the correlation coefficient (R2) 98%, which indicates that the model can explain 98% of the data. Later, a response surface-based desirability technique was used to minimize roughness of milled surface. The outcome of the proposed algorithm is compared with RSM optimizer. It has been noted that the outcomes achieved with the SAMP approach are more advantageous than RSM approach and found 18% minimum value of roughness of milled surface. Main reason to get better result in case of SAMP Rao algorithm is that it is based on the iterative search process with random values of cutting parameters with in defined range. SAMP Rao Algorithm provides cutting settings of 133.5 m min−1, 0.13 mm/tooth feed rate, and 2.06 mm of milling depth along with a minimal roughness of milled surface of 0.37 μm.

The Analytical and Experimental Analysis of the Machined Surface Roughness in High-Feed Tangential Turning

A main topic in mass production of machine parts is how to increase the productivity to produce more parts in a given time while maintaining the prescribed surface quality on the machined surfaces. Novel machining procedures have been introduced to achieve this goal; however, the further development of already established and wide-spread procedures can offer simply accessible solutions. Tangential turning is a rediscovered variant of the traditional turning procedure, where a specially designed cutting tool ensures chip removal with a feed tangential to the workpiece. This process results in low surface roughness even at higher feed rates. In this paper, the achievable surface roughness is analyzed by analytical and experimental steps. In the mathematical analysis, the theoretical surface roughness is determined using the constructive geometric modelling method. The worked-out equations are validated in cutting experiments on 42CrMo4 grade steel workpieces. The theoretical and experimental analyses show that the strictly prescribed surface roughness can be achieved with high feed rates by the application of tangential turning.

Numerical Simulation Study of Wall Thickness Change Rule of Single Point Progressive Molding of Al5083

With the development and progress of science and technology, the application of single-point progressive molding is more and more extensive, but single-point progressive molding still exists the problem of excessive thinning of wall thickness of molded parts, which seriously affects the quality of molded parts. The article takes Al5083 plate forming cone as the research object, uses Abaqus finite element simulation software, according to the principle of single variable, respectively explores the influence of process parameters such as tool head diameter, layer spacing, feed rate and residual height on the average wall thickness reduction rate and the maximum wall thickness reduction rate of the molded parts. The results show that: increasing the tool head diameter, the average wall thickness reduction rate increases and the maximum wall thickness reduction rate decreases; the average wall thickness reduction rate and the maximum wall thickness reduction rate increase with the increase of ply spacing; the average wall thickness reduction rate and the maximum wall thickness reduction rate increase with the increase of the tool feed rate; the average wall thickness reduction rate decreases and the maximum wall thickness reduction rate increases with the increase of the residual height.

Prediction of Bonding Strength of Heat-Treated Wood Based on an Improved Harris Hawk Algorithm Optimized BP Neural Network Model (IHHO-BP)

In this study, we proposed an improved Harris Hawks Optimization (IHHO) algorithm based on the Sobol sequence, Whale Optimization Algorithm (WOA), and t-distribution perturbation. The improved IHHO algorithm was then used to optimize the BP neural network, resulting in the IHHO-BP model. This model was employed to predict the bonding strength of heat-treated wood under varying conditions of temperature, time, feed rate, cutting speed, and grit size. To validate the effectiveness and accuracy of the proposed model, it was compared with the original BP neural network model, WOA-BP, and HHO-BP benchmark models. The results showed that the IHHO-BP model reduced the Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Mean Absolute Percentage Error (MAPE) by at least 51.16%, 40.38%, and 51.93%, respectively, while increasing the coefficient of determination (R2) by at least 10.85%. This indicates significant model optimization, enhanced generalization capability, and higher prediction accuracy, better meeting practical engineering needs. Predicting the bonding strength of heat-treated wood using this model can reduce production costs and consumption, thereby significantly improving production efficiency.

Polyelectrolyte gelatin-chitosan hydrogel optimized for 3D bioprinting in skin tissue engineering

Bioprinting is a promising automated platform that enables the simultaneous deposition of multiple types of cells and biomaterials to fabricate complex three-dimensional (3D) tissue constructs. Collagen-based biomaterial used in most of the previous works on skin bioprinting has poor printability and long crosslinking time. This posed an immense challenge to create 3D constructs with pre-determined shape and configuration at high throughput. Recently, the use of chitosan for wound healing applications has attracted huge attention due to its attractive traits such as its antimicrobial properties and ability to trigger hemostasis. In this paper, we optimized polyelectrolyte gelatin-chitosan hydrogel for 3D bioprinting. Modification to the chitosan was carried out via the oppositely charged functional groups from chitosan and gelatin at a specific pH of ~pH 6.5 to form polyelectrolyte complexes. The polyelectrolyte hydrogels were evaluated in terms of physical interactions within polymer blend, rheological properties (viscosities, storage and loss modulus), printing resolution at varying pressures and feed rates and biocompatibility. The polyelectrolyte gelatin-chitosan hydrogels formulated in this work was optimized for 3D bioprinting at room temperature to achieve high shape fidelity of the printed 3D constructs and good biocompatibility with fibroblast skin cells.

Coaxial nozzle-assisted electrohydrodynamic printing for microscale 3D cell-laden constructs.

Cell printing has found wide applications in biomedical fields due to its unique capability in fabricating living tissue constructs with precise control over cell arrangements. However, it is still challenging to print cell-laden 3D structures simultaneously with high resolution and high cell viability. Here a coaxial nozzle-assisted electrohydrodynamic cell printing strategy was developed to fabricate living 3D cell-laden constructs. Critical process parameters such as feeding rate and stage moving speed were evaluated to achieve smaller hydrogel filaments. The effect of CaCl2 feeding rate on the printing of 3D alginate hydrogel constructs was also investigated. The results indicated that the presented strategy can print 3D hydrogel structures with relatively uniform filament dimension (about 80 μm) and cell distribution. The viability of the encapsulated cells was over 90%. We envision that the coaxial nozzle-assisted electrohydrodynamic printing will become a promising cell printing strategy to advance biomedical innovations.

Acute and chronic effects of the antifouling booster biocide Irgarol 1051 on the water flea Moina macrocopa revealed by multi-biomarker determination

Irgarol 1051 is an herbicide extensively utilized in antifouling paint due to its ability to inhibit photosynthesis. Irgarol and its photodegradation products are highly persistent in waters and sediments, although they are present in low concentrations. However, our understanding of the harmful effects of Irgarol on non-target organisms remains limited. In this study, we assessed the effects of acute (24 h) and chronic (14 days across three generations) exposure to different concentrations (including the 1/10 NOEC, NOEC, and 1/10 LC50 calculated from the 24-h acute toxicity test) of Irgarol using the water flea Moina macrocopa. Acute exposure to 1/10 LC50 significantly decreased survival, feeding rate, thoracic limb activity, heart rate, and acetylcholinesterase activity. Elevated levels of intracellular reactive oxygen species and malondialdehyde, along with a significant increase in catalase and superoxide dismutase activity, suggested the induction of oxidative stress in response to 1/10 LC50. An initial boost in glutathione level and the enzymatic activities of glutathione peroxidase and glutathione reductase, followed by a plunge, implies some compromise in the antioxidant defense system. Upon chronic exposure to the NOEC value, both generations F1 and F2 displayed a significant decrease in survival rate, body length, number of neonates per brood, and delayed sexual maturation, suggesting maternal transfer of potential damage through generations. Taken together, Irgarol induced acute toxicity through physiological and cholinergic damage, accompanied by the induction of oxidative stress, in the water flea. Even its sub-lethal concentrations can induce detrimental effects across generations when consistently exposed.

Investigation of process parameters of electrohydrodynamic jetting for 3D printed PCL fibrous scaffolds with complex geometries

Tissue engineering is a promising technology in the field of regenerative medicine with its potential to create tissues de novo. Though there has been a good progress in this field so far, there still exists the challenge of providing a 3D micro-architecture to the artificial tissue construct, to mimic the native cell or tissue environment. Both 3D printing and 3D bioprinting are looked upon as an excellent solution due to their capabilities of mimicking the native tissue architecture layer-by-layer with high precision and appreciable resolution. Electrohydrodynamic jetting (E-jetting) is one type of 3D printing, in which, a high electric voltage is applied between the extruding nozzle and the substrate in order to print highly controlled fibres. In this study, an E-jetting system was developed in-house for the purpose of 3D printing of fibrous scaffolds. The effect of various E-jetting parameters, namely the supply voltage, solution concentration, nozzle-to-substrate distance, stage (printing) speed and solution dispensing feed rate on the diameter of printed fibres were studied at the first stage. Optimized parameters were then used to print Polycaprolactone (PCL) scaffolds of highly complex geometries, i.e., semi-lunar and spiral geometries, with the aim of demonstrating the flexibility and capability of the system to fabricate complex geometry scaffolds and biomimic the complex 3D micro-architecture of native tissue environment. The spiral geometry is expected to result in better cell migration during cell culture and tissue maturation.

Laser-assisted Belt Grinding with Creep Feed for Enhanced Surface Integrity and Abrasive wear Reduction

Creep feed belt grinding (CFBG) is a vital machining technique used for intricate curved parts like aero-engine blades and flaps. CFBG effectively removes material by using larger depths of cut and lower feed rates, but high loads can lead to severe belt wear and thermal damage defects in the process. Laser-assisted processing technology can mitigate tool wear and enhance machining quality. This research compared and analyzed belt wear behavior and its impact on the surface integrity of titanium alloys in laser-assisted creep feed belt grinding (LCFBG) and CFBG processes. The following conclusions were drawn: The local thermal effect of the laser softened the material, reduced the grinding force. The wear pattern of the abrasive grains changed from abrasive fracture and stripping to steady abrasive wear. The effective life of the belt increased by about 33 %. In addition, due to reduction in grinding force, the thermo-mechanical coupling effect caused by material removal is reduced, and the grinding temperature is lowered. As a result of the reduction in grinding force and temperature, the mechanical and thermal stresses are reduced, the oxidation reaction on the surface of the titanium alloy is weakened, and the residual stress is lowered, leading to an improvement in surface quality.

Polyculture of pikeperch (Sander lucioperca) and Russian sturgeon (Acipenser gueldenstaedtii) using an artificial common pellet – Implications on feed to fish nutrient transfers in recirculating aquaculture system (RAS)

The purpose of this research was to investigate the effects of monoculture and polyculture on the utilization of an artificial common pellet to produce nutritious products, specifically pikeperch and Russian sturgeon, in a recirculating aquaculture system (RAS) for 84 days. The experiment was conducted under controlled conditions, with specific parameters for: water temperature (21.8±0.4 °C), initial weight of the fish (pikeperch: 18.17±2.65 g; sturgeon: 18.23±3.62 g), volume of the containers (working volume of 272 litres) and feeding rate (1.5 %). Five experimental groups were tested in triplicates, including monoculture groups (pikeperch: 63.46±18.49 g; sturgeon: 93.52±50.40 g) and three polyculture combinations [P90: 90 % pikeperch (68.63±13.79 g) + 10 % sturgeon (86.10±33.38 g); P80: 80 % pikeperch (76.88±18.06 g) + 20 % sturgeon (103.53±44.60 g); P70: 70 % pikeperch (81.51±19.24 g) + 30 % Russian sturgeon (94.48±33.25 g)]. The results indicated that the addition of Russian sturgeon to pikeperch tanks could lead to efficient transfer of feed lipid to fish biomass through sturgeons, but not pikeperch. Polycultures showed better lipid absorption (P70 lipid-ADC 96.06±1.96 %) from the common pellet than monocultures (pikeperch: lipid-ADC 91.93±6.37 %; sturgeon: lipid-ADC 97.08±2.07 %). Fillet lipid content of pikeperch remained unaltered across RAS monocultures and polycultures but changed positively in Russian sturgeon in polyculture (P70 2.64±0.71 % > P0 1.75±0.75 %). In both species, polyculture fillets accumulated 5–7 % higher MUFA (oleic acid, C18:1n-9) than monoculture fillets. The major conclusions drawn from this research are that polyculture group P90 had both fish species flesh with highest muscle reserves of glycine and proline. In polyculture, critically indispensable muscle lysine reserves depleted in pikeperch, but Russian sturgeon muscle amino acid profile was stable. Given the global constraints on land availability, the study proposes RAS polyculture as a potentially productive and nutritious aquaculture system of the future. The research also suggests that resilient species for RAS polyculture need to be identified, proposing Russian sturgeon as a possible candidate.

Low humidity enhances Zika virus infection and dissemination in Aedes aegypti mosquitoes.

As climate change alters Earth's biomes, it is expected the transmission dynamics of mosquito-borne viruses will change. While the effects of temperature changes on mosquito-virus interactions and the spread of the pathogens have been elucidated over the last decade, the impact of relative humidity changes is still relatively unknown. To overcome this knowledge gap, we exposed Aedes aegypti females to various humidity conditions. We measured different components of vectorial capacity such as survival, blood-feeding rates, and changes in infection and dissemination of Zika virus. Survival decreased as the humidity level decreased, while infection rates increased as the humidity level decreased. Alternatively, blood feeding rates and disseminated infection rates peaked at the intermediate 50% relative humidity treatment but were the same in the 30% and 80% relative humidity treatments. These results provide empirical evidence that Ae. aegypti exposure to low humidity can enhance Zika virus infection in the mosquito, which has important implications in predicting how climate change will impact mosquito-borne viruses.IMPORTANCEViruses transmitted by mosquitoes to humans are a major public health burden and are expected to increase under climate change. While we know that temperature is an important driver of variation in arbovirus replication in the mosquito, very little is known about how other relevant climate variables such as humidity will influence the interaction between mosquitoes and the viruses they transmit. Given the variability in humidity across environments, and the predicted changes in humidity under climate change, it is imperative that we also study the impact that it has on mosquito infection and transmission of arboviruses.

Coaxial Electrohydrodynamic Bioprinting of Pre-vascularized Cell-laden Constructs for Tissue Engineering.

Recapitulating the vascular networks that maintain the delivery of nutrition, oxygen, and byproducts for the living cells within the three-dimensional (3D) tissue constructs is a challenging issue in the tissue-engineering area. Here, a novel coaxial electrohydrodynamic (EHD) bioprinting strategy is presented to fabricate thick pre-vascularized cell-laden constructs. The alginate and collagen/calcium chloride solution were utilized as the outer-layer and inner-layer bioink, respectively, in the coaxial printing nozzle to produce the core-sheath hydrogel filaments. The effect of process parameters (the feeding rate of alginate and collagen and the moving speed of the printing stage) on the size of core and sheath lines within the printed filaments was investigated. The core-sheath filaments were printed in the predefined pattern to fabricate lattice hydrogel with perfusable lumen structures. Endothelialized lumen structures were fabricated by culturing the core-sheath filaments with endothelial cells laden in the core collagen hydrogel. Multilayer core-sheath filaments were successfully printed into 3D porous hydrogel constructs with a thickness of more than 3 mm. Finally, 3D pre-vascularized cardiac constructs were successfully generated, indicating the efficacy of our strategy to engineer living tissues with complex vascular structures.

Short- and Long-Term Outcomes of Thoracoscopic and Open RepairFor Esophageal Atresia and Tracheoesophageal Fistula

BackgroundThe aim was to evaluate short- and long-term outcomes for thoracoscopic repair of EA/TEF and compare with open repair. MethodsPatients who underwent EA/TEF repair during 2000-2020 were evaluated retrospectively. Patients with delayed repair were excluded. Demographic, operative, outcome data was collected. Outcomes were compared using Wilcoxon-rank sum tests for continuous, Chi-squared/Fisher’s exact tests for categorical data. ResultsThere were 104 patients with primary repair, 49 (47.1%) underwent thoracoscopic repair per surgeon’s choice. Type C accounted for 101 (97.1%) of the cases. Gestational age and birth weight were higher in the thoracoscopy group (p=0.001). The rate of ≥3 VACTERL anomalies was higher in the OR group (p=0.016). Operative time, rate of anastomotic leak, time to first oral feeding were similar (p>0.05). Thoracoscopy group had decreased length of ventilation (p=0.026) and length of stay (p=0.029). The incidence of anastomotic stricture was higher in the thoracoscopy group (p=0.012). Recurrent TEF was one case in each group. Rates of tube feeding at discharge and in first year were similar (p>0.05), rate in third year was decreased (p=0.032) in the thoracoscopy group. Rates of anti-reflux medication in first and third years, and fundoplication rate were similar (p>0.05). ConclusionsMany of the short- and long-term outcomes are comparable between thoracoscopic and open repair of EA/TEF. Length of ventilation, length of stay are decreased in the thoracoscopy group. Anastomotic stricture is higher, the need for long-term tube feeding is lower after thoracoscopic repair. Although these results could be affected by selection bias, they are still promising for advancing thoracoscopic repair of EA/TEF safely and efficiently. Level of EvidenceLevel III

Host-feeding preferences and temperature shape the dynamics of West Nile virus: a mathematical model to predict the impacts of vector-host interactions and vector management on [formula omitted]

West Nile virus (WNV) is prevalent across the United States, but its transmission patterns and spatio-temporal intensity vary significantly, particularly in the Eastern United States. For instance, Chicago has long been a hotspot for WNV cases due to its high cumulative incidence of infection, with the number of cases varying considerably from year to year. The abilities of host species to maintain and disseminate WNV, along with eco-epidemiological factors that influence vector-host contact rates underlie WNV transmission potential. There is growing evidence that several vectors exhibit strong feeding preferences towards different host communities. In our research study, we construct a process based weather driven ordinary differential equation (ODE) model to understand the impact of one vector species (Culex pipiens), its preferred avian and non-preferred human hosts on the basic reproduction number (R0). In developing this WNV transmission model, we account for the feeding index, which is defined as the relative preference of the vectors for taking blood meals from a competent avian host versus a non-competent mammalian host. We also include continuous introduction of infected agents into the model during the simulations as the introduction of WNV is not a single event phenomenon. We derive an analytic form of R0 to predict the conditions under which there will be an outbreak of WNV and the relationship between the feeding index and the efficacy of adulticide is highly nonlinear. In our mechanistic model, we also demonstrate that adulticide treatments produced significant reductions in the Culex pipiens population. Sensitivity analysis demonstrates that feeding index and rate of introduction of infected agents are two important factors beside the efficacy of adulticide. We validate our model by comparing simulations to surveillance data collected for the Culex pipiens complex in Cook County, Illinois, USA. Our results reveal that the interaction between the feeding index and mosquito abatement strategy is intricate, especially considering the fluctuating temperature conditions. This induces heterogeneous transmission patterns that need to be incorporated when modelling multi-host, multi-vector transmission models.

Arc behavior and droplet transfer characteristics during oscillating laser-arc hybrid welding of 2024 Al alloy based on Zr-core-Al-shell wire

A novel zirconium (Zr)-core-aluminum (Al)-shell wire (ZCASW) combined with oscillating laser-arc hybrid welding (O-LAHW) process was employed for the welding of aluminum alloy 2024 (AA2024). The arc stability and characteristics, droplet transfer behavior and weld formation were systematically investigated. The results show that electrical signal waveform determines wire feeding rate, which affects the welding stability and weld quality. The increment in wire feeding rate increases magnetic field intensity and narrows arc cross-sectional area, which leads to arc contraction. The oscillating laser increases arc width and arc area, thereby expanding the conductive channel and greatly improving conductive ability of hybrid plasma, which promotes interactions between plasmas and helps to droplet transfer. Meanwhile, owing to the melting points differences between Zr wire and Al wire in ZCASW filler material, the melting rate of outer Al wire is larger than that of central Zr wire during welding, thereby resulting in two kinds of droplet transfer modes, and electromagnetic force and metal vapor reaction force strongly influence droplet transfer behavior. The oscillating laser improves the weld quality, which is deteriorated due to the appearance of spatters as wire feeding rate increases. When 1 m/min wire feeding rate is selected, a perfect formation is obtained. The current study offers insight into the formation mechanism of high-quality weld and welding stability during O-LAHW of AA2024 combined with ZCASW filler material.

Experimental research on sustainable drilling of Hastelloy X superalloy: Impact of hBN, GNP, LN2 and hybrid eco-friendly cooling/lubrication strategies

In this study, the effect of sustainable cooling and lubrication strategies such as MQL, LN2, LN2 +MQL, LN2 +hBN/GA, LN2 +GNP/GA, LN2 +hBN-GNP/GA on drilling nickel-based Hastelloy X alloy was examined. The environmental impacts and health risks of traditional petroleum-based cutting fluids used in drilling operations have led researchers to look for ecological alternatives. In this context, combinations of nanofluids enriched with minimum quantity lubrication (MQL), liquid nitrogen (LN2), and nanosized hBN and GNP particles have been tested. The experiments were carried out at cutting speeds of 20 and 30 m/min and feed rates of 0.04 and 0.06 mm/rev. Nanofluids characteristics i.e., viscosity, Ph, thermal conductivity and wettability, and drilling performance were evaluated with criteria such as cutting force, surface roughness, hole quality and tool wear. The results obtained showed that the hybrid methods combining LN2 and nanofluid-based MQL provided superior performance in terms of both cooling and lubrication, and the condition directly positively affected the processing outputs. This study contributes to the literature by revealing the potential of ecological cooling/lubrication methods in the sustainable production of difficult-to-machine materials such as Hastelloy X.

Processing correlations of laser direct energy deposited Inconel718 based on multi-field numerical simulation

Laser direct energy deposited (LDED) Inconel718 always have problems of non-uniform temperature distribution because of the complex flow of molten pool and layer-by-layer fabrication characterization which directly affected the microstructure and mechanical properties of materials. In this work, Inconel718 revealed a refined grains and a weave structure exhibiting excellent mechanical properties which were superior to those of the conventional casting process were successfully fabricated by adopt a high-precision and intelligent coaxial powder feeding system during the LDED processing. Moreover, based on multi-field numerical simulation method, a two-phase flow model and a transient thermal mechanical deformation model were established to simulate the LDED processing, while takes into account the evaporated mass loss of the inconel718 alloy. The morphology prediction of laser directed energy deposition by multi-physics numerical simulation, the relationship among the laser process parameters, i.e., the laser power, scanning speed and the amount of powder feeding, the temperature filed and the microstructure and mechanical properties of Inconel718 alloy during LDED were investigated and established. The simulated results consistent well with the experimental results. Results shown that the relative density of sample was sensitive to the laser power, the precision and stability of the powder feeding rate. With increasing laser power, the grain size of Inconel718 is refined, and the microhardness and tensile properties of the materials increased. The optimized LDED processing parameters were determined. Evaluating the mechanical properties of the materials LDEDed at a laser power of 600W and a scanning speed of 8.5mms-1 exhibited a high tensile strength of 944±5MPa and a good elongation of 29±0.5%. This work suggests that the processing parameters can be optimized to prepare densified materials with excellent mechanical properties.

Effect of Grinding Conditions on Clinker Grinding Efficiency: Ball Size, Mill Rotation Speed, and Feed Rate

The production of cement, an essential material in civil engineering, requires a substantial energy input, with a significant portion of this energy consumed during the grinding stage. This study addresses the gap in the literature concerning the collective impact of key parameters, including ball size, feed rate, and mill speed, on grinding efficiency. Nine spherical balls, ranging from 15–65 mm, were utilized in six distinct distributions, alongside varying feed rates and mill speeds. ANOVA, Taguchi, and regression analyses were employed to explore their influence on grinding efficiency and cement properties. The findings revealed that ball size variation significantly affects grinding performance, with smaller diameter balls yielding higher efficiency due to increased abrasion and fine formation. Conversely, elevating mill speed generally diminishes grinding efficiency, particularly at speeds approaching 90% of the critical speed, impacting ball shoulder and foot angles. Moreover, increasing the feed rate affects the grinding performance differently based on ball distribution, with finer distributions experiencing adverse effects. Signal-to-noise ratios facilitated determining the optimal control factor levels to minimize energy consumption. Quadratic regression models exhibited strong predictive capabilities for energy consumption in grinding. Ultimately, the optimal grinding performance was achieved with Bond-type ball distribution No. 6, considering ball size, mill speed, and feed-rate interactions, albeit with considerations regarding grinding time and energy efficiency.