Low Feed Rate Research Articles

Research on the Grinding Process of Superhard Particles in the Fluidized Bed Opposed Jet Mill Based on the CFD-DEM Methodology

The process of superhard particle breakage in the grinding zone of the fluidized bed opposed jet mill is investigated using the CFD-DEM (computational fluid dynamics-discrete element method) coupling method with the Tavares UFRJ Breakage Model in the present study. The effects of structural and operational parameters, such as target plate structure, nozzle position, air inlet velocity, and feed rate, on the equipment stress distribution, airflow velocity, pressure field, particle velocity, and cumulative particle size distribution are thoroughly studied to determine the optimal structural and operational parameters. Experimental validation is conducted, including scanning electron microscope (SEM) observation of particle morphology and analysis of particle size distribution of ground product particles. The simulation results indicate that the wear rate of the structure without a target plate is lower than that of the structure with a target plate in the grinding central zone. Therefore, the structure without a target plate is chosen for further investigation. The cumulative particle size distribution after grinding is influenced by nozzle position, air inlet velocity, and feed rate. The particle D50 is positively correlated with nozzle spacing and feed rate, while it is negatively correlated with air inlet velocity. The optimal grinding effect is achieved when the distance between the nozzle and the center of the grinding zone ranges from 52.5 mm to 72.55 mm, the air inlet velocity is 950 m/s, and the feed rate is 10.5 g/s. Through experimental investigation, it has been observed that when the feed rate is 10 g/s, the particle size distribution becomes more uniform. Furthermore, consistent trends in the cumulative particle size distribution in the experiment and simulation results can be found, which validates the present numerical model. It was observed that particles at low feed rates retain certain angular edges, while particle roundness increases at high feed rates.

Ramie Fiber Woven Composite: The Effect of Number of Layers of Woven Fibers on the Thrust Force in the Drilling Process

Composite material is a combination of two or more materials to obtain better properties and capabilities of the constituent materials. Applications for the use of composites can now be found in industrial equipment to household appliances. To produce these products required machining process. The aim of the study was to determine the effect of the number of layers of woven fiber and the diameter of the drill bit on the thrust of the ramie woven fiber composite in the machining process. The research method was based on ASTM D 5766/D 5766M-02 (Standard Test Method for Tensile Strength Open Hole Laminated Polymer Matrix Composites), the method of making composite material specimens using the hand lay-up method, and the drilling process was carried out with various machining parameters such as composite thickness with variations of 3 layers, 4 layers, 5 layers, and without layers (0 layers). The maximum thrust value obtained was 153.54 ± 3.3 N, with 5 layers of hemp fiber reinforcement, the highest feed rate was 0.15 mm/rev, and the lowest spindle speed was 88 rpm, while the minimum thrust value was 29.52. ± 3.12 N with 0 layers of ramie fiber reinforcement, and the lowest feed rate is 0.05 mm/rev with the highest spindle speed of 1500 rpm.

Investigation of the effect of ultrasonic vibration on the performance of the friction drilling by FEM simulation

The friction drilling process is very important in various industries such as automotive, aerospace, and oil and gas industries. Therefore, they have always sought to find methods to improve this process. One of these methods is to optimize the application of ultrasonic vibrations in the process, and limited research has been done in this regard. The current research aims to investigate the effect of ultrasonic vibrations simultaneously with the parameters of drilling on the friction drilling process to optimize this process with the help of finite element simulation. Due to the nature of the complex transformations of the process, a Coupled Eulerian–Lagrangian model of the process was first created in the Abaqus software. Then, the process simulation was carried out in the presence and absence of ultrasonic vibrations. Rotational speed, feed rate, and amplitude of vibrations are the influencing parameters, and sheet temperature and axial force, and torque applied to the tool are the parameters investigated in this research. The results show that higher rotation speed and lower feed rate lead to a reduction of axial force and torque. Also, the application of ultrasonic vibration reduces up to 50.48% the axial force and up to 46.67% torque, and this reduction is improved by increasing the range of vibrations. The optimal mode was selected After analyzing 12 different modes based on the lowest amount of axial force and torque on the pin. It was found that the ideal mode occurs at a feed rate of 4.23 m/s and a rotation speed of 3000 rpm, with a 20-µm range. These findings and optimizing drilling parameters bring new horizons in material bonding techniques in various industries.

تطوير وتقييم وحدة الفحم الحيوي ذات التدفق المستمر للكتلة الحيوية لقشور الأرز

This study aims to develop and evaluate a locally manufactured carbonization unit with a screw conveyor. Various carbonization temperatures (350, 400, and 450°C) and feeding rates (50, 75, and 100 kg/h) were examined to determine optimal conditions for producing biochar from rice husk (RH). The results revealed that increasing the pyrolysis temperature from 350 to 450°C decreased RH biochar yield, while increasing the feeding rate from 50 to 100 kg/h increased it. Ash content was 22.4% at 350°C for 100 kg/h, and the maximum value was 31.4% at 450°C and 50 kg/h. The BET surface area of the biochar increased from 105.71 to 312.32 m2/g at 450°C, with slight non-significant changes at a 100 kg/h feed rate. RH biochar showed decreasing H and O values with higher temperatures and lower feed rates. RH biochar at 450°C and 50 kg/h showed increased macro porosity and surface area, rendering it suitable for agricultural application as a soil amendment.

Wire-arc spray directed energy deposition: Correlation of chamber kits refurbishing and particle defects reduction in Ta/TaN thin-film physical deposition processes

Physical Vapor Deposition (PVD) of Tantalum/Tantalum Nitride (Ta/TaN) liner and barrier plays a crucial role in the copper-interconnecting part of semiconductor manufacturing, and this is used for the 130 nm–5nm technology node and beyond. This study focuses on the surface preparation and characterization of wire-arc spray directed energy deposition (DED) coating in the refurbishment process of PVD chamber kits. Spray coating adhesion strength is enhanced due to the pretreatment of the substrate with grit blasting, which creates a suitable surface texture, and the replacement of aluminum alloy as wire-arc spray DED coating material from pure aluminum (99.8%). However, it was experimentally found that using high adhesion strength coating chamber kits increases the probability of out-of-control (OOC) occurrences in the mid-stage of the kit lifetime, and the fundamental reasons may be attributed to the spiky surface morphology of wire-arc spray DED coating layers. Finite element analysis simulates stress distribution and identifies stress concentration regions within the multilayer Ta/TaN thin film using two surface morphologies with significantly different curvature radii of spray coatings. Differences in wire-arc spray DED processing parameters include a slower travel speed, a longer spray time, and a lower feed rate. It is numerically simulated and experimentally observed that coating surface morphology dramatically affects thin film delamination, which is the primary cause of particle defects. This study emphasizes the potential mechanisms for forming particle defects, improved uniformity in spray coatings, and increased surface curvature radius to minimize stress concentration.

PREDICTION OF TORQUE IN DRILLING WOVEN JUTE FABRIC REINFORCED EPOXY COMPOSITES USING THE ADAPTIVE NETWORK-BASED FUZZY INFERENCE SYSTEM AND RESPONSE SURFACE METHODOLOGY

Jute fiber reinforced epoxy (JREp) composites were prepared by the compression moulding technique by varying the fiber content (0, 20, 30 and 40 wt%). Fabricated JREp composites were subjected to a drilling study to observe the impact of factors such as spindle speed (rpm), feed rate (mm/min) and fiber content (wt%) on the output response – torque. A set of experiments were designed and conducted as per Taguchi’s Design of Experiment. The obtained torque results were found in the range from 14.84 to 32.28 N-m. The minimum value of torque was achieved for the composite drilled using an HSS twist drill (90°-point angle) at a high spindle speed (3000 rpm), with low feed rate (25 mm/min) on low fiber loaded JREp composite (20JREp). ANOVA analysis showed that the developed regression model was fairly significant and torque was mainly influenced by the feed rate. Mathematical models were developed for drilling JREp composites using response surface methodology (RSM) and adaptive neuro fuzzy inference system (ANFIS), and compared for their efficacy. The coefficient of determination (R2) values for RSM and ANFIS were 0.9778 and 0.9982, respectively, which conveys that both models were beneficial to predict the torque. The average checking error percentage (0.0000222) was obtained for the ANFIS model trained using ‘gbellmf’ membership function with 100 epochs. FESEM images of the drilled surface were captured to analyse the mode of failure endured by the JREp composites.

Influence of cutting tool design on ultrasonic-assisted drilling of fiber metal laminates

Ultrasonic-assisted drilling (UAD) is a machining process that is known to improve the hole quality and reduce cutting forces. Previous studies focused on optimizing cutting parameters to improve the hole quality in conventional drilling (CD) and UAD, as well as to finding the optimum vibration parameters (frequency and amplitude) that will increase the effectiveness of the UAD process. However, the influence of cutting tool type during UAD has been largely overlooked. This research aims to address this gap by analyzing the effect of cutting tool type during UAD on the cutting forces and hole quality in GLARE (Glass Laminate Aluminum-Reinforced Epoxy) laminates. Four types of drills, namely, twist drill (TD), double cone drill (DCD), a step drill type 1 (SD1), and step drill type 2 (SD2) with different step length, were selected for this study. The lowest thrust force (47.04 N) and torque (0.079 Nm) were achieved using twist drill, while DCD, SD1, and SD2 exhibited higher thrust forces (12.81%, 20.69%, 41.3%) and torques (94%, 92%, 91%), respectively. In addition, TD produced high-quality holes with lowest surface roughness (Ra 1.66 μm, Rz 10.58 μm) and minimal burr formation (entry burr height 152.3 μm, exit burr height 69.22 μm). Conversely, DCD, SD1, and SD2 showed higher surface roughness Ra (23%, 16%, 24%) and Rz (16%, 37%, 29%), respectively, compared to the TD. Holes drilled using SD1 and SD2 generally had smaller burr height. Overall, UAD system effectively reduced cutting forces at low spindle speed and feed rate. To achieve higher drilling quality, specifically to reduce the surface roughness and exit burr height, a medium spindle speed of 3000 rpm, a feed rate of 225 mm/min is recommended. Drilling at higher cutting parameters using UAD resulted in a decline in hole quality, except for entry burr height.

Liquid Atomization in Rotary Slinger Injectors: Role of Liquid Delivery Manifold

In rotary injectors, the method of liquid delivery can play an important role in the quality of liquid atomization. In slingers, which are employed in small gas turbine engines, the liquid delivery manifold is a key component in the atomizer assembly, which not only delivers the liquid to the atomizer but also acts as a fuel metering device. In the present work, we investigate the liquid atomization in a slinger atomizer with a focus on the effect of the number of liquid delivery ports and port size in the static manifold. Different optical diagnostics are employed to visualize primary liquid breakup and measure droplet size. The results showed that, at a low liquid feed rate, a smaller number of injection ports or port size promotes supercritical breakup (annular liquid exit and disintegration) at an orifice exit such that the breakup length and droplet size are smaller. Also, hole-to-hole variation in the liquid breakup mode is noticed, which refers to different breakup mechanisms in adjacent slinger orifices. On the other hand, Coriolis-induced film breakup is promoted when the liquid feed rate increases. The present study highlights that the design of the delivery manifold can potentially influence spray performance in slinger injectors.

Migration mortality in birds

Bird migration is one of the greatest wildlife spectacles, producing massive global changes in the distributions of birds twice each year. To understand the evolution of this phenomenon, it is important to know the costs of these journeys in terms of the mortality they impose. The use of mark/re‐sighting and tracking studies has now made it possible, for some bird species, to separate mortality during migration from mortality during stationary periods. This paper aims to assess this information, based mainly on 31 published studies, most of which concern long‐distance migrations of passerines, large waterfowl and raptors. Most of these studies revealed that mortality rates were greater during migration than at other times – in some species more than 20 times greater. Overall, on the basis of median values, mortality per unit time during autumn journeys was about 3.0 times greater than mortality during stationary periods, during spring journeys about 6.3 times greater, and during autumn and spring journeys combined 4.4 times greater. The greater overall mortality on spring journeys was largely associated with more adverse wind conditions in spring than in autumn. High mortality rates were especially evident in birds crossing large ecological barriers, such as the Sahara Desert or the Gulf of Mexico, and were higher in that part of their journey than when crossing more benign terrain. There was no increase in mortality during migration in the adults of some long‐lived species with high annual survival and predominantly overland journeys; for these birds, much larger samples of year‐round tracked individuals will be needed to reveal any seasonal variations in mortality. Within certain species, birds that travelled long distances experienced greater mortality over the journey than those that travelled short distances, but in other species no such relationship was found. In species in which adults and juveniles were followed over the same journey, juveniles showed greater mortality. To judge from other studies, this difference could be attributed to the inexperience of juveniles, their lower feeding rates and flight efficiency, greater vulnerability to hazards such as weather and predation, or more frequent navigational errors. Broadly speaking, the risks of migration vary with features of the birds themselves, with the terrain to be crossed and with weather at the time. It may be assumed that migration persists in the long term because the costs (in terms of associated mortality) are more than offset by the benefits of breeding and wintering in different areas (in terms of improved overall survival and breeding success). To provide further understanding of migration mortality, suggestions are made on the types of studies required and on how they could best be conducted.

Statistical analysis on the influence of drilling parameters on GFRP-PUF sandwich composite structure

ABSTRACT Composite sandwich structures are finding increasing applications in various fields and industries such as aerospace, automotive, acoustics and so on due to their high strength-to-weight ratio and better insulation properties. To facilitate the assembly of these structures, fasteners are employed, and drilling is one of the secondary manufacturing processes that can produce cost-effective and good-quality holes for fastening. This paper deals with characterising the quality of the drilled holes in glass fibre-reinforced plastic-polyurethane foam sandwich structures. This experiment has been designed using Taguchi’s L9 orthogonal array. The results indicate that smaller drill diameter and lower feed rate produce delamination of lower magnitude at entry and exit while higher spindle speeds followed by lower feed rates produced holes with minimal deviation from the ideal form.

Burr constitution analysis in ultrasonic-assisted drilling of CFRP/nano-graphene via experimental and data-driven methodologies

In this study, a comprehensive investigation was undertaken to analyze the impact of various factors on thrust force and burr damage in carbon fiber reinforced polymer laminates during drilling operations. The factors examined included the incorporation of nano-graphene, the application of ultrasonic vibration, the type of cutting tool, and the feed rate. Statistical and machine learning techniques were employed to analyze the data, and image processing was utilized to illustrate the extent of burr damage surrounding the drilled holes. The developed model exhibited satisfactory prediction accuracy with minimal error rates. Statistical analysis revealed that the feed rate exerted the greatest influence on thrust force and facilitated the burr generation. Likewise, the addition of nano-graphene resulted in an increased thrust force due to improved rupture limits, consequently leading to cleaner holes with minimal burr damage. Furthermore, the implementation of ultrasonic vibration and the use of high-cobalt cutting tools were found to enhance drilling performance by reducing thrust force and minimizing the burr formation. The best hole quality was achieved at the lowest feed rate, in combination with a cutting tool containing 8% cobalt and the utilization of ultrasonic vibration.

Development of a Protocol for the Direct Breastfeeding of Premature Infants in Neonatal Intensive Care Units.

This study aimed to develop a direct breastfeeding protocol for premature infants admitted to neonatal intensive care units (NICUs) and investigate its efficacy. Direct breastfeeding increases the amount and duration of breastfeeding. However, NICUs have low direct feeding rates owing to medical staff anxiety, lack of knowledge and experience, and fear of overwork. Accordingly, this study developed a protocol for direct breastfeeding in the NICU and evaluated its effect. The protocol was developed through a literature review, expert validation, and preliminary investigation. Its application effects were identified using a nonexperimental, evidence-based research design targeting premature infants, their mothers, and NICU nurses. The protocol comprised 5 areas and 23 items. Application of the protocol resulted in continuous weight gain of the infants and increased self-efficacy in the mothers' direct breastfeeding ( t = 3.219, P = .004). Significant increases were noted in NICU nurses' direct breastfeeding activities ( t = 3.93, P < .001), breastfeeding rates in the NICU ( P = .037), and direct breastfeeding rates ( P = .007). Results underscore the value of an evidence-based protocol for improving breastfeeding rates in premature infants. This study highlights the need for continuous nursing education on protocol applications and human resource support.

Pemesinan Paduan Ti-6Al-4V ELI

Titanium alloy material Ti-6Al-4V ELI (Extra Low Interstitial) is a type of alloy that has very similar properties to Ti-6Al-4V (Grade 5) alloy, which is the most widely used material, but only differs in terms of properties. his tenacity. Ti-6Al-4V ELI has higher ductility and better fracture toughness. In addition, this material also has a good ability to work at high temperatures without losing its main properties. The main properties of this material are corrosion toughness at high temperatures and excellent weight to strength ratio. Referring to these advantages, the alloy material of the Ti-6Al-4V ELI type has been developed in many fields including the field of planting materials in the medical field, the aircraft industry, applications in the field of military weapons, the manufacture of racing vehicle components and also high pressure vessels for storing materials. low-temperature (cryogenic) liquid nitrogen [16].. During the machining process of titanium alloy, many things become obstacles because this material is a material that is difficult to machine. This is because the titanium alloy has high hardness, there is often a reaction between the cutting tool and the workpiece material during the cutting process, and there is an accumulation of high temperatures in the cutting area. Factors cutting speed and feed rate are the two dominant factors on the formation of cutting tool wear, both wear on the face or crater side. Damage to the cutting tool is also followed by damage to the surface of the workpiece being machined or the surface quality of the workpiece. The dominant wear that occurs in the rib face area is wear due to adhesion, notch wear, while wear in the crater area is diffusion that occurs during the machining process. Meanwhile, the cutting temperature has a direct impact on the surface quality of the workpiece being machined. The factor of high cutting speed with low feed rate is a combination of factors that provide good cutting force. Meanwhile, insert type cutting tools that have a hard coating, such as TiN, TiAlN and TiCrN play a significant role in the formation of tool wear. Likewise, hard coated tools provide better performance compared to uncoated insert tools. Machining with the Minimum Quantity Lubrication (MQL) method gives better results compared to dry machining and machining using flooded cooling.Keywords: machining, Ti-6Al-4V ELI, cutting tool, materials.

Modeling and surface morphological study in drilling of Al 2024 alloy

With concern to profuse usability of drilling operations in various industries, almost 1/3rd of the all the machining operations, the main focus is to obtain a proper quality of hole in less time at optimum cost. Aluminium alloy 2024 (Al 2024) is largely applied in various industries specially, aircraft, automotive, marine etc. because of its outstanding union towards strength, corrosion resistance, and weldability. Cutting time, cutting temperature and surface morphological investigation during drilling is very much necessary for obtaining a quality hole that has not been substantially researched so much. Therefore, a proper and thorough study of these responses is quite important regarding the hole quality. With this view, in this work, drilling of Al 2024 alloy is performed with three process parameters (input) viz. spindle speed (v), feed rate (f) and drill bit diameter (d) and performance parameters (output) as cutting time (s), cutting temperature (°C) and surface roughness (μm). Three different drill bit diameters of high speed steel (HSS) of size viz. 6 mm, 8 mm and 10 mm are used in drilling. Each process parameter has three levels. The surface morphological study is also conducted to know the depth of hole morphology details after drilling. To make the drilling operation environment friendly, it is performed in dry atmosphere. Using full factorial design, total 27 experiments are conducted. The experimental results showed that high spindle speed along with high feed rate decreases the cutting time, whereas it increases the cutting temperature. For better surface finish medium spindle speed along with low feed rate is recommended. From analysis of variance (ANOVA), all the three models developed for cutting time, cutting temperature and surface roughness are found statistically significant. Spindle speed and feed are the influential parameters to cutting time, cutting temperature and surface roughness. A mathematical model is developed using response surface methodology (RSM) to predict the responses cutting time, cutting temperature and surface roughness with better accuracy. The coefficient of determination (R2) for cutting time, cutting temperature and surface roughness is found as 96.65%, 95.88% and 93.65% respectively, which indicated that the developed models could be used for prediction with better accuracy. The morphological study shows that scratches, trenches, abrasive wear are visible on the hole surface. At high spindle speed surface grain refinement is observed more which causes a better surface finish.

Ductile–brittle transition and ductile-regime removal mechanisms in micro- and nanoscale machining of ZnS crystals

The ductile–brittle transition and ductile-regime removal mechanisms of ZnS crystal, a typical soft-brittle infrared optical material, have remained unclear at the micro- and nanoscale. In this context, this study modeled the energies consumed in two machining modes, namely ductile deformation and brittle fracture, during the ultraprecision cutting of ZnS crystal. Subsequently, based on the transition point of the energy mode, the critical undeformed chip thickness (CUCT) for the ductile–brittle transition of the material was determined. Additionally, the effect of tool parameters on CUCT was quantitatively analyzed, and the correctness of the model was verified by scratch experiments. Moreover, the cutting parameters that affect the maximum undeformed chip thickness (MUCT) were analyzed. By comparing the MUCT and CUCT, the cutting conditions to realize ductile-regime machining were predicted. The correctness of the ductile-regime machining conditions was also verified through surface quality characterization after face-cutting experiments. The MUCT can be controlled to be less than the CUCT by using a cutting tool with a sufficiently large tool rake angle, a nose radius and a reduced feed rate, thus realizing the ductile-regime removal of the material. The surface morphology, chip morphology, and surface roughness of machined ZnS crystal confirmed the validity of the model. Using a diamond cutting tool with a large cutting edge angle (–25°) and nose radius (1.2 mm) as well as a low feed rate (0.5 μm/rev) and depth of cut (3 μm), the generation of cracks and pits was effectively inhibited, resulting in a smooth surface with a surface roughness of 1.60 nm. Overall, the findings of this study provide important insights into the superfinishing of soft–brittle materials such as ZnS crystal.

Artificial neural network in the prediction of surface roughness: A comparative study

Surface roughness is a key parameter to consider in the machining of aluminum alloy. It is rendered as one of the important determinants of the performance of mechanical instruments or components. Owing to its excellent mechanical properties, and ease of machinability, Aluminum 6061 (Al6061) is rendered a popular choice in many industries. Achieving a desired surface finish is crucial for the performance and longevity of machined components. This study aimed to compare the predictive performance of the artificial neural network (ANN) model versus the response surface methodology (RSM) in the prediction of surface roughness in the turning process of Al6061. ANN performed better than RSM in the prediction of surface roughness (A20 index 0.93 and 0.86 for ANN and RSM models respectively). MAPE and sMAPE were also found to be lower in the ANN model compared with the RSM model (8.06 versus 9.69, and 0.039 versus 0.047 respectively) indicating that the ANN model had a better predictive performance compared with the RSM model. Both ANN and RSM models showed that cutting speed and feed rate were the most important determinants of surface roughness in the turning process of Al6061 in other words to achieve a smoother surface during the turning process of Al6061 high cutting speed and low feed rate should be used. The findings of this study reflect the potential utility of ANN in the prediction and subsequently optimizing cutting parameters to achieve a smoother surface.

Solidification and corrosion mechanisms: A novel metallurgical bonding Ti-6Al-4V coating on mild steel

The FeTi brittle phase is a key factor affecting the performance of titanium alloy coatings. Reducing the FeTi brittle phase in the texture is one of the effective ways to prepare titanium alloy coatings with excellent performance. This work uses laser cladding technology to prepare Ti-6Al-4V coatings with excellent mechanical properties and corrosion resistance on the surface of mild steel. The relationship between the cladding process, microstructures, and performances of Ti-6Al-4V coating has been revealed. Low laser power and high powder feeding rate are beneficial for the formation of a more complete microstructure of Ti-6Al-4V coating, which can significantly reduce keyholes and microcracks at the FeTi interface zone. The shear strength of the 1000 W-1.5 r/min specimen is the highest (88.8 ± 7.1 MPa), and the high-angle grain boundaries (HAGBs) of Ti are used as the blocking site for cracks to prevent the propagation. The 1000 W-1.5 r/min specimen has a corrected Ecorr (−0.3145 V vs. Ag/AgCl) and smaller Icorr (0.3182 μA·cm−2), exhibiting excellent corrosion resistance. When the Ti-6Al-4V coating is intact, the TiO2 passivation film formed on the surface can effectively prevent the corrosion process from progressing. When there are through cracks caused by residual stress in the Ti-6Al-4V coating, the electrolyte solution can reach the FeTi interface zone through microcracks to corrode the Fe in the substrate, leading to coating failure. The research results provide valuable reference for the preparation of titanium alloy coatings with excellent performance on the surface of mild steel.

AISI D2 Soğuk İş Çeliğinin Delinmesinde Deneysel ve Sonlu Elemanlar Analizi Yoluyla Delik Kalitelerinin İyileştirilmesi ve İşleme Parametrelerinin Optimizasyonu

Increasing supply chain problems in recent years have a negative impact on costs in many areas. Due to the global crisis, raw material prices increased and the manufacturing sector was seriously affected. Production planning and material saving should be done correctly in order to minimize the losses in the manufacturing sector. The most efficient way to reduce production costs is to use suitable cutting tools and choose the right machining parameters. In this study, the drilling of AISI D2 steel, which is widely used in the mold industry, was examined and optimum machining parameters were determined. TiN coated drills are used for drilling operations. The effects of machining parameters on Surface Roughness (Ra) and Thrust Force (Fz) were investigated by Taguchi and ANOVA. Surface roughness and thrust force values during drilling were measured. Thrust force values were also analyzed numerically by the Finite Element (FE) method. Ra and Fz were also low at low feed rate and low cutting speeds. While the feed rate affected Ra the most, the Fz affected the cutting speed the most. The lowest Ra and Fz were at 30 mm/min feed rate and 25 m/min cutting speed. According to the ANOVA, it was determined that the machining parameters were effective on both Ra and Fz. R2 values for Ra and Fz are calculated over 95%.

Optimization of product characteristics of porous carbon agglomerates using a design of experiments in fluidized bed agglomeration

Spraying parameters during particle agglomeration processes can affect the agglomeration kinetics and particle growth. This study was conducted to better understand the influence of the spraying parameters in a fluidized bed wet agglomeration process, and the influence on the stability characteristics of carbon tablets. A formulation based on fine carbon and peroxide powder, as well as carboxymethyl cellulose as a binder, was used to produce agglomerates in a first production step. Thereafter in a second production step carbon tablets with a high porosity were molded for the customer goods industry. The optimization of the compressive strength of these carbon tablets was the goal of the trials. Carbon agglomerates were produced with a laboratory scale granulator called “ProCell” and were compressed with a five-cavity mechanical press. The screening of the agglomeration process parameters and their influence on the agglomerates quality, as well as the performance characteristics of the carbon tablets, were investigated using a multilevel factorial design. The experimental runs were done by varying atomized air pressure and feed rate of the fluid. This was determined by the design model. The findings of the statistical trials showed that low atomized air pressure and a low feed rate lead to a higher tablet compressive strength.

ОПРЕДЕЛЕНИЕ ДИАПАЗОНА ЭФФЕКТИВНЫХ РЕЖИМОВ ШЛИФОВАНИЯ И МАТЕРИАЛОВ ШЛИФОВАЛЬНОГО КРУГА ДЛЯ ОБРАБОТКИ СТАЛИ 95Х18

The development of a mathematical model for the grinding treatment of steel 95X18 with recommended grinding wheels, namely a wheel of silicon carbide green, el’bor wheel, diamond wheel is discussed. When studying the influence of grinding modes and grinding wheel materials during the processing of 95X18 steel on the roughness of the treated surface, a multifactorial experiment was carried out. The roughness of the treated surface was evaluated according to the Ra parameter, using a portable profilometer of the MarSurf PS1 model. Based on the data obtained, it is possible to choose the optimal cutting mode based on the required roughness of the treated surface. It has been established that in order to achieve a stable quality of the treated surface Ra 0.63, it is necessary to use a diamond wheel at cutting speeds from 10 to 25 m / s and low feed rates. The obtained regression equations showed that an increase in the cutting speed or a decrease in the feed led to a decrease in the roughness of the treated surfaces. The main provisions of the metal cutting technology and the mechanical engineering technology were used.