Increase In Feed Rate Research Articles

Performances of cryo-treated and untreated cutting tools in machining of AA7075 aerospace aluminium alloy

The quality of drilled holes in aluminium alloys used in the aerospace industry is vital to ensure high-precision structural integrity. For this reason, optimum selection of cost-effective cutting tools and cutting parameters is of great importance. Nowadays, due to their high cost and supply difficulties, there is a great interest in improving the performance of traditional HSS cutting tools as an alternative to ceramic, carbide and coated cutting tools. HSS cutting tools are widely used in different industries due to their cost-effectiveness and suitability to improve tool performance. In this research, the performances of cryo-treated (DC&T) and untreated (UT) HSS cutting tools used in dry machining of AA7075 aluminium alloys were investigated. Thanks to DC&T processes applied to HSS cutting tool, improvements have occurred in its microstructure. The hardness value of HSS cutting tool increased by 6.89% with the effect of DC&T processes applied. When the highest and lowest Ra values obtained using DC&T and UT HSS cutting tools were compared, it was seen that DC&T HSS cutting tool performed better by 11.05% and 25.91%, respectively. It has been determined that the hole surface quality of the aluminium workpiece machined with DC&T and UT HSS drills is negatively affected by the increase in spindle speed and feed rate. The highest S/N ratios calculated according to Ra values of holes drilled on aluminium workpieces using DC&T and UT HSS cutting tools were found to be -7.12 dB (2.27 μm) and -9.62 dB (3.03 μm), respectively. In the ANOVA analysis, it was determined that the most effective parameters on Ra values were spindle speed (70.62%), tools (18.19%) and feed rate (9.98%), respectively. In the regression analysis, R2 value for Ra values was calculated as 98.30%. High R2 value result shows that the model developed is quite successful in estimating Ra values.

Fixed-Diamond Abrasive Wire-Saw Cutting Force Modeling Based on Changes in Contact Arc Lengths.

Monocrystalline silicon is widely used in the semiconductor market, but its hard and brittle physical properties make processing difficult. Fixed-diamond abrasive wire-saw (FAW) cutting is currently the most commonly used cutting method for hard and brittle materials due to advantages such as narrow cutting seams, low pollution, low cutting force and simple cutting process. During the process of cutting a wafer, the contact between the part and the wire is curved, and the arc length changes during the cutting process. This paper establishes a model of contact arc length by analyzing the cutting system. At the same time, a model of the random distribution of abrasive particles is established to solve the cutting force during the cutting process, using iterative algorithms to calculate cutting forces and chip surface saw marks. The error between the experiment and simulation of the average cutting force in the stable stage is less than 6%, and the errors with respect to the central angle and curvature of the saw arc on the wafer surface are less than 5% between the experiment and simulation. The relationship between the bow angle, contact arc length and cutting parameters is studied using simulations. The results show that the variation trend of the bow angle and contact arc length is consistent, increasing with an increase in the part feed rate and decreasing with an increase in the wire velocity.

Investigation and Statistical Analysis for Optimizing Surface Roughness, Cutting Forces, Temperature, and Productivity in Turning Grey Cast Iron

This paper investigated the influence of cutting parameters, including feed rate, cutting speed, tool nose radius, and wet or dry cutting conditions, on the resultant force, cutting edge/workpiece temperature, and surface roughness when turning grey cast iron. Results showed that increasing the feed rate increased the resultant force, cutting temperature, and surface roughness. At the same time, increasing the cutting speed and nose radius increased the cutting temperature, which in turn reduced the resultant force. For practical applications, basic mathematical calculations based on the sole effect of each parameter on the output of the experiments were used to estimate the extent of percentage increase in cutting temperature due to increasing feed rate, cutting speed, and nose radius. Similarly, the same approach was used to estimate the effect of increasing feed rate, cutting speed, and nose radius on average surface roughness. Results showed that increasing the feed rate increases the cutting temperature by 5 to 11% depending on the nose radius and cutting speed. On the other hand, increasing the cutting speed was found to have limited effect on cutting temperature with small nose radius whereas this effect increases with increasing the nose radius reaching about 11%. Increasing the nose radius also increases the cutting temperature, depending mainly on cutting speed, reaching a maximum of 21% at higher cutting speeds. Results also showed that increasing the feed rate increased the average surface roughness considerably to about 120% at high cutting speeds and a large nose radius. On the other hand, increasing the cutting speed and nose radius reduced the surface roughness (i.e., improved surface quality) by a maximum of 29 and 23%, respectively. In order to study the combined effects of the cutting parameters on the three responses, namely, the resultant cutting force, cutting temperature, and surface roughness, full factorial design and ANOVA were used, where it was found to be in good agreement with mathematical calculations. Additionally, the desirability function optimization tool was used to minimize the measured responses whilst maximizing the material removal rate.

The Effect of Overnutrition on Mediated Collagen in Drosophila Melanogaster Physiology

Obesity affects approximately 13% of the adult population, resulting in excessive fat cell deposition and metabolic dysfunction. Collagen, a protein that supports skin regeneration, muscle building, and pain relief, is studied in Drosophila melanogaster under different diet conditions. This experiment aims to test whether overnutrition affects physiology and collagen due to any anatomical changes in Drosophila Melanogaster, more commonly known as fruit flies. The research conducted over several weeks utilizes two diets: an obesity-inducing diet containing excessive glucose and coconut oil and a traditional diet of blue food medium, yeast, and water. The study groups include a wild-type, collagen-mutated, and obesity-mutated group, with multiple assays measuring how the obesity-inducing diet affects each population and their collagen levels. The results reveal that the obese group experienced higher food consumption levels but had lower locomotive ability than the other test groups. Hydroxyproline, the building amino acid for collagen, and collagen levels were higher in the obesity mutant than in the wild-type and collagen mutated group. The study shows that anatomical changes in organisms are influenced by both diet and movement. The obesity group, on an obesity-inducing diet, experienced decreased movement related to increased food intake and decreased neural activity. The high-fat and high-sugar diet suppressed neuronal autophagy, created inaccurate hunger and satiety perceptions, and increased collagen deposition. Anatomical changes were observed in collagen-heavy tissue areas, whereas decreased neural activity and increased feeding rates were behavioral changes. The study emphasized the importance of a healthy diet and exercise in promoting overall health.

Effect of rotational speed and feed rate on microstructure and mechanical properties of 6061 aluminum alloy manufactured by additive friction stir deposition

Additive friction stir deposition (AFSD) is attractive for its ability to create freeform and fully dense structures without melting and solidification. Hence, additive friction stir deposition is an alternative to fusion-based additive manufacturing technology. In this study, the influence of the AFSD parameter (i.e., rotational speed and feed rate) on the mechanical properties and microstructure of 6061 aluminum alloy is investigated. The as-deposited 6061 aluminum alloy exhibits a relatively homogeneous microstructure with extensive equiaxed grains. Compared to the feedstock material, the ultimate tensile strength of the as-deposited 6061 aluminum alloy decreased to 65% from 320 to 210 MPa. The results of electron backscatter diffraction indicate that continuous dynamic recrystallization occurs during the AFSD process. Furthermore, it is evidence that the grain size and ultimate tensile strength are positively correlated with feed rate and rotational speed, whereas the elongation at break decreases with the increase in feed rate and rotational speed.

Effect of casting modification materials on cutting forces of an Al12Si alloy used in aircraft technology

Abstract In this study, the effect of modification Al-12Si (Etial 140) casting alloy with Al10Sr, CuSn5, and Al10Sr + CuSn5 master alloys has been investigated with respect to the cutting forces. In order to characterize the morphology of materials used in this study, metallography, hardness, density tests, and chemical analysis were performed. An optical microscope was used to examine the microstructure of the samples. Machinability tests were performed with the turning method by using a titanium diboride-coated cementite carbide cutting tool. All experiments were carried out under dry machining conditions with three different cutting speeds and feed rates with a constant cut depth. After the turning test, scanning electron microscope (SEM) images were used to examine the build-up edge (BUE) formation on the cutting tool. It was determined that the modification process has a positive effect on increasing the density and hardness. According to the results, it was observed that cutting (Fc), feed (Ff), and tangential (Fr) forces decreased for all material groups with increasing cutting speed V. Furthermore, Fc, Ff, and Fr forces increased for all material groups with increasing feed rate f. Finally, the highest cutting forces were observed on the Etial 140 c + Al10Sr master alloy.

Effect of powder feeding rate on electric charging and discharging in powder loading

The effect of the feeding rate of particles conveyed pneumatically through a pipeline on electrostatic discharge during powder loading is investigated. Measurement and theoretical calculation results of specific charges in repeated contact with the pipeline wall indicate that the specific charge can reach 63% of the equilibrium specific charge within 1 s. As the powder feeding rate increases, the specific charge decreases owing to an increase in the space density of the particles and a decrease in the number of particles in contact with the pipeline wall. Four types of discharges are observed in the silo during continuous powder loading, which differ in terms of generation time and duration, and no broad bulk surface discharges are observed in the latter half of the loading. Even though the specific charge increases as the powder feeding rate decreases, the frequency of electrostatic discharges is reduced when the net charge is low.

EXPERIMENTAL EVALUATION OF PARAMETERS AFFECTING DELAMINATION FACTOR, TENSILE STRENGTH, THRUST FORCE AND SURFACE ROUGHNESS IN DRILLING OF GFRP

The drilling of glass fiber-reinforced plastic (GFRP) composites gained importance since they are used as structural components in many industries such as automotive, aerospace, and aviation. A large number of holes are needed in the industry to join these composite parts. However, some failures occur in drilling GFRP composites, such as delamination, matrix cracking, and fiber breakage. These failures not only reduce the strength of the composite, but also reduce its service life. Drilling parameters, drill bits, and woven types have a great influence on the occurrence of these failures by greatly influencing the thrust force, surface quality, and cutting temperature. In this study, the effects of drilling parameters and woven types of GFRP composites on thrust force, surface roughness, delamination factor, and cutting temperature were examined in the drilling of uni-directional (UD), [Formula: see text] and 0[Formula: see text] GFRP woven composites. The effects of drilling parameters and the delamination factor on the tensile strength of the drilled specimen were also investigated. The result of this study indicated that thrust force, delamination factor, and surface roughness increased with increasing cutting speed and feed rate. An increase in feed rate decreased the cutting temperature, while an increase in cutting speed increased the cutting temperature. Also, it was found that the delamination factor had a critical influence on the tensile strength of the GFRP composites.

The use of an artificial neural network for predicting the machining characterizing of wood materials densified by compressing

In this study, an approach for artificial neural network (ANN) was presented to predict and control arithmetical mean surface roughness value (Ra), machining properties of wood materials densified by compressing in a computer numerical control (CNC) machine. Black poplar (Populus nigra L.) tree species were used as the experimental material. After specimens were densified by Thermo-Mechanical (TM) method at 0%, 20%, and 40% ratios, machining process of specimens were performed at 1000, 1500, and 2000 mm/min feed speeds and in 12000, 15000, 18000 rpm rotation speed on a CNC vertical wood machining center by using two different cutters. Data used for the training and testing of an ANN. Cutter type, compression ratio, feed rate, and spindle speed were selected as Four parameters. While hidden layer of the Ra model has ten neurons, one hidden layer was used, Compression ratio is the most significant parameter, followed by feed speed for Ra values. surface roughness increases with increased feed rate. Ra values in training, validation, and testing the data set for Ra were 0.97122, 0.8538, and 0.76685, respectively. The Mean Square Error (MSE) value was determined as 0.0019914 test of the network. The proposed ANN model came to agreement with the measured values in predicting surface roughness Ra values of MAPE. The MAPE value was calculated as 6.61, which can be considered a very good prediction (MAPE< 10 % = very good prediction). The study showed that obtained ANN prediction model is a practical and efficient tool to model the Ra of wood. For reducing energy, time and cost in the wood industry (densification and CNC wood machining), current research results can be implemented.

The effect of operational parameters on the size of chips in the finishing wood-based materials by milling

The effect of operational parameters on the creation of chip particles in the CNC finishing processingof wood-based materials. The object of this study was a comparison of created chips from the process of milling two wood-based materials: medium-density fiberboard, and particleboard, using a modern CNC 5-axis milling center. The materials in the form of blocks were milled at constant revolutions of the cutting tool (18,000 rev/min), with changeable variables of feed rates (8, 10, and 12 m/min), and width of cut (1, 2, and 3 mm). The size of created chips was measured by gravimetric weighing from sieving analysis of the retained volume of chips on sieves with pre-defined mesh sizes. The main emphasis was aimed at studying particles of chipsobtained in the finishing process of the milling below <0.125mm. However, the others are mentioned and discussed. Gravimetric differences of the retained volume of chip mass show that created MDF chips are mostly in the size range of <0.250 to 0.125 mm, and particleboard in the size range of <0.500 to 0.250 mm. Distribution of average values in dependence on different conditions shows a decreasing effect with increasing feed rate on the amount of very small chip particles in the volume of both materials. Increasing the feed rate can decrease the amount of very particles in the range below <0.125 mm in the volume of chip mass.

Investigation of the Effects of Welding Force, Vibration and Temperature on Mechanical Properties and Microstructure in FSW Welding

Defects such as porosity and cracking are serious problems in the joining of aluminium and its alloys by melt welding methods. In this case, it is important that the aluminum pairs are welded by friction stir welding (FSW), which is depend on joining at a temperature below the melting temperature by means of a stirrer pin. In this study, AA5182 pairs were joined in the different welding parameters by FSW. The effects of tool pin profily, feed rate and rotation speed on the temperature, force and vibration formed during welding were experimentally investigated. As the rotation speed rised, the temperature increased and the welding force decreased. But, with increasing feed rate, the temperature decreased and welding force and vibration have increased. Mechanical properties of the joints were adversely affected by low temperature, high welding force and high vibration.

Comprehensive prediction model of drilling temperature of UD-CFRP laminates considering the combined action of main cutting edge and chisel edge

The accuracy of predicting drilling temperature in CFRP drilling is helpful to process optimization and defect suppression. The previous models for predicting CFRP drilling temperature are few and need to be more systematic. Combined with theoretical modeling and experimental verification, a comprehensive theoretical model is developed to predict the temperature distribution during the drilling process of unidirectional CFRP (UD-CFRP), which considers the synergy of the chisel edge and main cutting edge of the drill bit, as well as the influence of fiber orientation angle (FOA). Results show that the predicted peak temperatures parallel to and vertical to the fiber direction present tiny errors of 2.26–5.27% and 4.44–7.55% respectively, indicating that the model is reliable. At 1 mm from the hole wall of UD-CFRP, the peak temperature decreases with the increase of FOA. The drilling temperature decreases with the increase of feed rate and increases with the increase of spindle speed. At the outlet layer of UD-CFRP, the contribution of spindle speed to temperature rise is more significant than the feed rate.

On the Influence of Manufacturing Parameters on the Microstructure, Mechanical Properties and Corrosion Resistance of AISI 316L Steel Deposited by Laser Engineered Net Shaping (LENS®).

Samples of 316L SS were manufactured by Laser Engineered Net Shaping (LENS®) using different technological parameters. The deposited samples were investigated in terms of microstructure, mechanical properties, phase content and corrosion resistance (salt chamber and electrochemical corrosion). Parameters were chosen to obtain a proper sample built for layer thicknesses of 0.2, 0.4 and 0.7 mm by changing the laser feed rate while keeping the powder feed rate constant. After a comprehensive analysis of the results, it was found that the manufacturing parameters slightly affected the resulting microstructure and also had a minor impact (almost undetectable considering the uncertainty of the measurement) on the mechanical properties of samples. Decreases in resistance to electrochemical pitting corrosion and environmental corrosion with an increased feed rate and a decrease in layer thickness and grain size were observed; however, all additively manufactured samples were found to be less prone to corrosion than the reference material. In the investigated processing window, no influence of deposition parameters on the phase content of the final product was found-all the samples were found to possess austenitic microstructure with almost no detectable ferrite.

Real-Time Monitoring of Pellet Plastication in a Full-Flight Screw and Kneading Disk Elements of a Co-Rotating Self-Wiping Twin-Screw Extruder by Acoustic Emission (AE) Sensing

The plastication of pellets in a co-rotating twin-screw extruder is a significant concern for product homogeneity and stability in the plastic industry. We developed a sensing technology for pellet plastication in a plastication and melting zone in a self-wiping co-rotating twin-screw extruder. The collapse of the solid part of the pellets emits an elastic wave as an acoustic emission (AE) that is measured on the kneading section of the twin-screw extruder using homo polypropylene pellets. The recorded power of the AE signal was used as an indicator of the molten volume fraction (MVF) in the range of zero (fully solid) to unity (fully melted). MVF decreased with increasing feed rate monotonically in the range of 2-9 kg/h at a screw rotation speed of 150 rotations per minute (rpm) because of the reduction in the residence time of pellets in the extruder. However, the increase in feed rate from 9 to 23 kg/h at 150 rpm resulted in an increase in the MVF as the friction and compaction of pellets caused their melting. The AE sensor could elucidate the pellet's plastication phenomena caused by friction, compaction of pellets, and melt removal in the twin-screw extruder.

Manufacturing Methods Induced Property Variations in Ti6Al4V Using High-Speed Machining and Additive Manufacturing (AM)

Additive manufacturing techniques are replacing conventional subtractive machining processes; however, the surface quality and defects have been a key roadblock to expanding AM’s uses. This paper describes experimental investigations in the high-speed dry machining and additive manufacturing (AM) of titanium alloy (Ti6Al4V), discussing the effect of machining and AM conditions on the surface characteristics due to the micro-deformation layer. Analysis of the machined surfaces shows the deposition of microparticles at a high cutting speed of 170 m/min at moderate feed rates. The predominant thermal softening effect at a high cutting speed causes restructuring of the micro-deformation layer. Thus, the machined surface shows fewer alterations and a correspondingly lower surface roughness. A high cutting speed also favors the induction of high residual stresses that are compressive. Shallow grooves are seen throughout the surface along the feed spacing with a higher depth of cut of 0.8 mm. An increase in the cutting speed from 170 m/min to 190 m/min leads to a 61% increase in the surface finish owing to a rise in machining temperature leading to thermal softening, and subsequent restructuring of the machined surface layer occurs. For the feed rate, the surface finish values decrease gradually as the feed rate increases, and the worst finish of 1.37 µm is attained at a feed rate of 0.875 mm/rev. This study also compares different AM processes for Ti6Al4V based on the defects and their effects on mechanical properties, such as tensile and fatigue strength. It was observed that the ultimate tensile strength and the yield strength were approximately 20% more in SLM and direct energy deposition as compared to electron beam melting. The mechanism of these effects is also explained by elaborating on the influence of grain size, phase, and other microstructural behaviors on the final mechanical properties of the produced part.

Research on cutting parameters of low-temperature liquid CO2 assisted PCD tool turning bearing ring

The polycrystalline diamond (PCD) tool will produce severe wear when cutting the bearing ring which is a ferrous metal material. In order to reduce the wear of the PCD tool and achieve higher quality bearing ring machining, the cutting parameters of turning bearing ring with low-temperature liquid carbon dioxide (CO2) assisted PCD tool was studied. In this paper, experiments were carried out based on the completed cryogenic cooling system. The experimental results show that the reference cutting temperature increases with the increase of feed rate and cutting speed. The optimal parameters extend the tool life by 2.5 times and make the cutting temperature more stable. The change in cutting speed has a more noticeable impact on the reference cutting temperature than the feed rate. The surface roughness of the workpiece increases with the increase in feed rate and cutting speed. The optimal parameters of feed rate and cutting speed reduce the surface roughness of the workpiece by 81.5 % and 45.8 %, respectively. The primary wear forms of the PCD tool are graphitization, diffusion wear, adhesion wear and tool edge breaking. The tool wear increases with the increase of feed rate and cutting speed. The optimal parameters of feed rate and cutting speed reduce flank wear of the PCD tool by 42.7 % and 47.8 %, respectively. Moreover, the technological parameters of feed rate and cutting speed are presented for reference in actual machining.

Study on Grinding Force of Two-Dimensional Ultrasonic Vibration Grinding 2.5D-C/SiC Composite Material

The grinding force is an important index during the grinding process, which affects the surface quality and other aspects after machining. However, the research on the grinding force of ceramic matrix composites assisted by two-dimensional ultrasonic vibration-assisted grinding is very weak. In this paper, the impact of the relationship between the critical cutting depth and the maximum undeformed chip thickness on the removal mode of ceramic matrix composites was analyzed. On this basis, the grinding force model of two-dimensional ultrasonic vibration-assisted grinding were developed for ductile removal and brittle removal, respectively. Finally, the correctness of the model was verified, and the impact of grinding parameters on the grinding force was analyzed. The experimental results show that compared with the conventional grinding force, the two-dimensional ultrasonic vibration assisted grinding force decreases obviously. When the feed rate and grinding depth increase, the grinding force increases. When the grinding velocity and ultrasonic amplitude increase, the grinding force decreases. Compared with the experimental value, the average relative error of normal grinding force is 8.49%, and the average relative error of tangential grinding force is 13.59%. The experimental and theoretical values of the grinding force have a good fitting relationship.

Study on Surface Integrity and Fatigue Properties of TC4 Titanium Alloy by Surface Ultrasonic Rolling.

In this paper, the influence of a surface ultrasonic rolling process on the surface integrity of TC4 titanium alloy and its influence on the fatigue properties were studied. By comparing and analyzing the surface roughness, microhardness, residual stress, microstructure, and fatigue fracture, the surface strengthening and modification mechanism of TC4 titanium alloy is discussed. The results show that the surface roughness of titanium alloy is observably decreased after the suitable surface ultrasonic rolling process, and the maximum Ra value can be reduced to 0.052 μm. The axial residual stress on the specimen surface can be increased to -685 MPa. The hardening rate of the surface hardness of the sample was 35%. The residual compressive stress and hardness of the sample surface increased with the increase of static pressure. However, the increase of feed rate and rational speed was less. After surface ultrasonic rolling, the sample surface exhibited obvious grain refinement, the number of high-angle boundaries increased to include the formation of nano-equiaxed grains. The fatigue strength increased by 52% from 280 MPa to 425 MPa. Under 450 MPa, the fatigue life of samples with SUR 2 was the highest, at about 7.7 times that of the original samples. The surface integrity of titanium alloy samples after surface ultrasonic rolling treatment is greatly improved, which is the reason for the significant increase in fatigue life of the samples.

Finite difference numerical modeling and experimental validation of workpiece surface temperature in micro-grinding

The objective of this work is to characterize the heat transfer and temperature generation into the workpiece during micro-slot grinding. A numerical model for predicting micro-grinding temperature is established based on the finite difference method (FDM). Workpiece volume is divided into small elementary sections and temperature in small sections near and away from the machining zone is calculated using thermo-physical model as well as validated by experimentally measured temperature using infrared technique. Temperature in micro-slot grinding increases during vertical insertion of the tool and becomes stable when the tool transverse in the feed direction. Simulation results show that transient heat transfer becomes dominant on increased feed rate values that result in an overall lowering of heat supply into the surface. Results also reveal that modification in the tool design has a significant impact on the reduction of workpiece temperature due to reduced contact length, reduced cutting forces, friction, and rubbing at the tool-workpiece interface. The proposed model is capable of solving transient problems in micro-slot grinding and is flexible to deal with different boundary conditions. This analysis will help in temperature prediction and establishing temperature reduction strategies that could potentially increase machining precision.

Performance evaluation of different carbide inserts in turning of newly developed Al‐12Si‐0.1Sr alloy

AbstractAn Al‐12Si‐0.1Sr alloy ingot was manufactured using a permanent mold casting technique. The microstructure and mechanical properties of this alloy were researched. Effects of different cutting conditions (cutting speed‐V: 200 m/min, 300 m/min, and 400 m/min and feed rate‐f: 0.05 mm/rev, 0.1 mm/rev, and 0.15 mm/rev) on the cutting force (F) and surface roughness (Ra) during machining using uncoated and physical vapor deposition‐ titanium aluminum nitride coated carbide inserts were also revealed. Microstructure of the alloys consists of α phase, intermetallic δ and Al4Sr phases, thin spherical eutectic, and irregular coarse‐shaped primary silicon particles. Cutting force and surface roughness decreased with the increased cutting speed during turning with uncoated, and titanium aluminum nitride coated inserts while they increased feed rate. A built‐up edge and built‐up layer were formed in both cutting inserts. The built‐up edge and built‐up layer decreased with increasing cutting speed and increased feed rate. The cutting force, surface roughness, built‐up edge, and built‐up layer were lower in uncoated inserts compared to the titanium aluminum nitride coated inserts.