Aluminum Alloy Drill Research Articles

Impact of Chilled Air Nozzle Types on Surface Integrity in Drilling of Aluminum Alloy 1050

Impact of Chilled Air Nozzle Types on Surface Integrity in Drilling of Aluminum Alloy 1050

Special Issue on Advanced Metal Cutting Technologies

Cutting technologies are utilized in many industrial sectors, such as automobile, aircraft, and medical-device manufacturing as well as dies and molds. Thus, the requirements for higher geometric accuracy, better surface integrity, and longer component service lifetimes have substantially increased. In addition, maintaining high machining efficiency while simultaneously reducing power consumption and CO2 emissions during machining is important for sustainable development. This special issue features 11 papers on the most recent advances in cutting technologies for metals and composite materials. - Reverse finishing characteristics of drilling surfaces - Machining error simulation for end milling - Visualization of cutting phenomena using a single-crystal diamond tool - Milling of TiB2 particle-reinforced high-modulus steel - Electrodischarge-assisted turning of carbon fiber-reinforced polymers - Suppression of chatter vibration during double-insert turning - Prediction of surface roughness components during turning - Microtome blades for high-precision tissue sectioning - Boiling of coolant near the cutting edge in high-speed machining - Residual stress during drilling of aluminum alloy - Effect of strain hardening on burr control during drilling This issue provides an understanding of recent developments in cutting technologies, aiming to inspire further research in this field. We deeply appreciate the careful work of all the authors and thank the reviewers for their diligent efforts.

Evaluation Approach for Residual Stress in Drilling of Aluminum Alloy

Residual stress is one of the critical evaluation factors as well as machining accuracy and surface finish in cutting. From the perspective of the fastening strength of parts, residual stress in drilling has an influence on the product or part life. Especially in the aircraft manufacturing, the tensile residual stress is crucial as it can cause major accidents. However, few studies have focused on residual stress in drilling so far. Most of them investigated the characteristics of residual stress based on the experimental data. This paper discusses residual stress in drilling in terms of its mechanical effect. The residual stresses in the inner surfaces of holes were measured in the depth direction from the top of the plate. The change in the residual stress has good correlation with the chip flow direction and the load applied to the inner surface, which acts as a counter force to the cutting force near the outermost ends of the lips. The cutting force is determined using an analytical model based on the minimum cutting energy. The correlation between the residual stress and the direction of the load applied to the inner surface depends on the margin width and back taper on the peripheral sides of a drill. The effect of the margin contact on the residual stress is characterized by linear regression analysis. Finally, an analysis-neural network hybrid system was developed to estimate the residual stresses in drilling. In the system, the mechanical effects of the drilling process, which are the magnitude and direction of the load applied to the inner surface, are obtained through analytical simulation. Meanwhile, the margin effects are expressed as the coefficients in the linear functions, which are associated with the margin width and back taper angle by a neural network. Then, another neural network, working as a post process, estimates the residual stresses using the information of mechanical and margin effects. The developed system is validated by presenting a comparison between the estimated and the actual residual stresses.

Influence of Reverse Finishing on Characteristics of Drilling Surface

Aluminum alloys are often used in automobile and aircraft parts that require higher dimensional accuracy and durability. Drilling is often used in the machining process of these products and accounts for about 60% of the machining performed on these products. Deterioration of finishing surface accuracy in drilling causes problems such as decreased tool life due to wear and increased cost due to the introduction of the finishing process. The objective of this study is to evaluate the finished surface characteristics in the drilling of aluminum alloys using reverse finishing, with a focus on the cutting direction of finishing, with respect to the roughing direction. The torque and thrust force are smaller in reverse finishing than in forward finishing. The reduction effects of cutting force in reverse finishing were more significant when the finishing depth of cut was smaller in relation to the roughing-affected layer. Under conditions where the finishing depth was equal to or greater than the roughing-affected layer, it was possible to reduce cutting forces and improve surface roughness while obtaining compressive residual stresses equivalent to forward finishing.

Development of Hybrid Optimization Model Using Grey-ANFIS-Jaya Algorithm for CNC Drilling of Aluminium Alloy

Aluminium alloys are gaining popularity in a diversity of engineering applications because of their extraordinary features such as strength, resistance to oxidation, and so on. AA5052 (Al-Mg series) is generally used in antirust uses, particularly in desalination related activities, due to its better resistance to corrosion in marine applications at temperature ranges up to 125°C, lower cost, better heat-carrying capacity, and nontoxicity of its corrosion components. Drilling is one of the most commonly adopted material removal processes that is adopted in numerous engineering uses. Taguchi’s technique is engaged to arrange and examine the tests, by treating the drilling diameter and speed and as independent process factors. The studies were carried out using an L27 orthogonal array. Material removal rate (MRR), surface roughness (SR), and form/orientation error are deemed as output characteristics. Taguchi’s analysis was engaged to discover the best process factors. ANOVA is used to examine the influence of process variables. Suitable application of artificial intelligence tools for making effective decision assists the manufacturer in accomplishing the benefits in numerous engineering domains. To obtain the maximum material removal and minimum roughness, circularity (circ), and perpendicularity errors (perp), the process variables have been optimized with the help of grey-ANFIS-amalgamated with Jaya algorithm. The multiperformance index was developed using grey theory. Statistical error analysis is used to estimate the performance of the established optimization model. Based on the investigative outcomes, the best-suited process variable combinations will be used to provide improved and enhanced multiperformance characteristics.

An Effectiveness in Manufacturing Quality on Surface Roughness and Built-Up Edge in Drilling Operation towards Aircraft Component

Aircraft is still dominated by aluminum alloys despite the growth of composites and other lightweight materials due to their fatigue crack resistance, superior damage tolerance, and mature production methods. Assembly process of the aircraft's structures, must be involved for rivets and bolts, required a precise dimension compliance into the aviation guideline. Poor hole quality is one of the major challenges might cause cracks in the aircraft structure and reduce their reliability thus, manufacturing costs are directly affected by this rejection of parts at the assembly stage. The aim of this paper is to study on feed rate, towards surface roughness and Built Up Edges (BUE), and drilling of aluminium alloys used in aircraft component. An experimental approach was used to determine the most efficient feed rate for drilling operations. Observations were made on the BUE formation and roughness of the surface after each drill had completed up to 30 holes in order to meet the requirements of machined parts. From the experiment's findings, it was observed that the BUE formation and surface roughness both marginally changed as feed rates were varied. This experiment's most efficient feed rate was 0.15 m/min, and met the experiment's goal of determining the most efficient drilling feed rate. In conclusion, as feed rate increased, Ra (surface roughness) increased as well, while BUE decreased. While, Ra was set to a high feed rate, its value increased marginally. Drilling on aluminum alloy T6-6061 was accomplished at an efficient feed rate, resulting in improved product quality and reduced tool and workpiece damage.

Machining aerospace aluminium alloy with cryo-treated and untreated HSS cutting tools

ABSTRACT In this study, effects of drilling parameters and cryogenic treatment, which were applied to the cutting tool (M35 HSS drill bit), on the burr width, surface roughness (Ra), chip formation and tool wear were investigated in drilling of AA2024-T3 aluminium alloy under dry drilling conditions. In this context, the drilling parameters determined based on the Taguchi experimental design were employed, and also, the analysis of variance (ANOVA) and regression analysis were performed. The spindle speed (1500, 3000 and 4500 rev/min), feed rate (100, 150 and 200 mm/min) and cutting tool (cryo-treated and untreated M35 HSS tools) were selected as machining parameters. In terms of average burr width, the performance of the cryo-treated (DC&T) HSS drill bit was 28.91% (for the highest value) and 46.96% (for the lowest value) better than that of the untreated (UT) HSS drill bit. According to Ra values, the performance of DC&T HSS drill bit was 13.29% (for highest value) and 12.01% (for lowest value) better than that of UT HSS drill bit. The flank wear (VB) of UT HSS drill bit was found to be approximately four times greater than the flank wear of DC&T HSS drill bit.

Prediction of thrust force in indexable drilling of aluminum alloys with machine learning algorithms

The thrust force has a direct effect on important output responses such as surface roughness, power consumption, and tool wear. The measurement process for thrust forces is very time-consuming and costly. Low success rates are achieved in the estimation of thrust force. The mechanical properties and chemical composition of the workpiece material were not taken into account as input properties in the previously established models. However, these features are of high importance in the formation of the thrust force. In this study, it is aimed at estimating the thrust force with the least input feature with a high success rate by establishing single and hybrid models with different machine learning algorithms. As a result, the thrust force can be successfully predicted by machine learning algorithms by entering two properties. Successful thrust force estimation will provide more accurate process planning, material selection, and optimization.

Robotic Drilling of Aluminum Alloy

This paper presents an experimental approach to evaluate the ability of a six-axis industrial robot to drill aluminum alloy parts. A strategy based on statistical tests has been studied to quantify and predict the relative contribution of cutting parameters on cutting force and shape errors during drilling. This technique is based on the identification of relevant sources of error during high-speed robotic fitting. The machining quality was quantified in terms of dimensional and geometric tolerance, chip formation and evacuation, burr formation, edge build-up, tool wear and surface damage. Statistical analysis of the experimental results reveals a strong dependence between part accuracy and drilling force. An experimental model was developed to represent and predict the cutting force during drilling and an accurate error prediction capability was distinguished. It was found that at high cutting speed and feed rate, the cutting force was the main source of error affecting the accuracy of the machined parts. Verification experiments are performed, and the results reveal that dimensional defects are significantly reduced by a heat treatment effect (90 HRE) and the thrust force decreases with an increase in cutting speed. The recommended cutting speed for robotic drilling is 6000 rpm with a feed rate of 0.15 mm/min. This study provides important technical guidance for improving the robotic drilling of aluminum alloy in practice.

Study on Wear Resistance of Nickel Cladding Layer with Imitation Shell Convex Strip Structure on the Surface of 7075 Aluminum Alloy Drill Pipe

In this study, a nickel cladding layer with a bionic convex strip structure was applied to the surface of an aluminum alloy drill pipe, and laser cladding technology was used to improve the wear resistance of the aluminum alloy drill pipe. Firstly, by observing the morphological characteristics of the shell surface, the ratio of the width of the convex strips to the spacing between the convex strips was obtained as 0.39–0.53, and thus a model of the bionic structure was constructed. Numerical simulations were performed, and the results showed that the wear of the bionic structure was reduced by 77.6% compared with that of the smooth structure. Subsequently, the cladding layers of both structures were coated on the drill pipe using nickel powder as the material, and wear tests were performed. The microstructure, composition, and hardness behavior of the cladding layers were analyzed using scanning electron microscopy, an X-ray diffractometer, and a microhardness tester. It was found that the cladding layer mainly consists of Al3Ni2, and there is a transition layer between the cladding layer and the aluminum alloy matrix, whose hardness is lower than that of Al3Ni2. In addition, the groove space can be formed between the convex strips, which effectively reduces the frequency of the debris flow. The results of the wear tests show that the wear of the cladding layer with the bionic structure is reduced by 74.0%. Similar results in numerical simulations and experiments verified that the designed cladding layer with a bionic convex strip structure can significantly improve the wear resistance of aluminum alloy drill pipes.

Research on Cuttings Carrying Principle of New Aluminum Alloy Drill Pipe and Numerical Simulation Analysis

In order to improve the cuttings transport ability and well hole purification effect of horizontal shale gas wells in the Sichuan and Chongqing area, a new type of aluminum alloy drill pipe is put forward, and the floatability is validated by theoretical analysis and actual parameter calculation. According to the cuttings migration mechanism, the cuttings cleaning simulation model of the new aluminum alloy drill pipe and the traditional steel drill pipe was established by Fluent, and the hexahedral mesh is used to divide the model. Thus, the mesh independence and convergence of the two models are verified. Then, the simulation model is verified by comparing the calculation results of the two simulation models with the experimental data of the indoor cuttings migration device. Finally, the rock-cleaning ability of the two drill pipes is analyzed under the conditions of changing the cuttings particle size, well inclination angle, displacement, and mechanical speed. Compared with the traditional steel drill pipe, the new aluminum alloy drill pipe can improve the borehole purification capacity by 13% on average. This research result is of great significance in reducing the quality of cuttings in the annulus and improving the borehole purification effect.

THE EFFECT OF COOLING METHOD ON SURFACE ROUGHNESS IN DEEP HOLE DRILLING OF ALUMINIUM ALLOYS

This paper presents the results of an experimental study investigating the effect of usage of different cooling methods in drilling of aluminum alloys with different surface roughness properties of these materials. Two alloys were tested: EN AW2024 and AlSi10Mg with a high silicon content. A comparison was made between surface roughness parameters obtained as a result of the usage of different cooling and lubrication methods such as emulsion cooling, MQL and compressed air cooling. In the experiment, holes with the depth range from 5xD to 15xD were machined using different hole machining strategies.

The Role of Al4C3 Morphology in Tensile Properties of Carbon Fiber Reinforced 2024 Aluminum Alloy during Thermal Exposure.

The aluminum alloy drill pipe suffers long-term high-temperature conditions during ultra-deep well drilling. In this paper, the samples were prepared by vacuum hot pressing, followed by hot extrusion and T6 heat treatment. The mechanical properties of short carbon fiber reinforced 2024 aluminum alloy composites (SCFs/2024 Al) and the microstructure evolution at the interface region thermal exposure at 160 °C for 500 h are discussed. The experimental results showed that the effect of short carbon fiber on 2024 aluminum alloy remained steady throughout the whole process of the heat exposure experiment. The distribution and volume of interface products (Al4C3) changed with the prolonging of heat exposure time, and connected after coarsening. The evolution of the morphology of Al4C3 relieved the stress of the interface between carbon fiber and aluminum alloy matrix and enhanced the mechanical properties of the composite.

Effectiveness of lubricating coatings in dry drilling of aluminium alloys

Effectiveness of lubricating coatings in dry drilling of aluminium alloys

Comparison of Tool Wear Mechanisms During Drilling of Aluminium Alloy 7075 in Dry and Chilled Air Conditions

Aluminium alloys are widely used in manufacturing industry due to the need of lightweight components and low production cost. However, mechanical assembly of the alloy which requires drilling operations is challenging due to chip accumulation and heat at the cutting tool and workpiece interface. This often causes material adhesion on cutting edges, built-up edge, accelerated tool wear, shorter tool life and poor drilled hole quality. This paper investigates the effect drilling conditions (dry and chilled air at 10°C) on the wear mechanisms of tungsten carbide cutting tools during drilling Aluminium alloy 7075 (Al 7075) at two different feed rates. Chilled or cold air was used as a cooling medium in drilling Al 7075 to promote green manufacturing. Drilling operations of Al 7075 were performed at a constant cutting speed of 123 m/min with feed rates of 0.01 and 0.1 mm/rev. The cutting tools’ flank wear were measured using an optical microscope with Dino-Capture software and further examination on the tool wear (e.g., built-up edge, built-up layer, and crack) were conducted using Scanning Electron Microscopy (SEM). The results of this study indicate that at higher feed rate of 0.1 mm/rev, adhesive wear is dominant due to the presence of evident material adhesion and fractures on the cutting edges. The use of chilled air was found to cause less material adhesion, however more edge fracture occurred which could be due to workpiece hardening. Therefore, it is inferred that drilling Al 7075 with chilled air requires harder and stronger cutting tool in order prolong the tool life.

Sustainability in drilling of aluminum alloy

Drilling is an extremely crucial process and enormously used in manufacturing assembling components. On the other hand, the 6061-aluminum alloy is most used in modern industry. Therefore, sustainable drilling of this alloy to reduce the use of power and coolant without compromising the quality is promising for the modern industries. This study investigates the active peak power, burr formation, diameter error, circularity error, cylindricity and surface roughness for different cooling methods such as dry, minimum quantity lubrication (MQL), liquid nitrogen (LN2) and air cooling (AIR) under different speeds and feeds. It is found that cooling methods have negligible effect of active power consumption which increases with the increase of speed and feed. Clear trends of the dimensional errors are not noticed with the variation of parameters considered in this investigation. The influences of coolants on surface roughness and chip thickness ratio also don’t follow any trend. The surface roughness increases with the increase of feeds and speeds. The chip thickness ratio tends to increase with the increase of speed and decrease of feed. It is noted that a specific coolant is required at certain speed and feed to obtain a desired outcome. The balance of hardening and softening effects of workpiece materials at different cutting conditions and rigidity of machine tools controls the desired sustainable outcomes.

Prediction of the Deformation of Aluminum Alloy Drill Pipes in Thermal Assembly Based on a BP Neural Network

The connection between the steel joint and aluminum alloy pipe is the weak part of the aluminum alloy drill pipe. Practically, the interference connection between the aluminum alloy rod and the steel joint is usually realized by thermal assembly. In this paper, the relationship between the cooling water flow rate, initial heating temperature and the thermal deformation of the steel joint in interference thermal assembly was studied and predicted. Firstly, the temperature data of each measuring point of the steel joint were obtained by a thermal assembly experiment. Based on the theory of thermoelasticity, the analytical solution of the thermal deformation of the steel joint was studied. The temperature function was fitted by the least square method, and the calculated value of radial thermal deformation of the section was finally obtained. Based on the BP neural network algorithm, the thermal deformation of steel joint section was predicted. Besides, a prediction model was established, which was about the relationship between cooling water flow rate, initial heating temperature and interference. The magnitude of interference fit of steel joint was predicted. The magnitude of the interference fit of the steel joint was predicted. A polynomial model, exponential model and Gaussian model were adopted to predict the sectional deformation so as to compare and analyze the predictive performance of a BP neural network, among which the polynomial model was used to predict the magnitude of the interference fit. Through a comparative analysis of the fitting residual (RE) and sum of squares of the error (SSE), it can be known that a BP neural network has good prediction accuracy. The predicted results showed that the error of the prediction model increases with the increase of the heating temperature in the prediction model of the steel node interference and related factors. When the cooling water velocity hit 0.038 m/s, the prediction accuracy was the highest. The prediction error increases with the increase or decrease of the velocity. Especially when the velocity increases, the trend of error increasing became more obvious. The analysis shows that this method has better prediction accuracy.

Tool wear and burr formation during drilling of aluminum alloy 7075 in dry and with cutting fluid

Aluminum alloy 7075 (Al 7075) has been widely used in aerospace and automotive industries to replace heavier alloys. This is because of its superior properties of high specific strength, high corrosion resistance, good formability, recyclability and low fabrication cost. However, the ductility and heat generation during drilling Al 7075 often produces a burr at the entrance and exit of the workpiece surface. This research investigates the effect of cutting speeds and drilling conditions on the burr formation of Al 7075. Drilling was performed in dry and with conventional cutting fluid using 6.0 mm high speed steel drills with cutting speeds of 22, 44 and 66 m/min at a constant feed rate of 0.15 mm/rev. The use of cutting fluid in drilling Al 7075 caused lower tool wear by 42%, 38% and 30%, respectively, at 22, 44 and 66 m/min, compared to dry drilling. As for burr formation, drilling with cutting fluid on average resulted in 20% lower burr root width and 10% lower burr height than dry drilling for all cutting speeds. This study indicated that drilling Al 7075 using the cutting speed of 44 m/min with cutting fluid is beneficial as it resulted in the least tool wear and minimum burr formation.

Failure analysis on aluminum alloy drill pipe with pits and parallel transverse cracks

In recent years, aluminum alloy drill pipe are used more and more frequently in the exploration and development of the deep wells, ultra-deep wells and sour gas wells due to the high strength, light weight and corrosion resistance to H2S and CO2. However, the pitting and fracture failure sometimes occurred, resulting in giant economic losses and fatal disaster. In this study, the failure analysis of aluminum alloy drill pipe was addressed and the formation cause of the pits and parallel transvers cracks was investigated. Results show that the chemical composition and the regular mechanical properties (including tensile and impact properties) meet ISO 15546:2011 standard requirements. But the tensile strength of samples immersed in the mud environment is lower than that of ISO 15546:2011 standard requirements. Metallographic analysis results show intermittent ribbon Al6(MnFe) solid solution, S (CuMgAl2) phase and AlFeSi phase distributed on α solid solution. The failure cause of aluminum alloy drill pipe is mainly attributed to the brittleness sensitivity of intermittent banded second phase and inclusions to corrosive media from mud environment. Cracks and pits are prone to generate here. XRD and EDS analysis results of corrosion products and the pits bottom show that the main corrosion products are Al2O3, Al2S3, AlPO4, BaSO4 and CaCl5. S and Cl are from environment media. The microscopic morphology analysis results of the tensile and impact specimens fracture show that the fracture is the brittle fracture caused by the environmental medium.

Investigation of Thrust Force, Drill Bit Temperature and Burr Height in the Drilling of Aluminum Alloy Used in Ammunition Wing Drive Systems

Investigation of Thrust Force, Drill Bit Temperature and Burr Height in the Drilling of Aluminum Alloy Used in Ammunition Wing Drive Systems