Machining Of Aluminum Alloys Research Articles

Processing and Microstructural Characterization of Metallic Powders Produced from Chips of AA2024 Alloy

Accumulated metal waste during machining of aluminum alloys is considered for further recycling to promote environmentally sustainable production. This study aims to characterize the ball-milling process of AA2024 aluminum chips as an alternative to the remelting procedure. The proposed processing modes provide a powder particle size distribution with a d50 of 100–325 μm after 100 min milling. Stearic acid, as a process control agent (PCA), slows down powder refinement if introduced at the early stages of milling. The powder tends to form a flake-shaped morphology owing to the impact of plastic deformation altered by the PCA. Microhardness variation is linked to the joint effect of voids, strengthening phases, mechanically affected zones, and grain structure. Further, the paper reports the crystallite sizes ranging from 25 nm to 45 nm and the lattice strain < 1%. Finally, an outlook on hot-powder compaction and the associated properties of the material are presented.

Processing, tool wear measurement using machine vision system and optimization of machining parameters of boron carbide and rice husk ash reinforced AA 7075 hybrid composite

This work is focused on the fabrication and machining of Aluminium Alloy (AA) 7075, AA 7075/B4C composite and AA 7075/B4C/RHA hybrid composite. The composites were fabricated using stir casting technique. The highest hardness value was reported on AA 7075-5 B4C-5 RHA hybrid composite. It was 72% higher than pure AA 7075. Scanning electron microscopy (SEM) was used to study the surfaces of fabricated and machined surfaces of the composites. The theoretical density was calculated by the rule of mixture and actual density was calculated by the Archimedes principle. Energy dispersive spectroscopy (EDS) analysis was used to confirm the distribution of reinforcements in AA7075. Turning of AA 7075, AA 7075/B4C composite and AA 7075/B4C/RHA hybrid composites were done by using plain carbide inserts. The various responses studied were Surface Roughness (SR), Material Removal Rate (MRR) and Tool Wear (TW). The analysis and optimization of the experimental results were carried out using response surface methodology. The feed rate was considered as the most influencing parameter for SR and MRR. Speed was considered as the most influencing factor for tool wear and the wt% of reinforcement is considered as least influencing factor for MRR.

Cutting Environment Impact on the Aluminium Alloy Machining

Abstract The paper is focused on the experiment where the effects of the cutting environment and feed of drilling on the bores roughness and cylindricity were evaluated. Dry drilling of aluminium alloys (without using cutting fluids) is an environmentally friendly machining process but also an extremely difficult task, which is due to the tendency of aluminium to adhere to the drills made of conventional materials such as high-speed steel; and therefore three cutting environments (namely two different emulsions and compressed air) were used in the experiment. The article demonstrates multicriterial optimization of input factors (cutting environment, feed) for two defined target functions: roughness and cylindricity). The measured values were subjected to mathematico–statistical Analysis of Variance (ANOVA). ANOVA was used for examining the effects of machining parameters and their contribution to the surface roughness and bores cylindricity. The optimal cutting parameters were evaluated for “Smaller-the-Better” quality characteristics of both output responses, as can be seen in our article published previously. Based on the ANOVA, we determined that cutting environment exhibited higher percentage of contribution on bores quality than feed of machining. The results show 77.37 % impact of cutting environment and 8.13 % impact of feed on quality of machined bores.

Analysis of Electrical Discharge Machining

Breakdown in liquid dielectric medium, plasma channel, and heat transfer in the course of electrical discharge machining are studied. Specific features and most important parameters of electrical discharge machining of titanium and aluminum alloys are determined. Theoretical, experimental, and simulated results indicate that the adequacy hypothesis can be accepted at a confidence level of 95%, since the Fisher criterion is no greater than the reference value.

Microhardness and wear behaviour of polycrystalline diamond after warm laser shock processing with and without coating

Cutting tools made of ultra-hard materials such as polycrystalline diamonds offer superior wear resistance in precision machining of Aluminium alloys. However, the wear properties of these materials are dependent on their microstructural characteristics such as grain size and binder percentage. In this context, the present paper evaluates the effects of two low-energy fibre laser processes (nanosecond pulse duration) on microstructural changes of polycrystalline diamond composites and consequently investigates wear and friction characteristics and micro hardness properties. Pockets were first achieved using a single mode SPI pulsed fibre laser (1064 nm wavelength) inducing both laser shock processing (LSP) and laser peening without coating (LPwC) and characterised using a combination of scanning electron microscopy (SEM), white light interferometry, energy dispersive X-Ray (EDX) and micro hardness analyses. The as-received and processed materials were tested on a pin-on-disc for the evaluation of their wear performance. An analytical model based on the asperities of pin and disc after wear test is proposed to predict the trend of wear performance of different laser-processed materials. LSP with vinyl and quartz at a scanning speed of 500 mm s−1 achieved a micro-hardness of 110 GPa at a depth of 632 nm. LPwC at 0.8 GW cm−2 produced hybrid microstructures which share characteristics of laser shock processing and selective laser melted structures. For laser feed speed in the region of 1000 mm s−1, micro-indentation tests revealed an improvement of hardness from 70 GPa to 95 GPa at a depth of 670 nm for LPwC. Tribotest revealed enhanced wear performance for all laser-processed pins and reduced coefficient of friction also validated by increased material removal rate when compared to the as-received material. To the best of authors' knowledge, it is reported for the first time that an improvement of wear performance can be achieved on polycrystalline diamond through LSP and LPwC.

Effect of Cutting Parameters on Machining Induced Distortion in Thin Wall Thin Floor Parts

This paper presents experimental study on the effect of machining parameters viz., feed, speed, width of cut and depth of cut on machining induced distortion. Machining experiments were done using Response Surface Methodology. Optimization of machining parameters for minimum machining induced distortion was also carried. Four factor, three level Box-Behnken method with analysis of variance is used in dry machining aluminium alloy 2014 T651 with two flute solid carbide Ø 10 mm milling tool. Machining simulation experiments were also carried out using Deform 3D software to know the effects of these parameters on forces and temperature generated for correlation with machining induced distortion. Results show that feed, width of cut and depth of cut have significant effect on machining induced distortion. It is observed that, there is an increase in machining induced distortion due to increase in cutting forces in Z – direction and temperature with increase in feed, depth of cut and width of cut during milling thin-wall thin-floor components. The optimal combination of cutting parameters arrived with target values of distortion and twist less than 0.09 mm is feed 0.18 to 0.2 mm/tooth, speed 180 to 210 m/min., width of cut 5.6 mm and depth of cut 0.4 mm.

Surface Texturing Potential on Carbide Insert in Reducing Aluminium Alloy Adhesiveness during Machining

Aluminum alloy is a widely used material which contributes greatly in numerous engineering applications. Aluminum alloy can be considered as having low strength and it is less likely to experience tooling difficulty. However, the complexity of machining aluminum alloy is related to its adhesive behavior, which capable to impede the machining operations where build-up-edge can be observed easily to occur. Since machining process generates a lot of energy due to friction and adhesive contact between tool and material, it is suggested to apply wet cutting method during machining of aluminum alloy to decrease the likeliness of aluminum alloy chip to adhere onto the tool surface. However, this method of machining is still having low effectiveness whereas the limitation of cutting fluid to enter the tool-chip sticking zone. Thus, the fabrication of textures on carbide insert rake surface is one of the predominant methods to enhance the sustainability of turning process with aluminum alloy workpiece. In this study, grinding process was utilized using Okamoto ACC52ST surface grinding machine to fabricate textures, where it is assumed that high effectiveness of lubricant can be retained and friction at tool-chip interface can be reduced. Turning process was conducted with the application of ROMI C420 lathe machine to investigate the adhesive behavior of aluminum alloy. It is observed that, the adhesive behavior of aluminum alloy was minimized with the application of textured carbide insert especially in wet cutting condition in general. Additionally, it can observed that, even at relatively high cutting speed and depth of cut, less adhesion behavior of aluminum alloy is obtained for textured carbide insert in wet cutting condition. This can be considered as a gain in productivity, whereas the adhesive behavior for non-textured carbide insert can only be reduced if only low cutting speed condition and wet cutting method are utilized.

DLC and DLC-WS2 Coatings for Machining of Aluminium Alloys

Machine-tool life is one limiting factor affecting productivity. The requirement for wear-resistant materials for cutting tools to increase their longevity is therefore critical. Titanium diboride (TiB2) coated cutting tools have been successfully employed for machining of AlSi alloys widely used in the automotive industry. This paper presents a methodological approach to improving the self-lubricating properties within the cutting zone of a tungsten carbide milling insert precoated with TiB2, thereby increasing the operational life of the tool. A unique hybrid Physical Vapor Deposition (PVD) system was used in this study, allowing diamond-like carbon (DLC) to be deposited by filtered cathodic vacuum arc (FCVA) while PVD magnetron sputtering was employed to deposit WS2. A series of ~100-nm monolayer DLC coatings were prepared at a negative bias voltage ranging between −50 and −200 V, along with multilayered DLC-WS2 coatings (total thickness ~500 nm) with varying number of layers (two to 24 in total). The wear rate of the coated milling inserts was investigated by measuring the flank wear during face milling of an Al-10Si. It was ascertained that employing monolayer DLC coating reduced the coated tool wear rate by ~85% compared to a TiB2 benchmark. Combining DLC with WS2 as a multilayered coating further improved tool life. The best tribological properties were found for a two-layer DLC-WS2 coating which decreased wear rate by ~75% compared to TiB2, with a measured coefficient of friction of 0.05.

Experimental Investigation on Cryogenic Assisted Abrasive Water Jet Machining of Aluminium Alloy

The purpose of the present investigation was to evaluate the abrasive water jet cutting performance by the application of a cryogenic liquid nitrogen jet in the cutting process. This technique was developed for improving the process capability of conventional abrasive water jet machining and enable a higher depth of cut and material removal rate, and better kerf profile and surface integrity. The experiments were conducted on AA5083-H32 aluminium alloy, using two different cutting methods, namely, abrasive water jet cutting and cryogenic assisted abrasive water jet cutting. Both cutting conditions were investigated by varying the water jet pressure, the abrasive mesh size and the abrasive water jet impact angle. Optical microscopy and Scanning Electron Microscope with Energy Dispersive X-ray Spectroscopy was used for studying the micro structure and morphology of the cut surfaces under both cutting conditions. There was an improvement in cutting performance features such as depth of penetration, material removal rate and kerf profile with the use of cryogenic assistance cutting approach. These results were produced due to the beneficial modification of erosion mechanism in the cutting zone as well as a reduction in particle embedment with the cut surface by about 56%.

INFLUENCE OF FECL3 ON MATERIAL REMOVAL RATE AND SURFACE ROUGHNESS IN CHEMICAL MACHINING PROCESS

Non-traditional machining process is more used to manufacture geometrically complicated and an accurate parts for electronics, aerospace and automotive industries. Chemical machining process is one of non-traditional machining methods, it is as well named as chemical etching. The current research is aimed to study the influence of the machining time, machining temperature, etching solution concentration on the material removal rate and surface roughness of aluminum alloy by using mix of acid FeCl3. There are three of machining temperatures (25, 30 and 35 ºC) with three machining times (4, 8, and 12min) and etching solution concentration (25%, 50%, and 75%) were used as machining conditions. These conditions are significant variables that have effect on finishing performance of chemically machined aluminum alloy. Machining time has the greatest effect among these variables. The time is the most important parameter for maximum Material Removal Rate (MRR), and the interaction between temperature and etchant concentration is the next important parameter for maximum MRR. The time is the greatest parameter for minimum Ra, the interaction between time and temperature is the next significant parameter for less Ra.

Machinability behavior of Aluminium Alloys: A Brief Study

Abstract Aluminium alloys are the most promising material which provides highest mechanical strength in the field of hard machined material. Owing to its higher strength to weight ratio, it is extensively applied in the aerospace and aeronautical manufacturing enterprises. Over the years, the requirement for eco-friendly and cost-effective machining practices have been developed continuously, and many researchers have shown keen interest for increasing more advanced machining process. During machining of aluminium alloy materials, the appropriate choice of machining process and cooling situations play an imperative role as it affects the performance. The current research article focuses on a comprehensive review of power consumption during machining of aluminium alloy. Additionally, comparisons are performed between Dry and MQL cooling system and critical observation for tool wear, cutting temperature, and surface roughness using various types of cutting insert have been considered. Application of ionic fluids as a coolant for aluminium alloys machining were not found in literature and it can be the novel choice for the researchers to carry out their works. This exploration will definitely provide appropriate selection of cutting conditions during machining of various aluminium alloys for machinist and researchers.

Исследование процессов электроэрозионной обработки

AbstractBreakdown in liquid dielectric medium, plasma channel, and heat transfer in the course of electrical discharge machining are studied. Specific features and most important parameters of electrical discharge machining of titanium and aluminum alloys are determined. Theoretical, experimental, and simulated results indicate that the adequacy hypothesis can be accepted at a confidence level of 95%, since the Fisher criterion is no greater than the reference value.

Increase effectiveness electrical discharge machining of titanium and aluminum alloys by application of electrodes from composite materialss

Increase effectiveness electrical discharge machining of titanium and aluminum alloys by application of electrodes from composite materialss

Experimental Analysis of AA6063 Aluminium Alloy Machining by EDM with Hexagonal Shaped Tool Electrode

Abstract Electro-discharge machining (EDM) of AA6063 Aluminium Alloy was performed by varying the peak current (Ip), pulse on time (Ton), gap voltage (Vg) and duty factor (τ). Using a hexagonal shaped copper tool electrode, EDM was performed by considering Box-Behken response surface design with 27 number of experimental runs. Material removal rate (MRR) and surface roughness (SR) were considered as response features for evaluating machining performance. Based on the obtained results, regression equations for MRR and SR were developed, and the effects of the input parameters on the machining performance were analyzed through surface plots. The experimental analysis showed that the peak current was the most influential parameter affecting the machining performance followed by pulse on time, gap voltage and duty factor.

An Experimental Investigation of Machining Aluminum Alloy Al5052 with EDM

Electrical Discharge Machining (EDM) is a non-conventional machining process, with a wide range of applicability and capabilities in modern industry. As a non-contact machining process, it has no limitations regarding the workpiece material mechanical properties, i.e. toughness and strength, with most important factors being the electrical conductivity and the thermal properties of the material. The material removal mechanism is relatively simple, including a spark occurrence between the electrode and the workpiece, which are immerged in a dielectric fluid. An amount of material, from both the electrode and the workpiece, melts or evaporates due to spark’s thermal energy. Machining parameters, namely the pulse current Ip and the pulse-on time Ton, highly affect the process’ performances, and so have to be carefully chosen, according the workpiece material and the desired machining results. The current study is an experimental investigation of machining aluminum alloy Al5052, with EDM for different machining parameters (Ip and Ton) setups. The material removal rate (MRR), the Surface Roughness (SR), the White Layer (WL) formation and the micro-hardness of the Heat Affected Zone (HAZ), were measured or calculated. Finally, using statistical tools, mathematical expressions of correlation between machining parameters and results are proposed. The current experimental study concluded that the MRR strongly depends on the pulse-on current, while the Surface Roughness mainly depends on the pulse-on time. Furthermore, the interaction and the combination of the machining parameters, namely the pulse-on current and the pulse-on time, have a major impact on the process efficiency. Lastly, the existence of a HAZ with decreased microhardness was verified.

Experimental Investigation and Optimization of SiC Abrasive Water Jet Machining of Aluminium Alloys

Investigation of the parameters variation over the abrasive water jet machining of aluminium 2014 alloy was studied using the Taguchi technique. Traverse speed, standoff distance, pressure and mass flow rate were considered as the process parameters and were varied at three levels. The depth of cut was taken as the response, and it was measured and analysed statistically. The optimal parameters to achieve the maximum depth of cut were identified with the main effect plot. Most influencing parameters over the depth of cut were identified with the analysis of variance and response table. A mathematical relationship was developed to predict the depth of cut.

Prediction of specific grinding forces and surface roughness in machining of AL6061-T6 alloy using ANFIS technique

PurposeOptimisation of grinding processes involves enhancing the surface quality and reducing the cost of manufacturing through reduction of power consumptions. Recent research works have indicated the minimum quantity lubrication (MQL) system is used to achieve near dry machining of alloys and hard materials. This study aims to provide an experimental analysis of the grinding process during machining of aluminium alloy (Al6061-T6). MQL nanofluid was used as the lubricant for the grinding operations. The lubricant was formed by suspending silicon dioxide nanoparticles in canola vegetable oil. The effect of input parameters (i.e. nanoparticle concentration, depth of cut, air pressure and feed rate) on the grinding forces and surface quality was studied. Adaptive neuro-fuzzy inference system (ANFIS) prediction modelling was used to predict the specific normal force, specific tangential force and surface quality, the ANFIS models were found to have prediction accuracies of 97.4, 96.6 and 98.5 per cent, respectively. Further study shows that both the specific grinding forces and surface roughness are inversely proportional to the nanofluid concentration. Also, the depth of cut and table feed rate were found to have a directly proportional relationship with both the grinding forces and surface roughness. Moreover, higher MQL air pressure was found to offer better delivery of the atomised nanofluid into the grinding region.Design/methodology/approachGrinding experiments were performed using MQL nanofluid as the lubricant. The lubricant was formed by suspending silicon dioxide nanoparticles in canola vegetable oil. The effect of input parameters (i.e. nanoparticle concentration, depth of cut, air pressure and feed rate) on the grinding forces and surface quality has been studied.FindingsThe grinding process parameters were optimised using Taguchi S/N ratio analysis, whereas the prediction of the response parameters was done using ANFIS modelling technique. The developed ANFIS models for predicting the specific normal force, specific tangential force and surface quality were found to have prediction accuracies of 97.4, 96.6 and 98.5 per cent, respectively. Further findings show that both the specific grinding forces and surface roughness are inversely proportional to the percentage of nanoparticle concentration in the lubricant. Also, the depth of cut and table feed rate were found to exhibit a direct proportional relationship with both the grinding forces and surface roughness, while high MQL air pressure was observed to offer more efficient delivery of the atomised nanofluid into the grinding region.Practical implicationsThe work can applied into manufacturing industries to prevent unnecessary trials and material wastages.Originality/valueThe purpose of this study is to develop an artificial intelligent model for predicting the outcomes of MQL grinding of the aluminium alloy material using ANFIS modelling technique.

Improvement in Surface Quality of Microchannel Structures Fabricated by Revolving Tip-Based Machining

In the present paper, the process parameters of revolving tip-based machining were optimized for the fabrication of microchannel structures. It was found that in comparison with the micromilling process, the main factor affecting the surface quality of revolving tip-based machining originated from residual materials produced in each revolution. Three process parameters, including cutting depth, feeding rate, and tool path strategy, were studied experimentally to optimize the surface quality of the machined aluminum alloy and polymethylmethacrylate (PMMA). It was noticed that at smaller cutting depths (< 3 µm) and feeding rates (< 20 µm/s) with fixed revolving parameters (50 Hz frequency and 6 µm radius), microchannels with better bottom surfaces were formed. Two different types of tool path strategies were designed and compared to obtain the best surface quality (Sa) of aluminum alloy (21 nm) and PMMA (19 nm).

A Modified Johnson–Cook Constitutive Model and Its Application to High Speed Machining of 7050-T7451 Aluminum Alloy

Constitutive model is the most commonly used method to describe the material deformation behavior during machining process. This paper aims to investigate the material dynamic deformation during high speed machining of 7050-T7451 aluminum alloy with the aid of split Hopkinson pressure bar (SHPB) system and finite element (FE) analysis. First, the quasi static and dynamic compression behaviors of 7050-T7451 aluminum alloy are tested at different loading conditions with a wide range of strain rates (0.001 s, 4000 s, 6000 s, 8000 s, and 12,000 s) and temperatures (room temperature, 100 °C, 200 °C, 300 °C, and 400 °C). The influences of temperature on strain and strain rate hardening effects are revealed based on the flow stress behavior and microstructural alteration of tested specimens. Second, a modified Johnson–Cook (JCM) constitutive model is proposed considering the influence of temperature on strain and strain rate hardening. The prediction accuracies of Johnson–Cook (JC) and JCM constitutive models are compared, which indicates that the predicted flow stresses of JCM model agree better with the experimental results. Then the established JC and JCM models are embedded into FE analysis of orthogonal cutting for 7050-T7451 aluminum alloy. The reliabilities of two material models are evaluated with chip morphology and cutting force as assessment criteria. Finally, the material dynamic deformation behavior during high speed machining and compression test is compared. The research results can help to reveal the dynamic properties of 7050-T7451 aluminum alloy and provide mechanical foundation for FE analysis of high speed machining.

Machinability of AA7075-T6/carbon nanotube surface composite fabricated by friction stir processing

Chip adhesion on rake face of cutting tool and subsequent formation of built-up-edge are critical problems in machining of aluminum alloys. In the current work, carbon nanotube as a solid lubricant has been integrated with aluminum 7075-T6 alloy through friction stir processing and the machinability of fabricated surface composite has been evaluated. Here, firstly, a series of friction stir processing experiment has been carried out to find optimum pass number regarding uniform dispersion of carbon nanotube in aluminum matrix. Then, a total number of 27 drilling experiments under different values of spindle speed and travel speed have been carried out on raw material, friction stir processed material without addition of carbon nanotube, and friction stir processed with addition of carbon nanotube. The obtained results showed that addition of carbon nanotube as reinforcement causes reduction of machining thrust force and surface roughness due to excellent lubrication property. Tribological observations through scanning electron microscopy and wear test revealed that the main mechanism for enhancing the machinability is reduction of friction coefficient as a result of carbon nanotube addition.