Machining Of Aluminium Matrix Composites Research Articles

Determination of optimal performance in wire electrical discharge machining of Al/Al2O3/22p composites using response surface methods and grey relational analysis

ABSTRACT In this study, wire electrical discharge machining of aluminium matrix composites has been experimentally investigated. A metal matrix composite Al/Al2O3/22 p has been machined at various combinations of machining parameters such as pulse on-time, off-time, wire speed and wire tension. Empirical models have been developed to predict the cutting rate, surface roughness and kerf width of the machined composite material. The models were developed by using the technique of response surface methodology. The experiments were conducted in standard roughing mode by using carefully planned response surface design matrix (central composite design). The model predictions are in good agreement with the experimental results. The R 2 values of the proposed cutting rate and kerf width models are above 0.99, where as it is 0.98 for the surface roughness model. The pulse on-time was found to influence cutting rate and surface finish significantly. Kerf width was found to be affected by pulse on-time, off-time, wire speed and wire tension. In addition, a model was developed to correlate the multiple performance characteristic called as grey relational grade and the process parameters. The grey relational grade was significantly affected by pulse on-time and off-time time. The R 2 value for the grey relational grade model was 0.94. Optimal parameter setting was determined for the multiple performance characteristic. The improvement in cutting rate was significant with reasonably smooth surfaces and narrow kerf width. However, the surface finish was found to be dominated by the presence of protruding ceramic particles on the machined surfaces.

Impact of BUE on surface ruggedness for machining of aluminium matrix composites (6061/fly ash)

ABSTRACT Nowadays, when the aluminium metal matrix is machined, the devices are prematurely decepted mainly by adhesive wear. The adhesive wear leads to deterioration of surface texture and changes the cutting tool signature. Change of tool signature leads to over power consumption, reduction in effective use of the cutting tool and increase of surface roughness. The surface roughness on the machined component and formation of lay is dependent on the machining parameters, tool signature and machining conditions. This paper demonstrates the effect of Built Up Edge (BUE and Built Up Edge (BUL) on the surface roughness of the composites of fly ash in aluminium using K10. The results achieved were compared with Al6061 aluminium and Al6061 fly ash composites for different cutting edge speeds and feeds at a constant deep cut. The results of the experiment established the significant impact of cutting edge speed and feed on the making of the built-up edge and coating creation that rises surface rugging. Investigation specifies that the cutting edge speed and feed has the uppermost influence on the built-up edge and built-up layer creation while machining such as Al6061 aluminium and Al6061 fly ash composite and hence variation in surface roughness.

Enhancement of material removal rate in magnetic field-assisted micro electric discharge machining of Aluminium Matrix Composites

Micro-electrical discharge machining (Micro-EDM) is a micro-machining process in which miniaturised and precision parts/components are manufactured with good dimensional accuracy and fine surface finish. The present work investigates the effect of magnetic field-assisted Micro-EDM of Aluminium Matrix Composites with a Tungsten electrode using the Response Surface Methodology (RSM). Experiments are conducted based on RSM based central composite design. The process parameters considered for this study are voltage, capacitance and feed rate. The material removal rate (MRR) is considered as the output process parameter. The response surface-based mathematical model is developed for MRR. The model is statistically significant and all the three machining parameters and interaction effects are also significant on the MRR. Experimental investigation shows that the addition of magnetic field in Micro-EDM increases the MRR. Finally the predicted values and experimental values are validated by confirmation experiments.

Selection of optimal processing condition during WEDM of compocasted AA6061/cenosphere AMCs based on grey-based hybrid approach

ABSTRACTInvestigation on the machining of Aluminium Matrix Composites (AMCs) through non-conventional approach are the current attention over the conventional machining approach of those may produces additional complexity in industrial manufacturing. The current research focused on investigating the machinability characteristics of the newly prepared compocasted AA6061/ cenosphere AMCs implementing a non-traditional material removal process via spark erosion called Electro Discharge Machining (Wire-EDM). The performance measure of the system for the different combinations of independent process variables were considered as cutting rate (CR), Kerf Width (KW) and Surface Roughness (SR). Experimental design were carried out based on Response Surface Methodology (RSM) employed face centered Central Composite Design (CCD) required for the analysis. A hybrid approach comprises of grey relation theory in conjunction with RSM Grey- Response Surface Methodology (GRSM) were executed for the prediction of optimal settings of machining condition which yield the optimum performance characteristics of the system. The model fit summary revealing an adequate fitness of the developed model to the actual system, as the R-square value was found to be 0.9607,close to unity and a larger (<4.0) adequate precision value of 20.87. Noticeable improvement were attained on cutting speed (3.234%), kerf width (2.7415%) and surface roughness (7.053%) implementing the optimal setting of machining parameters based on the proposed hybrid GRSM approach. Generous improvement was also noticed on the 3D optical Wire Electro Discharge (WED) machined surface texture demonstrating the quality of surface roughness and texture using hybrid GRSM predicted processing conditions.

Experimental Investigations on Effect of Ceramic B4C Particulate Addition on Cutting Forces and Surface Roughness during Turning of 6061Al Alloy

ABSTRACTAluminium matrix composites are of great interest for researchers in recent years because of their excellent combinations of engineering properties over traditional materials. The machinability of these aluminium matrix composites has become vital for manufacturing industries. During machining of aluminium matrix composites, the cutting forces and surface roughness are dependent on machining parameters (feed rate, cutting speed and depth of cut) and manufacturing parameters (size of the particles, volume fraction, porosity, hardness). With this backdrop, the present work is aimed at investigating the effect of machining parameters, viz. cutting speed, feed rate and depth of cut on the cutting force components, namely, feed force (Ff), radial force (Fd), cutting force (Fc) and surface roughness. The experiments were performed on 0, 5, 7 and 9 wt% B4C particulate of 88 µm size reinforced composite specimens. The prepared specimens were subjected to turning operation on a conventional lathe machine using polycrystalline diamond (PCD) tool to evaluate the effect of B4C particulate addition with varying percentages on cutting forces and surface roughness. Results reveal that the cutting force components decrease with the increase in the wt% of ceramic B4C particulate reinforcement, which can be attributed mainly to increase in porosity, hardness and dislocation densities. SEM image obtained from composite having low wt% of ceramic B4C particulates (5 wt%), which is machined at higher cutting speed and higher depth of cut, has clearly shown the presence of built-up edge (BUE) at the tip of polycrystalline diamond tool. Further, cutting forces increased with increase in feed rate and depth of cut for both 6061Al matrix and 6061Al-B4C composites. It is observed that the surface quality is significantly improved when the cutting speed is increased, and depth of cut and feed rate are decreased.

Machinability Assessment of Aluminium-Graphite-Silicon Carbide Hybrid Composites

Aluminium silicon carbide particulate composites have wide ranging applications in automobile, aerospace and military industries because of their attractive properties such as high strength-to weight ratio, high wear resistance, high temperature stability etc. From the machining point of view, these are one of the most difficult-to-machine materials, primarily due to the presence of SiC reinforcements causing an excessive wear of cutting tools during machining. On the other hand aluminium-graphite composites are widely used in tribological applications because of their excellent antifriction properties, wear resistance and antiseizure characteristics. Investigations have been carried out in this work to assess the machinability of aluminium matrix composites containing both SiC and graphite particulates as reinforcements. Turning experiments have been conducted on Aluminium-Graphite-Silicon Carbide hybrid composites using Carbide and PCD tool inserts to determine the flank wear. Experiments have been carried out based on Central Composite Design approach.

Machinability of Aluminium Matrix Composites

The today's interest in MMCp results from a number of their creative properties, which can be designed through a proper selection of reinforcing components and technological parameters. The composite machine elements such us engine, compressor parts obtained by casting methods require the specially final machining. The introduction of hard ceramic particles increase wear resistance of composite material compared to unreinforcement alloy. Simultaneously increase wear and reducing the durability of tools cutting. The presence of ceramic particles (SiC, Cs) in aluminium matrix influence on surface geometry formed in track of processing. In this paper the results of investigations of geometry surface of composite after machining will be presented. Applied machining conditions for composite material were the same as for unreinforcement alloy, it made possible to compare the conditions of machining processing. It the piston skirt was conducted light profilometry investigation were the parameters 2D and 3D surface topography evaluated. Results shows dependency of surface parameters (Ra, Rz) after machining on kind, size and volume fraction of reinforcement particles applied in composite material.

Comparative Study on the Machinability Aspects of Aluminium Silicon Carbide and Aluminium Graphite Composites

Aluminium matrix composites find wide applications in the present industrial scenario due to their desirable properties. Study of the effect of process parameters on machinability of aluminium matrix composites is of paramount importance in the field of manufacturing engineering. Machining of a composite depends on the properties and relative content of the reinforcement and the matrix materials as well as on its response to the machining process. In this article, investigations on the machinability aspects of aluminium–silicon carbide and aluminium–graphite composites are presented. Experiments have been carried out through the Design of Experiments technique and regression machinability models have been developed, which express the degree to which the resultant force depends upon the cutting parameters and the percentage of reinforcement present in the aluminium matrix composites machined. A comparative study of the effect of cutting parameters on the resultant force has been presented.

Optimisation of cutting conditions in machining of aluminium matrix composites using a numerical and experimental model

In this paper, a methodology aiming at the selection of the optimised values for cutting conditions in machining processes, as turning and drilling aluminium matrix composites is proposed. An hybrid technique based on an evolutionary search over a design space obtained by experimental way is considered. The machining forces, the surface finish and the tool wear are experimentally measured considering the feed and the cutting velocity as predefined parameters. Using genetic algorithms for the optimal search of cutting conditions, the chromosomes represent cutting conditions defined according to a temporal scale and are composed by random keys. The merit functions are established based on multicriteria and evaluated using the experimental values obtained for the machining forces, the surface finish and the tool wear. The evolution of the solutions is based on an elitist strategy.

Effect of Reinforcement on the Machining of Aluminium Matrix Composites Obtained by Powder Metallurgy

Effect of Reinforcement on the Machining of Aluminium Matrix Composites Obtained by Powder Metallurgy

Cumulative tool wear in machining metal matrix composites Part II: Machinability

Models for cumulative tool wear are used to study the machinability of aluminium matrix composites reinforced with SiC or Al 2O 3 particles. Cutting conditions to simulate a finishing operation were employed. Effects of cutting tool materials, heat treatment, and hot isostatic pressing were investigated. Carbide tools can be utilized in a roughing operation, while cubic boron nitride and polycrystalline diamond tools could be used to finish-machine the composites. The latter tools have acceptable tool lives, and cause minimum damage to the sub-surface. The hard aluminium matrix as a result of heat treatment significantly shortens the tool life. Fractured and delaminated particles along or underneath a machined surface could be of concern when composites are used in critical applications.

Prediction of tool life in turning aluminium matrix composites

The machining of aluminium matrix composites reinforced with particulates (MMCp) causes problems because of rapid tool wear due to the extremely high hardness of particles such as silicon carbide and aluminium oxide. Practical considerations for machining MMCp include selection of the cutting speeds and surface roughness. A rapid method for determination of the Taylor relation is presented.