Drilling Of Metal Matrix Composites Research Articles

Prediction model for torque on drilling of metal matrix composites

In manufacturing and assembly units, drilling is one of the most important process to make the final form of the product by means of fasteners. The thrust force and drilling torque induced during drilling process affect the quality of holes drilled in the form of roughness, circularity error etc. This paper focuses on the investigation of parameters in drilling that have influence over the torque needed to cut the Metal Matrix Composites (MMC), by variation of the diameter of the twist drill bit, keeping the tip angle and other features in geometry as a constant. Roughness after machining is a key factor when it comes to high precision applications such as manufacturing of gauges in metrological operations. The input parameters include combinations of three different speeds and three different feeds and the output we concentrate on this paper is the torque as indicated by the title itself. The prediction models of the data sets are obtained using Response Surface Methodology and Fuzzy Logic, and the results obtained are compared to the experimental values themselves to see how much the models are accurate in predicting the results.

Optimisation of Spindle Speed and Feed Rate for Drilling of Al-SiCp Metal Matrix Composites using ANOVA and Genetic Algorithm

This paper presents the influence of the spindle speed and feed rate of the drilling on machinability of metal matrix composites (MMC) manufactured using stir casting technique. The drilling of MMC is carried out using Ti-Al-N coated and uncoated solid carbide drills. Analysis of variance technique is used to find the percentage of contribution for each drilling parameters and then regression equations were developed to find the thrust force and torque. The drilling parameters were also optimized using Genetic Algorithm. For the optimum values of spindle speed and feed rate, the tool life in terms of tool wear and number of holes drilled was compared for the cases of coated and uncoated drills. From the analysis, it was inferred that feed rate is the significant factor affecting thrust force and torque. Coated solid carbide drill performed than better than the uncoated carbide drill.

Investigating the Effect of Ultrasonic Vibration on Hole Accuracy in Drilling of Metal Matrix Composites

Generally in the drilling of new engineering materials such as metal matrix composites, problems frequently occur in terms of poor finished surface, tool stress, tool wear, high drilling forces as well as low process reliability. A useful and promising method to overcome these problems is the use of ultrasonic vibration as an assistance, where high-frequency and low amplitude vibration are added to the conventional movement of cutting tools or workpieces. This research presents the new design of an ultrasonic assisted system and the experimental investigation of ultrasonically assisted drilling of Al/SiC metal matrix composites under different cutting conditions. The effect of cutting conditions and ultrasonic amplitude on the circularity, cylindericity, and hole oversize of the ultrasonically and conventionally drilled workpieces were investigated. The obtained results show that the ultrasonic vibration can improve the hole quality.

Drilling of metal matrix composites: Experimental and finite element analysis

Drilling is an indispensable machining operation, which is mostly performed for making holes in an intricate composite part. In this research investigation, a finite element model has been developed to simulate the drilling behavior of Al1100/10% SiC metal matrix composite using finite element platform (ABAQUS/Explicit). The effect of cutting speed and feed rate on thrust force has also been experimentally evaluated. It was found that the magnitude of thrust force obtained from the proposed finite element model is in close agreement with the experimental values. It was also established that the proposed finite element model is quite efficient to predict the thrust force signals generated during drilling of metal matrix composites.

Design and development of abrasive-assisted drilling process for improvement in surface finish during drilling of metal matrix composites

A novel technique called abrasive-assisted drilling has been designed and developed to improve the surface finish of the drilled hole wall during the drilling of Al6063/10%SiC metal matrix composites. The developed process eliminates the use of supplementary surface finishing process such as abrasive flow machining or deburring of drilled hole, which adds to the cost of product. With the help of this technique, fine polished drilled hole wall surface can be produced by removing small fragments of material generated by the high-energy abrasive particles. A considerable increase in surface finish of the drilled hole wall has been observed for metal matrix composites. Taguchi’s methodology has been used to explore the effect of input process parameters on the surface roughness and hole oversize of the drilled hole. The input process parameters under consideration are rotational speed, finishing time, abrasive size and abrasive concentration.

Electric discharge drilling of metal matrix composites with different tool geometries

There exist numerous challenges during hole making in super alloys and other advanced materials such as the metal matrix composites. The conventional hole making operations such as drilling sometimes becomes uneconomical because of low productivity and poor quality. It becomes necessary to conceptualize and develop processes that are not only economical but also produce high-quality holes. Electric discharge drilling process is one such process that combines the effect of the electric discharge machining and the conventional drilling. In the present experimental investigation, experiments have been performed on a modified electric discharge machining setup with a facility to rotate the electrode. The work-piece material has been selected as Al6063/10% SiC metal matrix composite as tool wear is an important limitation during its conventional drilling. The major objective is to investigate the effect of the geometry of tool electrode on the process performance that has not been investigated exhaustively. The material removal rate has been selected as the measure of performance and criteria for comparison. It has been found that the geometry of the tool electrode influences the material removal rate and should be selected judiciously.

Process Optimization for Electro-Discharge Drilling of Metal Matrix Composites

The introduction of unconventional processes is a revolution in the field of manufacturing technology. These have been discovered not to abolish the conventional processes, but to increase their flexibility. Electro-discharge drilling (EDD) is hybrid machining process, which has been assembled with the z-axis numerical control electro-discharge machining (ZNC-EDM) set- up. EDD process is basically hole making process for electrically conductive super alloys and difficult to machine materials. The present discussion will attempt to highlight the recent developments in the field of drilling of metal matrix composites. Finally, the present work extracts the outline of the optimized process parameters (discharge current, arc on time and tool speed) for maximum material removal rate, minimum tool wear rate and a satisfactory amount of improvement has been noticed in the machining performance of EDD.

Burr Minimization in Step Drilling of Al-Fly Ash/Gr Hybrid Composites by Taguchi Method

Metal Matrix Composites (MMCs) have emerged as a potential material especially for automotive and aerospace industries. In view of the growing engineering applications of these composites, the machining parameters have to be optimized in order to attain good surface quality, reduced tool wear and cutting forces. In this paper, the influences of the feed and step drill’s geometries such as step angle and step size on the exit burr height have been investigated for burr minimization in drilling of MMCs. Experimental study was conducted for Al-15wt.% fly ash composites and Al-15wt.% fly ash /1.5wt.% graphite hybrid composites which are fabricated through stir casting method. Optimum drilling parameters were identified for burr minimization by the application of Taguchi method, analysis of variance (ANOVA) and the results were validated by confirmation test. Results revealed that feed and step drill’s geometries step angle and step size were the most influential factors on the formation of burr. Dynamom¬eter was employed to measure the thrust that was being applied to the work piece when it was drilled. The inclusion of graphite as supplementary reinforcement in Al / fly ash reinforced composite reduces the thrust force and exit burr height considerably.

Burr Size Reduction in Drilling of Al/SiC Metal Matrix Composite by Ultrasonic Assistance

Metal matrix composites (MMCs) have received considerable attention due to their excellent engineering properties. Accuracy and surface finish play an important role in modern industry. Undesired projections of materials, known as burrs, reduce the part quality and negatively affect the assembly process. In this study, reducing burr size in drilling of MMC is performed by adding ultrasonic vibration to the process. Al/SiCp MMC with 5 wt% of SiC particulates in dry drilling operation with HSS drill tools coated with TiN was investigated. The effect of ultrasonic assistance on burr size was studied. The results demonstrate that under suitable ultrasonic vibration conditions, in comparison with the conventional drilling, the burr height and width could be reduced.

Design Optimization of Cutting Parameters when Drilling Metal Matrix Composites

The Taguchi method is used to find the optimal cutting parameters when drilling metal matrix composites (MMCs) with a polycrystalline diamond (PCD) tool. The combined effects of cutting parameters (cutting velocity and feed rate) and cutting time on three performance measures (tool wear (VBmax), the specific cutting pressure (Ks) and hole surface roughness (Ra)) were investigated employing an orthogonal array, signal to noise (S/N) ratio and the analysis of variance (ANOVA). The optimal cutting parameters for each performance measure were obtained, and the main cutting parameters that affect the cutting performance in drilling operations can be found. The relationship between the drilling parameters and the performance measures were determined using multiple linear regressions. Confirmation tests of the optimal levels with the initial machining parameters are carried out in order to illustrate the effectiveness of this approach for drilling MMCs.

Experimental modelling and analysis of drilling (Al<SUB align=right>2O<SUB align=right>3)p/6061 metal matrix composites using PCD tool

Metal matrix composites (MMCs) machining is not difficult but presents different machining requirements compared to other materials because of the abrasive characteristics of the reinforced particulates. In order to use these materials for regular production, it is necessary to develop methods by which the machining process can be optimised. The objective of this research was to develop mathematical models to predict drilling forces. Cutting parameters included in the mathematical models are cutting speed, feed rate, and volume fraction of reinforcement. Experiments were conducted by using PCD tools to drill Al2O3 particulate reinforced aluminium-based metal matrix. The Response Surface Methodology (RSM) were used to analyse experimental data and develop semi-empirical models. Semi-empirical drilling force models, which was developed for conventional materials, was modified to suit the drilling of MMCs and was verified with the present experimental study as well as the available data from the literature.

Cutting force, tool wear and surface finish in drilling metal matrix composites

In this paper the evolution of the cutting force, tool wear and surface finish, measured when drilling the metal matrix composite A356/20/SiCp-T6, is presented. The experimental work was developed through the continuous measurement of the torque with an appropriate piezoelectric dynamometer and the results were used to derive the cutting power (ranging from 0.1 to 0.4 kW) and the specific cutting pressure, K s (1700-3500 N/mm2). The tool wear type was identified and its evolution with cutting time was measured for different sets of cutting conditions, using polycrystalline diamond drills. The holes' surface finish was evaluated and very good results, exceeding standard values for drilling, were obtained ( R a between 0.25 and 1.2 μm).

Effect of drill wear on cutting forces in the drilling of metal-matrix composites

Holes were drilled in 6061 T-6 aluminum alloy as well as in a particle reinforced metal matrix composite (MMCp) consisting of 20 vol.% SiC particles, 12 Am in diameter, in a 6061 aluminum matrix (6061/SiC/20p, or Duralcan« F3S.20S). HSS (high speed steel) drills of 10 mm diameter were used, and measurements were made of thrust (normal force), torque and flank wear for several feed rates and drill speeds. It was found that when drilling Duralcan« with unworn drills, both torque and thrust varied with feed rate raised to the power 0.81, as for classical materials. When flank wear V b became significant, torque varied linearly with V b and with f°.s but no empirical relation with physically meaningful parameters was found to fit the thrust data. Speed had no significant effect on wear or on drilling forces. Flank wear proceeded linearly with depth of material drilled, or with the total distance passed by the lip or cutting edge of the drill. A linear relation between both thrust and torque against flank wear was observed, so that either thrust or torque may be measured to give an indication of wear of the drill. The linear relation between torque and wear of the drill implies a linear variation of specific cutting energy with flank wear. Drilling forces are controlled by the matrix material and not by the particles.