Papers by Keyword: Material Removal Rate (MRR)

Abstract: In this work, a Material removal rate (MRR), Tool wear rate (TWR), Radial and overcut (ROC), a study on the die-sinking Electrical discharge machining (EDM) of Al-LM6/SiC/B4C hybrid composites has been carried out. The selection of above-mentioned hybrid composite was made considering its widespread application in aerospace, automotive, defense, biomedical and marine industries, due to its light weight and higher mechanical properties. This experiment was made only for the finish stage and has been carried out on the influence of four design factors: composition, discharge current (Ip), Pulse-on-time (Ton), Radial overcut (ROC) and Duty factors (Tau), over the previously mentioned, responded variables. This has been done by means of the method of design of experiment (DOE) which allows us to carry out the above-mentioned analysis performing a relatively small number of experiments. The study indicates that when discharge current (Ip) increases, Material removal rate increased. In the case of Tool wear rate the most influencing factor is discharge current, then pulse on time. In radial over cut most influence factor is discharge current then pulse on time, duty factor and composition has least.

Abstract: Quality of the product is the major concern in manufacturing industries from customers as well as producers point of view. There are number of factors in the product such as surface condition, height, weight, length, width etc., which may be consider for the measurement of the quality. Surface roughness and Metal Removal Rate (MRR) are the two main outcomes on which numerous researchers have applied different approaches for several years to get optimum results. In this study, Taguchi Method is applied for getting optimum parameters settings for Surface roughness and Metal Removal Rate (MRR) in case of turning AlMg3 (AA5754) in CNC Lathe machine, which is an aluminum alloy having diameter 20 mm and length 100 mm. The three parameters i.e. spindle speed, feed rate and depth of cut with 3 levels are taken as the process variables and the working ranges of these parameters for conducting experiments are selected based on Taguchi’s L9 Orthogonal Array (OA) design. To analyze the significant process parameters; main effect plots for data means and for S/N ratio are generated using Minitab statistical software.

Abstract: Electro Chemical Discharge Machining (ECDM) process has been developed as an innovative machining process for machining non-conductive materials. The various application of this hybrid process is used in many industries like nuclear, medical and automobile industries. The scope of ECDM in micro machining of semiconducting materials is still found to be promising challenge for researchers. Due to many advanced properties of silicon, its use in MEMS industries is enormous. Many researchers have carried out lot of empirical estimation for discharges in ECDM. However very less work has been reported in the modelling of the ECDM process. Present work mainly concentrates on Finite Element Modelling (FEM) of micro holes machined on silicon wafers with ECDM process. A thermal FEM of spark discharge in the ECDM is carried out. The results from FEM are compared with experimental results and are found to be satisfactory. The model developed can be used for prediction of MRR for a particular combination of workpiece-tool arrangement.

Abstract: Electro Chemical Discharge Machining (ECDM) process is an innovative micro machining process to machine electrically conducting and non-conductive materials for micro level application. In this paper an attempt has been made to machine micro channels with ECDM process for micro fluidic application. Micro channels are machined for three different speeds for borosilicate glass with tungsten copper alloy tool of 300 micron diameter with optimized process parameters. Flow rate across micro channels are measured and are found to be reliable for micro fluidic application. Micro channels are found to have good surface finish when machined with optimal conditions. Micro ECDM process is found to be cheaper and faster process compared to existing machining operations in non-conducting materials.

Abstract: Geometrical precision machined surface is generally understood as mainly precision shape, orientation, location and run-out. As a rule, it is measuring the appropriate deviations from the nominal surface. The geometric size of this deviation from the nominal surface can in practice affect the conventionally measured value for the dimension and the dimension whilst maintaining the required tolerance. Because the WEDM technology is among the most accurate technology, the small final geometric accuracy deviation has also a negative impact on the final quality of the machined surface. The paper aimed to describe errors geometrical precision of machined surface which occurs in wire electrical discharge machining (WEDM) and quantify their scope.

Abstract: The paper describes the basic physical regularities of material removal in Electrical discharge machining (EDM) of tool steel. One of the parameters, that material removal regularities quite accurately identifies, is the tool wear rate (TWR). This parameter, however, describes only the regularities concerning the tool electrode wear. More complex parameter for assessing regularities of material removal in EDM is thus electrode wear ratio (EWR). This parameter, except the size of the wear of the tool electrode, also describes the size of the workpiece material removal. Research on material removal was carried out on samples made out of tool steel EN X32CrMoV12-28 using Cu-ETP electrode EN CW004A. Aim of this paper was also based on the selection of main process parameters that significantly influence the material removal in EDM to define the individual specifics with regard to minimizing EWR.

Abstract: Laser machining is one of the most widely used advanced noncontact machining processes used for creating new surfaces, structures, cavities and also complex electro-mechanical devices, usually with very small dimensions, by laser radiation. It is the process in which the material’s thermophysical properties rather than mechanical properties determine the machinability. Design of process parameters is highly critical for successful material removal and high machine surface quality. In the paper the laser beam milling is experimentally studied applying the nanosecond pulse fibre laser and alumina ceramic as working material. The influence of pulse energy, pulse repetition rate, scanning speed and tracks displacement on material removal efficiency and the quality of machined surface is reported.

Abstract: Cobalt-base alloys are normally applied to materials that require wear, corrosion, and heat resistance. Today, the alloy of cobalt–chromium–molybdenum (Co–Cr–Mo) is employed in aerospace and medical fields. Through the thermal erosion process of Electrical Discharge Machining (EDM), an electrically-produced spark vaporizes materials that are electrically conductive. This paper examines the viability of improvement of material removal rate in the micro-electric discharge machining of cobalt chromium molybdenum (Co-Cr-Mo) using Fe2O3 nanopowder-mixed dielectric fluid. For the purpose of this research, a copper electrode with 300μm diameter and positive polarity was utilized. The performance measures of the machining process were investigated regarding the material removal rate (MRR). For analysis of EDM of the CoCrMo, response surface methodology (RSM) was employed. Two concentrations of nanopowder were added to dielectric (2g/land 4g/l). Findings showed that if Iron oxide nanopowders (Fe2O3) exists in the dielectric, MRRcan be significantly improved. Amongst the two concentrations of powder-mixed micro-EDM, 2 g/l of nanopowder provided higher MRR in comparison with 4g/l and without powder cases.

Abstract: Sapphire is one of difficult-to-machine materials because of its high hardness and brittleness. It can be used for an optical window or cover named as sapphire glass and a substrate for semiconductor circuits. Before preparing the required surface roughness of sapphire substrate, the geometrical shape should be retained through mechanical machining processes. The lapping and diamond mechanical polishing (DMP) are essentially used for achieving the required thickness and surface roughness of sapphire substrate prior to chemical mechanical polishing (CMP). In this study, we introduce a lap grinding process using fixed abrasives to substitute lapping and DMP. The material removal rates (MRRs) were measured under various machining conditions. The semi-empirical model on MRR was introduced based on the information of grinding pallet. This paper may provide a preliminary experimental study on the lap grinding of sapphire substrate.

Abstract: Fluid Jet Polishing (FJP) is a promising ultra-precision machining technology which shows great potential with regard to the application value in the generation of freeform surfaces with sub-micrometre form accuracy and nanometric surface finish. The polishing tool influence function (TIF), which is affected by various parameters and commonly assessed in terms of width, maximum depth and volumetric material removal rate, is critically required for corrective polishing and deterministic machining. In this study, a series of experiments was conducted to study the effect of various process parameters on the polishing tool influence function. The polishing machine used is a Zeeko IRP 200 ultra-precision freeform polishing machine, with three linear axes and three rotational axes. All polishing experiments were performed on BK7, which is one of the most common technical optical glass materials for high-quality optical components in the visible range. These specimens were polished using Al₂O₃ (Aluminium oxide) abrasive particles and measured by a Zygo Nexview 3D Optical Surface Profiler. All these experiments were conducted by changing one process parameter and keeping the other process parameters constant. In this paper, the experimental results are described in detail to show the relationships between the material removal and the various parameters (i.e. slurry pressure, standoff distance, impingement angle, etc.), and some interesting experimental results are explained.