Conditions For Material Removal Rate Research Articles

Optimization of machining parameters in EDM using Taguchi based grey relational analysis

The present investigation optimizes process parameters such tool size, peak current, pulse on time, and dielectric pressure in the EDM process. The material removal rate affects the machining operation's quality. The goal of the present work is to maximize material removal rate using Taguchi technique-based optimization of machining parameters. On an EDM, the experimental study for machining operations was carried out. For EN-31, machining operations are carried out using an orthogonal array with L9. The ANOVA technique was used to evaluate the experimental results. Using a technique called as grey relational analysis, the optimum conditions for material removal rate are determined. The optimum approach for a set of linked parameters is evaluated using the grey relation grade.

Assessment of CVD- and PVD-Coated Carbides and PVD-Coated Cermet Inserts in the Optimization of Surface Roughness in Turning of AISI 1045 Steel.

In this study, an experimental and statistic investigation approach based on analysis of variance (ANOVA) and response surface methodology (RSM) techniques was performed to find the significant main effects and two-factor interaction effects and to determine how the controllable factors such as cutting speed, feed rate, depth of cut (DOC), tool nose radius, substrate and coating method of cutting tools influence surface quality in turning of AISI 1045 steel. The first optimal or near-optimal conditions for the quality of the generated surface and the second ones, including maximum material removal rate, were established using the proposed regression equations. The group mean roughness of the turned workpieces was lower from using chemical vapor deposition (CVD)-coated carbide inserts than the group means of other types of inserts; however they could not achieve the specific lowest roughness. The physical vapor deposition (PVD)-coated carbide and cermet inserts achieved the best surface quality when the specific combinations within the range interval of controllable factors were used in the experiment, showing that they may be applied to finish turning processes or even to particular high material removal rate conditions associated with the lowest roughness.

A study on laser assisted acute angle milling strategies and preheating distance

Laser assisted machining (LAM) has emerged as one of the technologies that can be effectively employed to machine difficult-to-cut materials such as nickel alloy, ceramics and titanium that are increasingly used in the medical instruments, automobiles and aerospace industries. LAM has been widely studied, however most of those studies were basic research on turning or milling with a simple tool path. To machine complex shaped products in three dimensions further research on laser-assisted milling (LAMill) is required. In this study, laser assisted acute angle milling was proposed as a stepping stone for machining complex shapes. When acute angle machining was performed with LAMill, two factors affecting machining characteristics were identified. These factors were the preheating distance (dP) and distance between the laser beam focus and center of the cutting tool (dL). Prior to experimental verification, the proper depth of cut (DOC) and dP were determined by transient thermal analysis using the software ANSYS. Experiments were carried out using the same machining conditions for material removal rate (MRR) in order to confirm the effect of dP and dL on the machining characteristics. Experimental results showed that dP affects cutting force and dL affects tool wear. The range of dP and minimum dL needed to improving machinability during laser assisted acute angle milling were experimentally verified. Based on these results, the minimum acute angle that can be machined using LAMill was also derived.

Multi-objective machining parameter optimisation of aluminium alloy 6063 by the Taguchi-artificial neural network/genetic algorithm approach

This study investigates the turning of aluminium alloy 6063 to optimise the material removal rate (MRR) and surface roughness (Ra) simultaneously. L27 Taguchi's orthogonal experiments were conducted by incorporating machining parameters of speed (260, 470, 840 rev/min), feed (0.2, 0.3, 0.4 mm/rev) and depth of cut (0.5, 1.0, 1.5). Analysis of variance (ANOVA) and signal-to-noise ratio were applied to determine the optimal control settings and validated by confirmatory tests. The performance characteristics were modelled by second-order regression, artificial neural network (ANN) and genetic algorithm (GA). The results indicate that the optimal conditions for MRR (375 mm3/min) and Ra (1.298 μm) were in agreement with the confirmatory tests. Regression models showed that the optimal points for MRR and Ra can be enhanced by the effect of interactions, but the ANN predicted the experimental data with better accuracy. The GA further elicited a set of optimal solutions for improving machining performance.

Effect of tool design parameters study in micro rotary ultrasonic machining process

Selection of tooling to perform specific operations like drilling and milling on ceramic materials using rotary ultrasonic machining process is an important aspect to meet stringent dimensions on workpiece as well as intended performance of tool. This phenomenon is more critical for micro rotary ultrasonic machining. In the present study, an effort was made to do micro drilling operation of O0.3 mm tool with varying geometry, having different wall thicknesses and abrasive grain sizes using design of experiments. The effect of tool-based parameters like grain size and wall thickness has been studied on axial cutting force, radial cutting force, tool wear, edge chipping area and taper. After examining axial and radial cutting forces, it has been concluded that lower wall thickness (80 μm) tool is good for drilling operation; and higher wall thickness (100 μm) tool is good for milling operation under same material removal rate conditions. It has been also investigated that lower wall thickness (80 μm) tool has less edge chipping area and less taper and can impart high drilling depth as compared to higher wall thickness (100 and 150 μm) tool. It is also concluded that lesser grain size (15 μm) tools are advantageous in terms of edge chipping area and cutting force for drilling and milling operations as compared to higher grain size (30, 35 and 45 μm) tool at constant material removal rate. Higher grain size tools have been broken at 1.13 mm3/h material removal rate conditions due to bad profile accuracy. But higher grain size tools have worked fairly well at less material removal rate condition. Higher grain size tools produced less wear. Tool wear was found minimum in higher wall thickness (100 μm) tool having higher abrasive grain size (30 μm). Using inferred results, O0.3 mm drilling experiments have been carried out on six aerospace ceramic materials. Also, groove of 0.5 mm size using O0.3 mm optimised tool has been successfully carried out in sintered SiC.

Modeling of un-deformed chip thickness in RUM process and study of size effects in μ-RUM

Un-deformed chip thickness is a critical parameter in machining processes. Measuring un-deformed chip thickness experimentally is a complicated process, especially in micro machining and may not even be measured accurately. The un-deformed chip thickness has an influence on material removal rate, cutting forces, specific energy and surface finish etc. In ceramic machining, it is also an indication of material removal mode such as ductile or brittle fracture. In the present study, an effort is made to model undeformed chip thickness, cutting forces and specific cutting energy in rotary ultrasonic machining (RUM) applied to the side milling operation. RUM may be considered as super-imposition of ultrasonic vibrations on the grinding process. The kinematics of ultrasonic motion has been applied to the grinding for the development of the RUM process models. To validate the models, machining experiments have been performed on borosilicate glass in RUM and grinding modes. Percentage of ductile mode of fracture for the machined surfaces has been evaluated using SEM images. Surface roughness values have also been compared for the same material removal rate conditions to ascertain fracture mode. Developed models have been verified and found that ductile mode of fracture as well as surface finish were higher in RUM as compared to grinding process for same material removal rate. RUM process for six aerospace grade materials has also been tried using micro and macro tools and size effects studied.

Experimental investigations of ceramic machining using µ-grinding and µ-rotary ultrasonic machining processes: A comparative study

ABSTRACTComparative experimental investigations of µ-grinding and µ-rotary ultrasonic machining (µ-RUM) were made on borosilicate and Zerodur materials to know the efficacy of the processes for micro electro mechanical system (MEMS) application. The electroplated diamond tool of Ø 300 µm for drilling operation and Ø 300 µm to Ø 6 mm for milling operation has been tried in the computer numerical control (CNC) machine with an HSK63 ultrasonic actuator. A suitable interface has been developed to hold the micro tool with the ER11 taper in the existing ER20 collet ultrasonic tool holder. Cutting force, edge-chipping area, and taper in drilling operation; and surface finish, material removal mode, specific energy and un-deformed chip thickness in milling operation were evaluated for both processes under the same material removal rate conditions. The experimental results showed that µ-RUM could perform in a less spindle speed machine as compared to µ-grinding. It was inferred that the maximum and minimum amount of reduction in cutting force, edge chipping, and taper were found to be (49.3%, 10.8%), (87%, 40%), and (95.56%, 4.76%), respectively, in µ-RUM compared to µ-grinding for drilling operation. It was also concluded that surface finish and ductile mode of fracture were higher in µ-RUM compared to µ-grinding for the milling operations. These effects were more pronounced as tool size decreased.

Analysis of Response Variables in WEDM of Inconel 718 Using Taguchi Technique

Wire Electrical Discharge Machining (WEDM) is used extensively in the machining of conductive materials where it is essential to generate intricate and complex shapes with higher dimensional accuracy and surface finish. The applications are in the field of aerospace, automobile, mould making and medical industries. Over the years, WEDM has remained as a competitive and economical machining option fulfilling the machining requirements imposed by the short product development cycles and the growing cost pressures. Taking into consideration the development of mechanical industry, demands for alloy materials having high hardness, toughness and impact resistance are increasing. Machine tool industry has also made exponential growth in its manufacturing capabilities in last two decade but still machine tools are not utilized at their full potential. This limitation is a result of the failure to run the machine tools at their optimum operating conditions. The problem of arriving at the exact analysis of the operating parameters has attracted the attention of the researchers and practicing engineers for a very long time. In the present work, an attempt has been made to analyse the machining conditions for Material Removal Rate (MRR), Surface Roughness (SR), cutting width (kerf) and dimensional deviation during WEDM of Inconel 718 using DoE such as Taguchi methodology, L8 Orthogonal Array. The experimental analysis is carried out using Minitab 16 software and it was observed that pulse-on-time is the most influential factor for all the response variables such as MRR, SR, Kerf and dimensional deviation at 95% confidence level, with contributions of 54.32%, 58.42%, 83.21% and 36.11% respectively. Along with this, peak current was observed to be next significant parameter for kerf and dimensional deviation whereas for MRR and SR servo voltage was observed to be the next significant parameter.

Environmental Impact Characterization of Milling and Implications for Potential Energy Savings in Industry

Since machining is a prevalent process in product manufacture this study reviews the accuracy of a specific energy characterization model to predict the electrical energy consumed by a 3-axis milling machine tool during processing. The energy characterization model had an accuracy of 97.4% for the part manufactured under varied material removal rate conditions and highlighted the potential for energy reduction using higher cutting speeds. Interviews with cutting tool manufacturers and end users showed that there is a genuine potential for energy reduction during milling operations due to the extensive use of uncoated cutting tools in industry.

An empirical study of parameters in abrasive jet machining

Abrasive jet machining (AJM) is a process that removes material by directing a high velocity stream of abrasive particles onto a workpiece. This paper reports a study of the results of machining under various conditions. A commercial AJM machine was used, with nozzles of diameter ranging from 0.45 to 0.65 mm, the nozzle materials being either tungsten carbide or sapphire, both of which have high tool lives. Silicon carbide and aluminium oxide were the two abrasives used. Other parameters studied were nozzle tip distances (5–10 mm), spray angles (60° and 90°) and pressures (5 and 7 bars). The materials machined were glass, ceramics, and electro-discharge machined (EDM) die steel. Material removal rate and the machined cavity dimensions were measured. The blind holes that were drilled were found to be not circular and cylindrical but almost elliptical and bell mouthed. High material removal rate conditions did not necessarily yield small narrow clean-cut machined areas, a desirable factor for AJM applications. Empirical evaluation was carried out to characterize quantitatively the effects of various machining conditions. During the course of these investigations a red hot region was found to form under certain conditions and accompanied by high material removal; a metallurgical study of this red hot zone and its relation to optimum AJM machining conditions are presented.