Performance Of Machining Process Research Articles

Parametric optimization of some non-traditional machining processes using artificial bee colony algorithm

Selection of the optimal values of different operating parameters is of utmost importance for enhancing the performance of various non-traditional machining (NTM) processes. The performance measures (responses) of different NTM processes usually include metal removal rate, surface roughness, radial overcut, tool wear rate, heat affected zone, etc. In this paper, artificial bee colony (ABC) algorithm is employed to search out the optimal combinations of different operating parameters for three widely used NTM processes, i.e. electrochemical machining, electrochemical discharge machining and electrochemical micromachining processes. Both the single and multi-objective optimization problems for the considered NTM processes are solved using this algorithm. The results obtained while applying the ABC algorithm for parametric optimization of these three NTM processes are compared with those derived by the past researchers, which prove the applicability and suitability of the ABC algorithm in enhancing the performance measures of the considered NTM processes.

Optimisation of electrical discharge machining process with CuW powder metallurgy electrode using grey relation theory

In this paper, an attempt has been made to correlate the usefulness of powder metallurgy (PM) electrodes in electrical discharge machining (EDM). This paper explains the same with the help of experimentation on AISID2 steel in kerosene with CuW (25% Cu and 75% W) PM electrode. An L18 orthogonal array was used to identify the effect of process parameters (viz. electrode material, duty cycle, flushing pressure and current) on the performance characteristics i.e., material removal rate surface roughness and surface hardness. A grey relation grade obtained from the grey relation analysis is used to solve the EDM process with multiple performance characteristics. Experimental results have shown that electric discharge machining process performance can be improved efficiently through this approach. It is found that copper tungsten PM electrode gives better multi-objective performance than conventional copper electrode.

Development of electrostatic solid lubrication system for improvement in machining process performance

Liquid lubricants have traditionally been used to control the high heat generation in machining; however, the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. Minimization or possible elimination of cutting fluids substituting their functions by some other means is emerging as a thrust area of research in machining. Solid lubricant assisted machining is a novel concept to control the machining zone temperature without polluting the environment. The focus of this study is to explore the possibility of application of graphite as a lubricating medium in drilling of AISI 4340 steel, as a means to reduce the heat generated due to friction, towards finding an alternative to conventional coolants. To this end, an optimized solid lubricant application method, electrostatic solid lubrication experimental setup has been envisaged for effective supply of solid lubricant mixture as a high velocity jet and at an extremely low flow rate to the machining zone, thus meeting environmental requirements. The process performance is judged in terms of thrust force, tool wear, chip thickness, hole diameter and surface finish of machined workpiece keeping the other conditions constant. A comparison with the results obtained in wet and dry machining is also provided. The results obtained from the experiments show the effectiveness of the use of the solid lubricant as a viable alternative to wet and dry machining through reduction in the cutting zone temperature and favourable change in chip–tool and work–tool interaction. The proper selection and application of solid lubricant can lead to low cost, and this concept could emerge as an effective alternative to conventional coolants.

Benefits of using real-time pulse discriminating system in micro-EDM monitoring and control system

This paper deals with the implementation of real-time pulse discriminating system for monitoring and improving the performance of micro electrical discharge machining (EDM) process. Currently, the average gap voltage information is applied to control micro-EDM process, ensuring that the process takes place in a proper gap state. In this work, a real-time pulse discriminating system is employed as the basic platform of micro-EDM control system for a more detailed interpretation of the state of micro-EDM process. Experimental verifications show that the pulse distributions are good indicators for predicting material removal rate (MRR) and tool wear ratio (TWR) of the ongoing process. Furthermore, the real-time pulse discriminating-based control system is able to shorten the machining time to half, that of a typical control system without pulse discriminating capability and also produce more accurate machined features.

Estimation of effective error parameters in high-speed micro-endmilling

In micro-endmilling, tool alignment errors and tool manufacturing errors such as flute deviation and cutting edge offset from the tool axis are relatively large compared to the associated chip load and machined features. Two effective error parameters have been defined to represent the effect of these errors on the machining accuracy and process performance: maximum radius of rotation and difference in the radii of rotation. Methods have been developed to estimate these parameters based on feature measurement on a machined artifact and acoustic emission signals during machining. Experiments were conducted to estimate the effective error parameters of three different tools at several different orientations. The estimation results show that there are significant variations in the effective errors among the tools, which indicates that estimation of the effective error parameters in micro-endmilling is important for achieving good processes performance on-line.

An Analytical Model for the Prediction of Minimum Chip Thickness in Micromachining

In micromachining, the uncut chip thickness is comparable or even less than the tool edge radius and as a result a chip will not be generated if the uncut chip thickness is less than a critical value, viz., the minimum chip thickness. The minimum chip thickness effect significantly affects machining process performance in terms of cutting forces, tool wear, surface integrity, process stability, etc. In this paper, an analytical model has been developed to predict the minimum chip thickness values, which are critical for the process model development and process planning and optimization. The model accounts for the effects of thermal softening and strain hardening on the minimum chip thickness. The influence of cutting velocity and tool edge radius on the minimum chip thickness has been taken into account. The model has been experimentally validated with 1040 steel and Al6082-T6 over a range of cutting velocities and tool edge radii. The developed model has then been applied to investigate the effects of cutting velocity and edge radius on the normalized minimum chip thickness for various carbon steels with different carbon contents and Al6082-T6.

Design of experiments to study and optimize process performance

Design of experiments is one of the many problem‐solving quality tools that can be used for various investigations such as finding the significant factors in a process, the effect of each factor on the outcome, the variance in the process, troubleshooting the machine problems, screening the parameters, and modeling the processes. Many industries use this tool to stay competitive worldwide by designing robust products as well as improving quality and reliability of a product. By using strategically designed and statistically performed experiments, it is possible to study the effect of several variables at one time, and to study inter‐relationships and interactions. Proposes a strategy to apply the design of experiments to study and optimize the performance of a process. Additionally, the formulation and solution to a multi‐objective optimization problem have been presented. As a case study, experimental design technique used by the authors to study the performance of a wire electrical discharge machining process for machining beryllium copper alloys is presented.

Improvement of EDM Performance With Advanced Monitoring and Control Systems

The electrical discharge machining (EDM) process performance depends on maintaining an appropriate machining gap with a servo system and discharge pulse parameters with a pulse power generator. The integration of the state-of-the-art monitoring and control technologies can substantially improve the performance of the EDM process. This paper reviews the research and development of advanced monitoring and control systems for die-sinking EDM and wire EDM during the last two decades. Important research activities include different EDM gap monitoring systems, servo and pulse adaptive control systems, and knowledge base control systems.

Mechanical design of a new tooling mechanism with on-line controllability of inclination angle

Tool angles are the very important parameters in determining the machining process performance and have significant effects on cutting force, tool wear, tool life, process stability, chip control, etc. This paper presents details of designing a new tooling mechanism which can change on-line the cutting edge inclination angle in turning operations. The mechanism is realised through the use of three specific slopes which work simultaneously to compensate the tooltip deviation due to the change of inclination angles so that the tooltip always stays at one point in space, i.e. its working point. The new tooling mechanism may be used to on-line control and optiimise the machining process.

Heat transfer through electrolytic solutions under the action of electrolytic currents

Heat transfer rates from an electrically heated thin platinum wire in dilute NaOH and Na 2CO 3 solutions of different concentrations have been measured under the influence of electrolytic currents, using a sensitive Kelvin double bridge. In the low concentration region, the rate of heat transfer is initially found to increase with concentration and then to decrease with further increase in concentration. An explanation of these results on the basis of the behaviour of the thermal boundary layer surrounding the hot wire electrode is suggested. It has been indicated that these results can be employed to improve the performance of boiler systems and electro chemical machining processes.