Performance Of Machining Process Research Articles

Improving the Performance of the Machining Process by Using Ultra‐Advanced Tools in a Clean Turning of Inconel 686 Using the Minimum Quantity Lubrication Method

ABSTRACTThe high tensile strength and high resistance of nickel‐based superalloy 686 against high temperatures and corrosion rates have made it a widely used in important applications such as the aerospace industry, high pollution‐ and corrosion‐resistance equipment manufacturing and petrochemical industry. Therefore, the machining of this advanced alloy with its unique properties is extremely important and can be challenging. Significant increase in input parameters levels, reduction of machining costs, improvement of surface and subsurface properties and clean production are among the issues that should be considered in dealing with Inconel 686 turning operations. Simultaneous application of advanced tools such as polycrystalline diamond (PCD) and polycrystalline cubic boron nitride (PCBN) and optimised minimum quantity lubrication (MQL) method and evaluating the results obtained with a wide range of output parameters related to machining process performance and tribological properties can be proposed as an innovation and a solution to this problem in this article. This study analyses several output parameters with different speeds and feeds to evaluate the effect of cutting insert type on machining process performance and tribological properties. The output parameters include tool wear, residual stress, cutting zone temperature, surface smoothness, machining forces and workpiece surface defects. The results indicated that using the optimised MQL method reduces the size of lubricant droplets and increases the surface covered by cooling. With these changes, the performance of the machining process and the parameters related to the surface integrity increase significantly. Among the parameters associated with the performance of the machining process, the PCD tool reduces the cutting zone temperature by 23%, the tool wear by 19% and the machining forces by 18% compared to the PCBN tool. In the parameters related to surface integrity, this method reduces the residual stress by 19% and the surface roughness by 9% compared to the PCBN tool. From the production index perspective, the PCD tool can significantly increase the cutting speed and feed rate, reducing production time and costs.

Experimental investigations and process optimization of SKD61 for sinking EDM

ABSTRACT Electrical parameters are vital for electrical discharge machining (EDM) process performance. The study utilized the combination of Taguchi and grey relational analysis (GRA) to optimize sinking EDM. Optimization of peak current, pulse duration, duty ratio and electrode lifting time affecting material removal rate (MRR), relative electrode wear rate (REWR) and surface roughness (SR) in sinking EDM. Analysis of variance (ANOVA) shows that peak current and pulse duration significantly affect MRR and REWR, respectively. Peak current and pulse duration significantly affect SR. The optimized parameters were subjected to EDM experiments and the results are 8.54% increase in MRR, 11.11% decrease in REWR and 9.42% decrease in SR. It was found that at a peak current of 1A, the discharge pit not only depends on peak current and pulse duration but also on pulse off time. Compared to conventional optimization methods, this study analyzed the microstructure and recast layer of the workpieces.

Fundamental investigation on the time-variance of process stability

Disturbance factors, such as self-excited tool vibrations, limit the performance of modern machining processes and thus restrict the quality, productivity and sustainability of industrially manufactured components. The dynamic process stability is subjected to significant variances especially at the beginning of the tool life. To precisely quantify these variances, series of milling tests were conducted and analyzed using tools made of high speed steel (HSS) and cemented carbide for the machining of EN AW-7075. In all test series, a critical initial decrease of the stability limit was detected directly at the beginning of the tool life. In the following, a significant increase and subsequent almost constant stability limit was observed. In the case of the HSS cutters the achieved stability limit exceeded the initial level substantially. An increase in the process forces and flank wear was also measured over tool life but the progression cannot directly explain the extend and characteristics regarding the stability limit. The findings described have a considerable impact on the appropriate design of manufacturing processes and experiments to determine the dynamic stability of cutting operations.

Understanding tool chip interaction through experimental and numerical analysis during vibration assisted turning of AISI D3 steel

Vibration Assisted Turning (VAT) is a hybrid machining process where the material is machined with the help of a tool vibrating at ultrasonic frequency. VAT results in significant changes in process characteristics compared to conventional machining, like reducing the machining forces and tool wear. The chips produced during the machining operation can provide valuable insight into the process characteristics like machining zone temperature, friction at the tool-chip interface and chip load that primarily alter the process performance. One can understand and have a better control on the machining process performance by studying the formation of these chips and the tool-chip interaction. The work presents an experimental and numerical study to analyze the chip formation during VAT while machining AISI D3 steel. The chips formed while machining at different vibration amplitudes were observed to be of different colors, widths, and thicknesses. These were found to correlate to the forces generated and the surface integrity produced. A decrease in the chip width and thickness was observed with an increase in the amplitude that helps to reduce the chip load and hence forces. Also, the temperature at the machining zone increased with an increase in amplitude as seen from different color of chips produced and carbon content of the chip. The numerical model, developed to analyze the effect of the vibration amplitude on the contact pressure at the chip-tool interface, showed that the average contact pressure reduced upon applying ultrasonic vibration to the tool, thereby reducing the coefficient of friction and frictional forces. Also, with increase in vibration amplitude, the coefficient of friction was found increasing but it still remained lower than that in conventional turning. The study would help to understand the reduction the overall machining forces and chip morphology and thereby to have a better control on the process performance.

Experimental Investigation of the Derivative Cutting When Machining AISI 1045 with Micro-Textured Cutting Tools

In the context of satisfying sustainability requirements nowadays, dry machining is one of the ideal strategies to eliminate the environmental and human health burdens of machining processes. In addition, micro-textured cutting tools are used to improve the performance of dry machining processes. Micro-textures reduce the chip-tool contact length and thus reduce friction and heat, which results in fewer cutting forces and temperature. However, the action of micro-cutting of the bottom side of the chip, which is known as derivative cutting, cuts down the gains of using textured tools, where derivative cutting leads to higher cutting forces, heat, and tool wear. This study aimed to investigate the effects of significant texture design parameters (i.e., micro-groove width) when cutting AISI 1045 steel using different machining parameters (i.e., 75 m/min and 150 m/min of cutting velocity, 0.05 and 0.10 mm/rev of feed). Three different textured cutting tool designs were prepared using the laser texturing technique and then utilized in machining experiments. In addition, the measured machining outputs were forces, power consumption, flank wear, and surface roughness. There were no marks for the derivative cutting when using the textured cutting tool with the narrowest micro-grooves according to the obtained microscopical images after the machining tests. In addition, the textured cutting tool, which included the narrowest micro-grooves, showed better performance compared to the non-textured cutting tool and the other textured tool designs in terms of cutting and feed forces, power consumption, flank tool wear, and surface roughness at the used cutting conditions. This confirmed that the careful optimal design of the micro-textured tools can reduce or eliminate the severity of the derivative cutting, and thus improve the overall machining performance.

Parametric Analysis of Surface Roughness and Metal Removal Rate during Electrical Discharge Machining of O1 Tool Steel

This work studies the impact of input machining parameters of Electrical Discharge Machining (EDM) on the machining process performance. Tool steel O1 was selected as the workpiece material, copper as the electrode material, and kerosene as the dielectric medium. Experimental runs have been carried out with a Design of Experiment (DOE) technique. Twenty tests are accomplished with the current range of (18 to 24 Ampere), a pulse duration range of (150 to 200 µs), and a pulse-off time range of (25 to 75 µs). Based upon the experimental study's output results, the EDM parameter's effect (voltage of power supply, discharge current, pulse duration, and pulse pause interval) on the responses of the process represented by surface roughness value Ra and Metal Removal MR rate. The results obtained by the DOE approach are analyzed by STATISTICA software. It has been concluded that an increase in the current and pulse duration maximizes both metal removal rate and surface roughness. At the same time, they are minimized by maximizing the pulse pause interval.

A Numerical Model for Predicting the Effect of Tool Nose Radius on Machining Process Performance during Orthogonal Cutting of AISI 1045 Steel.

This paper presents the development of a numerical model for predicting and studying the effects of tool nose geometries and its interactions with cutting parameters during orthogonal cutting of AISI 1045 steel. The process performance characteristics studied were cutting temperature, effective stress, cutting forces and tool wear. The cutting simulations were done using the commercial DEFORM-2D R V 11.3 software, based on the finite element method (FEM). The cutting tool used had a round nose with various nose radii (0.01–0.9 mm), while the machining parameters tested were the feed rate (0.1–0.3 mm/rev), the cutting speed (100–500 m/min) and the rake angle (–5° to +10°). The interactions between the tool nose radius and the cutting parameters (speed, feed) were found to affect mostly the cutting stress and, slightly, the tool wear rate. These interactions did not much influence the cutting temperature, that was found to be high when the tool nose radius and/or the cutting speed were high. The maximum temperature was found to occur at the middle of the tool-chip contact length and at the interaction of nose radius and flank face of the tool. Except for some fluctuations, there was no significant difference in tool wear rate between small and large nose radius scales.

Performance monitoring and failure prediction system for wire electric discharge machining process through multiple sensor signals

This study aims to develop a pulse classification algorithm to understand wire electric discharge machining (wire EDM) process stability and performance based on the discharge pulse characteristics. Also, a process data driven failure prediction system is proposed. The wire EDM monitoring system includes high sampling rate differential probes and current probes. The features extracted through pulse train analysis were spark discharge energy, ignition delay time, spark frequency and proportion of various discharges. A pulse discrimination algorithm was proposed, which classifies the discharges into open circuit sparks, arc discharges, short circuit sparks and normal sparks. It was observed that higher proportions of short circuit pulses resulted in inferior part quality. The differences in the pulse cycle during stable and unstable machining were studied based on the extracted features. It was found that the discharge frequency and the proportion of arc and short circuit pulses were extremely high before the wire breakages. An artificial neural network (ANN) model was developed to predict the process responses, like cutting speed and surface roughness, from the process data. Also, an intelligent algorithm was developed based on the extracted in-process data to predict the unstable conditions, leading to machining failures. The accuracy of the algorithm was confirmed to be very high by conducting confirmation tests.

Graphene applications in Unconventional Machining Processes –A review

Graphene is being involved widely in research worldwide because of its unique properties such as high thermal conductivity and electrical conductivity, which are very important in machining the hardest materials by Unconventional Machining Processes. Due to the unique properties of Graphene, the researches focusing on improving the performance of Unconventional Machining Processes diverts their researchers to analyze Graphene applications in those processes. Many types of research carried out in the analysis of Graphene as a wide variety of applications in Electrical Discharge Machining and Wire Cut Electrical Machining. In this paper, the applications of Graphene as a different role are reviewed and summarized.

Development and Investigation of an Inexpensive Low Frequency Vibration Platform for Enhancing the Performance of Electrical Discharge Machining Process.

Difficulty in debris removal and the transport of fresh dielectric into discharge gap hinders the process performance of electrical discharge machining (EDM) process. Therefore, in this work, an economical low frequency vibration platform was developed to improve the performance of EDM through vibration assistance. The developed vibratory platform functions on an eccentric weight principle and generates a low frequency vibration in the range of 0–100 Hz. The performance of EDM was evaluated in terms of the average surface roughness (Ra), material removal rate (MRR), and tool wear rate (TWR) whilst varying the input machining parameters viz. the pulse-on-time (Ton), peak current (Ip), vibration frequency (VF), and tool rotational speed (TRS). The peak current was found to be the most significant parameter and contributed by 78.16%, 65.86%, and 59.52% to the Ra, MRR, and TWR, respectively. The low frequency work piece vibration contributed to an enhanced surface finish owing to an improved flushing at the discharge gap and debris removal. However, VF range below 100 Hz was not found to be suitable for the satisfactory improvement of the MRR and reduction of the TWR in an electrical discharge drilling operation at selected machining conditions.

Influence of Cutting Parameters to Surface Area Roughness in Dimple Machining Using Milling Process

Surface quality is among the predominant criterion in measuring machining process performance, including milling. It is extremely dependent on the process variable, such as cutting parameters and cutting tool conditions. The main intention of this research work is to study the effect of the milling machining parameters, including depth of cut, spindle speed, feed rate as well as machining pattern to the final surface area roughness of the fabricated dimple structure. The concave profile of the dimple is machined at the right angle to a flat Al6061 specimen using a ball end mill attached to a 3-axis CNC milling machine, and the surface area of the concave profile is measured using 3D measuring laser microscope. It is observed that surface area roughness reacts with the spindle speed and feed rate with different tool sizes. Based on the result gained, the work has successfully characterised the influence of studied milling parameters on the dimple surface area roughness, where within the range of the studied parameter, the surface area roughness varies only less than 2.2 μm. The research work will be continued further on the incline milling technique and micro size ball end mill.

Improving the Performance of Steel Machining Processes through Cutting by Vibration Control.

Machining processes through cutting are accompanied by dynamic phenomena that influence the quality of the processed surfaces. Thus, this research aimed to design, make, and use a tool with optimal functional geometry, which allowed a reduction of the dynamic phenomena that occur in the cutting process. In order to carry out the research, the process of cutting by front turning with transversal advance was taken into account. Additionally, semi-finished products with a diameter of Ø = 150 mm made of C45 steel were chosen for processing (1.0503). The manufacturing processes were performed with the help of two tools: a cutting tool, the classic construction version, and another that was the improved construction version. In the first stage of the research, an analysis was made of the vibrations that appear in the cutting process when using the two types of tools. Vibration analysis considered the following: use of the Fast Fourier Transform (FFT) method, application of the Short-Time Fourier-Transformation (STFT) method, and observation of the acceleration of vibrations recorded during processing. After the vibration analysis, the roughness of the surfaces was measured and the parameter Ra was taken into account, but a series of diagrams were also drawn regarding the curved profiles, filtered profiles, and Abbott–Firestone curve. The research showed that use of the tool that is the improved constructive variant allows accentuated reduction of vibrations correlated with an improvement of the quality of the processed surfaces.

Machining quality comparison of Al-TiB2 composite using conventional EDM and magnetic force-assisted powder-mixed EDM

ABSTRACT Now a day’s researchers are working hard to improve the process performance of unconventional or advanced machining processes by hybridising them with other mechanisms. In the present research, a hybrid variant of electrical discharge machining (EDM) has been proposed by developing a setup to create a rotating magnetic field near the machining zone and also by mixing a conductive powder (chromium, 325 mesh size) on a separate dielectric tank. The machining performance of indigenously developed hybrid magnetic force assisted powder mixed electric discharge machining (MFPEDM) has been compared with conventional EDM during machining of Al-TiB2 metal matrix composite. The comparison results elucidate considerable improvements in material removal rate (39.27%), surface finish (54.45%), and overcut (44.97%) by MFPEDM as compared to EDM.

Parametric Optimization and Effect of Nano-Graphene Mixed Dielectric Fluid on Performance of Wire Electrical Discharge Machining Process of Ni55.8Ti Shape Memory Alloy.

In the current scenario of manufacturing competitiveness, it is a requirement that new technologies are implemented in order to overcome the challenges of achieving component accuracy, high quality, acceptable surface finish, an increase in the production rate, and enhanced product life with a reduced environmental impact. Along with these conventional challenges, the machining of newly developed smart materials, such as shape memory alloys, also require inputs of intelligent machining strategies. Wire electrical discharge machining (WEDM) is one of the non-traditional machining methods which is independent of the mechanical properties of the work sample and is best suited for machining nitinol shape memory alloys. Nano powder-mixed dielectric fluid for the WEDM process is one of the ways of improving the process capabilities. In the current study, Taguchi’s L16 orthogonal array was implemented to perform the experiments. Current, pulse-on time, pulse-off time, and nano-graphene powder concentration were selected as input process parameters, with material removal rate (MRR) and surface roughness (SR) as output machining characteristics for investigations. The heat transfer search (HTS) algorithm was implemented for obtaining optimal combinations of input parameters for MRR and SR. Single objective optimization showed a maximum MRR of 1.55 mm3/s, and minimum SR of 2.68 µm. The Pareto curve was generated which gives the optimal non-dominant solutions.

Regression and ANFIS-based models for predicting of surface roughness and thrust force during drilling of biocomposites

Biocomposites are increasingly being applied in the automotive industry. For assembly purpose, drilling process is often performed in these biocomposites parts to produce holes. The machining behavior of biocomposites is affected by the matrix, the reinforcements (nature and size), by the cutting conditions and the mechanical properties of biocomposites. Some of the newly developed biocomposites are made of a polypropylene/polyolefin blend matrix, which has low thermal conductivity and low softening temperature. Therefore, the selection of cutting parameters should be done with care to avoid thermal-induced damages occurred during drilling biocomposites. Also, due to the heterogeneous and anisotropic properties of biocomposites, it is essential to develop models for predicting the effects of these factors on the machining process performance indicators. In this research work, a full factorial design is used to investigate the effects of machining parameters (feed rate, drill diameter, spindle speed, and reinforcement type) on machinability indicators during the drilling of the three new biocomposites: Polypropylene/Polyolefin matrix reinforced with biocarbon particles and/or miscanthus fibers. The regression and ANFIS-based models are established for predicting thrust force (Ft) and surface roughness (Ra) based on empirical data. The results obtained show that, for each tested biocomposite, the proposed ANFIS models have better predictive accuracy for thrust force and surface roughness than the regression-based models. Furthermore, the drilling parameters and reinforcements used in these biocomposites considerably affect their machinability.

Improvement in machining process performance using solid lubricant assisted minimum quantity lubrication

ABSTRACT To improve the quality of the product produced considering productivity, it is important to evaluate the factors affecting the machining experimentally and analytically. Looking at the harmful effects of conventional cutting fluid on the environment and workers’ health, in the current research work effort has been made to explore the effectiveness of minimum quantity lubrication (MQL) and solid lubricant in machining. Micron-sized calcium fluoride (CaF2) solid lubricant powder particles are mixed in SAE 40 cutting oil and applied to the machining area with minimum quantity lubrication. The effect of different particle sizes and wt% of CaF2 has been analysed by measuring surface roughness, chip-tool interface temperature, flank wear of the tool, and cutting forces. Results demonstrated that the smaller size and 20 wt% of CaF2 powder have improved the process performance by lowering surface roughness and tool wear. The effectiveness of solid lubricant can be viewed as an alternative compared to wet machining. The results can be used by related industries to improve machining performance with the use of MQL and solid lubricants leading towards clean and sustainable manufacturing.

A review on various methods to improve process capabilities of electrical discharge machining process

The propensity to increase the machining performance of various electric discharge machining (EDM) processes is becoming more and more prominent by many researchers. The exploitation of vibration to the workpiece, tool, and dielectric fluid in various mediums like fluid and gas, the addition of additives to dielectric medium examined by the researchers. The results of the research show a significant improvement in the process in terms of enriched material removal rate (MRR), reduced tool wear, and quality finish. This research article reviews the application of vibration to the electrodes, dielectric medium, and the use of different additives in a dielectric medium in various EDM processes. The review of various vibration-assisted techniques, powder mixed EDM, and their impact on output performance parameters have been described. Literature suggested that the exploitation of vibration to the electrodes enhanced the output process parameters in terms of higher MRR, minimum tool wear, and superior surface quality due to optimum flushing performance of contaminants from the gap. The application of vibration also reduced the short-circuiting, increased discharge frequency, and stabilizes the machining process. The literature on adding additives in various EDM processes also reported a significant improvement in the machining performance by reduced short-circuiting thereby reducing insulating characteristics of the dielectric medium. Based on the review the research opportunities for researchers for further research have been identified to strengthen the capabilities and capacity of various EDM processes.

Design and performance analysis of Multi-linear Horn for Ultrasonic machining application using FEM approach

This work reports an ultrasonic horn design and development for improving the performance of ultrasonic machining process in terms of better material removal rate for the same input conditions. The suitable operating frequency range (20 kHz-25 kHz) of the horn is analyzed with the help of finite element approach using the Ansys and for modelling Creo software is used. Typically, the machining tool vibrates around 10-20 μm, but for effective machining requires the more magnitude or intensity (80-200 μm) of vibration within this frequency range. Performance of ultrasonic horn mainly depends on the geometrical aspects and type of material used. In this work, we focus on the ultrasonic horn with an innovative design compared to earlier reported works to obtain the maximum magnification factor within permissible stress limits. The standard criteria “stresses below the permissible limit and mode shapes at different resonance frequencies (modal analysis)” are considered while designing the horn for avoiding the tool and horn failures during machining. The optimum numbers of elements are identified to mitigate computational time based on the optimum mesh criteria. In this study, we have analysed the equivalent stresses, magnification factor (ratio of output to input amplitude) of the horn by harmonic response analysis, which can be used to arrive at the effective machining processes. Finally, the magnification factor is increased within the safe stress limit using our innovative horn design. Newly, designed horn’s performance is compared and validated with the earlier reported literature at a similar input parameters or loading conditions.

Study on Machining Process Performance of Turbine Blade Based by MQL

MQL (Minimum Quantity Lubrication) is a potential solution for green cutting, but there is several process problem for application. Based on the precise control of the main parameters such as oil quantity, air pressure and target distance of micro lubrication, this paper applied the orthogonal experiment for process optimization. Finally, a comparative test of micro lubrication with dry-machining, air and pouring cooling was carried out. The test results show that the MQL can effectively reduce tool wear, cutting force and surface roughness, verifying the feasibility of micro lubrication processing technology for high-temperature parts of turbine blade materials.

Effect of WEDM parameters on material removal rate and kerf’s width of cobalt chromium molybdenum using full factorials design

ABSTRACT The use of non-conventional process for machining superalloys provides a better alternative compared to conventional machining. Conventional tool oriented processes like CNC machining demands higher manufacturing cost resulted from higher tool wear rate. In contrast, modern machining processes like Wire Electro-Discharge Machining (WEDM) eliminates such cost by offering contactless machining. This research investigated the effect of WEDM machining parameters, namely pulse-on-time (Ton ; 2 µs – 6 µs), pulse-of-time (Toff ; 10 µs – 30 µs), and peak current (Ip ; 10A – 14A) on the material removal rate (MRR), kerf’s width and surface integrity when machining cobalt chromium molybdenum (CoCrMo). Design of Experiment (DOE) with experimental runs of 11 full factorials design was deployed to determine the optimum parameter interaction. The result was analysed using analysis of variance (ANOVA) and mathematical models were developed to determine the relationship between the machining parameters and process performance (MRR and kerf’s width). Confirmation tests were then performed to ensure the adequacy of the result. It was found that the most significant parameter that affected both MRR and kerf’s width was pulse-on-time (Ton ). The optimum result could be achieved when pulse-on-time (Ton ) was set at a high level (6 µs) for MRR and low level (2 µs) for kerf’s width.