Showing papers by "Mozammel Mia published in 2018"

Modeling and optimization of tool wear in MQL-assisted milling of Inconel 718 superalloy using evolutionary techniques

Abstract: The Inconel 718 alloy, a difficult-to-cut superalloy with an extensive demand on aircraft and nuclear industries, being a low thermally conductive material exhibits a poor machinability. Consequently, the cutting tool is severely affected, and the tool cost is increased. In this context, an intelligent solution is presented in this paper—investigation of minimum quantity lubrication (MQL) and the selection of best machining conditions using evolutionary optimization techniques. A series of milling experiments on Inconel 718 alloy was conducted under dry, conventional flood, and MQL cooling modes. Afterward, the particle swarm optimization (PSO) and bacteria foraging optimization (BFO) were employed to optimize the cutting speed, feed rate, and depth-of-cut to minimize the flank wear (VBmax) parameter of a cutting tool. Though both the PSO and BFO models performed well, the validated results showed the superiority of PSO. Furthermore, it was found that the MQL performed better than the dry and flood cooling condition with respect to the reduction of the tool flank wear.

Influence of Ranque-Hilsch vortex tube and nitrogen gas assisted MQL in precision turning of Al 6061-T6

Abstract: Dry machining is undesirable to produce precision surface due to thermal adversities especially for a low melting point material such as Al 6061-T6. Likewise, the conventional flood cooling is neither economically viable nor eco-friendly. In this context, three novel cooling-lubrication (C/L) technologies namely the nitrogen gas cooling (NGC), nitrogen gas assisted minimum quantity lubrication (NGMQL) and Ranque-Hilsch vortex tube (RHVT) NGMQL are investigated along with the air cooling (AC) in turning with an attempt to reduce surface roughness (Ra) and tool flank wear (VBmax). The machining was conducted using uncoated WC insert at two-levels of cutting speed and feed rate; and, as medium of cooling/lubrication the nitrogen gas and/or canola oil is employed. The SEM and 3D topographic images were analyzed for the machined surfaces, worn tool surfaces and chips. Results showed that the RHVT-NGMQL revealed the least surface roughness and tool wear (∼75% improvement compared to other C/Ls). Notable wear modes were: in dry cutting the plastic deformation, BUE and adhesion; in NGC the BUE; in NGMQL the rubbing and adhesion; in RHVT-NGMQL the adhesion. In micro-level, no significant difference in chip structure was found for the studied C/L methods In addition, the Composite Desirability optimization was adopted to systematically minimize Ra and VB max concurrently. It was found that the optimum speed vc = 160 m/min and feed rate f = 0.06 mm/rev under RHVT-NGMQL C/L condition has the potential to generate a precision surface with a roughness value

Multi-Objective Optimization for Grinding of AISI D2 Steel with Al₂O₃ Wheel under MQL.

Abstract: In the present study, the machinability indices of surface grinding of AISI D2 steel under dry, flood cooling, and minimum quantity lubrication (MQL) conditions are compared. The comparison was confined within three responses, namely, the surface quality, surface temperature, and normal force. For deeper insight, the surface topography of MQL-assisted ground surface was analyzed too. Furthermore, the statistical analysis of variance (ANOVA) was employed to extract the major influencing factors on the above-mentioned responses. Apart from this, the multi-objective optimization by Grey⁻Taguchi method was performed to suggest the best parameter settings for system-wide optimal performance. The central composite experimental design plan was adopted to orient the inputs wherein the inclusion of MQL flow rate as an input adds addition novelty to this study. The mathematical models were formulated using Response Surface Methodology (RSM). It was found that the developed models are statistically significant, with optimum conditions of depth of cut of 15 µm, table speed of 3 m/min, cutting speed 25 m/min, and MQL flow rate 250 mL/h. It was also found that MQL outperformed the dry as well as wet condition in surface grinding due to its effective penetration ability and improved heat dissipation property.

Machinability Investigations of Inconel-800 Super Alloy under Sustainable Cooling Conditions.

Abstract: With regard to the manufacturing of innovative hard-machining super alloys (i.e., Inconel-800), a potential alternative for improving the process is using a novel cutting fluid approach. Generally, the cutting fluids allow the maintenance of a better tool topography that can generate a superior surface quality of machined material. However, the chemical components of fluids involved in that process may produce harmful effects on human health and can trigger environmental concerns. By decreasing the cutting fluids amount while using sustainable methods (i.e., dry), Near Dry Machining (NDM) will be possible in order to resolve these problems. This paper discusses the features of two innovative techniques for machining an Inconel-800 superalloy by plain turning while considering some critical parameters such as the cutting force, surface characteristics (Ra), the tool wear rate, and chip morphology. The research findings highlight the near-dry machining process robustness over the dry machining routine while its great potential to resolve the heat transfer concerns in this manufacturing method was demonstrated. The results confirm other benefits of these methods (i.e., NDM) linked to the sustainability aspects in terms of the clean process, friendly environment, and permits as well as in terms of improving the manufacturing characteristics.

Synthesis, Characterization, Corrosion Resistance and In-Vitro Bioactivity Behavior of Biodegradable Mg⁻Zn⁻Mn⁻(Si⁻HA) Composite for Orthopaedic Applications.

Abstract: Recently, magnesium (Mg) has gained attention as a potential material for orthopedics devices, owing to the combination of its biodegradability and similar mechanical characteristics to those of bones However, the rapid decay rate of Mg alloy is one of the critical barriers amongst its widespread applications that have provided numerous research scopes to the scientists In this present, porous Mg-based biodegradable structures have been fabricated through the hybridization of elemental alloying and spark plasma sintering technology As key alloying elements, the suitable proportions of silicon (Si) and hydroxyapatite (HA) are used to enhance the mechanical, chemical, and geometrical features It has been found that the addition of HA and Si element results in higher degree of structural porosity with low elastic modulus and hardness of the Mg⁻Zn⁻Mn matrix, respectively Further, addition of both HA and Si elements has refined the grain structure and improved the hardness of the as-fabricated structures Moreover, the characterization results validate the formation of various biocompatible phases, which enhances the corrosion performance and biomechanical integrity Moreover, the fabricated composites show an excellent bioactivity and offer a channel/interface to MG-63 cells for attachment, proliferation and differentiation The overall results of the present study advocate the usefulness of developed structures for orthopedics applications

Modeling flatness deviation in face milling considering angular movement of the machine tool system components and tool flank wear

Abstract: The torsional angle, χYDeg, of a machine tool-device-spindle unit is formulated in a face-milling operation. As there is no angular compliance in the technical specifications for the machine tool, a novel method is proposed for the determination of the angular compliance values of a GF2171S5 machine milling system. Deviation from flatness, ΔZfl, is therefore also modeled in this paper, for the first time, by considering the parameters of milling and tool wear. The proposed model performs an acceptable evaluation of various types of flatness deviation for different flank wear values. The face milling and tool-wear parameters and their influence on the torsional angle of the tool-device-spindle unit are calculated. Besides, the effects of different settings on the machining process and the material-cutting speed vc and depth ap, cutting-edge angles kr, and tool slenderness-lo/D in combination with various depths of flank wear VB on the torsional angle of the mill χYDeg and flatness deviation ΔZfl are investigated. This method of determining the angular torsional values can be applied to other milling machines. Moreover, the model can be used to compensate the torsional angle of the mill face, thereby minimizing the flatness deviation.

Investigations on Surface Milling of Hardened AISI 4140 Steel with Pulse Jet MQL Applicator

Abstract: In this article, an experimental investigation was performed in milling hardened AISI 4140 steel of hardness 40 HRC. The machining was performed in both dry and minimal quantity lubricant (MQL) conditions, as part of neat machining, to make a strong comparison of the undertaken machining environments. The MQL was impinged int the form of pulse jet, by using the specially developed pulse-jet-attachment, to ensure that the cutting fluid can be applied in different timed pulses and quantities at critical zones. The tool wear, cutting force and surface roughness were taken as the quality responses while cutting speed, table feed rate and flow rate of the pulse were considered as influential factors. The depth of cut was kept constant at 1.50 mm because of its less significant effects and the straight oil was adopted as cutting fluid in pulse-jet-MQL. The effects of different factors, on the quality responses, are analyzed using ANOVA. It is observed that MQL applicator system exhibits overall better performance when compared to dry milling by reducing surface roughness, cutting force and prolonging tool life but a flow rate of 150 ml/h has tremendous effects on the responses. This investigation and afterward results are expected to aid the industrial practitioner and researcher to adopt the pulse-MQL in high speed milling to prolong tool life, reduce tool wear, diminish cutting force generation and promote better surface finish.

Modeling of Surface Roughness Using RSM, FL and SA in Dry Hard Turning

Abstract: This paper presents the development of mathematical, predictive and optimization models of average surface roughness parameter ( $$R_{a}$$ ) in turning hardened AISI 1060 steel using coated carbide tool in dry condition. Herein, the mathematical model is formulated by response surface methodology (RSM), predictive model by fuzzy inference system (FIS), and optimization model by simulated annealing (SA) technique. For all these models, the cutting speed, feed rate and material hardness were considered as input factors for full factorial experimental design plan. After the experimental runs, the collected data are used for model development and its subsequent validation. It was found, by statistical analysis, that the quadratic model is suggested for $$R_{a}$$ in RSM. The adequacy of the models was checked by error analysis and validation test. Furthermore, the constructed model was compared with an analytical model. The analysis of variance revealed that the material hardness exerts the most dominant effect, followed by the feed rate and then cutting speed. Eventually, the RSM model was found with a coefficient of determination value of 99.64%; FIS model revealed 79.82% prediction accuracy; and SA model resulted in more than 70% improved surface roughness. Therefore, these models can be used in industries to effectively control the hard turning process to achieve a good surface quality.

Analysis of the Deviation in a Low-Cost System for Stepless Digital Control of Conventional Lathe Spindle Speeds

Abstract: A conventional manual lathe electric motor drives the multi-stage gearbox transmitting torque to the spindle so that the workpiece makes contact with the machine tool at a given speed. The cutting speed is proportional to both the diameter of the workpiece and the spindle speed, however, the increments in spindle speed are limited. Manual lathe machines cannot be regulated at the optimum cutting speeds for all diameters. An innovative modernization of the main driveline of a TSB16 manual lathe is proposed in this paper, allowing for a cost-effective system for digital control of spindle speeds using an inverter. The inverter is controlled using an 8-bit AO (analog output) converter with special software developed with Visual Basic. The results of the analysis and various test runs with this new system for automated control of spindle rotation, showed that the required cutting speed can be achieved for any workpiece diameter. The deviation of cutting-speed of the upgraded system for any turning diameter is greatly reduced in comparison with the deviation of cutting-speed of a manual lathe. Finally, tests on this versatile system demonstrated a cost-effective method for modernizing the drive system of conventional lathe machines.