Machinability Aspects Research Articles

Introducing new green machining technology to enhance process performance and reduce environmental pollution in the metal processing industry.

The pursuit of enhanced cooling and lubrication methods for machining processes that are energy-efficient, environmentally friendly, and cost-effective is receiving significant attention from both academia and industry. The reduction of CO2 emissions is closely tied to electrical and embodied energy consumption. This study introduces a novel LN2 oil-on-water (LNOoW) cooling/lubrication (lubricooling) approach for the machining of Ti-6Al-4V alloy. Machinability aspects, energy-related aspects, environmental-related aspects, and economic aspects are measured and compared. More specifically, surface quality, electrical energy, cutting forces, and tool wear were measured in machinability aspects. Similarly, specific total energy and specific cumulative Energy Demand (S_CED), specific carbon emission, and production costs were measured to investigate the energy and environmental and economic aspects, respectively. The LNOoW provided the best machinability results compared with other approaches. Result found that LNOoW produced 37.5% better surface quality, removed 159.17% more material, and reduced 50.56% specific cutting energy and 53.63% specific costs as compared to traditional dry cutting conditions. The 39% increment in specific carbon emissions observed in the LN2 oil-on-water (LNOoW) approach in comparison to the dry-cutting method can be mitigated through the implementation of sustainable practices in the production of liquid nitrogen (LN2). The information provided in this study serves as a valuable resource for the development of environmentally friendly machining processes. The study also helps get the sustainable development goals (SDGs) of the United Nations.

MACHINABILITY ASPECTS OF NON-TEXTURED AND MICRO-TEXTURED CUTTING INSERTS IN TURNING OF TITANIUM Gr 2

The machinability of a cutting tool merely depends on cutting temperature, surface finish, and tool life, etc. To investigate the machinability of non-textured plain cutting inserts and micro-textured cutting inserts, various novel micro-textures have been fabricated using a femtosecond laser machine on the rack face of the double-sided square cutting insert without amputating its TiCN coating. The turning operation has been performed on a Titanium Gr 2 rod of diameter 50 mm on a three-jaw self-centered lathe machine. Type of insert, rotational speed, and cutting feed rate are the main parameters with various levels. L27 orthogonal array has been used for the design of experiments. Significant reduction in cutting tool temperature and surface roughness has been observed using micro-textured cutting inserts. The cutting insert with Honeycomb micro-texture gives superior results with a minimum cutting temperature of 210∘ C and a maximum of 76% improvement in surface finish.

Parametric Optimization of Powder-Mixed EDM of AA2014/Si3N4/Mg/Cenosphere Hybrid Composites Using Fuzzy Logic: Analysis of Mechanical, Machining, Microstructural, and Morphological Characterizations

This research focuses on a comprehensive exploration of the experimental and mechanical aspects of the electrical discharge machining (EDM) process, specifically targeting the machining characteristics of AA2014/Si3N4/Mg/cenosphere hybrid composites. The aim is to optimize the process parameters for enhanced machining performance through a combination of testing, optimization, and modelling methodologies. The study examines the effects of key EDM variables—peak current, pulse on time, and pulse off time—on critical output responses: surface roughness (Ra), electrode wear rate (EWR), and material removal rate (MRR). Leveraging an L9 Taguchi orthogonal array experimental design, the impact of controllable factors on these responses is analysed. An integrated approach utilizing MATLAB’s logic toolbox and Mamdani’s technique is employed to model the EDM process, and a multiple-response performance index is calculated using fuzzy logic theory, enabling multiobjective optimizations. Furthermore, a mechanical behaviour evaluation of AA2014/Si3N4/Mg/cenosphere hybrid composites is performed through mechanical testing, with a comparison between experimental machining results and predicted values. Scanning electron microscopy (SEM) images reveal the presence of filler reinforcements within the base alloy, displaying an improved microstructure and uniform reinforcement dispersion. An X-ray diffraction (XRD) analysis confirms the major elemental constituents—aluminium, silicon, and magnesium—in the hybrid composites. A microstructural analysis of the hybrid metal matrix composites (MMCs) prepared for EDM showcases closely packed reinforcement structures, circular ash-coloured spots indicating silicon and nitrates, and a fine dispersion of cenosphere reinforcement particles. The study’s outcomes demonstrate a promising application potential for these hybrid composites in various fields.

Comparative performance investigation and sustainability assessment in electrical discharge machining of SS316 using different dielectrics

In electrical discharge machining, the material removal phenomenon is heavily influenced by the breakdown strength of the dielectric fluid and the inter-electrode gap monitoring. This innovative research addresses a comparative performance evaluation and sustainability assessment between biodegradable palm oil and conventional EDM oil during machining of stainless steel (SS-316) using copper electrode. The cutting performance is investigated by comprehensive result analysis of various machinability aspects including material removal rate, surface integrity, tool wear rate, radial overcut of machined components. According to the findings, machining with palm oil dielectric outperformed the usual EDM oil with regards to improved material removal, surface morphology and finish, increased machined surface hardness with minimum surface crack density and hole overcut. Pyrolysis of conventional EDM dielectric oil leads to deposition of thin film carbon on bottom surface of the copper electrode which prevents the quick tool wear due to its higher breakdown voltage. The total machining cost expenditure per component under palm oil (INR383) is reduced by 11% than expenditure in traditional EDM oil (INR426). Compared to EDM oil, machining under biodegradable palm oil as dielectric fluid is better socio-economical viable and environmental conscious to enhance sustainability.

Effect of process parameters in high speed machining of Ti-6Al-4 V by using multiple methodology

There are several statistical techniques available for enhancing the different machining aspects of the high speed machining process. Following the completion of the experiments, calculations of several reaction parameters, including MRR and SR, were made. In this study work, the GRA, the Topsis, and the Taguchi approach are compared. This research compares the effects of optimizing an entire operation's machining parameter. In order to encourage an optimal balance between productivity and surface quality, the advancement is thus completed with the usage of subsequently enhanced qualities. In the experiment, the optimum point of view yielded similar results in the case of Topsis and Taguchi techniques. From an optimal point of view those levels were respectively level 2 for cutting speed, level 2 for feed rate, level 3 for depth of cut and level 1 for step over. Confirmatory studies demonstrate that the improvement in preference values in the experimental and initial settings is, respectively, 0.999641 and 0.483, which is sufficient, when TOPSIS and GRA are used.

Prediction of Thrust Force and Torque for High-Speed Drilling of AL6061 with TMPTO-Based Bio-Lubricants Using Machine Learning

This study was designed to examine the effects of a trimethylolpropane trioleate (TMPTO)-based lubricant on thrust force and torque under the high-speed drilling of Al-6061 as an effective environmentally friendly cutting fluid. The tribological performance of three lubricant blends was evaluated based on ASTM standards. TMPTO base oil, notably enhances load-carrying capacity under extreme pressure conditions, with a seizer load of 7848 N. The best-performing oil was further optimized using a Taguchi-based design experiment to investigate the effect of different additive concentrations on thrust force and torque under actual contact conditions. Experiments were conducted using three critical machining parameters: additive concentration, spindle speed, and feed rate. The results of the ANOVA analysis reveal that spindle speed contributes most substantially (62.99%) to torque, with feed rate (23.72%) and additive concentration (7.74%) also showing significant impacts. On the other hand, thrust force is primarily influenced by feed rate (73.52%), followed by spindle speed (16.82%), and additive concentration (6.28%). Furthermore, a machine learning model was developed to predict and compare a few significant aspects of high-speed drilling machinability, including thrust force and torque. Three different error metrics were utilized in order to assess the performance of the predicted values, namely the coefficient of determination (R2), mean absolute percentage error (MAPE) and mean square error (MSE), which are all based on the coefficient of determination. Compared to other models, decision tree produces more accurate prediction values for cutting forces. The present study provides a novel approach for evaluating the most promising biodegradable lube oils and predicting cutting forces by formulating a perfect blend.

An Analysis on the Machinability Aspects of the Turning Process Using WEDM for Profile Generation

An Analysis on the Machinability Aspects of the Turning Process Using WEDM for Profile Generation

Investigating Thermal Conductivity of Ferrofluids

Heat transfer is one of the most important aspects of large-scale industries and machines, linking importantly to the efficiency associated with different mechanisms while also emphasizing the importance of sustainable, low-cost methods of heat transfer. One such method is the use of ferrofluids. Through this paper, it is clearly explained that the conductivity of ferrofluids has vast applications across industries and using its magnetic and thermal properties, it can be a cost-effective solution as well. Previously researched works in this field ferrofluids are also acknowledged and furthered as per experimental data.

Parametric optimization of electric discharge machining of Ni 55.65Ti based shape memory alloy using NSGA II with TOPSIS

Nickel–Titanium based shape memory alloys (SMAs) are a unique category of smart materials that possess remarkable properties like super-elasticity, shape memory effect, high wear and corrosion resistance, thereby rendering them appropriate for uses such as composite structures, aerospace, and biomedical uses etc. These distinctive features make these alloys ‘difficult in machining’ using the traditional approach of machining process. In the present investigation, machinability aspects of Ni55.65Ti-SMAs using non-traditional electric discharge machining process has been studied. The effect of input process parameters i.e., pulse time ON, duty factor, peak current on the surface roughness and material removal rate has been investigated. The output responses viz. Minimum surface roughness along with maximum material removal rate having values of 6.828 μm and 4.552 mm3/sec respectively were achieved. Furthermore, empirical modelling and ANOVA study have been executed based on the full factorial design analysis. The non-dominated sorting genetic algorithm IIalgorithm IIalg2 commonly known as NSGA II, used crowding distance approach for multi-objective process optimization. The results obtained with NSGA-II were again ranked using Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) approach to give a more thorough understanding of the solution space and opt for the best possible solution.

Different Aspects of Machinability in Turning of AISI 304 Stainless Steel: A Sustainable Approach with MQL Technology

Machining of AISI 304 austenitic stainless steel is considered to be difficult due to its structural aspects and low thermal conductivity, which leads to increased temperatures during machining. To overcome the challenges of machining AISI 304 stainless steel, several cooling and lubricating techniques have been developed. The main objective of this experimental study is to evaluate the different turning conditions of AISI304 stainless steel under dry and minimum quantity lubrication (MQL) environment conditions. The machining experiments were conducted using a two-level full factorial design method and utilized a TiC-coated cutting tool. The tool-tip temperature, cutting force and surface roughness were analyzed regarding three cutting parameters namely, cutting speed, feed rate and cutting depth. Also, chip macro-morphology was investigated to define the interaction at the tool-chip-workpiece region. The cutting medium affects the surface roughness significantly (more than 100%) for all cutting parameter values. In some environmental cutting conditions, high cutting speed provides 10% lesser surface roughness than low cutting speed parameters. Also, the cutting force decreases by 20% in low feed rate machining conditions. However, the effect of this parameter disappeared for cutting forces in high feed rates and low cutting depth conditions in both MQL and dry environments. Cutting speed was observed as the most influential factor on surface roughness, followed by feed rate. The depth of cut was the main parameter that caused the temperature to increase in the dry machining environment.

In pursuit of sustainability in machining thin walled α‑titanium tubes: An industry supported study

Cryogenic machining has emerged as a major sustainable machining techniques especially for difficult-to-cut alloys, including titanium, Inconel alloys in terms of its impact on cost savings for high-value manufacturing projects reduced energy consumption, enhanced worker safety, and eliminating the infrastructure and disposal needed for flood coolants. However, further study is needed to quantify the sustainable elements of machining processes to have a clearer vision for industries to transition from traditional techniques to such advanced techniques. In the currently known literature, the topic of high-speed machining of titanium tubes with thin walls is yet to be explored under advanced cooling technique. The studies on the machinability indicators including tool wear, power consumption etc. are the backbone to the assessment of sustainability aspect of machining. The quantification of sustainability indicators in terms of machining costs and carbon emissions will provide better insights to the industries to maximise their profits and have least negative impacts on the environment. Thus, this study focuses on analyzing sustainability of the machining processes in terms of economic and environmental factors while turning thin walled α‑titanium tubes under different cutting environments which include dry, wet and cryogenic machining under two different high cutting speeds of 150 m/min and 200 m/min. The economical aspect comprises the assessment of the different machining costs occurring during the machining. The environmental aspect includes the assessment of carbon emissions occurring during the machining operation. The backbone of the sustainability analysis is the machinability analysis which involves the investigation of power consumption and cutting tool-wear. A comprehensive study of tool wear and total power consumption has been presented to get a better perspective in the machinability of thin walled α‑titanium tubes while working in the cryogenic environment in comparison with dry and wet environments. The total machining cost is relatively less (approximately 27%) under cryogenic environment in comparison with a wet environment making it a more economical process. The total emissions of carbon are also found to be lowered (up to 9%) while machining under cryogenic environment in comparison with a wet environment making it a more environmentally friendly process. The cutting tool wear is found to be relatively low (up to 38.68% and 72.24%) under cryogenic environment in comparison with wet and dry environments respectively. Power consumption was compared for the three different environments to have detailed analysis in terms of productivity and sustainability. A significant reduction in total power consumption (up to 19.25%) was observed under cryogenic environment in comparison with wet environment.

Evaluation of Machining Parameters Affecting Cutting Forces in Dry Turning of GGG50 Ductile Cast Iron

Cutting forces in turning have dramatic impact on the cutting stability, tool wear index and surface quality. Machinability of cast iron is important as per this material is served as the main source in manufacturing specific parts of automotive industry. Also, this special material may require final operation to eliminate the manufacturing related defects and residuals. In this context, this study focuses on the optimization and analysis of cutting forces during dry turning of GGG50 material. Thus, Taguchi based experimental design was applied using three levels of cutting speed, feed rate and cutting depth and totally 9 experiments were performed. The discussions on the cutting forces were made based on statistical analysis, optimization approach and graphical presentations. Accordingly, feed rate is the most influentive parameter on cutting forces with the contribution rate about 71.2 %. Cutting speed and depth of cut follows it with the contributions of 21.7 % and 1.5 %. To achieve the minimized cutting forces the parameter group should be; 0.16 mm, 0.2 mm/rev, 80 m/min. This study is expected to be an auxiliary resource for designers and manufacturers in the field to improve the machinability aspects of casted materials.

Structure of the human respiratory complex II

Human complex II is a key protein complex that links two essential energy-producing processes: the tricarboxylic acid cycle and oxidative phosphorylation. Deficiencies due to mutagenesis have been shown to cause mitochondrial disease and some types of cancers. However, the structure of this complex is yet to be resolved, hindering a comprehensive understanding of the functional aspects of this molecular machine. Here, we have determined the structure of human complex II in the presence of ubiquinone at 2.86Å resolution by cryoelectron microscopy, showing it comprises two water-soluble subunits, SDHA and SDHB, and two membrane-spanning subunits, SDHC and SDHD. This structure allows us to propose a route for electron transfer. In addition, clinically relevant mutations are mapped onto the structure. This mapping provides a molecular understanding to explain why these variants have the potential to produce disease.

A critical review on different aspects of electric discharge machining

EDM is a common manufacturing technique that separates the tool and the workpiece during the sparking process. This prevents the tool and the workpiece from contaminating each other. EDM requires a variety of tool and the components in order to determine the Metal Elimination Rate and the Tool Degradation Rate. The MRR and TWR were significantly altered as a direct result of the utilisation of a variety of dielectric fluids. The procedure parameters of EDM, which include current supplied, the voltage differential, process timely manner and blend off time etc., are the main variables that need to be analysed in order to determine MRR and TWR. This is true regardless of the distinct characteristics dielectric fluids that are being used. Several distinct optimisation strategies, including Taguchi, ANOVA, and TOPSIS, were utilised in order to optimise the processing parameter in such a way that it would result in a high MRR and a low TWR. In order to evaluate and optimise the data using MiniTab, an orthogonal matrix consisting of L9 and L27 elements is utilised. In the current article that is a review, the research studies that were conducted with various types of dielectric fluid, tools, and work pieces, as well as variable processing parameters and variable optimisation techniques, are identified and then described in detail.

Relationship between energy consumption and surface integrity aspects in electrical discharge machining of hot work die steel

The present work deals with the relationship between energy consumption and surface integrity aspects in electrical discharge machining (EDM) of hot work die steel. Initially, the non-conventional machining experiments were performed with 1.2344 hot work die steel material and the surface integrity aspects such as surface topography, power spectral density analysis, surface roughness etc. were measured with high end instruments. Then, the energy consumption data during machining was analyzed with Labview software. Finally, the relationship between two technological contributors were established and the results were compared with different process parameters. The results demonstrated that there is a direct relationship between the energy and surface integrity aspects while performing EDM experiments. The lowest Sa and Sz values were reached for the highest tested pulse voltage values (U = 200 V) and were respectively lower by 34% and 44% than ones reached during EDM with the lowest pulse voltage U = 80 V.

Investigation on the effect of hybrid nanofluid in MQL condition in orthogonal turning and a sustainability assessment

The installation of cost- and energy-efficient chip removal processes is the key point for sustainability. In the literature, many sustainability assessments have been made for minimum quantity lubrication (MQL) and mono nanofluid-assisted MQL (N-MQL) methods, considering energy consumption and costs. However, there are deficiencies in the assessment of sustainability in terms of machining cost and carbon emission amount in studies using the hybrid nanofluid MQL (HN-MQL) method. In the presented study, the Taguchi experiment design was established with different cutting conditions (dry, MQL, 0.2% MWCNT nanoparticle reinforced N-MQL, 0.1% MWCNT+0.1% MoS2 nanoparticle reinforced HN-MQL), different cutting speeds (175, 225, 275 and 325 m/min), and different feed values (0.1, 0.15, 0.2 and 0.25 mm/rev) in the orthogonal turning of S235JR structural steel, and optimum cutting parameters were determined in terms of cutting temperature and cutting forces by ANOVA analysis. This was followed by the sustainability assessment of the experiments conducted to quantify the sustainability aspect of machining in terms of total machining costs and total carbon emissions. While assessing machinability parameters, it was found that the best results out of all the performed experiments for both cutting forces and cutting temperatures were obtained under N-MQL conditions. It was determined that the most effective parameter on cutting force and thrust force was feed with 86.8% and 65% contribution ratios, respectively, and cutting conditions had the most effect on cutting temperature with 93.2% contribution ratio. The total machining cost were lowered by significant amount (up to 76%, 73% and 61% in comparison with dry, MQL and HN-MQL) under N-MQL cutting environment owing to the reduction in energy consumption and better tool life in comparison with other parameters. The overall carbon emissions were also most optimal (better by up to 60% and 37% in comparison with MQL and HN-MQL) under the N-MQL cutting environment in comparison with other cutting environments. The sustainable aspects of the machining process were enhanced more under higher cutting speeds than under lower cutting speeds.

Status and Scope of Automated Coconut Harvester in India: A Review

Coconut plays a substantial role in the Indian economy. South Indian states, namely Kerala, Karnataka, Tamil Nadu, and Andhra Pradesh are the leading producers accounting for more than 90% of the total coconut produced in the country. The traditional/conventional process of coconut harvesting includes climbing on the tree and cutting the coconut bunches with a cutter, which involves high risk. Climbing on a coconut tree is the main risk factor and it is life-threatening. The present review paper presents the status and future research need for automated coconut harvesting machines in India. The maximum speed or climbing with remote controlled coconut harvester was reported 0.055 ms-1. This paper also focuses on the basic components of the automated coconut harvesting machine, as well as the advantages and disadvantages of each component are critically analyzed based on its findings, future research needs are proposed in order to meet all the fundamental aspects of autonomous coconut harvesting machines.

Modeling product carbon footprint for manufacturing process

To reduce carbon intensity and improve energy efficiency in product manufacturing, a comprehensive carbon emission model is essential. Most of the existing researches focus on specific aspects of part machining and lack a quantitative model of the product manufacturing process. Therefore, this paper decomposes and evolves the carbon footprint of product manufacturing from the workshop layer, forming a systematic carbon emission quantitative model. The product manufacturing process is divided into manufacturing equipment layer, part layer, product layer and workshop layer. The sources of carbon emissions in each layer are analyzed and modeled. Finally, take a certain type of wind turbine gearbox as an example. The carbon emissions model for manufacturing process of wind turbine gearbox is established, which provides directions for carbon emission reduction of related manufacturing enterprises. The results show that the rear housing, front housing, and 1st plant carrier are the main carbon emission parts of wind turbine gearbox.

Cooling and lubrication techniques in grinding: A state-of-the-art review, applications, and sustainability assessment

Grinding technology is an essential manufacturing operation, in particular, when a component with a superfinishing and an ultra-resolution is yearned. Meeting the required strict quality checklist with maintaining a high level of productivity and sustainability is a substantive issue. The recent paper outlines the lubrication and cooling technologies and mediums that are used for grinding. Furthermore, it provides a basis for a critical assessment of the different lubrication/cooling techniques in terms of machining outputs, environmental impact, hygiene effect, etc. Meanwhile, the paper put light on the sustainability of different cooling/lubrication strategies. The sustainability of machining aims to get the product with the best accuracy and surface quality, minimum energy consumption, low environmental impact, reasonable economy, and minimum effect on worker’s health. The paper revealed that despite some cooling/lubrication mediums like mineral oils and semisynthetic, afford sufficient lubrication or cooling, they have a significant negative impact on the environment and public health. On the other hand, emulsions can overcome environmental problems but the economy and the energy consumption during grinding are still a matter of concern. Biodegradable and vegetable oils are considered eco-friendly oils, but they suffer from a lack of thermal stability which affects their ability of efficiently cooling. Using the cooling medium with the lowest amount can achieve the goal of the economy but it may be reflected negatively on the machinability. Furthermore, cryogenic lubrication doesn’t provide sufficient lubrication to reduce friction and hence energy consumption. The research described in the paper is such a comprehensive compilation of knowledge regarding the machinability and machining performance under different cooling and lubrication systems that it will aid the next generation of scientists in identifying current advancements as well as potential future directions of research on ecological aspects of machining for sustainability.

A novel quantifiable approach of estimating energy consumption, carbon emissions and cost factors in manufacturing of bearing steel based on triple bottom-line approach

The theory of “triple bottom line (TBL)” widens the traditional measures of corporate success to account for their positive effects on three additional dimensions: society, the natural world, and the economy. People, planet, and prosperity are commonly referred to collectively as the “three P's” of sustainability. The measurement of social and ecological categories presents difficulties in implementing the TBL approach in the manufacturing sector. The present work deals with the novel quantifiable approach of estimating energy consumption, carbon emissions and cost factors in the machining manufacturing of bearing steel based on a triple bottom-line approach. The AISI-52100 bearing steel was selected for machining tests under minimum quantity lubrication (MQL) and hybrid MQL-dry ice blasting cooling conditions. Then, the technological aspects such as product quality and cutting forces were evaluated along with the energy consumption, carbon footprints and economical aspects in machining of AISI-52100 bearing steel. Based on the results, it was determined that the MQL reduced cutting forces up to 20.7%, energy consumption up to 13.3%, while MQL-dry ice blasting reduced the surface roughness up to 15%. The cost of dry ice accounted for almost 30% of total machining expenses. Overall performance index (OPI) results for a proposed hybrid MQL dry ice blasting system favored MQL due to its superior sustainability features. Therefore, the purpose of this research is to organize our understanding of sustainability in a way that takes into account the environmental and financial implications of various industrial processes.