Analysis of Productivity and Machining Efficiency in Sustainable Machining of Titanium Alloy (original) (raw)
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Procedia CIRP, 2014
The current drive for achieving the implementation of sustainability concepts in manufacturing calls for sustainable machining practices to be adopted. A key area of research is the search for environmentally benign cooling strategies. Vegetable oils have often been proposed as sustainable alternatives to the conventional synthetic emulsion coolants. Techniques like dry and cryogenic machining, minimum quantity lubrication (MQL) and minimum quantity cooled lubrication (MQCL) have also been proposed. The current study investigates the effect of six different strategies on the flank tool wear, surface roughness and energy consumption during turning of titanium Ti-6Al-4V using uncoated carbide tool at certain speed and feed. The use of rapeseed vegetable oil in MQL and MQCL configuration turns out to be an overall sustainable alternative. Thus confirming the promise predicted in the use of vegetable oil as a lubricant for machining.
Machining Science and Technology, 2019
Titanium, a difficult-to-cut material, consumes higher time and cost in removing material by machining to produce parts. Machining of Ti alloys has got serious attention owing to its reactive nature with tool materials at elevated temperature that aggravates tool wear. Reportedly, effective and efficient cooling and lubrication at the tool-work interface can ameliorate the machinability of Ti-alloys. In this perspective, this article interrogates the underlying mechanism of critical responses such as surface roughness, temperature, tool life and machining cost under dry, minimum quantity lubrication (MQL) and cryogenic liquid nitrogen (LN2) modes. The effect of cutting speeds and feed rates on such responses have been considered as a function of cooling strategy to standardize the cooling technique as the best alternative for machining. Cryogenic cooling seems to be preponderant regarding machining cost, temperature, surface roughness and tool life in hard turning of a-b titanium alloy. The feasibility of cryogenic cooling was investigated using the iso-response technique in comparison with dry and MQL-assisted hard turning. Experimental results revealed longer tool life and lower machining cost under cryogenic condition followed by MQL and dry machining. Moreover, cryogenic LN2 has been identified as an appropriate alternative to reduce the temperature and surface roughness. On contrary, dry turning evoked a high-temperature and rapid tool wear. In a nutshell, cryogenic assisted hard turning has acceded as a sustainable strategy from an environmental and economic perspective.
Mechanical Sciences, 2019
Productivity and economy are key elements of any sustainable manufacturing system. While productivity is associated to quantity and quality, economy focuses on energy efficient processes achieving an overall high output to input ratio. Machining of hard-to-cut materials has always posed a challenge due to increased tool wear and energy loss. Cryogenics have emerged as an effective means to improve sustainability in the recent past. In the present research the use of cooling conditions has been investigated as an input variable to analyze its effect on tool wear, specific cutting energy and surface roughness in combination with other input machining parameters of feed rate, cutting speed and depth of cut. Experimental design was based on Taguchi design of experiment. Analysis of Variance (ANOVA) was carried out to ascertain the contribution ratio of each input. Results showed the positive effect of coolant usage, particularly cryogenic, on process responses. Tool wear was improved by 33 % whereas specific cutting energy and surface roughness were improved by 10 % and 9 % respectively by adapting the optimum machining conditions.
Lubricants
The lubrication capacity and penetration ability of the minimum quantity cooling lubrication-based strategy is linked with lubrication specific parameters (oil flow rates and air pressure), cutting conditions, and chip formation. It points out the complex selection involved in the MQCL-assisted strategy to attain optimal machining performance. Lubrication during metal cutting operations is a complex phenomenon, as it is a strong function of the cutting conditions. In addition, it also depends on the physical properties of the lubricant and chemical interactions. Minimum Quantity Lubrication (MQL) has been criticized due to the absence of cooling parts; MQCL is a modified version where a cooling part in the form of sub-zero temperatures is provided. The aim of this paper was to investigate the influence of different lubrication flow parameters under minimum quantity cooling lubrication (MQCL) when machining aeronautic titanium alloy (Ti6Al4V) using Titanium Aluminum Nitride—Physical ...
International Journal of Lightweight Materials and Manufacture, 2018
Titanium alloys, despite their high strength-to-weight ratio, are considered as difficult-to-machine materials. Their poor machinability is attributed, among other reasons, to the accumulation of intense heat near the cutting edge that leads to brisk tool damage. The tool damage, in turn, causes deterioration of work surface quality, consumption of more energy and hike in machining forces. The paper focuses on application of innovative lubro-cooling approaches and variation in cutting parameters with a fixed material removal rate for the sake of impeding tool damage and improving associated performance measures. Two cryogenic coolants (liquid nitrogen and carbon dioxide snow), minimum quantity of lubrication (micro-lubrication) and hybridization of the two were tested for effective dissipation of heat in face-turning of a commonly used titanium alloy. Additionally, the effects of removing a given volume of the alloy in one and two cutting passes (with a fixed material removal rate) on tool wear, work surface roughness, cutting energy consumption and machining forces were also experimentally investigated. The double-pass approach was found to have performed better regarding surface roughness, cutting energy and machining forces. Hybrid application of liquid nitrogen and microlubrication, carbon dioxide snow, and hybrid application of snow and micro-lubrication yielded the best results regarding tool wear, cutting energy consumption, and work surface roughness, respectively. The solitary application of micro-lubrication yielded significant reduction in the cutting force component.
The International Journal of Advanced Manufacturing Technology, 2018
Recently, the manufacturing sector is increasingly keen to apply sustainability at all levels of sustainability from system to products and processes. At the processes level, cutting fluids (CFs) are among the most unsustainable materials and need to be addressed properly in accordance with three main and decisive aspects, also known as the triple bottom line: ecology, society, and economics. Minimum quantity lubrication (MQL) is a promising technique that minimizes the use of CFs, thus improving sustainability. This paper presents a review of the literature available on the use of the MQL technique during different machining processes involving titanium alloys (Ti-6Al-4V). To carry out the study, four search engines were used to focus on the most cited articles published over a span of 17 years from 2000 to 2016. The performance and drawbacks are compiled for each eco-friendly technique: dry, MQL, and cryogenics with combinations of MQL and cryogenics, critically considering machining parameters such as cutting speed, feed rate, and output measures, namely surface roughness, tool life, and cutting temperature. After drawing conclusions from critical evaluation of research body, future research avenues in the field are proposed for the academics and industry.
International Journal
Titanium alloys have very high tensile strength and toughness, light weight, extraordinary corrosion resistance, and ability to withstand extreme temperatures. However, the high cost of both raw materials and processing limit their use to military applications, aircraft, spacecraft, medical devices, connecting rods on expensive sports cars, some premium sports equipment and consumer electronics. Surface finish plays vital role in service life of components, to ensure a great reliability of sensitive aeronautical components, surface integrity of titanium alloys should be satisfied. Therefore, it required to optimize process parameters like cutting speed, feed and depth of cut while machining titanium components for better surface finish and also high tool life in order to reduce the tool cost. In order to reduce high temperatures in the machining zone, cutting fluids are employed in machining. Cutting fluid improves the surface conditions of the work piece, tool life and the process as a whole. It also helps in carrying away the heat and debris produced during machining. This project work deals with performance evaluation and optimization of process parameter in turning of Ti6Al4V alloy with different coolant conditions using Taguchi's design of experiments methodology on surface roughness by uncoated carbide tool. The results have been compared among dry, flooded with Servo cut oil and water and flooded with Synthetic oil coolant conditions. From the experimental investigations, the cutting performance on Ti6Al4V alloy with synthetic oil is found to be better when compared to dry and servo cut oil and water in reducing surface roughness. The results from ANOVA shows that while machining Ti6Al4V alloy, the Synthetic oil is more effective under high cutting speed, high depth of cut and low feed rate compared to dry and servo cut oil and water conditions. The ANOVA also reveals that feed rate is dominant parameter under dry, servo cut oil and water and synthetic oil conditions in optimizing the surface roughness.
In pursuit of sustainable cutting fluid strategy for machining Ti-6Al-4V using life cycle analysis
Sustainable Materials and Technologies, 2021
The need for developing sustainable manufacturing processes which should have a good balance between economic viability and environmental protection is one of the key challenges against manufacturers. The conventional carbonbased cutting fluids used in machining processes are found to be unsustainable in terms of a higher impact on ecology and hence it is required to develop alternative sustainable cutting fluid strategies. However, the research that compares conventional, cryogenic and Minimum Quantity Lubrication (MQL) machining based on all pillars of sustainability i.e., machining performance, environmental impact and human health is still lacking. With this view, this novel study on Ti-6Al-4V machining compares conventional flood coolant with MQL and liquid carbon dioxide (LCO 2) as a cryogenic coolant based on the machining performance and Life Cycle Assessment (LCA) analysis. Though lower impacts on the environment are observed for MQL machining, it is not sustainable as it has been observed 75% reduced tool life with a higher cutting force and surface roughness in comparison with flood and cryogenic machining. The flood machining is found to be non-sustainable as it has more than 50% of total impacts generated for most of the ReCiPe 2016 (H) midpoint categories. Thus, cryogenic machining is emerged as sustainable machining to have a good balance between machining performance and impacts on the environment for turning Ti-6Al-4V.
The International Journal of Advanced Manufacturing Technology, 2017
Titanium alloys are widely used in engineering applications due to their superior properties. However, machining of titanium alloys has always been a problem due to high cutting temperatures. Though flood lubrication is a solution, it is not encouraged in sustainable machining. This paper describes a study that used sustainable lubricants in turning of Ti6Al4V. Soybean oil-based lubricants were used with/without addition of micro-graphite particles in minimum quantity lubrication (MQL) at the rate of 40 mL/h. PVDcoated carbide tools were used for machining under different cutting conditions. To minimize the number of experiments, Taguchi's L 9 array is used. Five different lubricating conditions, namely, dry machining, commercial cutting fluid with and without micro-graphite, and soybean-based cutting fluid with and without graphite, were studied. Tool wear, cutting forces, and surface roughness were measured in the experiments. ANOVA analysis was carried out to estimate the optimal conditions. Among the considered combinations, it was found that the cutting speed of 90 m/min, feed of 0.3 mm/rev, and depth of cut of 0.5 mm were optimal for overall machining performance. Confirmation tests were carried out at these conditions to validate the findings.
Journal of Cleaner Production, 2018
Modern manufacturing industries thrive for energy efficient, clean and sustainable machining processes. However, achieving these objectives becomes difficult especially in machining Ti-6Al-4V as it retains its properties at high temperature. Cryogenic liquid nitrogen (LN 2) is a clean machining environment that has potential to improve the machinability performance for Ti-6Al-4V. LN 2 promotes sustainability and facilitates low carbon emission. Orientation and number of employed LN 2 jets influence the cutting energy, quality and productivity. Moreover, a balance between energy consumption and quality-productivity is required for sustainable production. In this respect, this research work studies the cutting force, specific energy, temperature, surface quality (i.e. surface roughness), and material removal rate under the impingement of LN 2 as mono-jet and dual-jets. This study has three parts: evaluation of the role of factors on the output parameters, optimization of parameters, and lastly the life cycle assessment (LCA) of cryogenic LN 2 assisted machining. Owing to irreconcilable nature of single-objective optimization, multi-response optimization was conducted using Grey-Taguchi integrated approach. It was found that LN 2 dual-jets were most effective in reducing the specific energy consumption and temperature, and improving surface quality. This can be attributed to the faster and effective heat removal by LN 2 from the critical interfaces. Other optimum parameters were cutting speed of 140 m/min and feed rate of 0.16 mm/rev. It was found that LCA showed that there is a clear relation between cooling strategy and environmental aspects such as resources, energy, human health, and biodiversity, etc. that directly affects the machining performance of Ti-6Al-4V alloy.