Vegetable-oil based metalworking fluids research developments for machining processes: survey, applications and challenges

Cutting fluids provide cooling at the cutting tool and on the surface of work piece, lubricate the tool-workpiece interface and evacuate chips from the cutting zone in the machining processes. The primary reason for using cutting fluid is to reduce the temperature at cutting zone and friction wear either through cooling or lubrication. To maximize the efficiency of cutting fluids in machining processes the knowledge of machining conditions and cutting fluid types are critically important. However, misemploy of the cutting fluid and non efficient method of disposal can raise health issues and environmental impact. In this paper, an attempt has been made to provide overview of cutting fluids type, cooling techniques and main alternatives as dry machining, cryogenic cooling, minimum quantity lubrication and hybrid cooling minimizing use of cutting fluids. The inclusion of solid lubricants, nano fluids in lubrication/cooling techniques results in increase in the productivity of the process due to reduction in friction and heat at the cutting zone. The cutting parameters and type of tools utilized by various researchers have been summed up and introduced in this paper to provide useful information to various researcher works.

In machining processes, MQL method is substantially preferred in terms of sustainable production because of lower usage of cutting fluid and better cutting performance in comparison with traditional techniques. On the other hand, it is also critical that the cutting fluid used is not hazardous to human and environmental health. In the present study, we aimed to investigate the cutting performance of AISI O2 steel in the presence of the cutting fluid containing various amounts of environmentally friendly Nano hexagonal boron nitride (Nano h-BN) based ethylene glycol (EG) by minimum quantity lubrication (MQL) method. Nano h-BN at 1% and 2% percentage by volume was added to the ethylene glycol and sonication was carried out for one hour for both prepared cutting fluids. Based on the experimental results using prepared cutting fluids, the highest cutting tool life was obtained in tests using 2% h-BN containing cutting fluid with 2.4 m cutting length. The improvement in tool life was approximately 46% using 2% h-BN containing cutting fluid compared to using 1% h-BN containing cutting fluid in milling tests. 2% h-BN containing cutting fluid compared to dry conditions in terms of tool life, the increase was approximately 78%. The improvement in surface roughness value measured on milled surface of workpiece material was approximately 60% using 2% h-BN containing cutting fluid compared to dry conditions. Compared to using 1% h-BN containing cutting fluid the improvement in surface roughness values was approximately 46%. A reduction in the cutting forces measured by the increased h-BN ratio in the prepared ethylene glycol based cutting fluid has occurred. As a result of SEM images and EDS analysis of worn tools, it was observed that the dominant wear mechanism was abrasion in all applied tests.

Due to the friction between the clearing face of the tool and the workpiece, high temperature is raised during the metal-cutting operations. Plastic deformation occurs as well as temperature rises due to the heat generation in both workpiece and tool, resulting in the reduction of tool life. The machined surface will also become rougher, and the propensity for built-up edges to shape will increase. As a result, choosing the right cutting fluid is critical as well as important during the machining process. This article provides an in-depth study of a cutting fluid selection problem using a very underutilized CODAS MCDM during cylindrical grinding operation. The simplicity and user-friendly nature of CODAS method motivates the authors to use it for this specific analysis. The aim of this article is to propose the best cutting fluid among four available alternatives on the basis of eight essential parameters. The final findings indicate that Alternative 4 and Alternative 1 are the best and worst cutting fluid respectively. The current rankings are compared to previously proposed rankings derived using various MCDM tools. The outcomes from this present analysis using CODAS shows an excellent correlation with those results obtained by previous researchers. The robustness of the CODAS MCDM is also justified as well as validated through sensitivity analysis.

Cutting fluids are used in machining processes to increase the quality of machined surfaces, extend the life of tools, and lessen the effect of friction and heat on contact surfaces. The least costly, least hazardous to the environment, and least poisonous lubricant would be the perfect choice. It should also be resistant to low temperatures, have high lubricating qualities, be recyclable, and have stability against oxidation, hydrolysis, and heat. Its viscosity should also fall between the ideal range and not exceed it. Taking the needed properties of the cutting fluids into consideration, for the machining process choosing the best cutting fluid is essential. Five types of cutting fluids are examined in this paper that are often used in machining operations: canola oil, mineral oil, synthetic ester, PAG (Polyalkylene Glycol), and TMPTO (trimethylolpropane trioleate). In this study, the Multicriteria decision-making (MCDM) techniques were used to identify the best choice of cutting fluids based on several parameters, such as low temperature, toxicity, lubricating ability, hydrolytic stability, thermal stability, viscosity index, oxidative stability, and cost. The most popular TOPSIS methods and Shannon's Entropy were utilized to choose these cutting fluids optimally. The TOPSIS approach is used to calculate the final ranking, and Shannon’s entropy method is utilized to calculate the weight of the criterion. According to the result with the more lucid rating, PAG cutting fluid was shown to be the most effective, followed by synthetic ester in second place, as well as last place achieved by vegetable-based canola oil.

Cutting fluids are generally used for lubrication and cooling the machined surface during the turning operation. The petroleum-based oil, when used for the machining process, has raised many health and environmental issues. The use of bio oils during machining process results in environmental-friendly working atmosphere, with minimal health hazardous among workers. Many researchers have worked on the effect of process parameters, surface characteristics of the machined surface by using bio oils as lubricants. The metallurgical transformation takes place on the machined surface during the machined surface. But the studies on using the bio oils on improving the machined surface, chip formation and generation of cutting force needs to be studied in details with comparison with other process methods. The change in the microstructure, during the machined process also needs to be studied thoroughly, where mere literatures are available. With this direction, the experimental studies were conducted to study the machining parameters during the turning process by using gingelly oil as cutting fluids. The studies showed that there was a gradual decrease in cutting force and improved surface finish on the machined part. The improvement in the machinability during the cutting process with respect to chip length, pitch and surface roughness was discussed for all the process. Finally, the changes in the microstructure on the metal surface for the different cutting forces were studied.

This study examines the treatment of industrial wastewater generated during vibro-abrasive steel and Zn-Al alloy parts machining in a Polish metal-processing plant. The machining process uses grinding fluids, which are sent for disposal after becoming saturated with contaminants, incurring high costs. A two-stage filtration process was investigated: an initial bag filtration (pore size 5 µm) followed by a low-pressure (4 bar) ultrafiltration with polyacrylonitrile membranes (30 kDa cut-off). The studies were carried out on a laboratory scale in a cross-flow system using a batch configuration. The initial filtrate flux was 0.116 mL min−1 cm−2 and 0.050 mL min−1 cm−2 for Zn-Al alloy and the steel wastewater, respectively. Key physicochemical parameters, including turbidity, COD, and TOC, were analysed for raw wastewater, feed, retentate, and permeate. Significant reductions in contaminant concentrations were achieved, with comparable total efficiencies for both the wastewaters tested. The reductions in turbidity, COD, TOC, anionic surfactants, total phosphorus and non-ionic surfactants ranged from 80% to almost 100%. A complete removal of total suspended solids was achieved. The novelty of this research lies in applying polyacrylonitrile flat-sheet membranes to treat wastewater from vibratory machining of ferrous and non-ferrous materials and recycle reclaimed water, which has not been systematically explored in previous studies. The study demonstrates the potential of low-pressure membrane filtration for wastewater recycling, offering insights into environmentally friendly and energy-efficient management of industrial wastewater.

The influence of the metal working fluids on machine tool failures

Hard machining performance of indigenously developed green cutting fluid using flood cooling and minimum quantity cutting fluid

This article is a comprehensive collection of tables listing: dangerous reactions of chemicals and designations of etchants; chemical-polishing solutions for irons and steels and nonferrous materials; attack-polishing solutions, macrostructure etchants for iron and steel; and major microstructure etchants for common phases and constituents in ferrous materials.

Comparative Life Cycle Assessment of a microalgae-based oil metal working fluid with its petroleum-based and vegetable-based counterparts

Metalworking fluids (MWFs) increase productivity and the quality of manufacturing operations by cooling and lubricating during metal forming and cutting processes. Despite their widespread use, they pose significant health and environmental hazards throughout their life cycle. An obvious environmental improvement to MWF technology would be to improve the lifetime of the fluid while utilizing more environmentally friendly and less energy-consuming materials without compromising existing performance levels. This investigation focuses on the design of mixed anionionc:nonionic emulsifier systems for petroleum and bio-based MWFs that improve fluid lifetime by providing emulsion stability under hard water conditions, a common cause of emulsion destabilization leading to MWF disposal. Experimental conditions were designed to evaluate the impact of emulsifier structural characteristics (straight chain, branched tail, branched head) and the molar ratios of anionic to nonionic surfactant and oil to total surfactant. Results from the 2500 formulations generated indicate that the use of a twin-headed anionic surfactant can provide improved hard water stability for both mineral oil- and vegetable oil-based formulations, even in the absence of a chelating agent and a coupler. Results also suggest that an oil:total surfactant molar ratio of 0.5 or less is necessary for particle size stability in hard water conditions for these systems. The newly developed petroleum and bio-based formulations with improved hard water stability are competitive with commercially available MWFs in performance evaluations for tramp oil rejection, contact angle, and tapping torque efficiency. These results can be used to design MWF formulations with fewer components and extended lifetime under hard water conditions, both of which would lead to a reduction in the life cycle environmental impact of MWFs.

Long term corrosion test data in marine environments are essential data to guide the design and application of marine engineering. Corrosion test results, over a 16 year period from October 1986 to October 2002, using eight kinds of metallic materials are reported in this paper. Materials were exposed in the splash zone, tidal zone, and full immersion zone of four corrosion test stations located in Qingdao, Zhoushan, Xiamen and Yulin respectively, and therefore the corrosion behaviour of various ferrous and non-ferrous materials in these marine environments has been obtained. The corrosion of carbon steel in the seawater fits the following general relationship: D=A+K(t–1). The variation in the general corrosion rates for the different carbon steels in seawater is relatively small and consistent. However, the pitting corrosion rates for the different carbon steels are all significantly different. The marine splash zone is about 0–2˙4 m above the mean high water level of the seawater. The corrosion peak was located about 0˙6 to 1˙2 m above the mean high water level. The order of the corrosion potential of stainless steels with the corrosion resistance of stainless steels is consistent in seawater. The corrosion of copper was found to be serious in the full immersion zone of the Yulin sea area. The effective lifetime of the cathodic protection for a wrapped aluminising layer of the hard and ultrahard aluminium may be 16 years.

Various ferrous and non-ferrous materials and their combinations are used in car body production in automotive industry. These materials need to fulfil several criteria before being approved. Some of the criteria are the results of regulation and legislation with the environmental and safety concerns and some are the requirements of the customers. In many occasions different factors are conflicting and therefore a successful design would only be possible through an optimized and balanced solution. The most commonly used method for joining the materials is resistance spot welding. Some materials or their combinations are very difficult or even impossible to join by resistance spot welding. Therefore, the car producers are seeking for alternative joining methods such as cold metal transfer, TOPTIG or mechanical joining. The paper deals with evaluation of properties of the joints made by two methods of mechanical joining - clinching and clinch-riveting. The steel sheets of DX51D+Z, H220PD and DC06 were used for experiments. The tensile test for observing the carrying capacity, metallographicall analysis and microhardness test were used for the evaluation of joints properties.

Model development for numerical analysis of the bonding strength for friction welded lightweight structures

Corrosion is a crucial worldwide problem that strongly affects metals. Out of the several ways to prevent corrosion, volatile corrosion inhibitors (VCIs) are predominantly used as a method of temporary protection. These compounds have the ability to vaporize and condense on the surface of the ferrous or nonferrous material and make the substrate less susceptible to corrosion but work only in a confined space. VCI compounds form a monomolecular layer over the metal surface, thereby preventing the electrochemical reactions on the metal surface which lead to corrosion. This review article outlines the use of volatile corrosion inhibitors (VCIs) as a temporary corrosion protection technique, their working mechanisms and the various compounds used as VCI. It also anchors on the latest research works which have been carried out on VCI coatings along with a glimpse of the works that were carried out in the past. The various factors affecting the volatile corrosion inhibitors along with the merits of VCI coatings are discussed in this paper. Formulations for both strippable and permanent VCI coatings are also reported with the various testing methods. Lastly, an overview of the recent developments of VCI coatings along with the various green VCI is given.