R R Srikant

Nanofluids as a potential solution for Minimum Quantity Lubrication: A review

Several studies are being carried out to curtail the heat generated in machining. Among the various alternatives available, cutting fluids remain to be the choice. However, the various limitations of the cutting fluids restrict their application. Hence, different techniques are being explored to replace the use of cutting fluids, minimum quantity lubrication being one of them. This present article tries to review the available literature and examine nanofluids as potential candidates for minimum quantity lubrication.

Solid lubricants in machining

This article presents a review of solid lubricants application in different machining processes such as grinding, milling, drilling, and turning. Of late, several reasons have led to the increased usage of solid lubricants in machining. The heat generated in the cutting zone during machining is critical in deciding the workpiece quality. Although cutting fluids are widely employed to carry away the heat in machining, their usage poses threat to ecology and the health of workers. Hence, there arises a need to identify eco-friendly and user-friendly alternatives to conventional cutting fluids. Modern tribology has facilitated the use of solid lubricants as an alternative to cutting fluids in machining. Graphite, calcium fluoride, molybdenum disulphide, and boric acid are the general solid lubricants used in machining. Process performance is improved with the application of solid lubricants in machining. By reducing coefficient of friction, cutting forces and tool wear are reduced in machining with solid lubricants. Reduction in cutting forces results in lower specific energy requirement and thus reduces production cost. Surface quality of the machined workpiece is also improved with solid lubricants.

Preparation and characterization of properties of nanographite-based cutting fluid for machining operations:

Soluble oils are the most popularly used oils in metal-cutting industry. However, the regular application strategy, flood cooling, involves the problem related to its disposal. Hence, mist application can be seen as an alternative procedure. Since less amount of cutting fluid is used, its capacity to carry away heat and provide adequate lubrication is limited. Therefore, the heat carrying and lubricating abilities of soluble oil need to be enhanced. Graphite has better lubricating and cooling properties, and hence inclusion of graphite nano particles in cutting fluid may help in formulating a better coolant in machining operation. This paper consists of two parts. The first part consists of preparation of nano cutting fluid by different methods followed by their stability evaluation, and second part consists of characterization of the basic properties of nano cutting fluid.

Experimental investigations on influence of mist cooling using nanofluids on machining parameters in turning AISI 1040 steel

Soluble oils are the largest class of oils used in metal cutting industry. Flood cooling involves problems related to its treatment and disposal. Minimum quantity lubrication in the form of mist application can be used to replace flood cooling. But as less amount of cutting fluid is used in minimum quantity lubrication, its capacity to carry away heat and providing adequate lubrication is limited. Hence, the heat-carrying and lubricating ability of soluble oil has to be enhanced. Graphite has better lubricating and cooling properties and hence inclusion of graphite nanoparticles in cutting fluid may help in formulating a better coolant in machining operation. This article compares the performance of mist application of nanographite-soluble oil with dry lubrication, flood lubrication and mist application of soluble oil without nanographite in turning AISI 1040 steel. Performance is evaluated based on experimental measurement of average chip–tool interface temperature, tool wear and cutting forces. The results showed that use of nanographite-soluble oil in mist application has greatly improved the cutting conditions by lowering the temperature generated, reducing the tool wear and reducing the cutting forces.

Online tool wear prediction in wet machining using modified back propagation neural network

Tool wear monitoring is one of the critical issues in the automated industry. Though use of artificial neural networks for tool wear monitoring is widely reported in the literature, the models are built only for dry machining. In the present work, a neural network model for cutting fluid assisted machining is proposed. Experimentation has been carried out using different cutting fluids and the results were used to build up and test the model. Further, an improvement in the network is proposed using simulated annealing, which can automatically and effectively optimize the network architecture, as opposed to the conventional trial and error method.

Experimental investigation to study the performance of solid lubricants in turning of AISI1040 steel

Abstract Machining is one of the most fundamental and indispensable processes of the manufacturing industry. The heat generated in the cutting zone during machining is critical in deciding the workpiece quality. Though cutting fluids are widely employed to carry away the heat in machining, their usage poses threat to ecology and the health of workers. Hence, there arises a need to identify eco-friendly and user-friendly alternatives to conventional cutting fluids. Modern tribology has facilitated the use of solid lubricants. The present work features a specific study of the application of solid lubricants in turning of AISI1040 steel with carbide tool. Results show considerable improvement in reducing the cutting forces, coefficient of friction between chip and tool interface, average tool flank wear, and the surface roughness of the machined surface with solid lubricants. Among the selected lubricating conditions boric acid performed well compared to graphite. Chip thickness ratio is also evaluated to study the lubricating action of selected solid lubricants during turning.

Application of nanomaterials as coolants/ lubricants in machining

Machining is one of the most promising techniques used in manufacturing to generate workpiece with good surface finish and quality. High temperatures generated due to friction during machining adversely affect the quality of workpiece in spite of the use of cutting fluids. Application of conventional cutting fluids in machining threatens ecology and health of the workers. In order to combat the negative effects of conventional cutting fluids, ample research is in process to formulate modern cutting fluids endowed with user and eco friendly properties. This paper presents a wide spectrum of past and ongoing research on the formulation and performance of modern nanofluids as alternatives to conventional cutting fluids in machining. It is an attempt to focus on the affirmative effects of nanofluids in machining. The procedures implemented to prepare nanoparticles and nanoparticles are briefly presented. Basic properties of nanofluids, which affect the machining performance are discussed. Performance of nanofluids in terms of cutting forces, tool flank wear, cutting temperatures and surface finish is discussed.

Effect of Austempering and Martempering on the Properties of AISI 52100 Steel

The mechanical properties of steel decide its applicability for a particular condition. Heat treatment processes are commonly used to enhance the required properties of steel. The present work aims at experimentally investigating the effect of austempering and martempering on AISI 52100 steel. Different tests like microstructure analysis, hardness test, impact test, and wear test are carried out after heat treatment process. It was found that annealed steel was least hard and more wear prone, while martempered steel was hardest and least vulnerable to wear. Austempered steel had the highest impact strength and it is increased with soaking time up to certain level. Least wear rate is observed in martempered sample both in abrasion and dry sliding. However, least friction coefficient is shown by annealed samples.

Surface model and tool-wear prediction model for solid lubricant-assisted turning

Mathematical models for surface roughness and tool wear are developed through regression analysis of the experimental data collected from machining. Different particle sizes and flowrates of solid lubricants are employed in the study. Experimental results show a significant effect of solid lubricant particle size and flowrate on surface roughness and tool wear. Decrease in the particle size resulted in reduced tool wear and surface finish improvement. Various machining parameters such as cutting forces, tool wear, and surface roughness improved with an increase in the flowrate of solid lubricant up to a certain level and remained constant at higher flowrates. To estimate the effect of solid lubricants on machining, exponential models are proposed in the present work to predict tool wear and surface roughness as a function of solid lubricant particle size, flowrate, machining time, and cutting force. Predicted values obtained from the developed model and experimental results are compared, and error<10 per cent is observed.

Basic Properties and Performance of Vegetable Oil-Based Boric Acid Nanofluids in Machining

Machining is one of the most basic and essential processes in manufacturing industry. Quality of the workpiece essentially depends on the heat generated in the cutting zone during machining. The usage of cutting fluids poses a question of risk to ecology and health of workers, in spite of their extensive use in dissipating the heat. This paves search for user-friendly and eco-friendly alternatives to conventional cutting fluids. Keeping this aspect in perspective, the present work deals with the application of nano solid lubricant suspensions in lubricating oil in turning of AISI 1,040 steel using carbide tool. Boric acid solid lubricant suspensions of 100 nm particle size are added to coconut oil. Particle size of nano-boric aicd is confirmed through particle analyzer. XRD analysis is done to assess the purity of the sample. On weight-percentage basis boric acid nanoparticles are added to the oil. The variation of its basic properties like flash point, fire point, viscosity, thermal conductivity, and heat transfer coefficient is evaluated. Cutting tool temperatures, average tool flank wear, and the surface roughness of the machined surface is examined in machining.