Center for Nanotechnology

The generation of heat during machining at the cutting zone adversely affects the surface finish and tool life. The heat at the cutting zone, which plays a negative role due to poor thermal conductivity, resistance to wear, high strength at high temperatures and chemical degradation can be overcome by the use of proper lubrication. Advancements in the field of tribology have led to the use of solid lubricants replacing the conventional flood coolants. This work involves the use of nano-particulate graphite powder as a lubricant in turning operations whose performance is judged in terms of cutting forces, tool temperature and surface finish of the work piece. The experimentation revealed the increase in cutting forces and the tool temperature when the solid lubricant used is decreased in particle size. The surface finish deteriorated with the decrease in particle size of the lubricant in the nano regime.

Turning which is a widely employed method of metal removal process in the manufacturing industries generates a lot of temperatures due to the increase in cutting forces. In view of the high temperatures developed in the process, tool deteriorates and so good surface quality is hard to be achieved. Lubrication becomes critical to minimize the forces and temperatures generated during the process. In the present work, Boric Acid powder is used as a solid lubricant which is mixed with vegetable oils like coconut oil and soybean oil in turning process. The results indicate that there is a considerable improvement in the machining performance with Boric Acid assisted MQL in machining compared to dry and wet machining. Taguchi method is a powerful problem solving technique for improving process performance, yield and productivity. It is helpful to combine the speed, feed and depth of cut. In the present study, the combination using Taguchi DOE was taken as factors and levels and 32 experimental layout is framed. The current study makes an attempt to study the variations in tool temperature; cutting forces and surface roughness of the machined component under various machining conditions in order to find the optimum values. 1. Introduction In general cutting fluids are used to provide necessary lubrication and also to reduce the temperature and friction between the tool and the work piece during machining process. It is a mix of oil and water for machining steel materials. Selection and utilization of proper lubricant that can ameliorate the overall cutting phenomena is a significant aspect in cutting down the cutting forces and temperatures [1]. The conventional flood lubrication provided at the tool chip interface is becoming uneconomical for machining and not suited for the surroundings. It has been substituted by vegetable based MQL in turning of EN-31 steel; the issue indicates that the surface roughness of vegetable oil is close proximity with the mineral oil [2]. MQL by vegetable oil-based cutting fluid enables reduction in chip-tool interface temperature by 10% [3]. The chip-tool interface temperature is found reducing during machining of EN-31 steel with 10% Boric Acid Powder by weight mixed with SAE40 oil [4]. The performance of canola based cutting fluid with 8% extreme pressure during turning of AISI304L shows better results [5]. The execution of solid lubricant in terms of cutting force, tool temperature, tool wear and the surface finish of the workpiece is an alternative to dry and wet machining [6]. The influence of an anti wear/extreme pressure (AW/EP) additive on the tribological performance of coconut oil was also assessed through an experiment [7]. The potential of vegetable oil-based bio lubricants as alternative lubricants for automobile applications was described elaborately [8]. Coconut oil belongs to a unique group of vegetable oils called lauric oils, as they exhibit a lower weight gain, an indicator of oxidative stability, under oxidative environment and the highest pour point among all the vegetable oils [9]. Variation of cutting tool temperatures, average tool flank wear and surface roughness of the machined surface with cutting speed and feed were studied under the application of Boric Acid Powder solid lubricant suspensions of 50 nm particle size in SAE-40 and coconut oils in turning of AISI 1040 steel with carbide tool [10]. The effects of particle size and concentration of (CF)n on the friction and wear mechanism of metals shows a good performance [11]. The wear properties of soybean oil were different than the coconut oil because of its high content of unsaturated fatty acids and its susceptibility to undergo oxidation [12]. Chemically modified soybean oil exhibits superior low-temperature flow properties, improved thermo-oxidative stability, and better friction and wear properties [13]. Taguchi method was applied to optimize the cutting conditions to get low surface roughness values in turning of SCM alloy steel [14]. In the current study, Nano Boric Acid Powder was mixed in vegetable oils like soy and coconut oils in different weight ratios to reduce health hazards possessed by the mineral oils. 32 experiments are designed to investigate the chip-tool interface temperature and surface roughness of AISI 1040 steel under different weight percentages of solid lubricant.

Application of lubricant is a problem in many cases, apart from external lubrication; it is always being useful if the material itself has self-lubricating properties. Such kind of materials are GCI & PTFE+Graphite composites. In these, Graphite flakes acts as solid lubricant & when load is applied, these layers slide over another & provide lubricat ion. PTFE+Graphite is well known for its self-lubricating properties and widely emp loyed in applications, where d ry lubrication & good thermal stability are needed. Primary aim of this work is to study & compare t ribological properties of proposed self-lubricat ing materials. Tests are conducted on the POD apparatus using GCI disc and pin & PTFE+Graphite p in & AISI 1045 Steel disc specimens under different conditions. Later, linear Regression models are developed using input and output variables for both GCI Pin on GCI disc and PTFE filled with Graphite Pin on AISI 1040 Steel disc. Validation of the proposed mathematical equation wa s done by comparing experimental and predicted values of the experimentation and in all cases percentage error was found in between 0-6%. ANOVA was also performed on the experimental results to assess the conformity of the suggested mathematical model with 99% confidence levels.

In order to improve the performance of the cutting tool, it is required to model the metal cutting process at the system level. To predict and enhance the cutting tool performance the primary requirement of the system is the efficiency of the model explaining the interactions at the tool chip interface. The predominating parameters which influence the development of the system are work piece material and machining variables or sometimes both. Further the development of low cost methodology to study the chip tool interactions with minimum amount of testing is of more importance. Major part of the work is emphasized on the investigation and characterization of various zones on the rake face of tungsten carbide inserts. Tests have been carried out by machining AISI 1040 2 " Copyright ©ASME 2010 " steel using WC inserts with variable dry conditions examining the chip flow phenomenon on the rake face of considerable number of samples. Taguchi method is adopted for the design of experimental conditions. Results have shown an acceptable chip flow patterns and authors were able to quantify the wear zones on the rake face. The rake face is then characterized to represent all the possible cases of chip flow patterns, crater wear and chipping of the cutting edge. Side and end cutting edges are taken as datum lines for locating the wear zones. The quantification and locations of the wear zones might help the researchers and tool makers to concentrate more on the defined areas instead of the rake face in total.

The generation of heat during machining at the cutting zone adversely affects the surface finish and tool life. The heat at the cutting zone, which plays a negative role due to poor thermal conductivity, resistance to wear, high strength at high temperatures and chemical degradation can be overcome by the use of proper lubrication. Advancements in the field of tribology have led to the use of solid lubricants replacing the conventional flood coolants. This work involves the use of nano-particulate graphite powder as a lubricant in turning operations whose performance is judged in terms of cutting forces, tool temperature and surface finish of the work piece. The experimentation revealed the increase in cutting forces and the tool temperature when the solid lubricant used is decreased in particle size. The surface finish deteriorated with the decrease in particle size of the lubricant in the nano regime.

In order to improve the performance of the cutting tool, it is required to model the metal cutting process at the system level. To predict and enhance the cutting tool performance the primary requirement of the system is the efficiency of the model explaining the interactions at the tool chip interface. The predominating parameters which influence the development of the system are work piece material and machining variables or sometimes both. Further the development of low cost methodology to study the chip tool interactions with minimum amount of testing is of more importance. Major part of the work is emphasized on the investigation and characterization of various zones on the rake face of tungsten carbide inserts. Tests have been carried out by machining AISI 1040 "Copyright ©ASME 2010" steel using WC inserts with variable dry conditions examining the chip flow phenomenon on the rake face of considerable number of samples. Taguchi method is adopted for the design of experimental conditions. Results have shown an acceptable chip flow patterns and authors were able to quantify the wear zones on the rake face. The rake face is then characterized to represent all the possible cases of chip flow patterns, crater wear and chipping of the cutting edge. Side and end cutting edges are taken as datum lines for locating the wear zones. The quantification and locations of the wear zones might help the researchers and tool makers to concentrate more on the defined areas instead of the rake face in total.

Turning has been one of the most indispensable methods of metal removal. Much advancement has been made in the machining aspects with regards to the lubricants used. Nano crystalline powders used as lubricants in machining has been a subject of research. Turning is characterized by development of high temperatures at the cutting zone, which impairs the surface quality of the final product. The present investigation deals with the use of a mixture of nano crystalline Graphite and SAE40 oil as a lubricant and as an alternative to the cutting fluids to reduce friction and thereby improve the surface finish of the final product. It deals with the investigation of the influence of nano crystalline graphite particle size and its weight percentage with respect to SAE40 oil with regards to the variations in tool temperature, and surface roughnes.

Wave springs are precise flat wire compression springs that fit into assemblies that other springs cannot since the overall lengths and operating heights of Wave springs are lower than those of conventional round Wire springs, they will often reduce the size of an assembly by as much as 50%. Of course, this will also reduce the part weight and raw material cost of every spring produced. Wave springs operate as load bearing devices. They take up play and compensate for dimensional variations within assemblies. A virtually unlimited range of forces can be produced whereby loads build either gradually or abruptly to reach a predetermined working height. This establishes a precise spring rate in which load is proportional to deflection. Functional requirements are necessary for both dynamic and static spring applications. Special performance characteristics are individually built into each spring to satisfy a variety of precise operating conditions. Typically, a wave spring will occupy an externally small area for the amount of work it performs. The use of this product is demanded, but not limited to tight axial and radial space constraints. In this paper, a three dimensional finite element (FE) model for shock absorber spring is proposed. The present work deals the structural analysis for modelling the structural behaviour of wave springs. The design of spring in suspension system is very important. In this work a wave type of spring is designed and a 3D model is created using Pro/Engineer. The model is also changed by changing the length of the spring. Structural analysis has been conducted on the wave spring by varying the spring material such as Structural steel and Beryllium Copper. For this analysis, loads are considered as bike weight, single person and two persons. Structural analysis is done to validate the strength. The present study makes an attempt to compare the results for selecting best material for springs.

The past few decades have witnessed significant advancements in turning processes, cutting tools and coolant/lubricant chemistry. These developments have enhanced the machining capabilities of hard materials when machining at higher cutting conditions. Turning, being characterized by the development of high temperatures at the cutting zone, is critical with respect to the tool life and surface finish apart from other machining results like the forces generated. This phenomenon of heat generation at the cutting zone plays a negative role during turning operations due to their peculiar characteristics such as poor thermal conductivity, high strength at elevated temperature, resistance to wear and chemical degradation. Cutting fluids and solid lubricants are generally used to overcome the problem of heat generation at the cutting zone. The use of cutting fluids in the conventional way may not effectively control the heat generated in turning operation. Moreover, cutting fluids are a major source of pollution. With the advancement in technology, nano-level particulate solid lubricants are being used nowadays in machining operations, especially grinding and turning. The present work deals with the investigation of using nano-level particulate graphite powder as a solid lubricant and various tests were conducted by machining AISI 1040 steel using tungsten carbide inserts. The experiments were conducted by taking into account the parameters like feed rate ranging from 0.05 mm/rev to 0.125 mm/rev, cutting speed ranging from 51 m/min to 192.6 m/min and depth of cut from 0.25 mm to 1 mm. Four levels of each parameter are considered for experimentation. The results indicate that with the decrease in the nano-sized graphite powder, there is an increase of cutting forces-feed force, cutting force and thrust force. The temperatures at the tool-chip interface also increases with the decrease in the lubricant size. It is found that the surface roughness of the workpiece after machining deteriorated due to the size of the lubricant particle.

Turning, which is a widely employed method of metal removal process in manufacturing industries, generates many temperatures because of the increase in cutting forces. In view of the high temperatures developed in the process, tools deteriorate, and so good surface quality is difficult to achieve. Lubrication becomes critical to minimize the forces and temperatures generated during the process. In the present work, boric acid powder is used as a solid lubricant, which is mixed with vegetable oils such as coconut oil and soybean oil in turning process. The results indicate that there is a considerable improvement in the machining performance with boric acid assisted MQL in machining compared with dry and wet machining. Taguchi method is a powerful problem solving technique for improving process performance, yield, and productivity. Combining the speed, feed, and depth of cut is helpful. In the present study, the combination using Taguchi DOE was taken as factors, levels, and 32 experimental layouts are framed. The current study attempts to study the variations in tool temperature; cutting forces and surface roughness of the machined component under various machining conditions to find the optimum weight percentage of the solid lubricant used.

Temperature variation at a cutting zone during machining drastically affects the surface roughness and the life of a tool. Nano crystalline powders, in the recent past has played a very important role in altering the properties of a lubricant like surface finish, cutting temperature, machining ability in order to achieve optimum results. This work is mainly concentrated on the study of lubricants when mixed with MoS 2 nanoparticles. The role of MoS 2 nanoparticles in the lubricant at different weight concentrations are analysed for different particle sizes. The input parameters such as feed, speed, depth of cut and also the size of the particle are varied during the course of experimentation. Here, the minimum quantity lubrication is taken as 10ml/min. Full Factorial design of experimentation is used to determine the optimum machining parameters using MINI TAB software. This work involves the use of nanoparticles as a lubricant whose performance is judged in terms of tool temperature and surface finish of the workpiece.

Technological advancements in the development of cutting tools and coolant/lubricant chemistry have enhanced the machining capabilities of hard materials under higher machining conditions. Generation of high temperatures at the cutting zone during machining is one of the most important and pertinent problems which adversely affect the tool life and surface finish of the machined components. Generally, cutting fluids and solid lubricants are used to overcome the problem of heat generation, which is not effectively addressing the problems. With technological advancements in the field of tribology, nano-level particulate solid lubricants are being used nowadays in machining operations, especially in the areas of turning and grinding. The present investigation analyses the effect of using nano-particulate graphite powder as lubricant in the turning of AISI 1040 steel under variable machining conditions and to study its effect on cutting forces, tool temperature and surface roughness of the machined component. Experiments revealed that the increase in cutting forces and tool temperature resulting in the decrease of surface quality with the decrease in the size of nano-particulate graphite powder as lubricant.

Material selection is one of the major points that should be taken into account seriously in the engineering design stage. Each material has various properties such as mechanical, thermal, electrical, physical, environmental, optical and biological properties. It is expected that an information source such as the proposed database will provide all the necessary facts and figures to aid both designers and manufacturing engineers. In the scope of this Paper, the aim was to develop a database and a software package for material selection to help the design engineer in his decision making process. The database developed by using Microsoft Visual Studio and also contains different materials standards and can be updated if the user wants. Done the analysis for different components and results should be storage in Database by using visual studio. All features can be used as part of a sequential screening process, guiding the user to an eventual metal shortlist or selection.

A novel hybrid bio-composite is developed using bio-degradable Jute nanofibers reinforced in epoxy matrix. Synthesis of the jute fibers was carried out using a high energy ball mill. The nanofibers used were of particle sizes ranging from 10-30nm. The nano composites were processed using different weight percentages 0-5 wt. % of jute nanofibers reinforced with epoxy polymer matrix by hand lay-up technique. The mechanical and thermal properties of virgin (base) composite and nanocomposites (1-5wt.%) were compared using Dynamic Mechanical Analysis (DMA), Thermo gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC), DMA results revealed that the storage modulus and loss modulus of these nano composites was improved, where as the mechanical loss factor (tan delta) decreased. The nanocomposites were subjected to the heating cycle between 30oC-600oC to obtain their thermal behavior and TGA measured test were conducted in the temperature range of 30oC- 300oC to identify th...

Wave springs are precise flat wire compression springs that fit into assemblies that other springs cannot since the overall lengths and operating heights of Wave springs are lower than those of conventional round Wire springs, they will often reduce the size of an assembly by as much as 50%. Of course, this will also reduce the part weight and raw material cost of every spring produced. Wave springs operate as load bearing devices. They take up play and compensate for dimensional variations within assemblies. A virtually unlimited range of forces can be produced whereby loads build either gradually or abruptly to reach a predetermined working height. This establishes a precise spring rate in which load is proportional to deflection. Functional requirements are necessary for both dynamic and static spring applications. Special performance characteristics are individually built into each spring to satisfy a variety of precise operating conditions. Typically, a wave spring will occupy an externally small area for the amount of work it performs. The use of this product is demanded, but not limited to tight axial and radial space constraints. In this paper, a three dimensional finite element (FE) model for shock absorber spring is proposed. The present work deals the structural analysis for modelling the structural behaviour of wave springs. The design of spring in suspension system is very important. In this work a wave type of spring is designed and a 3D model is created using Pro/Engineer. The model is also changed by changing the length of the spring. Structural analysis has been conducted on the wave spring by varying the spring material such as Structural steel and Beryllium Copper. For this analysis, loads are considered as bike weight, single person and two persons. Structural analysis is done to validate the strength. The present study makes an attempt to compare the results for selecting best material for springs.