Tribology in Manufacturing - Report Example

Research Report on Tribology in Manufacturing Name Institutional Affiliation Date Table of Contents Introduction 3 Aims and Objectives 4 Literature Review 4 Introduction 4 Tribology in Manufacturing and Manufacturing Processes 5 MQL, Metalworking Fluids Machining & Tool-wear 7 How Nanoparticles Affect MQL 9 Cryogenic Machining 10 Expectation of the experimental results 11 Experimental Methodology 11 Apparatus and Arrangement 12 Test conditions 14 Setting up the apparatus 14 Procedure 14 Results 15 Discussion and Analysis 17 Conclusion 26 References 28 Introduction Manufacturing processes are considered to be one of the main fundamentals of building the earth. It is the backbone of the industrial community. An industrial revolution started in England and it was a development to produce materials by machines instead of hands (Siṃha, 2006). Different machines had different jobs; these jobs are cold manufacturing processes. Manufacturing processes are used to turn raw materials into finished materials and equipment (Siṃha, 2006). In manufacturing more complex material with precision and controls, super alloys and nano-composites are used to manufacture complex shapes that are stiff and rough. Super alloys and nano-composites can resist high temperatures. Moreover, in order to manufacture materials, fluids are applied during manufacturing processes, which are called metal working fluids (Hernandez et. al., 2008). Metalworking is conventionally two processes: metal deformation and metal cutting or removal (Siṃha, 2006). Metal working fluids (MWFs) are neatsfoot oil or water-based fluids, which are applied to improve the metalworking process by lubricating and cooling metals. Aims and Objectives The aim/objective of the project is to; Experimentally evaluate the effect of nanoparticles on the extreme pressure performance steel Compare and analyse the tool-wear of MQL and metalworking fluids machining, and decide what is the most suitable machining to be used to manufacture complex shapes with precision. Literature Review Introduction According to Siṃha (2006), metalworking fluids play an important role in manufacturing processes, including machining and forming. They help in the cooling of tool and work piece and the removal of chips. In addition, they reduce friction between the forming and machining parts and in the interaction with the surface of the workpiece. The integrity of a surface is normally determined by the metalworking fluid used and the manufacturing process. These factors significantly affect the components’ functionality in other subsequent utilisations. There are four important properties of the metalworking fluid that are usually given a major focus in forming and machining processes (Siṃha, 2006). These include the roughness, the profile depth of hardness, the wear resistance and the residual stress. The surface wear resistance is influenced by the material chemical properties and the manufacturing process involved, as well as, the type of the metalworking fluid used. Generally, the chemical conditions of any metalworking fluid perform a crucial role in the functional performance of the machines within the span of their service life and in the machining process itself (Siṃha, 2006). The extreme pressure additive and pressure additives are among the key factors that play an important role in the wear resistance. Wear resistance is significantly influenced by the chemical characteristics of a given metal surface and the interaction between the metal surfaces. The molecular concentration of various sulphur additives and their combination play an important role in the properties of the metalworking fluid being applied in a given forming and machining process. Siṃha (2006) highlights that the performance of cutting processes is limited, detrimentally, by wear and friction experienced by the cutting tool. In order to improve these cutting processes, it is necessary to understand their mechanisms. The systematic analysis of the wear mechanisms and friction within the tool’s active areas may be difficult to undertake due to complexity of a particular machining process. In regard to this, one of the issues of particular importance that need to be understood is the tribological’s detailed knowledge involving the interactions within the contact zones in order to design a machining process that is economical. Tribology in Manufacturing and Manufacturing Processes The tribological mechanisms are influenced by the environmental parameters, controlling parameters and contact partners (Wu, Tsui & Liu, 2007). A given tribological system, in regard to the common description, is marked by a basic body as the part which is subjected to wear, together with a counter body for which the wear is not influencing the course of the process. When it comes to definition, the cutting tool is the basic body while its counterpart in the tribological system is the workpiece. In addition, the environmental medium together with the interfacial element are of great importance in as far as tribological system’s behaviour is concerned. The other factors that influence the tribological system are abrasive materials found within the contact zone, cooling lubricants and reaction products. Additional variables within the tribological system that determine the wear mechanisms and friction include the feed rate and the cutting speed. The figure below demonstrates the cutting process in the set up of a tribological system. Figure 1: Cutting Process in the Setup up of a Tribological System Wear is inevitably caused by the friction that occurs between the contact partners and this alters the basic body’s shape, together with the counter body. Tribochemical reactions, abrasion, surface ruins and adhesion are the main present wear mechanisms. These wear mechanisms result to different forms of wear like material deposits, grooves, reaction products, scratches and surface cracks. All tribological systems elements should be adapted to particular requirements that conform to dry machining processes in order to guarantee high performance marked with satiable process reliability. This process of adaption will specifically influence the tool coating specifically the basic body and the cutting material, the interfacial MQL medium element and the counterpart of the basic body which is the workpiece material (Silva, 2005). MQL, Metalworking Fluids Machining & Tool-wear In Minimum Quantity Lubrication (MQL) technique of machining, small quantity of lubricants are applied to the interface between the workpiece and the tool (Dhar, Kamruzzaman & Ahmed, 2006). When dry cutting is undertaken and compared to the situation where Minimum Quantity Lubrication (MQL) lubricant is applied, it will be observed that, in the case of dry cutting, it leads to issues like short life span as a result of severe chipping. This puts Minimum Quantity Lubrication (MQL) at a higher level as compared to other techniques because it leads to controlled temperatures, better thrust force, long tool life and better torque (Guhring, N.D.). Palm oil has an incredible performance when it comes to cutting and machining and this is due to the characteristic of the palm oil to form a thin film which aids in the promotion of boundary lubrication when the machining process is being undertaken. In addition, palm oil posses certain suitable qualities like surface roughness, micro hardness as well as subsurface deformation. Therefore, palm oil can be given an upfront consideration compared to other Minimum Quantity Lubrication (MQL) lubricating oil types like synthetic ester. Strong emphasis is currently been laid on the technology that is environmentally friendly with regard to the growing concerns of the environmental issues. This is because of the application of the cutting fluids within the operations of the machining processes. There have also been persistent attempts to do away with the cutting fluids. This move has become a challenge since cooling process is still imperative when it comes to preserving the life of the cutting tools for economical purposes and also the qualities of the required surface. A typical example is where high dimensional exactness, tight tolerances and shape exactness is necessary or where there is involvement of materials that are difficult to cut or require critical machining. The best alternative among the cutting fluids is the Minimum Quantity Lubrication (MQL) given the aforementioned challenges. This technique is a hybrid of low fluid consumption and functionality of cooling factors (Piekoszewski, Szczerek & Tuszynski, 2001). The fluid consumption is usually as low as 80ml per hour. As low as it is, the low oil quantity is salient enough to suffice the tool friction and material adherence demands. The need to minimise the cutting fluid has for the past years gained tremendous relevance in the machining works and processes. Minimum Quantity Lubrication (MQL) helps in overcoming the challenges in dry operations. This is because it bases its principle on total utilisation such that there is no residue left behind. The applied lubricant oil flows from 10ml per hour to 100ml per hour at a range of pressure of 4Kgf/cm² to 6.50Kgf/m² (Nilesh, Dhatrak, Mahalle, N.D.). In this process, chips are usually being released in a dry condition so that the cost of recycling the cutting fluid is practically avoided. The capability of any given metalworking fluids lubricate and cool the contact zone that exists between the workpiece and the tool greatly depends on the substances that are surface-active including the extreme pressure additive and pressure additives (Kaynak et. al., 2014). This further depends also on the steel’s chemical surface properties. When stainless steel as well as low alloyed steel metals are analysed by applying a wear resistance examination using the metalworking fluids with definite relative additives concentration having various properties such as molecular structure and regarding activity, there is a critical observation that is made in light of the metalworking fluids. If in the same examination assessment is made on the wear resistance and then matched up against metals chemical properties, antagonistic effects as well as synergistic effects are observed. Such experimental results clearly suggest that the amount of the additive is not a significant factor compared to the relative ratio of polar to that of unpolar pressure additive and extreme pressure additive. The optimum result however, depends on the considered surfaces chemical properties. How Nanoparticles Affect MQL Nanoparticles such as MoS2 is important in adding value to the Minimum Quantity Lubrication (MQL) grinding, especially in a situation that involves usage of different base fluids that are off the shelf like soybean oil, paraffin oil or any related (Ambrosy, et. al., 2014). In addition, such a nanoparticle comes with myriad and unique benefits when incorporated with Minimum Quantity Lubrication (MQL). These nanoparticles help in improving the navigation within the grinding zone and at the same time, significantly minimise the grinding forces within the grinding zone. (Hernandez et. al., 2008). Another benefit of incorporating nanoparticles in the Minimum Quantity Lubrication (MQL) cutting lubricant is the increased life expectancy of most of the grinding wheels that are very expensive. Nanoparticles do this by tremendously raising the G-ratio ((Hernandez et. al., 2008). Cost effectiveness is a key element of the cutting oils because most of them are very expensive. When nanoparticles are used with the Minimum Quantity Lubrication (MQL) lubricating oils, better grinding performance with the inclusion of a small quantity of nMoS2 in the lubricant is registered. This can be as low as 5ml per minute as opposed to that of flood cooling which is 5400ml per minute. Moreover, the integration of small amount nanoparticles in the Minimum Quantity Lubrication (MQL) lubricant, especially when used with the organic chemistry related oils like canola oil has myriad advantages (Hernandez et. al. 2008). Some of them include minimal quantity of lubricant in order to economise this expensive oil lubricant, minimal financial expenditure on a lubricant among others when these additives are incorporated. In addition, the utilisation of nanoparticles in the Minimum Quantity Lubrication (MQL) cutting oil lubricant has an environmental advantage since it is environmentally friendly (Ambrosy, 2014). There is no pollution when canola oil or any other related nanoparticles-based oils are used. Cryogenic Machining The technology of Cryogenics is an old process and yet crucial in the manufacturing processes. This field of technology relates to deep freezing temperatures (Pusavec & Kopac, 2009). The common cryogenics include hydrogen, nitrogen, neon, helium, argon, krypton, methane, propane, and xenon. Even though pressure of over 50 kPa is required for carbon dioxide, it is also included in this list of cryogenics. Some of the major applications of cryogenics include the plants for air separation and medicinal purposes. In space technologies, cryogenics is used through liquefied oxygen and hydrogen for fuel, food cooling and freezing, blanketing and purging. Initially, cryogenic fluid was used for cooling purposes in the metal cutting processes that were started back in 1950s (Pusavec & Kopac, 2009). In those days, CO2, and Freon were used as cryogenic fluids that would be sprayed in the cutting area. The main limitation, however, was that the process consumed a lot of the cryogenic fluid and did not have the lubrication effect. Further, the process was associated with high cost and complexity in the delivery of the cryogenic fluid for the cutting zones. Lately, the processes have found application in storage and liquefaction systems and are becoming more affordable. There is a dire need to develop this technology and increase the technology to an industrial level. Nitrogen is highly preferred for this technology than CO2 or helium which are expensive and rare to find. Expectation of the experimental results The experiment results focus on illustrating the research objectives as highlighted under the project aims and objectives. Through the results, various conclusions and relationships can easily be drawn and be compared to the actual values. Experimental Methodology Rolling and Sliding Manufacturing Processes used in the 4-ball Tester involves three steel balls of 12.7 mm diameter clamped together after being covered wholly with the lubricant under test at a temperature of 75˚C (Ashby, Shercliff & Cebon, 2010). The top steel ball that is one of the other three balls having the same diameter is pressed using a 392N force through the cavity left between the three clamped balls. This top steel ball is then set to rotate at 1200 revolutions per minute for 60 minutes. Different lubricants are then compared by considering the mean size of the scar diameters curved on the lower three steel balls clamped together. This method is used to estimate the properties of grease that prevent relative wear subjected to certain test conditions. When the test conditions are slightly altered, the relative ratings also vary significantly (Ashby, Shercliff & Cebon, 2010). There is no relationship so far established existing between the field service and the 4-ball wear test. This technique is not suitable for identifying the disparity existing between non-extreme pressure and extreme pressure. Apparatus and Arrangement The apparatus used consists of: 4-ball tester together with its accessories as shown in Figure 2 and 3. A microscope with the ability to determine the diameters of the produced scars left on the three clamped ball set at a stationary point without necessarily removing the balls from their holder. It should have an accuracy of 0.01mm. Cleansing fluids for making the balls ready: The fluid should have the ability to remove the coating of the metal preservative from the balls and removing the carry-over effects that occur from one test to another. Figure 2: Precision Scientific Company 4-ball Test Arrangement Figure 3: Falex Corporation 4-ball Test Arrangement Test conditions The 4-ball test should be carried out under the following conditions; Parameter Condition Temperature 75 +/- 2 ˚C Speed 1200 +/- 60 rpm Duration 60 +/- 1 min Load 392 +/- N Setting up the apparatus Obtain a spindle velocity of 1200 +/- 60 rpm by setting up the drive of the test device. Vary the test temperature of the experiment by setting the temperature controller in order to obtain a constant temperature of 75 +/- 2 ˚C. Terminate the test using automatic timer in order to obtain a time lapse of 60 +/- 1 min. Balance the loading mechanism in order to obtain a zero reading after setting the test grease and all parts in to place. This precision should be verifiable when a load of 19.6N is subtracted or added. Procedure Properly and adequately clean the 4 test balls Clamp the parts for both the lower and upper balls Oil the cup with the aid of a cleaning fluid or any other suitable fluid. The cleaning process can be made more effective when ultrasonic vibration is used. Wipe the clamped parts with the help of a fresh lint-free wipe (industrial) to remove any traces of cleaning fluid. Once the parts are cleaned, use a fresh wipe to handle them Place one of the balls after cleaning into the ball chuck. Place the ball chuck right inside the spindle of the device and fasten to required tightness. Put a suitable amount of grease in the cup so that no void is left between the test balls Place the three lower balls in the cup and lock them in the right position. This can suitably be achieved by tightening the locknut manually. Coat the entire ball cup containing the test balls and chuck wholly and properly using grease ensuring that grease covers the cup up to the locknut’s top surface. Fix the entire assembly on the test machine. This has both grease specimen and cup assembly. Apply the test load gently to avoid shock loading. Switch on the temperature regulator once a suitable test load has been achieved to a constant temperature of 75 +/- 2 ˚C Upon attaining a suitable test temperature, start the drive motor and timer simultaneously. It was previously at a speed of 1200 +/- 60 rpm. After 60 +/- 1 min, switch off both the drive motor and the heaters. Remove the whole ball assembly. Estimate the wear scars that occur on the lower three balls with utmost precision of +/- 0.001mm. There are two methods used and this will be discussed in the next section. Precaution should be taken when handling the parts because they are normally hot after the experiment. Results There are two techniques of determining the wear scars that occur on the three lower balls. There is option 1 and option 2. a) Option 1 Option 1 entails cleaning the grease that surrounds the ball cup entire assembly. This is done without loosening all the balls in order to maintain their contact. This procedure can be done using a tissue. The three lower balls are left in the clamped position and the ball cup entire assembly is set on a specified base of the measuring equipment (microscope). Two measurements are made on each scar wears with one measurement taken along a line of radius that passes through the centre of the holder. The other measurement is taken a long a line that is perpendicular to the first one. Determine the arithmetic mean of 6 measurements which becomes the diameter of the scar in millimetres. b) Option 2 Option 2 entails removal of the lower balls out of their clamped contact position. The scar is then wiped clean and two measurements be taken at right angle to each other. Depending on the shape of the scar, approach of measurement is also different. In case of an elliptical scar, one measurement is undertaken with the striation while the other is done across striation. Care should be taken to ensure that the measured line is perpendicular to the surface. Similar to option 1, take the mean reading in millimetres of the scar diameter. There may be discrepancies in the measurement between experimental and measured value due to accuracy and precision issues. The deviation should not exceed 0.20mm. When this same result is conducted in a different laboratory with different conditions, the difference can be 0.37mm. This technique does not display any bias since the value obtained for wear preventing features is only determinable with respect to the used test method. Discussion and Analysis The analysis of the experiment is done using tables and graphs as shown below. The manufacturing productivity increases with increase in flexibility as shown in the graph below. Figure 4: Possibilities to Increase the Productivity of Manufacturing The analysis of the levels of technological parameters with the levels of variation regarding the cutting depth and cutting speed are tabulated as below. Table 1: The Levels of Technological Parameters The table below summarises the different lubricants and the amount of pressure and they can yield. Table 2: The Values of Pressures and Flow The figure below shows the data flow in monitoring and measuring in the MQL lubricant. Figure 5: Data Flow in Measuring and Monitoring The graph below depicts the variation of the Minimum Quantity Lubrication (MQL) and the conventional methods with regard to feed cutting forces and the feed speed in mm/rev. With a VC = 320m/min and a = 2.0 mm. Figure 6: Values of Feed Cutting The graph below depicts the variation of the Minimum Quantity Lubrication (MQL) and the conventional methods with regard to feed cutting forces and the feed speed in mm/rev. With a vc = 400m/min and a = 2.50 mm. Figure 7: Values of Penetration Cutting The graph below depicts the variation of the Minimum Quantity Lubrication (MQL) and the conventional methods with regard to the average cutting forces and the components of the cutting force. Figure 8: Comparison of the Mean Value of Components of Cutting Force for both Dosing Techniques The chart below summarises the chip shape during machining with conventional flooding. It shows the depth and the cutting speed. Figure 9: Chip Shape during Machining with Conventional Flooding The chart below summarises the chip shape during machining with Minimum Quantity Lubrication (MQL). It shows the depth and the cutting speed. Figure 10: Chip Shape During Processing with MQL Technique The chart below summarises the tool wear during machining with conventional CLF dosing. It shows the depth and the cutting speed. Figure 11: Tool Wear During Machining with Conventional CLF Dosing The chart below summarises the tool wear during machining with MQL technique. It shows the depth and the cutting speed. Figure 12: Tool Wear During Machining using MQL Technique The analysis of the MQL and the conventional techniques are shown in the graph below for a depth of 1.5mm and varying feed speed. Figure 13: Technological areas for depth a=1.5mm During the experiment, different types of errors may be encountered including systematic and random errors that may affect the accuracy of the results. Conclusion It has been observed through the experimental investigation that the cutting performance characteristics of the Minimum Quantity Lubrication (MQL) machining is much more suitable than that of conventional machining as well as that of dry machining with the aid of fluid supply flood cutting. This is because the Minimum Quantity Lubrication (MQL) has aggregated benefits such as the ability to reduce the temperature of the cutting process and tools. This in turn improves the interaction between the tool and the chip and at the same time maintains the cutting edge sharpness. Minimum Quantity Lubrication (MQL) jet improves the life of the tool, helps in the reduction of tool wear as well as the improved and better surface finish in comparison to the other wet and dry machining processes. Minimum Quantity Lubrication (MQL) the dimensional accuracy and surface finish is as a result of the minimisation of the damage that is caused at the tip of the tool and reduction of the tool wear. These points when put together have the power of synergy and integration since they ensure that the productivity of the process is improved as well as the improvement in the life of the tool. These in turn lead to increased feed and cutting speed. In any forming or machining process, efficiency combined with better tool life and improved work output are of great importance and are always given optimum priority. Nanoparticles such as MoS2 play an important role in adding value to the Minimum Quantity Lubrication (MQL) grinding especially in a situation that involves usage of different base fluids that are off the shelf like soybean oil, paraffin oil or any related. In addition, such a nanoparticle comes with myriad and unique benefits when incorporated with Minimum Quantity Lubrication (MQL). These nanoparticles help in improving the navigation within the grinding zone and at the same time, significantly minimise the grinding forces within the grinding zone. Another benefit of incorporating nanoparticles in the Minimum Quantity Lubrication (MQL) cutting lubricant is the increased life expectancy of most of the grinding wheels that are very expensive. Cost effectiveness is one of the most important features that can be taken care of by the application of nanoparticles in the cutting oil lubricants. References Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form AMBROSY, F., ZANGER, F., SCHULZE, V., & JAWAHIR, I. (2014). An Experimental Study of Cryogenic Machining on Nanocrystalline Surface Layer Generation. Procedia CIRP. 13, 169-174. Top of Form ASHBY, M., SHERCLIFF, H., & CEBON, D. (2010). Materials: engineering, science, processing and design. Oxford, Elsevier Butterworth-Heinemann. Bottom of Form DHAR, N., KAMRUZZAMAN, M., & AHMED, M. (2006). Effect of minimum quantity lubrication (MQL) on tool wear and surface roughness in turning AISI-4340 steel. Journal of Materials Processing Tech. 172, 299-304. Guhring (N.D.). Minimum Quantity Lubrication MQL. HERNANDEZ BATTEZ, A., GONZALEZ, R., VIESCA, J. L., FERNANDEZ, J. E., DIAZ FERNANDEZ, J. M., MACHADO, A., CHOU, R., & RIBA, J. (2008). CuO, ZrO2 and ZnO nanoparticles as antiwear additive in oil lubricants. WEAR -LAUSANNE-. 265, 422-428. KAYNAK, Y., ROBERTSON, S., KARACA, H., & JAWAHIR, I. (2015). Progressive tool-wear in machining of room-temperature austenitic NiTi alloys: The influence of cooling/lubricating, melting, and heat treatment conditions. Journal of Materials Processing Tech. 215, 95-104. Nilesh C.G., Dhatrak V.K. Mahalle A.M. (N.D.). Minimum Quantity Lubrication. IOSR Journal of Engineering (IOSRJEN). PIEKOSZEWSKI, W., SZCZEREK, M., & TUSZYNSKI, W. (2001). The action of lubricants under extreme pressure conditions in a modified four-ball tester. WEAR -LAUSANNE-. 249, 188-193. PUSAVEC F., STOIC A., & KOPAC J. (2009). The role of cryogenics in machining processes. Tehnicki Vjesnik. 16, 3-10. Silva L.R. (2005). Study of the Behavior of the Minimum Quantity Lubricant –MQL Technique Under Different Lubricating & Cooling Conditions when Grinding ABNT 4340 Steel. Vol. XXVII, No. 2. SIṂHA, R. (2006). Introduction to basic manufacturing process and workshop technology. New Delhi, New Age International (P), Publishers. WU, Y., TSUI, W., & LIU, T. (2007). Experimental analysis of tribological properties of lubricating oils with nanoparticle additives. Wear. 262, 819-825. Read More