ABSTRACT
This research focuses on investigation of energy consumption in orthogonal turning of AISI 304 alloy steel, with a view of coming up with optimized parameters to accomplish minimum energy consumption and surface roughness in dry and wet cutting environments using mineral oil and vegetable oil based cutting fluids. The procedure involved sourcing of mineral and Jathropha vegetable oil. The vegetable oil was subjected to GC-MS test to ascertain the fatty acid composition profile followed by formulation of emulsion cutting fluids from both mineral oil and the vegetable oil. The formulated mineral oil and Jathropha vegetable oil cutting fluids were then characterised and mineral oil-based cutting fluid was found to have a viscosity of 1.00mm2/s and pH value of 8.65. Both cutting fluids are corrosion resistant, milky in colour and of acceptable stability. Orthogonal turning experiments were then carried out based on design of experiment (DOE) using Response Surface Methodology (RSM) via minitab 17 statistical software. The input parameters for the experiments were cutting speed, feed rate and depth of cut while the measured responses were specific energy consumption and surface roughness. The results obtained from the orthogonal turning experiments were subjected to both Analysis of variance (ANOVA) and signal to noise (S/N) ratio analysis using minitab 17 statistical software. In dry turning, the ANOVA analysis revealed that depth of cut is most significant to both energy consumption (83.11%) and surface roughness (37.69%). In wet turning with mineral oil based cutting fluid, the ANOVA analysis showed that cutting speed is most significant to energy consumption (38.87%) while depth of cut is most significant to surface roughness (40.80%). In wet turning with vegetable oil based cutting fluid, the ANOVA analysis showed that feed rate is most significant to both energy consumption (52.44%) and surface roughness (92.77%). Multi response optimization via grey relational analysis (GRA) was also carried out and the result obtained was also subjected to ANOVA analysis. The ANOVA analysis of energy consumption and surface roughness in dry turning showed that depth of cut has the highest significant effect (43.89%) on both responses combined. In wet turning with mineral oil based cutting fluid, the most significant factor for the combined responses is depth of cut. (55.12%). In wet turning with vegetable oil based cutting fluid, the most significant factor was depth of cut (66.31%).
CHAPTER ONE
1.0 INTRODUCTION
1.1 Background to the Study
Energy consumption of manufacturing processes need to be reduced. This becomes very paramount in view of the rising concern arising from reduction of fossil fuels and the accompanying global warming with some sources for generation of electricity (Composco-Negrete and Calderon-Najera, 2018). Manufacturing sector is the one involved in the transformation of raw input to desired outputs to satisfy the needs of the society using enormous energy. Machining being one of the existing manufacturing methods is a technique involving removal of workpiece‟s surface layers in form of chips. Machining process is usually necessary where light tolerances on dimension and fine surface finish is required.
Turning is a machining operation which primarily involves rotation of the workpiece against a moving single-point cutting tool to facilitate cutting. Lathes are the primary machine tools used in turning. Orthogonal is a two-dimensional cutting process where the tool‟s cutting-edge inclination is zero. The tool‟s movement is at right angle to the it‟s cutting edge and it involves only two components of force.
Recently, rising cost for energy heavily burdens large number of industries especially manufacturing sector the world over. Hence, visualising from both economic and environmental points of view, there is urgent need for improvement and imbibing energy efficient – manufacturing. Machine tools which includes lathes, milling and shaping machines are extensively used in production and industrial sectors are very prominent for consumption of energy. Reduction of energy in industry is very paramount towards achieving environmentally friendly manufacturing. The intensity of energy consumption in industrial and production sector has resulted in increased focus consequent upon its inauspicious effect on the environmental and depletion of natural resources. Globally, 36% emission of carbon dioxide and 30% of the total energy consumed worldwide are due to the activities of manufacturing industries (Yansong et al., 2012). In view of the rising cost of electricity and increasing environmental awareness, it becomes imperative for the energy requirement profile of advanced parts production machines such as computer numerical control (CNC) machines to be better understood (Balogun and Mativenga, 2013).
1.1.1 Trends of human energy consumption
The energy consumed globally are obtained from various primary sources which include renewable such as mineral fuels and fossil fuels. Non-renewable energy sources like biomass and hydroelectric have also been very useful. Presented in Figure
1.1 is cumulative preliminary energy request (CPER) between 1820 and 2010.
1.1.2 Consequences of human energy consumption
One of the effects of energy consumption on the atmosphere is the increase of carbondioxide. In recent years, the increase in green house gases such carbon dioxide in the atmosphere has caused global temperature rise. Before the industrial revolution, the concentration of CO2 in the atmosphere was 280ppm, and has been gradually but steadily increasing since then (Chiba et al., 2019).
The principal factor in the determining the mean temperature of the atmosphere is the greenhouse consequence of CO2. Average temperature of the earth‟s surface varies directly to the atmospheric concentration of CO2 and the pronouncement of the greenhouse effect. The relationship between the temperature of the Antarctic and the atmospheric concentration of CO2 in the last 350,000 years is presented in Figure 1.4.
Directly or indirectly, energy consumption by human beings is the agent cause of problems arising from pollution. Health problems relating to pollution of air in large cities are due to burning of fuels in heat engines of motor vehicles and electric power generating plants. Electricity consumed somewhere lives the power generating plant area with some pollution. Nuclear power plant waste and some other problems arising from pollution are caused by the need to generate electricity for domestic and industrial consumption. Permanent damage could result from this, and could persist for generations.
1.1.3 Reduction of energy consumption
Energy consumption of human beings in the future is a matter of serious concern, visualizing from both environmental and economic perspectives. If the future of human energy consumption is effectively managed, environmental disasters and economic catastrophes can be avoided. Energy is consumed by human beings through devices or power- operated systems to execute energy-consuming jobs such as combustion of fuel in a vehicle engine to move from one place to another, electricity is consumed in a fridge to preserve and keep foods and drinks cool, consuming electricity in a lathe to turn a cylindrical workpiece from the initial dimension to the designed finished dimension of the needed component and other similar instruments. The sum of energy consumed by these and similar instruments accounts for energy consumed globally. In order to cut-down the energy consumed world over, the energy consumption in performing the tasks mentioned and other similar ones, either domestically or industrially must be reduced.
1.1.4 Machine tool energy consumption
In CNC machining techniques, the energy consumed by the machine (ECM) comprises of energy used in driving the spindle in order to machine the component from the initial to the final dimensions, energy consumed in axis feed, energy consumed by coolant pump, energy consumed by tool change system and other components that consumed a fixed amount of energy.
ET= ES+ Ef +Et+ EC + Efx 1.1
Where ET = total energy consumed (J); ES = energy consumed running the spindle (J); Ef
= energy consumed in axis feed (J); Et= energy consumed in changing tool (J); Ec= energy consumed by coolant pump (J); Efx = energy consumed by other components (J). To cut-down the sum of the energy consumed ET, energy consumed by various components shown in equation 1.1 must be reduced. This reduction can be accomplished by optimal choice of the machining environment and machining variables. A carefully researched energy consumption model can be very useful in this situation.
1.2 Statement of the Research Problem
Despite the fact that several investigations have been carried out on orthogonal cutting, energy consumption profile of orthogonal cutting of the selected material-AISI 304 has not been researched into, based on the available literature. This research work investigates the energy consumption profile in orthogonal cutting of AISI 304 alloy steel to fill the research gap indicated. Reduction of energy consumption in turning will reduce production cost and also enhance green production. Optimal selection of cutting environment, cutting variables – cutting depth, speed of cutting, and rate of feed, which will ultimately cut-down the energy consumed to the least possible, and also accomplish precise surface texture of the turned workpiece is paramount. This will ultimately enhance the turning efficiency, manufacturing economy and environmentally friendly manufacturing (EFM).
1.3 Significance of the Study
The objective of any business organization is to minimise cost and maximise profit. In Orthogonal turning, the use of lathe for turning of cylindrical components involves huge energy consumption which increases manufacturing cost and decreases profitability. When the maximum output of available factory capacity is required, metal removal rate is important, and cost factors are more common conditions, and production costs must be kept as low as possible. In most manufacturing situations, this is a balancing act between maximizing output and minimizing production costs (Abu, 2010). The metalworking process is primarily an economic activity. During the roughening operation, the goal is to remove a sufficient amount of metal in the shortest time or at the lowest cost; in the finishing operation, the standard is to produce an acceptable surface finish. The economics of metal removal or machining and the creation of a good surface can be based on time or cost (Gokaya et al., 2006; Abdullah et al., 2008)
The demand for huge energy is accomplished with emission of carbon dioxide, CO2 into the atmosphere and enhances the unwanted global climate change. Shailesh et al., (2015), revealed that the need to estimate and understand the energy consumption profile in machining processes are very vital as it is the cause for a large amount of environmental onus in manufacturing industries. According to Taha et al., (2010), every cutting variable has effect on power consumed in machining process. To accomplish minimum power consumption, combinations of cutting variables need to be optimized. Guo et al., (2012), reported that a method which comprises two responses is proposed for optimisation of machining variables in finish turning. Consequent upon newly generated models for energy consumption and surface roughness, minimum energy consumption and precise surface finish are accomplishable. This research shall seek to accomplish minimum energy consumption in orthogonal turning of AISI 304 alloy steel by proposing a regression equation which takes cognizance of all input independent cutting variables which include, rate of feed, cutting depth and speed of cutting as well as output dependent parameters which include energy consumption and surface roughness at different machining environment.
Some of the major properties which popularise the use of AISI 304 is its high resistance to corrosive environments, sulphates and other salts. It resists corrosion even in acidic environment such as nitric acid. It‟s excellent corrosion resistance property also extends to alkaline, organic and inorganic salts environments. Generally, this material is highly resistance to corrosion in atmosphere and even in high salt spray like marine environment. The material is used in the production of component parts of pumps, valves, marine fittings, fasteners, papers and pulp machineries‟ component parts as well as petrochemical equipment. Production of these components involves substantial orthogonal turning. The model proposed in this research work shall seek to minimize energy consumption, reduce manufacturing cost, and increase profit.
1.4 Aim and Objectives of the Study
This study is aimed at investigating energy consumption during orthogonal turning of AISI 304 alloy steel.
The objectives of the study are to:
(i) Ascertain the physiochemical properties of Jathropha vegetable oil;
(ii) Formulate and characterise the mineral oil and vegetable oil emulsion cutting fluids
(iii) Ascertain the optimal process variables for minimum energy consumption and surface roughness; and
(iv) Ascertain the optimal combined process parameters using the GRA.
(v) Generate optimum cutting parameters to accomplish optimal combined responses,
1.5 Scope and Limitation of the Study
This research encompasses formulation of vegetable oil-based cutting fluid with jathropha oil as base stock. Mineral oil-based cutting fluid will also be developed using the commercially available mineral oil as base stock. Orthogonal turning experiment shall then be executed on AISI 304 alloy steel in wet and dry environments. Wet cutting will be executed with the formulated mineral oil – based and vegetable oil-based – cutting fluids. In this study, response surface methodology (RSM) will be used and this is because it contains and imbedded factorial design with middle point augmented with axial points. The impacts of process variables on energy consumption and surface roughness will be studied. The input variables to be investigated are cutting depth, speed of cutting and rate of feed under different machining environment.
This material content is developed to serve as a GUIDE for students to conduct academic research
INVESTIGATION OF ENERGY CONSUMPTION AND SURFACE ROUGHNESS IN ORTHOGONAL TURNING OF AISI-304 ALLOY STEEL USING FORMULATED VEGETABLE OIL-BASED CUTTING FLUID
A1Project Hub Support Team Are Always (24/7) Online To Help You With Your Project
Chat Us on WhatsApp » 09063590000
DO YOU NEED CLARIFICATION? CALL OUR HELP DESK:
09063590000 (Country Code: +234)
YOU CAN REACH OUR SUPPORT TEAM VIA MAIL: [email protected]
09063590000 (Country Code: +234)
