Nineteenth Century Short Stories and the Gothic Genre Essay

Nineteenth Century Short Stories and the Gothic Genre The three short stories that I have chosen to compare and contrast are: The Signalman by Charles Dickens, An Arrest by Ambrose Bearcy and Napoleon and the Spectre by Charlotte Brontà «. All these stories were completed by the mid to late eighteenth hundreds. The Signalman is set by a railway in Britain, along a lonely stretch of a railway line in a steep cutting. An Arrest is set in America and for the most part in a forest. Napoleon and the Spectre is set in Paris. Gothic genre was one of the leading and most used genres of the nineteenth century and this genre is very prevalent in all three of the stories that I have chosen. The gothic genre originated from South†¦show more content†¦The darkness also gives a sense of mystery to the authors writing. In the glow of an angry sunset, the stranger re-visits the line to see the signalman. The word angry is far from comfortable or romantic. This line also gives an eerie feel to the fading light and gives a feel that suggests that something is must and is about to happen that is dark and evil. An Arrest by Ambrose Bearcy is a story of a murderer who was awaiting his trial, escaped by knocking down his jailer with an iron bar, and went into the forest. It was night and the forest in to which, he entered was renowned for being wild and unsafe. He goes for many a mile and some how manages to exit the forest and finds an old road and on the road there stood the figure of a man, motionless in the gloom. The gothic style protrudes from this line of the novel very clearly and adds to the sense of suspense and fear that is plaguing this scene. The fugitive is almost face to face with the figure of a man, and feels he cannot turn his back for fear of being filled with buckshot, so he stood there like a tree. The fugitive is hoping that if he stands still enough he will become a tree and escape this horror. Until the moon sailed into a patch of unclouded sky, the haunted man saw the visible embodiment of law lift an arm and point significantly beyond him. At which heShow MoreRelatedEssay on The Develoment of the Horror Genre1076 Words   |  5 Page s The term Gothic is significant for the understanding of the origins and development of the horror genre. Both of these genres differ, whilst Gothic literature is the text that explores the frightening extremes in mankind, horror focuses more on the unknown. The Gothic horror genre has changed over time and retains importance because it is the antecedent of the horror genre. Factors such as the definition of the word Gothic, the archetypes of the genre, and its social and historical contexts, haveRead MoreAnalysis Of Edgar Allan Poe s The Tell Tale Heart 1291 Words   |  6 PagesWhat honestly makes a novel gothic? Is it the madness, the horror or the secrets hidden in the story line that does it? 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The unnamed narrator is so in love with the Lady Ligeia, as she is with him, that her untimely death soon after their marriage was unable to separate them. Ligeia rejoins the narrator in life through the body of another, Lady Rowena Trevanion of Tremaine. Rowena is the secondRead MoreFive Short Stories of Edgar Allan Poe Essay1311 Words   |  6 PagesBarnabà ¡s Kanik Five short stories of Edgar Allan Poe Edgar Allan Poe (1809-1849) pioneered many of the most enduring forms of American popular culture, including detective story and the Gothic or sensational tale. I will compare and contrast five short stories of Poe: The Gold-Bug, The Purloined Letter, â€Å"Thou Art the Man†, The Cask of Amontillado and The Pit and the Pendulum. The genre, the purpose and role of the narrator and the parallelism between all of the stories will be examined. 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Electric Discharge Machining Free Essays

string(230) " EDM Electro Discharge Machining \(EDM\) is an electro-thermal non-traditional machining Process, where electrical energy is used to generate electrical spark and material removal mainly occurs due to thermal energy of the spark\." PROJECT REPORT ON INVESTIGATIONS INTO ELECTRIC DISCHARGE MACHINING USING EN-31 AND HCHCr WORK PIECE GUIDED BY:PROF. RAJESH MADARKAR SUBMITTED BY:ROSE DEE KAMLESH GEHANI SHARDUL AMIN SIDDHESH TIWARI SUVO SUNDAR CHATERJEE VIVEK WARADE DEPARTMENT OF INDUSTRIAL ENGINEERING SHRI RAMDEOBABA COLLEGE OF ENGINEERING AND MANAGEMENT KATOL ROAD,NAGPUR-440013 2011-2012 ABSTRACT The correct selection of manufacturing conditions is one of the most important aspects to take into consideration in the majority of manufacturing processes and, particularly, in processes related to Electrical Discharge Machining (EDM). It is a capable of machining geometrically complex or hard material components, that are precise and difficult-to-machine such as heat treated tool steels, composites, super alloys, ceramics, carbides, heat resistant steels etc. We will write a custom essay sample on Electric Discharge Machining or any similar topic only for you Order Now being widely used in die and mold making industries, aerospace, aeronautics and nuclear industries. The objective of this Project Report is to study the influence of operating parameters of pure copper electrode on the machining characteristics such as, material removal rate for work piece material EN-31 and HCHCr ( hardness 20-22 and 55-56) Keywords: EDM; TON; T ; MRR; IP;EN-31;HCHCr Purpose: In this investigation, the effects of various process parameters of sinker EDM like: †¢ pulse on time (TON), †¢ †¢ peak current (IP), Duty Cycle(T) have been investigated to reveal their impact on material removal rate of materials: †¢ EN 31 (Hardness: 20-22) HCHCR (Hardness:20-22) †¢ HCHCR (Hardness:55-56) using one variable at a time approach. The optimal set of process parameters has also been predicted to maximize the material removal rate. . Design/methodology/approach: The experimental studies were performed on ELECTRONICA SPRINTCUT EDM machine. Findings: The material removal rate (MRR) directly increases with increase in pulse on time (TON) upto a certain leve l after that it shows a declining trend and increases directly with peak current (IP) SHRI RAMDEOBABA COLLEGE OF ENGINEERING AND MANAGEMENT INDUSTRIAL ENGINEERING DEPARTMENT CERTIFICATE This is to certify that Ms. Rose dee (12),Mr. Kamlesh gehani (48),Shardul amin(76),Siddhesh tiwari(78),Suvo sundar chaterjee(81),Vivek warade(86) has submitted the project work on INVESTIGATION OF MACHINING PARAMETERS FOR EDM USING EN-31 AND HCHCr WORK PIECE during academic session 2011-2012 under the guidance of PROF. RAJESH MADARKAR as prescribed by Nagpur university and their work has been satisfactory PROJECT GUIDE PROF. RAJESH MADARKAR HEAD OF DEPARTMENT PROF. K. N. AGRAWAL PRINCIPAL Dr. V. S. DESHPANDE Acknowledgement Hard work, sincerity and proper guidance that’s what on needs to be successful in life, that is what we have realized working on a project No successful work can ever be the effect of a individual effort. We take this opportunity to express our deep gratitude towards everyone who has been of immense help throughout and till completion of this work. We earnestly express our thankfulness to Prof . Rajesh Madarkar , without whose invaluable guidance the present work would not see light of this day. The work would have been impossible without his co-operation and direction. In spite of being our teacher, his friendly approach has been constant source of inspiration and encouragement. We are really honored to have such a wonderful person as our guide. We are also thankful to the director of Dulocos Conveyors And Moulds Pvt. Ltd Mr. Khalid Husain We are also grateful towards everyone who has directly or indirectly contributed with their lively suggestions to make the project a success. CHAPTER 1 INTRODUCTION 1. 1 Background of EDM The history of EDM Machining Techniques goes as far back as the 1770s when it was discovered by an English Scientist. However, Electrical Discharge Machining was not fully taken advantage of until 1943 when Russian scientists learned how the erosive effects of the technique could be controlled and used for machining purposes. When it was originally observed by Joseph Priestly in 1770, EDM Machining was very imprecise and riddled with failures. Commercially developed in the mid 1970s, wire EDM began to be a viable technique that helped shape the metal working industry we see today. In the mid 1980s. The EDM techniques were transferred to a machine tool. This migration made EDM more widely available and appealing over traditional machining processes. The new concept of manufacturing uses non-conventional energy sources like sound, light, mechanical, chemical, electrical, electrons and ions. With the industrial and technological growth, development of harder and difficult to machine materials, which find wide application in aerospace, nuclear engineering and other industries owing to their high strength to weight ratio, hardness and heat resistance qualities has been witnessed. New developments in the field of material science have led to new engineering metallic materials, composite materials and high tech ceramics having good mechanical properties and thermal characteristics as well as sufficient electrical conductivity so that they can readily be machined by spark erosion. Nontraditional machining has grown out of the need to machine these exotic materials. The machining processes are non-traditional in the sense that they do not employ traditional tools for metal removal and instead they directly use other forms of energy. The problems of high complexity in shape, size and higher demand for product accuracy and surface finish can be solved through non-traditional methods. Currently, non-traditional processes possess virtually unlimited capabilities except for volumetric material removal rates, for which great advances have been made in the past few years to increase the material removal rates. As removal rate increases, the cost effectiveness of operations also increase, stimulating ever greater uses of nontraditional process. The Electrical Discharge Machining process is employed widely for making tools, dies and other precision parts. EDM has been replacing drilling, milling, grinding and other traditional machining operations and is now a well established machining option in many manufacturing industries throughout the world. And is capable of machining geometrically complex or hard material components, that are precise and difficult-to-machine such as heat treated tool steels, composites, super alloys, ceramics, carbides, heat resistant steels etc. being widely used in die and mold making industries, aerospace, aeronautics and nuclear industries. Electric Discharge Machininghas also made its presence felt in the new fields such as sports, medical and surgical, instruments, optical, including automotive RD areas. 1. 2 Introduction of EDM Electro Discharge Machining (EDM) is an electro-thermal non-traditional machining Process, where electrical energy is used to generate electrical spark and material removal mainly occurs due to thermal energy of the spark. You read "Electric Discharge Machining" in category "Essay examples" EDM is mainly used to machine difficult-to-machine materials and high strength temperature resistant alloys. EDM can be used to machine difficult geometries in small batches or even on job-shop basis. Work material to be machined by EDM has to be electrically conductive. 1. 3 Principle of EDM In this process the metal is removing from the work piece due to erosion case by rapidly recurring spark discharge taking place between the tool and work piece. Show the mechanical set up and electrical set up and electrical circuit for electro discharge machining. A thin gap about 0. 025mm is maintained between the tool and work piece by a servo system shown in fig 1. 1. Both tool and work piece are submerged in a dielectric fluid . Kerosene/EDM oil/deionized water is very common type of liquid dielectric although gaseous dielectrics are also used in certain cases. Figure1. 1 Set up of Electric discharge machining This fig. 1. 1 is shown the electric setup of the Electric discharge machining. The tool is made cathode and work piece is anode. When the voltage across the gap becomes sufficiently high it discharges through the gap in the form of the spark in interval of from 10 of micro seconds. And positive ions and electrons are ccelerated, producing a discharge channel that becomes conductive. It is just at this point when the spark jumps causing collisions between ions and electrons and creating a channel of plasma. A sudden drop of the electric resistance of the previous channel allows that current density reaches very high values producing an increase of ionization and the creation of a powerful magnetic field. The moment spark occurs sufficiently pressure developed between work and tool as a result of which a very high temperature is reached and at such high pressure and temperature that some metal is melted and eroded. Such localized extreme rise in temperature leads to material removal. Material removal occurs due to instant vaporization of the material as well as due to melting. The molten metal is not removed completely but only partially As the potential difference is withdrawn as shown in Fig. 1. 2, the plasma channel is no longer sustained. As the plasma channel collapse, it generates pressure or shock waves, which evacuates the molten material forming a crater of removed material around the site of the spark. 1. 4 Types of EDM Basically, there are two different types of EDM: 1. 4. 1) Die-sinking 1. 4. 2) wire-cut. 1. 4. 1Die-sinking EDM In the Sinker EDM Machining process, two metal parts submerged in an insulating liquid are connected to a source of current which is switched on and off automatically depending on the parameters set on the controller. When the current is switched on, an electric tension is created between the two metal parts. If the two parts are brought together to within a fraction of an inch, the electrical tension is discharged and a spark jumps across. Where it strikes, the metal is heated up so much that it melts. Sinker EDM, also called cavity type EDM or volume EDM consists of an electrode and workpiece submerged in an insulating liquid such as, more typically, oil or, less frequently, other dielectric fluids. The electrode and workpiece are connected to a suitable power supply. The power supply generates an electrical potential between the two parts. As the electrode approaches the workpiece, dielectric breakdown occurs in the fluid, forming a plasma channel, and a small spark jumps. These sparks usually strike one at a time because it is very unlikely that different locations in the inter-electrode space have the identical local electrical characteristics which would enable a spark to occur simultaneously in all such locations. These sparks happen in huge numbers at seemingly random locations between the electrode and the workpiece. As the base metal is eroded, and the spark gap subsequently increased, the electrode is lowered automatically by the machine so that the process can continue uninterrupted. Several hundred thousand sparks occur per second, with the actual duty cycle carefully controlled by the setup parameters. 1. 4. 2 Wire-cut EDM Wire EDM Machining (also known as Spark EDM) is an electro thermal production process in which a thin single-strand metal wire (usually brass) in conjunction with de-ionized water (used to conduct electricity) allows the wire to cut through metal by the use of heat from electrical sparks. a thin single-strand metal wire, usually brass, is fed through the workpiece, submerged in a tank of dielectric fluid, typically deionized water. Wire-cut EDM is typically used to cut plates as thick as 300mm and to make punches, tools, and dies from hard metals that are difficult to machine with other methods. Wire-cutting EDM is commonly used when low residual stresses are desired, because it does not require high cutting forces for removal of material. If the energy/power per pulse is relatively low (as in finishing operations), little change in the mechanical properties of a material is expected due to these low residual stresses, although material that hasn’t been stress-relieved can distort in the machining process. Due to the inherent properties of the process, wire EDM can easily machine complex parts and precision components out of hard conductive mate 1. 12 Application of EDM 1. The EDM process is most widely used by the mould-making tool and die industries, but is becoming a common method of making prototype and production parts, especially in the aerospace, automobile and electronics industries in which production quantities are relatively low. 2. It is used to machine extremely hard materials that are difficult to machine like alloys, tool steels, tungsten carbides etc. 3. It is used for forging, extrusion, wire drawing, thread cutting. . It is used for drilling of curved holes. 5. It is used for internal thread cutting and helical gear cutting. 6. It is used for machining sharp edges and corners that cannot be machined effectively by other machining processes. 7. Higher Tolerance limits can be obtained in EDM machining. Hence areas that require higher surface accuracy use the EDM machini ng process. 8. Ceramic materials that are difficult to machine can be machined by the EDM machining process. 9. Electric Discharge Machining has also made its presence felt in the new fields such as sports, medical and surgical, instruments, optical, including automotive R areas. 0. It is a promising technique to meet increasing demands for smaller components usually highly complicated, multi-functional parts used in the field of microelectronics. 1. 13 Advantages of EDM (a) Any material that is electrically conductive can be cut using the EDM process. (b) Hardened workpieces can be machined eliminating the deformation caused by heat treatment. (c) X, Y, and Z axes movements allow for the programming of complex profiles using simple electrode. (d) Complex dies sections and molds can be produced accurately, faster, and at lower costs. Due to the modern NC control systems on die sinking machines, even more complicated work pieces can be machined. (e) The high degree of automation and the use of tool and work piece changers allow the machines to work unattended for overnight or during the weekends (f) Forces are produced by the EDM-process and that, as already mentioned, flushing and hydraulic forces may become large for some work piece geometry. The large cutting forces of the mechanical materials removal processes, however, remain absent. (g) Thin fragile sections such as webs or fins can be easily machined without deforming the part. . 14 Limitation of EDM (a) The need for electrical conductivity – To be able to create discharges, the work piece has to be electrically conductive. Isolators, like plastics, glass and most ceramics, cannot be machined by EDM, although some exception like for example diamond is known. Machining of partial conductors like Si semi-conductors, partially conductive ceramics and ev en glass is also possible. (b) Predictability of the gap – The dimensions of the gap are not always easily predictable, especially with intricate work piece geometry. In these cases, the flushing conditions andthe contamination state of differ from the specified one. In the case of die-sinking EDM, the tool wear also contributes to a deviation of the desired work piece geometry and it could reduce the achievable accuracy. Intermediate measuring of the work piece or some preliminary tests can often solve the problems. (c) Low material removal rate- The material removal of the EDM-process is rather low, especially in the case of die-sinking EDM where the total volume of a cavity has to be removed by melting and evaporating the metal. With wire-EDM only the outline of the desired work piece shape has to be machined. Due to the low material removal rate, EDM is principally limited to the production of small series although some specific mass production applications are known. (d) Optimization of the electrical parameters – The choice of the electrical parameters of the EDM-process depends largely on the material combination of electrode and work piece and EDM manufactures only supply these parameters for a limited amount of material combinations. When machining special alloys, the user has to develop his own technology. CHAPTER 2 LITRATURE SURVEY 2. 1 INTRODUCTION Literature review is one of the scope studies. It works as guide to run this analysis. It will give part in order to get the information about electrical discharge machine (EDM) and will give idea to operate the test. From the early stage of the project, various literature studies have been done. Research journals, books, printed or online conference article were the main source in the project guides. Literature review section work as reference, to give information and guide base on journal and other source in the media. 2. Important parameters of EDM (a) Spark On-time (pulse time or Ton): The duration of time (? s) the current is allowed to flow per cycle. Material removal is directly proportional to the amount of energy applied during this on-time. This energy is really controlled by the peak current and the length of the on-time. (b) Spark Off-time (pause time or Toff ): The duration of time (? s) between the sparks (that is to say, on- time). This time allows the molten material to solidify and to be wash out of the arc gap. This parameter is to affect the speed and the stability of the cut. Thus, if the off-time is too short, it will cause sparks to be unstable. (c) Arc gap (or gap): The Arc gap is distance between the electrode and workpiece during the process of EDM. It may be called as spark gap. Spark gap can be maintained by servo system (fig no. -1). (d) Discharge current (current Ip): Current is measured in amp Allowed to per cycle. Discharge current is directly proportional to the Material removal rate. (e) Duty cycle (? ): It is a percentage of the on-time relative to the total cycle time. This parameter is calculated by dividing the on-time by the total cycle time (ontime pulse offtime). f) Voltage (V): It is a potential that can be measure by volt it is also effect to the material removal rate and allowed to per cycle. Voltage is given by in this experiment is 50 V. (g) Diameter of electrode (D): It is the electrode of Cu-tube there are two different size of diameter 4mm and 6mm in this experiment. This tool is used not only as a electrode but also for intern al flushing. (h) Over cut – It is a clearance per side between the electrode and the workpiece after the marching operation. 2. 3 Characteristics of EDM EDM specification by mechanism of process, metal removal rate and other function that shown in this table no . 1 2. 4 Dielectric fluid In EDM, as has been discussed earlier, material removal mainly occurs due to thermal evaporation and melting. As thermal processing is required to be carried out in absence of oxygen so that the process can be controlled and oxidation avoided. Oxidation often leads to poor surface conductivity (electrical) of the work piece hindering further machining. Hence, dielectric fluid should provide an oxygen free machining environment. Further it should have enough strong dielectric resistance so that it does not breakdown electrically too easily but at the same time ionize when electrons collide with its molecule. Moreover, during sparking it should be thermally resistant as well. The dielectric fluid has the following functions: (a) It helps in initiating discharge by serving as a conducting medium when ionised, and conveys the spark. It concentrates the energy to a very narrow region. (b) It helps in quenching the spark, cooling the work, tool electrode and enables arcing to be prevented. c) It carries away the eroded metal along with it. (d) It acts as a coolant in quenching the sparks. The electrode wear rate, metal removal rate and other operation characteristics are also influenced by the dielectric fluid. The dielectric generally fluid used are transformer on silicon oil, EDM oil, kerosene (paraffin oil) and de-ionized water are used as dielectric fluid in EDM. Tap water cannot be used as it ionizes too ear ly and thus breakdown due to presence of salts as impurities occur. Dielectric medium is generally flushed around the spark zone. It is also applied through the tool to achieve efficient removal of molten material. In this experiment using the Commercial grade EDM oil (specific gravity= 0. 763, freezing point= 94 °C) was used as dielectric fluid are used it is using as coolant and medium of workpiece and tool during the process of erosion. 2. 5. Flushing method Flushing is the most important function in any electrical discharge machining operation. Flushing is the process of introducing clean filtered dielectric fluid into the spark gap. There are a number of flushing methods used to remove the metal particles efficiently. 2. 5. Tool Material Tool material should be such that it would not undergo much tool wear when it is impinged by positive ions. Thus the localized temperature rise has to be less by tailoring or properly choosing its properties or even when temperature increases, there would be less melting. Further, the tool should be easily workable as intricate shaped geometric features are machined in EDM. Thus the basic characteristics of electrode materials are: 1. High electrical conductivity – electrons are cold emitted more easily and there is less bulk electrical heating. 2. High thermal conductivity – for the same heat load, the local temperature rise would be less due to faster heat conducted to the bulk of the tool and thus less tool wear. 3. Higher density – for the same heat load and same tool wear by weight there would be less volume removal or tool wear and thus less dimensional loss or inaccuracy. 4. High melting point – high melting point leads to less tool wear due to less tool material melting for the same heat load. 5. Easy manufacturability. 6. Cost – cheap. The followings are the different electrode materials which are used commonly in the industry: 1. Graphite 2. copper 3. Tellurium copper – 99% Cu + 0. 5% tellurium 4. Brass 2. 6. Design variable Design parameter, process parameter and constant parameter are following ones, Design parameters – 1. Material removal rate. 2. Tool wear rate 3. Over cut (OC) Machining parameter – 1. Discharge current (Ip) 2. Pulse on time (Ton) 3. Diameter of U-shaped tool Constant parameter1. Duty cycle 2. Voltage 3. Flushing pressure 4. Polarity 2. 7. Workpiece material It is capable of machining geometrically complex or hard material components, that are precise and difficult-to-machine such as heat treated tool steels, composites, super alloys, ceramics, carbides, heat resistant steels etc. There are different types of tool material are using the EDM method. And the tool steel contains carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion, their ability to hold a cutting edge, and/or their resistance to deformation at elevated temperatures (red-hardness). Tool steel is generally used in a heattreated state. Tool steels are made to a number of grades for different applications. In general, the edge temperature under expected use is an important determinant of both composition and required heat treatment. The higher carbon grades are typically used for such applications as stamping dies, metal cutting tools, etc. 2. 8 MACHINING PARAMETER SELECTION In this project , material removal rate (MRR) is important. This characteristic material removal rate (MRR) is a major influence resulting the machining performance. Among the numerous parameters affecting the EDM performance, the dielectric fluid has a very important role. The physical properties of the fluid influence the breakdown voltage and the ignition delay: however, the debris concentration in the fluid modifies these parameters, decreasing the dielectric strength by many orders of magnitude . But this parameter is neglect due to limitation of scope of studies. Surface roughness is also a very important parameter but is not taken into consideration due to unavailability of perthometer. 2. 9 MACHINING PERFORMANCE EVALUATION Material removal rate (MRR) is used to evaluate machining performance. The material removal rate (MRR) is expressed as the work piece removal rate (WRW) under a period of machining time in minute (T), which is : Ww=Weight loss Pw= Density of material The density of materials was measured on basis of volume displacement method using weighing machine and beaker 2. 10. Objective of the present work From the research papers refered , it is observed that few works has been reported on EDM on the material Al-Sic, EN-19, SKH 57 and various composite materials. The objective of the present work is an attempt to finding the effect of machining parameters on EN-31,HCHCr for material removal rate using a pure copper electrode . The machining parameter selected for experiment are pulse on time ,peak current and duty cycle ,using one variable at a time approach analysis for responses MRR has been carried out. CHAPTER 3 EXPERIMENTAL SETUP 3. 1 LABORATARY USED:1. ENVIRONMENTAL ENGINEERING LAB USED FOR WEIGHING WORKPIECE 2. WORKSHOP USED FOR CONDUCTING EXPERIMENT ON EDM 3. 2 Materials Used 1. 2. 3. 1. HCHCR (55-56) 2. HCHCR (20-22) 3. EN-31 (20-22) ELECTRODE Uses of Workpiece Materials: EN 31: †¢ High tensile strength machine parts. †¢ Gears and pinions. †¢ Axles †¢ Shafts †¢ Connecting rods †¢ Plastic moulds †¢ Forging dies for smaller section of ferrous non-ferrous items. HCHCr: †¢ Plastic moulding †¢ Dies †¢ Hot shearing tools †¢ Hardened rolls †¢ Thread rolling dies HARDNESS DEFINITION : †¢ It’s the ability of the material to resist permanent shape change. †¢ Rockwell scale is a hardness scale based on indentation hardness of material in which resistance of permanent plastic deformation due to a constant compression load from a sharp object †¢ Rockwell intrument used from DULOCOS CONVEYORS AND MOULDS PVT. LTD. DENSITY =Mass/Volume 1. Measured the mass of workpiece from weighing machine. 2. Measured the volume displaced with the help of beaker. 3. 3 EXPERIMENTAL CONDITIONS WORKING PARAMETERS Work piece materials DESCRIPTION EN-31(20-22),HCHCR(2022), HCHCR(55-56) Copper(Cu) Positive Kerosene 4,6,8 amps 35,45,55,65 TYPE CONSTANT Electrode Material Electrode Polarity Dielectric Fluid Peak Current(Ip) Pulse Duration(Ton) CONSTANT CONSTANT CONSTANT VARIABLE VARIABLE Duty Factor Working Time (Ton variable) 9 40 mins CONSTANT CONSTANT CONSTANT Working Time (Ip variable) 30 mins . 4 CALCULATING MRR: FORMULA USED Where: Ww: Weight of the material in gms. ?w : Density of the material in gm/cm3. T : Machining time in mins. CHAPTER 4 OBSERVATIONS AND RESULTS 4. 1 MATERIAL : EN-31 , HARDNESS : 20-22 ON ROCKWELL SCALE DENSITY: 5. 57 g/cm3 CHANGING PARAMETER: PULSE ON TIME(Ti) CHANGING PARAMETER: PEAK CURRENT (Ip) 4. 2 MATERIAL : HCHCr , HARDNESS : 20-22 ON ROCKWELL SCALE DENSITY: 5. 228 g/cm3 CHANGI NG PARAMETER: PULSE ON TIME(Ti) CHANGING PARAMETER: PEAK CURRENT (Ip) 4. 3 MATERIAL : HCHCr , HARDNESS : 55-56 ON ROCKWELL SCALE DENSITY: 8. 47 g/cm3 CHANGING PARAMETER: PULSE ON TIME(Ti) CHANGING PARAMETER: PEAK CURRENT (Ip) CHAPTER 5 RESULT ANALYSIS †¢ The experiments are based on one factor experiment strategy. †¢ In this only one input parameter was varied while keeping all others input parameters at constant values. †¢ During this experimental procedure, 6 sets of experiments were performed varying the Peak current( Ip) and Pulse time on (Ton) for three different materials. After analyzing the results of the experiments performed, various facts came into light. EXPERIMENT SET 1 PULSE ON TIME IS INCREASED The above graphs shows that material removal rate increases with the increase in the pulse on time and decreases after some time. So the pulse on time can be adjusted to get the desired material removal rate. The Declining Trend Of Graph †¢ Ton:- During puls e on time spark erosion takes place and metal is melted/vapourized †¢ Toff:-During pulse off time metal is washed away and solidified †¢ But as the Ton is increased at constant Input parameters, Toff starts to decrease due to which metal is stuck and is not removed properly and MRR decreases EXPERIMENT SET 2 PEAK CURRENT IS INCREASED †¢ The above graphs shows that material removal rate increases with the increase in the peak current. So value of peak current should be high to obtain higher MRR. CHAPTER 6 CONCLUSION The following conclusions are drawn from the experimental study: 1. The parameter PEAK CURRENT (IP) has direct effect on material removal rate as we increase peak current material removal rate increases 2. The PULSE ON TIME parameter has direct effect on the material removal rate with a declining trend, as we increase the pulse on time the material removal rate increases upto a certain level but starts to decrease after certain time. REFERENCES †¢ Saurabh kumar saha, Experimental Investigation of the Dry Electric Discharge Machining (Dry EDM) Process †¢ S. H. Tomadi, M. A. Hassan, Z. Hamedon, IAENG R. Daud, A. G. Khalid, Analysis of the Influence of EDM Parameters on Surface Quality and Electrode Wear of Tungsten Carbide †¢ M. M. Rahman, Md. Ashikur Rahman Khan, K. Kadirgama M. M. Noor and Rosli A. Bakar, Modeling of Material Removal on Machining of Ti-6Al-4V through EDM using Copper Tungsten Electrode and Positive Polarity †¢ Mohd Abd Larif Bin Abd Ghani, Effects Of Surface Roughness Using Different Electrodes On Electrical Discharge Machining (EDM) †¢ Mr. V. D. Patel, Prof. C. P. Patel , Mr. U. J. Patel, Analysis of Different Tool Material On MRR and Surface Roughness of Mild Steel In EDM INDEX 1. INTRODUCTION 2. LITERATURE SURVEY 3. EXPERIMENTAL SETUP 4. OBSERVATIONS AND RESULTS 5. RESULT ANALYSIS 6. CONCLUSION 7. REFERENCES How to cite Electric Discharge Machining, Essay examples Electric Discharge Machining Free Essays ELECTRIC DISCHARGE MACHINING INTRODUCTION * Sometimes it is referred to as spark machining, * Its a manufacturing process whereby a desired shape is obtained using electrical discharges (sparks). * Material is removed from the workpiece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. * One of the electrodes – ‘tool-electrode’ or ‘tool’ or ‘electrode’. We will write a custom essay sample on Electric Discharge Machining or any similar topic only for you Order Now * Other electrode – workpiece-electrode or ‘workpiece’. As distance between the two electrodes is reduced, the current intensity becomes greater than the strength of the dielectric (at least in some points) causing it to break. * EDM is a machining method primarily used for hard metals or those that would be very difficult to machine with traditional techniques. * EDM typically works with materials that are electrically conductive, although methods for machining insulating ceramics with EDM have been proposed. * EDM can cut intricate contours or cavities in hardened steel without the need for heat treatment to soften and re-harden them. This method can be used with any other metal or metal alloy such as titanium, hastelloy, kovar, and inconel. EDM – Working Principle * It is a process of metal removal based on the principle of material removal by an interrupted electric spark discharge between the electrode tool and the work piece. * In EDM, a potential di fference is applied between the tool and workpiece. * Essential – Both tool and work material are to be conductors. * The tool and work material are immersed in a dielectric medium. * Generally kerosene or deionised water is used as the dielectric medium. A gap is maintained between the tool and the workpiece. * Depending upon the applied potential difference (50 to 450 V) and the gap between the tool and workpiece, an electric field would be established. * Generally the tool is connected to the negative terminal (cathode) of the generator and the workpiece is connected to positive terminal (anode). * The high speed electrons then impinge on the job and ions on the tool. * The kinetic energy of the electrons and ions on impact with the surface of the job and tool respectively would be converted into thermal energy or heat flux. Such intense localized heat flux leads to extreme instantaneous confined rise in temperature which would be in excess of 10,000oC. * Such localized ex treme rise in temperature leads to material removal. * Material removal occurs due to instant vaporization of the material as well as due to melting. * The molten metal is not removed completely but only partially. EDM – Dielectric * In EDM, material removal mainly occurs due to thermal evaporation and melting. * As thermal processing is required to be carried out in absence of oxygen so that the process can be controlled and oxidation avoided. Oxidation often leads to poor surface conductivity (electrical) of the workpiece hindering further machining. * Hence, dielectric fluid should provide an oxygen free machining environment. * Further it should have enough strong dielectric resistance so that it does not breakdown electrically too easily. * But at the same time, it should ionize when electrons collide with its molecule. * Moreover, during sparking it should be thermally resistant as well. * Generally kerosene and deionised water is used as dielectric fluid in EDM. How to cite Electric Discharge Machining, Papers

Dbk Solution free essay sample

The current growth of Designs by Kate’s (DBK) business model is not sustainable for a future success of the company. In order to maintain, respectively improve its performance and thusly its position within the direct sales industry, it is essential that Kate Creevey realizes, how important the monetary reward for the sales representatives is. Therefore it is recommended that the compensation structure as a motivational tool should be changed in order to guarantee maximizing the key financial objectives, which can predominantly be defined as further volume growth. Sales growth is driven by two factors: in the first place by the number of sales representatives and secondly, by their increased productivity, when they become team leaders. This means, it is vital for DBK to â€Å"invest† in the acquisition and the keeping of sales representatives. One can think of two variants on how to approach a modification of the compensation structure, motivating the sales staff to develop their own team structure. The management of DBK could think of adapting leadership dollars or leadership dollars and commission rates. With the purpose of educating sales representatives of the advantages of a team build-up, Creevey should definitely invest the $1,000,000 into the four full-time trainers. Since the trainers will demonstrate to the prospective leaders, why it is good for them to move up the career ladder by acquiring new sales representatives, this will be a profitable step (for further explanation see Arguments). Moreover, it is vital for the company to understand, how relevant incentives are – beyond non-monetary benefits. For the purpose of driving team building within the company, Creevey should consider team incentives as a possible appealing and attractive enticement that goes further than the pure cash payout. Furthermore, Kate Creevey should consider how her business is overall positioned in the direct sales industry. Tupperware, Mary Kay or other competitors can rather be found in the high-price segment. This implies that the value proposition is higher for their products. This mere fact does not result in the conclusion that DBK should necessarily reposition, but it is definitely an option, which could further boost sales. Jewelry is highly suitable for selling in an upper price segment. Arguments Industry and Competitor Analysis Direct sales is a stable industry, with a steady, but low Compounded Annual Growth Rate (CAGR) of 0. 7%. Although, the volume of sales, decreased from 2005 to 2009 (which can partially be explained by the economic crisis, which started in 2007), it still is an attractive business sector for DBK, as it is positioned in the third strongest segment (Personal Care) with a niche product lineup, as no other noteworthy competitor is selling jewelry directly. As mentioned above, DBK is positioned as a company, which sells inexpensive jewelry. This might be a factor, which differentiates it from the competitors. However, as may be extracted from the interviews with one of the sales representatives, the reason why the direct sales approach is so successful, can be accounted for the â€Å"parties† and the resonant atmosphere, and not primarily because the products are cheap. If DBK wants to improve their financials, it can be worthy to think of reposition its business to a more exclusive, not department store-like jewelry. Appendix A shows that in comparison to its major competitors in the Personal Care segment (Avon and Mary Kay) DBK is behind in all areas (sales, market share, # of representatives and commission rates). This can be explicable by the fact, that the competitors are much longer in the business than DBK. However, this implies, that Kate Creevey needs to ensure that the company is further growing, to endure its continuance in the market. The SWOT-Analysis exhibits, that the occurring threats can all be shunned, when adapting the compensation structure as mentioned above (for a more detailed delineation see KPI-Analysis). The opportunity of having a greater pool of prospective recruits to choose from is positive. As this implies, if DBK manages to successfully employ plenty new sales representatives, it will have a good basis of jobholders to further grow its business, due to the fact that DBK’s attrition rate is very low. DBK needs to reduce its weakness, that most of their sales representatives have no experience in sales by make use of trainers (see KPI-Analysis), in order to share in the high potential of direct sales customers. KPI-Analysis Appendix B clearly shows, that from a sales representative’s point of view it does not pay to build a team. Assuming that a successful sales representative, who is in the company for about 2 years (meaning that his own sales are still on the rise of 20% annually and not declining, because he is shorter than 5 years in the company), acquires one sales representative in his circle of friends, it can be seen that already in their first month, let alone year together, it diminishes the sales of the leader. The more members he accepts in his team, the greater are his losses from his own revenue and hence, his profit. This is amplified with the number of years the team works together (in Appendix B, there is the assumption made, that the prospective recruits will be three years in the company, as this is the average duration of employment of a sales representative). The pure adjustment of commission rates to solve this problem would mean that DBK must raise them up beyond 50% – which is the maximum in the industry standard – to avoid the aforementioned effect. Appendix C illustrates an alternative approach (as a possible example), which has been calculated by an iterative process. Here, DBK could make an adaption of leadership dollars to 7% for leaders and an assimilation of commission rates to 30% to avoid the cannibalization of sales within a team. This would change the situation for the future leaders and make it attractive for them to recruit more people. It is constructed, that the more members the sales representative accepts, the better for him (0% for one level 1; 5% for two level 1; 10% for three level 1). However, it is presupposed that the team members are de facto sales representatives. The system is only working for the leader, when his team members are constantly increasing their sales, too. Managers and directors are not negligible, however, they are required to build a team to gain that status, which means, that DBK’s focus should in the first instance be on the potential leaders, because they promise a fast solution, as Creevey demanded. The adaption of their leadership dollars should be ensued in the next step. The hiring of the four full-time trainers can be substantiated by the fact that this investment can be balanced by recruiting 1. 060 sales representatives for the same time period of one year. Since one average sales representative’s value equals $2. 30 (see Figure 1. ) – including the costs directly associated with one sales representative (40% COGS and 30% SGA). Those trainers need to make sure, that the sales representatives understand, how building up a team, can firstly boost their own sales, and secondly help the company to grow (which should be in their interest, too). Action steps A key action step should be the implementation of a firmer team structure by strengthening the cohesion within teams through adoption of team rewards into the incentives structure. Those team benefits can be of monetary or non-monetary nature. For instance, following the example of Mary Kay, the most successful teams could be annually invited to a special event, created only for them, where they can win an award for the â€Å"best team of the year†. This can be conducive for employee motivation and further enhance the sales representatives’ loyalty for DBK. Creevey can follow the proposal of one of the representatives, to give â€Å"longevitiy bonuses† in the form of special jewelry pieces that they can sell only when they fulfill certain criteria, other incentives such as premium magazine subscriptions, etc. r cash payout. As aforementioned, further steps include hiring full-time trainers, reconstruct compensation structure – monetary-based and non-monetary-based, team-based and individual benefits, see above –, analyze potential of repositioning towards an upper-middle to lower-high-prize segment and improve overall communication within DBK of the advantages of teams and the effects it has for each individual.