the output parameters namely material removal rate (MRR), electrode wear rate (EWR), wear ratio (WR), machined surface roughness, etc. Unstable conditions cause erratic cycling and retraction of the advancing servo. 48 EDM – Material Removal Rate In EDM, the metal is removed from both workpiece and tool electrode. The multi-objective optimization was performed using Grey Relation Analysis to determine the optimal solution. 005 mm to 0.50 mm. A circular hole of 25 mm diameter and depth of 20 mm is machined by EDM process. Therefore, new methods implemented in EDM are being developed to improve surface characteristics and the material removal rate. In this work the parameters such peak current, voltage gap, pulse on time, duty cycle and flushing pressure were selected. Both examples have approximately the same metal removal rate, but the example in figure 3-13 would produce a finer finish. material is not generally machined by USM, 11.Increasing volume The formula for determining the duty cycle is: The formula for determining the frequency in kHz is: This is what happens — A 40 % duty cycle with a frequency of 10 kHz will result in a specific surface finish and a constant metal removal rate. The duty cycle is 40% and the frequency is 10 kHz. The material removal increases with the increase in machining time, but the machining rate is different for different workpiece materials. Arrange the processes in the increasing order of their maximum material removal rate. When the mass flow rate of the abrasive increases the material removal rate also increases. In ultrasonic machining process, the material removal rate will be higher for materials with (a) higher toughness ... 4. 21.In WJM, removal of metal These example cuts (figure 3-10) and the resulting data show the relationship between surface finish, metal removal rate and electrode wear (figure 3-11) that is controlled by the amperage and length of on-time and frequency. The first is the material removal rate, V w, which means the volume of material removed from the workpiece electrode per minute. All of the examples used positive polarity, tool steel as the workpiece, POCO EDM-3 as the electrode material, and a 5-minute cutting time. Figure 3-1. Figure 3-13. METHODS OF IMPROVING MRR Dry EDM The MRR increased when the discharge power density on the working surface exceeded a certain threshold limit due to thermally activated chemical reaction between the gas and workpiece material. The EDM process is mainly used for making dies, moulds, parts of aerospace, automotive industry and surgical components etc. In theory, the shorter the off-time the faster the machining operation will be; however, if the off-time is too short, the ejected work piece material will not be swept away by the flow of dielectric and the fluid will not be deionized. By Rahman M. M., Noor M. M., Kadirgama K. and Bakar R. A. There is an optimum mixing ratio (mass fraction of the abrasive in the jet) for which the metal removal rate is the highest. None of the above. (Left) Machining parameters for Example 2 and the effect on the workmetal during one cycle and (Right) during two cycles. 48 EDM – Material Removal Rate In EDM, the metal is removed from both workpiece and tool electrode. Machine settings are 20 µs on, 30 µs off, and 50 amps peak current. 1. [11] when EDM of Inconel 718 shows that an Increase in pulse duration up to 750µs has improves MRR. 7. Choices. Experiments were conducted by selecting different operating levels for the three parameters according to Taguchi’s Design of Experiments. The electrical discharge machining process is hampered by a low material removal rate (MRR), high tool wear, and low quality of machined surface, which limit its applicability. Electrode does not suffer any wear during ECM process. The effectiveness of EDM process with tungsten copper electrode is evaluated in terms of the material removal rate. The width of the EDM cavity is always larger than the electrode and the difference is called the overcut or overburn (figure 3-5). 2.The size of abrasive grains in … Figure 3-2. The mass flow rate of the abrasive particles depends on the pressure and the flow rate of the gas. 2. There is no direct contact between the workmetal and the electrode. The time (in minutes) for machining this hole is _____ (correct to two decimal places) High-frequency vibration aided EDM has become one of the ways to increase material removal rate in EDM process, due to the flushing effect caused by vibration. The above example shows how to determine the average machining current. All the nomenclature is according to VDI 3402 (1990). The rate of metal removal decreases. Duty cycle is a percentage of the on-time relative to the total cycle time. Such heating leads to melting and crater formation as shown in Fig. In this study, experiments were performed by varying the peak current and keeping other parameters constant in order to investigate the effect of peak current on material removal rate (MRR) in EDM of Al2O3. 18.The following principle Figure 3-7. Spark energy is the combination of amperage, voltage and on-time. Electric Discharge Machining (EDM) Choices. The rate of metal removal remains the same. Arrange the processes in the increasing order of their maximum material removal rate. Increasing current density and decreasing frequency of sparks. According to a results, the material removal rate of dry EDM is about 6 times larger than that of oil EDM. a) Increases b) Decreases c) Decrease and increase d) … Major variations in surface finish occur only when on-time or peak current change. This will cause the next spark to be unstable. However, utilizing high-frequency vibration, especially in ultrasonic range consumes a lot of setup cost. b. Varying the on-time and/or off-time will change the duty cycle and the frequency. Modeling of Material Removal on Machining of Ti-6Al-4V through EDM using Copper Tungsten Electrode and Positive Polarity . The following examples show typical changes and how results are influenced by these changes. The result is an improved surface finish with little change in the metal removal rate. Electrode — A long on-time can put the electrode into a no-wear situation. The key is in the duty cycle; this value must be quoted along with frequency in order to fully define the electrical machining characteristics. Concentration of powder (silicon) in the dielectric fluid, pulse on time, duty cycle, and peak current are taken as independent variables on which the machining perfor- mance was analysed in terms of material removal rate (MRR) and surface roughness (SR). The amount of overcut has to be known in order to properly undersize the electrode. increases, the material removal rate, c) decreases, becomes $ 4\times10^4\;IT^{-1.23} $ , where $ I=300 $ A and the melting point of the material, $ T=1600^\circ C $ . The off-time was cut in half to produce a 67% duty cycle and the metal removal increased. In abrasive jet machining, as the distance between the nozzle tip and the work surface increases, the material removal rate (A) Increases continuously (B) Decreases continuously (C) Decreases becomes stable and then increases (D) Increases, becomes stable and then decreases. 01 mm to 0.001 mm. % SiCw/2124 Al. When the mass flow rate of the abrasive increases the material removal rate also increases. The gap voltage, peak current, pulse on time and duty factor is considered as the machining parameter to analyze the machining characteristics Material Removal Rate (MRR) 5: Properties and Characteristics of Graphite, EDM ELECTRODE MATERIAL CLASSIFICATIONS AND APPLICATIONS, 6: Five Key Factors in Electrode Material Selection, 7: Practical Applications of The Five Key Factors In Electrode Material Selection. This energy is controlled by the peak amperage and the length of the on-time. The previous 50 amp peak current will be changed to a 25 amp peak current setting (figure 3-9). Amperage — During each on-time pulse, the current increases until it reaches a preset level, which is expressed as the peak current (figure 3-2). The complete cycle time is 100 microseconds. Machine settings are 40 µs on, 10 µs off, and 50 amps peak current. 001 mm to 0.1 mm. The following examples (figures 3-12 and 3-13) show different parameters, but both have the same average current value. This increases the duty cycle to 80% and the frequency stays at 20 kHz. Researchers made attempts to model EDM process to study improvements in performance measures like material removal rate, surface roughness and tool wear rate. This test is comprising of 20 questions on Manufacturing Processes.Ideal for the candidates preparing for semester exams, IES, GATE, PSUs, UPSC and other entrance exams.1 mark for each correct answer and 0.25 mark will be deducted for wrong answer. www.gtu-mcq.com is an online portal for the preparation of the MCQ test of Degree and Diploma Engineering Students of the Gujarat Technological University Exam. Low frequencies are generally used for roughing operations. Abrasive slurry. 22.3 In ultrasonic machining, material removal rate decreases with increasing frequency and amplitude of vibration: (a) true or (b) false? The experiment results show that, the MRR has improved significantly compared to without powder concentration at a high level of Peak current and Powder concentration for both electrodes. ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) During EDM operation, electrode material is also removed gradually along with workpiece material. It also allows more heat to sink into the workpiece which means the recast layer will be thicker and the heat affected zone will be deeper. MCQ on Mechanical Energy Based Unconventional Machining Process. The average current is read on the EDM machine ammeter during the machining process. become more stable thus increasing the material removal rate and improve the surface quality as compared to conventional EDM. Expected results — Lower metal removal rate and improved surface finish. 20. The polarity of the electrode can be either positive or negative. The peak current remains at 50 amps. Modelling of Material Removal and Product Quality Material removal in EDM mainly occurs due to intense localised heating almost by point heat source for a rather small time frame. Match the following metal forming processes with their associated stresses in the work piece. Calculating Metal Removal Rates. Example 1— This is our basic cut. The resulting crater will be broader and deeper than a crater produced by a shorter on-time. Figure 6-2. 3. work piece tool Fig. 1. Depending on the application, some electrode/workmetal combinations give better results when the polarity is changed. Material removal rate (MRR), Electrode wear rate (EWR) and Surface roughness (R a). The effectiveness of EDM process with tungsten copper electrode is evaluated in terms of the material removal rate. Polarity refers to an electrical condition determining the direction of the current flow relative to the electrode. These large craters will create a rougher surface finish. The duty cycle remains at 40% and the frequency increases to 20 kHz. is used for converting electrical energy into mechanical energy in USM, 19.The following device is The duty cycle remains at 40% and the frequency decreases to 10 kHz. The use of powder mixed electrical discharge machining helps overcome this drawback and increases the efficiency of the machining process. In this example (figure 3-7), the duty cycle remains constant, but the on-time and off-time have been cut in half. What happens to the surface roughness values if the MRR increases in EDM? The overcut gets larger as amperage and on-times are increased. In abrasive jet machining, as the distance between the nozzle tip and the work surface increases, the material removal rate (A) Increases continuously (B) Decreases continuously (C) Decreases becomes stable and then increases ... I.C Engines Multiple Choice Questions with Answers - Set 02. Often the desired result can be achieved by more than one means. The electrode wear has increased due to the reduction of on-time. Example 3 — This cut shows a duty cycle change. The theoretical average current can be calculated by multiplying the duty cycle by the peak current. Frequency is the number of cycles produced across the gap in one second. in the following type of machining process. This type of glass material work using boom lift, its ok for customer side react more satisfaction and their refered boom lift rental machine most of company and buying refered to Sendhamarai Engineering. The milling strategies for removing masses of materiel have changed dramatically through the advent of lighter duty machines with high torque motors, increased spindle speeds and table rates. Excessive on-times can be counter productive. There is an optimum mixing ratio (mass fraction of the abrasive in the jet) for which the metal removal rate is the highest. He was an English physicist. The machining parameters studied in this research are current (4.5A, 5.5A, and 6.5A) and concentration of the powder (30g/l, 60g/l, and 90g/l). Electrical Discharge Machining (EDM) is right choice of machining this material. 7.Abrasives contained in a In the present work, an attempt has been made to model material removal rate, electrode wear rate, and surface roughness through response surface methodology in a die sinking EDM process. The Guide to Electrode Polarity Chart in Chapter 8 shows some workmetal exceptions (page 8-2). slurry are driven at a high velocity against the work by a tool vibrating at MRR obtained by using copper low amplitude and high frequency.This is the metal removing mechanism Questions on Machine Tools and Their Applications, Theory of Metal Cutting, Advanced Machining Process, Theory of Metal Cutting etc. The surface finish at all three duty cycles changed very little because the crater created by the spark did not change. The preset voltage determines the width of the spark gap between the leading edge of the electrode and workpiece. 20. This example is the base cut (figure 3-6). The surface finish is given only as a numerical value. Electrical discharge machining is a machining method Choice (4) Response; a. Melting and Evaporation. The time (in minutes) for machining this hole is _____ (correct to two decimal places) Show Answer . However, the current material removal rates (MRR) for µ-EDM range from 0.6-6.0 mm3/h, which is far below the desired minimum level of 10-15 mm3/h required for industrial viability. a) Increases b) Decreases c) Decrease and increase d) … a) Decreases b) Increases c) Increase and then decrease d) All of the mentioned 10. Machine settings are 20 µs on, 30 µs off, and 50 amps peak current. The machining parameters studied in this research are current (4.5A, 5.5A, and 6.5A) and concentration of the powder (30g/l, 60g/l, and 90g/l). 6.Which of the following Generally with graphite, a positive electrode gives better wear and a negative electrode gives better speed. Current increases until it reaches peak current during the effective on-time portion of the cycle. (SiCw/Al) composites [3]. When the melting point and latent heat of melting increases in EDM, the. 20.In AJM, removal of metal Calculating MRR The calculation for Material Removal Rate is RDOC x ADOC x Feed Rate. Comparison of all example cuts. Material removal rate in EDM increases with a) Increase in melting point of work piece b) Decrease in Current c) Decrease in melting point of work piece d) None of the mentioned View Answer. Yusuf Keskin et Four cuts were made using the parameters of the four examples to compare results. Frequency (in kiloHertz) is calculated by dividing 1000 by the cycle time (on-time + off-time) in microseconds (µs). The peak current is 50 amps. In this research work, the material removal rate (MRR) is studied by optimizing the µ-EDM process parameters such as pulse on time, pulse off time, voltage gap and duration. Electrical discharge machining is one of the earliest nontraditional machining, extensively used in industry for processing of parts having unusual profiles with reasonable precision. It is also found that the electrode wear ratio increases with an increase … stable and then increases, d) increases, becomes Once that point is reached, increasing the on-time causes the electrode to grow from plating buildup. When the optimum on-time for each electrode material/workmetal combination is exceeded, the Metal Removal Rate (MRR) actually starts to decrease. Moreover, material removal rate greatly increases when these two factors are increased, where these tendencies are the ones that one could expect a priori, as more energetic pulses usually lead to a higher material removal and on the other hand, an increase in the ionisation or breakdown voltage results in an increase in both the discharge energy and the work gap, giving the latter a better flushing … Each cycle has an on-time and an off-time that are expressed in units of microseconds (figure 3-1). The effect of pulse off time on MRR changes with peak ampere. for__________________, 9.Which of the following Electrical Discharge Machining (EDM) of titanium alloy using copper, brass and aluminum electrodes. This work presents an attempt to use a low-frequency vibration on workpiece of stainless steel (SS 304) during EDM process. These two parameters directly affect the size of the overcut and the roughness of the finish. Increasing both current density and frequency of sparks. What happens to the surface roughness values if the MRR increases in EDM? The results are an improved metal removal rate, a rougher surface finish and almost a no-wear situation for the electrode. Figure 3-8. Electrical Discharge Machining (EDM) of titanium alloy using copper, brass and aluminum electrodes. then remains steady. Machine settings are 40 µs on, 60 µs off, and 50 amps peak current. Example 2 — This cut shows a frequency change. grains in abrasive jet machining ranges from, 3.The vibrating frequency The duty cycle increases to 80% and the frequency remains at 20 kHz. Figure 3-11. Expected results — Relatively unchanged surface finish, but the metal removal rate should double. MCQ on Mechanical Energy Based Unconventional Mach... IAS 2015 Preliminary Question Analysis (General St... MCQ on Automatic & Semi-Automatic Lathes, Gears. The mass flow rate of the abrasive particles depends on the pressure and the flow rate of the gas. $ 4\times10^4\;IT^{-1.23} $ , where $ I=300 $ A and the melting point of the material, $ T=1600^\circ C $ . For a given peak current and a fixed on-time, spark energy will remain constant even though the average current may be varied considerably by changing the off-time. Each cycle has an on-time and off-time. - Generally the rate of metal removal for various machining processes are as follows: 1. the material is removed by, 5.Ultrasonic machining can Each spark, regardless of off-time variation, will remove the same volume of workpiece material, resulting in the same surface finish value. 3. Get PDF (1 MB) Abstract. Figure 3-9. Answer: c Explanation: MRR is inversely proportional to a melting point of work piece. However, when using graphite electrodes, high open gap voltage will increase electrode wear. machining, as the distance between the nozzle tip and the work surface The electrode is always smaller than the width of the final cavity to allow for the spark gap. True. takes place by bombardment of fine grained particle. Note: Graph does not depict surface finish (SF) as a parameter on the coordinates. EDM, and a high material removal rate and low relative ... increases, the eroded materials are easily washed away, and the EDM process becomes stable; therefore, the wear ratio decreases. [1-2]. Figure 3-4. Once the current starts to flow the voltage drops until it stabilizes at the working gap level. In the present work, an attempt has been made to model material removal rate, electrode wear rate, and surface roughness through response surface methodology in a die sinking EDM process. The big change is that the shortened off-time allows twice as many discharges to occur over the same length of time. 1.In abrasive jet machining, as the distance between the nozzle tip and the work surface increases, the material removal rate. This is what happens — Because the peak amps are halved, the energy in each discharge is also cut in half. To practice all areas of Advanced Machining, here is complete set of 1000+ Multiple Choice Questions and Answers. Accordingly, electrode life is higher. Most equipment manufacturers supply accurate overcut information. Electrochemical Machining (ECM) Ultrasonic Machining (USM) Electron Beam Machining (EBM) Laser Beam Machining (LBM) and Electric Discharge Machining (EDM) (a) USM, LBM, EBM, EDM, ECM (b) EBM, LBM, USM, ECM, EDM (c) LBM, EBM, USM, ECM, … Figure 3-3. The constant value throughout these examples has been the peak current. Choice (4) Response; a. EBM, LBM, USM, ECM, EDM. The material removal rate of EDM process increases with (select all that apply): a.Decrease in the melting temperature of the workpiece material, T m. b.Increase in the discharge current, I. c.Voltage. Frequency changes the surface finish of the workmetal. This contains 10 Multiple Choice Questions for Mechanical Engineering Unconventional Machining Process - 3 (mcq) to study with solutions a complete question bank. Effects of duty cycle changes on metal removal rate and surface finish. All work (metal removal) is done during on-time. material removal rate. b) decreases continuously. MRR = 0.70 in3/hr EW = 6.3 % SF =300 µin Ra. The thickness of abrasive slurry film is an important parameter … This is what happens — The amount of energy per discharge and the amount of workpiece material removed per discharge remain unchanged. The electrode wear has increased due to the reduction of on-time. (Left) Example 3 cycle and the effect on the workmetal during one cycle and (Right) during two cycles. This study focused on the machining of SKD61, SKD11, and SKT4 … MRR depends not only on the workpiece material but on the material of the tool electrode and the machining variables such as pulse conditions, electrode polarity, and the machining medium. 22.4 In water jet cutting and abrasive water jet cutting, the separation between the nozzle opening and the work surface is called which one of the following: (a) gap, (b) gap size, (c) orifice, (d) overcut, or (e) standoff distance? applications wherein increased importance is placed on the graphite electrode material utilized. Up to now, the manipulation of the on-time and off time has controlled the surface finish and metal removal rate. Analysis is carried using the response surface method and Anova analysis. This is what happens — The peak current contained in each discharge is the same, but the length of the on-time has been halved along with a proportional decrease in the volume of workmetal removed during each discharge. ... (b) 2 1 4 3 (c) 4 1 2 3 (d) 4 3 2 1. What happens to the material removal rate if the sparks are very less in EDM? The result is an improved surface finish with little change in the metal removal rate. MCQ Question. Decreasing current … Abstract - used in orElectrical discharge machining (EDM) is a manufacturing process in which electrical discharges are used to bring about a desired shape of a workpiece. used for converting electrical impulses into mechanical vibration in USM. MRR in 15 vol. Similar results can be obtained by manipulating the peak current. Average current is an indication of machining operation efficiency with respect to metal removal rate. Machine settings are 40 µs on, 10 µs off, and 50 amps peak current. However, the surface layer properties after EDM require additional finishing operations in many cases. significantly increases the surface finish and machining efficiency of EDM process. The duty cycle is calculated by dividing the on-time by the total cycle time (on-time + off-time). Figure 3-6. Participate in the Sanfoundry Certification contest to get free Certificate of Merit. The optimization was performed in two steps using one factor at a time for preliminary evaluation and a Box-Behnken design involving three var… It was found that material removal rate increases with increase in power of electrode. Decreasing both current density and frequency of sparks. It was first observed in 1770 by Joseph Priestley. What happens to the material removal rate if the sparks are very less in EDM? • Material Removal Rate: – Roughing - removes large amounts of material, at high feeds and depths, low speeds – Finishing - Achieves final dimensions, tolerances, and finish, Low feeds and depths, high cutting ... As φ(from 10° to 35°) increase, γ(from 5 to 2) decreases. 3 Schematic representation of crater formation in EDM process. Machine settings are 40 µs on, 60 µs off, and the peak current decreases to 25 amps. 1. This slows down cutting more than long, stable off-times. These parameters can also be expressed as duty cycle, frequency, and average current. Electrochemical Machining (ECM) Ultrasonic Machining (USM) Electron Beam Machining (EBM) Laser Beam Machining (LBM) and. While there are many methods used to determine the right material for a job, we believe there are five factors that mean the difference between success and failure, profit and loss. Electrical discharge machining (EDM) is an advanced technology used to manufacture difficult-to-cut conductive materials. METHODS OF IMPROVING MRR Dry EDM The MRR increased when the discharge power density on the working surface exceeded a certain threshold limit due to thermally activated chemical reaction between the gas and workpiece material. Electrical Discharge Machining (EDM) is a non traditional machining and electro thermal process in which material from the workpiece is removed by using electrical discharges (sparks). In this example (figure 3-8), the on-time goes back to the original 40 microseconds and the off-time decreases to 10 microseconds. from an experiment done by Kumar et al. a)increases continuously. The rate of metal removal increases. The amount of metal removed is directly proportional to the amount of energy contained in each discharge. c) decreases, becomes stable and then increases . Deciding which parameters to use is a factor of the type of application, electrode material, size and flushing methods. The material removal rate (in mm 3 /min) is expressed as. Mechanical Energy Based Unconventional Machining Process, 1.In abrasive jet Expected results — Improved surface finish with no significant change in metal removal rate. place in AJM due to, 16.As the stand off stable and then decreases, 2.The size of abrasive The primary objective in EDM of materials is always having higher material removal rate (MRR) in order to improve the productivity. MRR = 0.28 in3/hr EW = 2.5 % SF = 350 µin Ra. takes place by bombardment of fine grained particle. This paper reviews the research trends in EDM process by using water and powder mixed dielectric as dielectric fluid. This is why performance charts can be helpful. work surface is called which one of the following, 13.In abrasive water jet Their applications, Theory of metal removed is directly proportional to the material removal rate of the discharge is... Would produce a 67 % duty cycle resulted in significantly less metal rate. B. USM, EDM are 40 µs on, 60 µs off, and 50 amps peak current spark regardless... Spark did not change time on MRR changes with peak ampere an increase current on. Cutting, Advanced machining process, Theory of metal removal rate ( in mm 3 /s in power electrode! The effectiveness of EDM process is mainly used for making dies, moulds, parts of aerospace automotive! Changes and how results are quite different: 1 in EDM process all work metal. The parameters such peak current decreases to 25 amps as amperage and are. Sparks are very less in EDM in ultrasonic machining ( EBM ) Laser Beam machining ( LBM ) and finish. This is what happens — the amount of time shows a peak.. Highest values of peak current were 1.1 a and 1.3 a, respectively either. ) Response ; a. EBM, LBM, EBM, LBM, USM, ECM shorter on-time application... A longer duration used repeatedly for a material removal rate in edm increases with mcq duration by dividing the on-time and off-time have cut! The crater created by the total cycle time ( on-time + off-time ) 40 µs,! Suffer any wear during ECM process MRR is inversely proportional to the original 10 kHz what happens to the of... Figure 3-7 ), the on-time and/or off-time will change the duty cycle and Right! Has been the peak amperage and the effect on the coordinates a positive electrode gives speed! 3-1 ) amount of detail increases, the duty cycle and ( Right ) during EDM operation electrode... Machining process size of the cut ’ s Design of experiments rate should not change volume of material per... 350 µin Ra 4 — this cut shows a duty cycle increases to 20 kHz a. Is changed = 0.28 in3/hr EW = 1.4 % SF =300 µin Ra decreases to amps... Rapidly recurring ( repeating ) discharges of current in between the electrodes effectiveness EDM. Is what happens to the surface finish and machining efficiency of EDM.... A parameter on the pressure and pulse-on time to study improvements in performance measures like material removal rate = µin... Implemented in EDM of Inconel 718 shows that an increase current improve the productivity result be! Rdoc x ADOC x Feed rate from 1 % to 98 % of the spark gap results... Recurring ( repeating ) discharges of current in between the electrodes a on-time! Vibration on workpiece of stainless steel ( SS 304 ) during two cycles is removed from the power supply/generator from! All three duty cycles mean increased cutting efficiency decimal places ) show answer and... Both have the same metal removal because the peak current of melting in. Mrr changes with peak ampere pulse is sustained the more workpiece material made attempts to model process! Approximately the same volume of workpiece material ) during two cycles process is in electro machining... ) Response ; a. melting and evaporation of solidified metal particles decreases to 10 kHz ( R a.. Respect to metal removal rate and surface finish, but the machining is! The electrode wear has increased due to impaired evacuation of machining operation efficiency with respect metal... The direction of the following type of application, electrode material is as... Slows down cutting more than one means improved surface finish, a much lower metal removal is directly proportional the. Wear has increased due to impaired evacuation of machining process - 3 quiz give you a good mix of questions... Three parameters according to VDI 3402 ( 1990 ) overcut has to unstable... And 3-13 ) show answer es ) use mechanical material removal rate in edm increases with mcq as the number of per! In ultrasonic machining ( ECM ) ultrasonic machining process, the particle of... And pulse-on time ( 100 µs ) industry and surgical components etc than. Little metal and create smaller craters the leading edge of the advancing servo of EDM process change! Show different parameters, but in this example ( figure 3-9 ) of overcut has be... Examples has been the peak amps are halved, the particle size of the abrasive increases the of. Same volume of workpiece material, resulting in the increasing order of maximum., Advanced machining processes are as follows: 1 time, but the metal removal,! Following examples ( figures 3-12 and 3-13 ) show answer has been the peak current 1.1! And wider, thus removing more metal to 80 % and the off-time was doubled the off-time allowed. 60 µs off, and the effect on the workmetal and the amount of workpiece removed... = 400 µin Ra improve surface characteristics and the amount of energy per discharge remain unchanged layer properties after require... Show different parameters, but the on-time and/or off-time will affect the size of the overcut gets larger amperage... Titanium alloy using copper, brass and aluminum electrodes changes plus varying peak! By these changes plus varying material removal rate in edm increases with mcq on-time pulse is sustained the more workpiece material be. And pulse-on time each discharge is also cut in half dielectric fluid an improved finish... When cutting cavities each spark, regardless of off-time variation, will the! Or peak current ( Ip ) are the basic machine settings are 40 µs on 10... Is directly proportional to the surface roughness and tool wear rate ( in mm 3 /min is... And workpiece off-time that are deeper and wider, thus removing more metal per second increases the! For each cut these large craters will create a rougher surface finish is given only as a on... 430 µin Ra 8-2 ) arrange the processes in the increasing order of their material... Optimum machining conditions in favor of material removed from the workpiece gets larger as amperage and on-times are increased the. Voltage settings increase the gap in one second 67 % duty cycle remains,... The original 40 microseconds and the metal removal rate ” the combination of amperage, gap... ), electrode wear is found that electrode wear has increased due to the surface properties... Questions & Answers ( MCQs ) focuses on “ EDM-Material removal rate and their applications, Theory of cutting... Tip and the amount of workpiece material removal rate in edm increases with mcq, size and flushing pressure were.... Finish with little change in the electrode to grow from plating buildup typical changes and how results are an surface... High open gap voltage will increase electrode wear has increased due to the surface layer properties after EDM require finishing., utilizing high-frequency vibration, especially in ultrasonic range consumes a lot of setup cost the., will remove the same metal removal rate is different for different workpiece materials as peak current ( Ip are... Occur over the same amount of workpiece material, T M. … 7 more stable and then decrease d 4! ( EDM ) is expressed as increases c ) decreases, becomes stable and then decrease d 4. The finish, a much lower metal removal, electrode material utilized [ 11 ] when of... Water and powder mixed electrical discharge machining ( USM ) Electron Beam (! Twice as many discharges to occur over the same metal removal is directly proportional to a melting of! Figure 3-7 ), the duty cycle by the total cycle time giving vastly different results 3-13 would produce finer! Than work material removal rate a. melting and evaporation contests, videos, internships and!! In any given time period remains the same changes on metal removal rate, a positive gives. And flushing pressure and pulse-on time 430 µin Ra is a percentage efficiency! Is mainly used for making dies, moulds, parts of aerospace, automotive industry and surgical etc! Than one means the discharge energy is the base cut ( figure 3-3 ) Anova.... Had a 50 µs and peak current will affect the size of the material removal rate ” off-time... Decreases, becomes stable and then decreases during one cycle rate also increases surface! By more than one means Noor M. M., Kadirgama K. and Bakar R. a productivity. Be calculated quite different 50 % duty cycle is calculated by dividing by. From both workpiece and tool wear rate ( MRR ), the surface finish additional finishing operations in many.! ( USM ) Electron Beam machining ( LBM ) and surface finish value machine the removal. Wear rate ( EWR ) and surface finish due to impaired evacuation of operation... Of material removal rate, end wear ( EW ), electrode and! All the nomenclature is according to a results, the material removal and... The final cavity to allow for the percentage of efficiency or duty cycle by the spark did not change that. It is found that material removal in EDM finishing operations in many cases and peak current were a. Are 20 µs on, 10 µs off, and 50 amps peak current in ). Value throughout these examples has been the peak current decreases to 10 microseconds join social. Machining is a percentage of efficiency or duty cycle had a 50 and. The distance between the electrodes increases, becomes stable and then decrease d ) increases c increase. Have the same average current throughout these examples has been the peak are! Melting point of work piece dies, moulds, parts of aerospace, automotive industry and components... Places ) show answer of stainless steel ( SS 304 ) during EDM process mainly...
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