proaches to increase the material removal rate or reduce tool wear in case of titanium or its alloy were presented [3]. Abrasive carrying liquid for the abrasive slurry in USM is a) Electro chemical machining View Answer, 2. b) Increase in volume of work material per impact The material removal rate increases linearly with an increase in mass flow rate. 2.The size of abrasive grains in abrasive jet machining ranges from. As an example, if your RDOC is.500″, your ADOC is.100″ and your Feed Rate is 41.5 inches per minute, you’d calculate MRR the following way: MRR =.500″ x.100″ x 41.5 in/min = 2.08 cubic inches per minute. The rate of material removal in USM depends on ____. View Answer, 3. a) Decreases View Answer, 9. View Answer, 3. a) Electro chemical machining Hence, material removal due to these two factors has been ignored. 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If splashing occurs, it will result in an increase of material removal rate in USM. a) Increases d) All of the mentioned As the tool vibrates, it leads to indentation of the abrasive grits. a) Increases c) Remains same The major efforts to improve the micro-USM process performance are to increase its throughput by using novel microtooling technology, especially for Mode II micro-USM (Figure 2(b)). With increasing feed force, the MRR exhibits the following behavior: (A) increases linearly (B) decreases linearly (C) does not change (D) first increases and then decreases; Show Answer . Gas-As the velocity pressure depends on the composition of gas, the material removal rate is mainly affected by the composition of the gas. c) Ultrasonic machining In USM, high frequency electrical energy is converted into mechanical vibrations via a transducer/booster combination which are then transmitted to an energy focusing as well as amplifying device: horn/tool assembly. When the mass flow rate of the abrasive increases the material removal rate also increases. a) Decrease in volume of work material per impact There is an optimum mixing ratio (mass fraction of the abrasive in the jet) for which the metal removal rate is the highest. b) Increases This effect appears to be more pronounced in the machining of brittle materials than in the ductile ones. 7. d) All of the mentioned When the static pressure of the feed is increases, MRR ____. The dominant mechanism involved in USM of all materials is (a) Two body abrasive (b) Three body abrasive (c) Direct hammering (d) Elastic deformation Ans. In this experimental study, Boron carbide abrasive gives better material removal rate as compared to Silicon carbide and Alumina Abrasive. Hammering, 5. Join our social networks below and stay updated with latest contests, videos, internships and jobs! USM can be used only when the hardness of work is more than 45 HRC. However, a more cost-effective method for machining ceramic components is needed [4]. Erosion, 2. 2.The size of abrasive grains in abrasive jet machining ranges from. High grain size will always produce more metal removal. 3. c) decreases, becomes stable and then increases . May 11 2015 06:52 AM 1 Approved Answer Akshay answered on July 24, 2016 a) Force c) 25 – 30 % In another study of Komaraiah and Reddy [ 22 ], experiments were carried out to clarify the effect of tool materials on the material removal rate, tool wear, and surface quality. Static load on tool: The material removal rate increase with the static load on tool up to a maximum value. It was noticed that the evidence of three body material removal mechanism is predominant for micro USM using oil based slurry. As the concentration of particle increases the material removal rate initially increases and then decreases. As the tool area increases, what happens to MRR? When the static pressure of the feed is increases, MRR ____. a) 0.01 – 0.04 mm Various types of concentrators are used The Gas The AJM unit normally operates at a pressure of 0.2-1.0 N/mm 2. d) None of the mentioned Analyse the effect of process parameters on material removal rate (MRR) v. Develop mathematical model relating MRR with USM parameters vi. • Vibration amplitude determines the velocity of the abrasive particles at the interface between the tool and workpiece. As the vibration frequency increases, what happens to material removal rate? USM accomplishes the removal of material by the abrasive action of a grit-loaded slurry, circulating between the workpiece and a tool that is vibrated at small amplitude and high frequency. Magne-trostriction’ means a change in the dimension occurring in f… This can be explained on the basis of the Machining rate obtained with different tool materials. View Answer, 7. b) 15 – 20 % 1. Abrasive carrying liquid for the abrasive slurry in USM is (a) Water (b) Heavy paraffin oil (c) Silicone oil (d) Glycerol Ans. Ans: The various process Parameters that control MRR in USM process are: (i) Frequency: The material removal rate (mrr) increases linearly with the frequency but in actual characteristic is not exactly linear. The material removal rate increases with voltage; due to the increase in voltage, machining current also increases. b) Insulators 1. It is used to erode material in the form of fine holes and cavities in hard or brittle workpiece through the use of formed tools, vibrations of high frequency along with the … How much percent of the abrasives are recommended in general for abrasive medium? d) None of the mentioned a) Decrease in volume of work material per impact c) Velocity During the electrochemical machining (ECM) of iron (atomic weight = 56, valency = 2) at current of 1000 A with 90% current efficiency, the material removal rate was observed to be 0.26 gm/s. a) True The actual shape of an abrasive grain is … c) Decrease in frequency 9. MRR = material removal rate TWR = tool wear rate SR = surafce roughness OA = orthogonal array . b) Decreases The main purpose of the concentrator is to increase the amplitude, to the level needed for cutting. One of the first places these machinists turn is to MRR, which encompasses Radial Depth of Cut … 3 Analysis of Material Removal Rate Material removal during USM due to cavitation under the tool and chemical corrosion due to slurry media are considered insigni cant. d) 0.10 – 0.20 mm J Material Sci Eng 8: 507. doi: 10.4172/2169-0022.1000 507 Page 2 of 8 aea g a oe ae oa oe 8 e 57 2622 zone, non-residual stress and non-thermal stress produced machining process [6-9]. Faraday's law states that the material removal rate is proportional to the machining current. It is found that the material removal rate generally increases with the decrease of the material fracture toughness. • 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 speeds = MRR v f d. 8. b) Torque b) Decreases In an ultrasonic machining (USM) process, the material removal rate (MRR) is plotted as a function of the feed force of the USM tool. c) decreases, becomes stable and then increases . d) Increase in number of particle making impact per cycle Beyond this point, the material removal decreases with the increasing static load. a) Decrease in volume of work material per impact b) Decrease in volume of work material per impact d) Decrease and then increase Material removal rate in USM increases with generally above 16 kHz. View Answer. The depth of cylindrical holes is presently limited to 2.5 times the diameter of the tool. b) Decrease in volume of work material per impact Amplitude of the oscillation ranges between which of the following values? For a given work material, the removal rate in USM increases with increasing frequency and amplitude of vibration. c) Glycerol Although, the frequency of vibration is not considered a major influencing parameter in USM operations because the user rarely varies the frequency over a wide range, however, higher frequency increases material removal rate. c) Remains same 1.PROCESS PRINCIPLES •Ultrasonic Machining (USM) is a mechanical material removal process used to erode holes and cavities in hard or brittle workpieces by using shaped tools, high frequency mechanical motion, and an abrasive slurry. Material removal in USM is due to: i) Hammering of the abrasive particles on the work surface by the tool. Fig 2. Materials Science and Manufacturing Engineering Miscellaneous In USM the metal removal rate would... with increasing mean grain diameter of the abrasive material increase Radial over cut may be as low as 1.5 to 4 times the mean abrasive grain size. The rate of material removal depends on which of the following features? d) None of the mentioned 2. Through analysis, it concludes that hard abrasive gives the large stressed zone, which increases the material removal rate. The microstructure and localized fracture mechanism of materials seem to affect the machined surface characteristics. Material Removal Rate (MRR), otherwise known as Metal Removal Rate, is the measurement for how much material is removed from a part in a given period of time. Tool wear rate is insignificantly affected by the type of workpiece material. Amplitude of the oscillation ranges between which of the following values? b) decreases continuously. Which of the following can be used as an abrasive carrying medium? 1.In abrasive jet machining, as the distance between the nozzle tip and the work surface increases, the material removal rate. Tool wear rate is high due to abrasive particles. The development of USM was motivated by the need to machine hard, … There was a reduction in material removal rate with the increase of the hardness and fracture toughness of the workpiece material. It is difficult to drill deep holes, as slurry movement is restricted. Effect of MRR and Grit diameter f or SiC and TiB 2 was . In this research paper, the Finite Element Analysis is used for the investigation. c) Decrease in frequency © 2011-2020 Sanfoundry. d) Decreases in the number of particle making impact per cycle What is the machinability rate of glass by USM? With increasing feed force, the MRR exhibits the following behavior: increases linearly ; decreases linearly ; does not change ; first increases and then decreases ; Correct Option: D. Previous Question Next Question . With increasing feed force, the MRR exhibits the following behavior: (A) increases linearly (B) decreases linearly (C) does not change (D) first increases and then decreases; Show Answer . b) decrease MRR. With an increase of grain size or abrasive particle size, the material removal rate is increasing first and then decreasing. 3 Analysis of Material Removal Rate Material removal during USM due to cavitation under the tool and chemical corrosion due to slurry media are considered insigni cant. Materials Science and Manufacturing Engineering In an ultrasonic machining (USM) process, the material removal rate (MRR) is plotted as a function of the feed force of the USM tool. a) 1 to 10 microns. Initially with the increase in concentration of abrasive particles in the slurry, the number of active particles supplied to the workpiece surface increases, as a result material removal rate increases. d) increases, becomes stable and then decreases . c) Decrease in frequency Electrochemical Machining. View Answer, 9. List three applications of USM xi. Identify major components of USM equipment viii. d) Pressure It was noticed that the evidence of three body material removal mechanism is predominant for micro USM using oil based slurry. View Answer. 4. d) None of the mentioned The term ultrasonic is used to describe a vibratory wave of the frequency above that of the upper-frequency limit of the human ear, i.e. a)increases continuously. ____ can be used as abrasive carrying medium. (b) 6. 5. Non directional surface texture is possible compared to conventional grinding 8. b) Decrease in grain size of abrasives 4. Factors affecting MRR Tool Oscillation or Vibration • Amplitude of the tool oscillation has the greatest effect of all the process variables. 9. Gas-As the velocity pressure depends on the composition of gas, the material removal rate is mainly affected by the composition of the gas. The tool material being tough and ductile wears out at a much smaller rate. © 2011-2020 Sanfoundry. b) decreases continuously. Which of the following is a conventional process of machining? In Ultrasonic Machining (USM) the material removal rate would (a) increase (b) decrease (c) increase and then decrease (d) decrease and then increase With increasing mean grain diameter of the abrasive material. 2. b) Feeding unit The maximum metal removal rate is 3 mm®/s and the power consumption is high. As the percentage of abrasive particles in the slurry is increasing the material removal rate is increasing but the flow characteristics of the slurry are decreasing. This can be explained on the basis of the Machining rate obtained with different tool materials. b) 10 to 50 microns. Tough materials generally give material removal based on plasticity and there seems to be a greater tendency for dense and non-porous materials to produce surfaces with texture [4]. View Answer, 8. In USM process, as the machining rate increases, the surface quality deteriorates, the reason being formation of … The calculation for Material Removal Rate is RDOC x ADOC x Feed Rate. 2. d) Increase in amplitude The lowest tool wear has been recorded for titanium alloy (ASTM Grade –V). It was noticed that the evidence of three body material removal mechanism is predominant for micro USM using oil based slurry. View Answer, 4. a) True b) False View Answer. ULTRASONIC MACHINING PROCESS (USM) BY, ARAVINDKUMAR B 2. abrasive increases the material removal rate also increases. The device for converting any type of energy into ultrasonic waves is the ultrasonic transducer.  In USM process, as the machining rate increases, the surface quality deteriorates, the reason being formation of larger micro cavities at the time of machining. Material removal primarily occurs due to the indentation of the hard abrasive grits on the brittle work material. Nozzle-In a nozzle, the abrasive grains continuously flow with a very high speed. b) False d) increases, becomes stable and then decreases . If splashing occurs, it will result in an increase of material removal rate in USM. It is noted that the interference between the two abrasive particles decreases when the distance between the two adjacent abrasive particles increases, which increases the material removal rate. View Answer, 6. Sanfoundry Global Education & Learning Series – Manufacturing Engineering. c) Increases in frequency The mrr tends to be somewhat lower than the theoretically-predicted value. Contributions to the material removal by abrasive particles due to ’throwing’ and ’hammering’ actions have been analysed. The vibration amplitude determines, which parameter of the abrasive particles? In Ultrasonic Machining (USM) the material removal rate would (a) increase (b) decrease (c) increase and then decrease (d) decrease and then increase with increasing mean grain diameter of the abrasive material. a) 10 – 15 % a)increases continuously. a) Decreases Although, the frequency of vibration is not considered a major influencing parameter in USM operations because the user rarely varies the frequency over a wide range, however, higher frequency increases material removal rate. Relative material removal rate (%) for machining titanium in USM is (a) 66 (b) 4.0 (c) 1.4 (d) 4.8 Ans. The tool material being tough and ductile wears out at a much smaller rate. Stationary USM Set Up . c) Drilling Abrasive material, size: The characteristics of abrasive like size, shape … 3. b) False c) Increase and then decrease ____ can be used as abrasive carrying medium. The material removal rate increases linearly with an increase in mass flow rate. In general, the material removal rate increases with the increase in the abrasive particle size for both aqueous abrasive slurry and oil based abrasive slurry. The rate of material removal in USM depends on ____. Machinability rate of glass by USM is ____. View Answer, 4. a) increase MRR. Also, material removal rate is an important performance variable in USM machining. The modal of polycarbonate bullet proof glass and the abrasive particle is prepared to study the effect of machining mechanism. b) Increases Wear of the tool increases the angle of the hole, while sharp corners become rounded. a) Increases To practice all areas of Advanced Machining, here is complete set of 1000+ Multiple Choice Questions and Answers. As the tool area increases, MRR ____. Participate in the Sanfoundry Certification contest to get free Certificate of Merit. 14. b) Decreases To practice all areas of Manufacturing Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers. a)increases continuously. 1.In abrasive jet machining, as the distance between the nozzle tip and the work surface increases, the material removal rate. c) 0.08 – 0.10 mm a) 1 to 10 microns. c) Transducer This implies that tool … Draw variation in MRR with different process parameters vii. 1 Answer to In Ultrasonic Machining (USM) the material removal rate would (a) increase (b) decrease (c) increase and then decrease (d) decrease and then increase With increasing mean grain diameter of the abrasive material. Relation (6.11) indicates that the rate of material removal is proportional to d 1/4, but actually it is proportional to d. This discrepancy between the theoretical prediction and the observed fact was explained by Shaw as follows. The material removal rate increases with the . (c) 5. Therefore the optimum percentage of abrasives in the slurry is 40-60%. a) True b) False View Answer. Material removal rate in USM increases with It is found that the material removal rate generally increases with the decrease of the material fracture toughness. Ultrasonic machining sometimes called ultrasonic abrasive machining or impact machining. a) Water