McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 201. |
In Electro discharge machining, materials with low melting point have which type of material removal rate? |
| A. | very low |
| B. | low |
| C. | medium |
| D. | high |
| Answer» D. high | |
| Explanation: in electro discharge machining, materials having low melting point have high material removal rates and vice-versa. | |
| 202. |
In Electro discharge machining, materials with low melting point have which type of surface roughness? |
| A. | rough |
| B. | smooth |
| C. | fine |
| D. | all of the mentioned |
| Answer» A. rough | |
| Explanation: in electro discharge machining, materials having low melting point have high rougher surfaces and vice-versa. | |
| 203. |
What happens to the material removal rate if the sparks are very less in EDM? |
| A. | decreases |
| B. | increases |
| C. | increase and then decrease |
| D. | all of the mentioned |
| Answer» A. decreases | |
| Explanation: in edm, if sparks generated are less then material removal rate decreases. | |
| 204. |
What is the relation between the melting point and the material removal rate? |
| A. | directly proportional |
| B. | inversely proportional |
| C. | indirectly proportional |
| D. | none of the mentioned |
| Answer» B. inversely proportional | |
| Explanation: in electro discharge machining, material removal rate is inversely proportional to the melting point. | |
| 205. |
What happens to the crater size if we increase the current keeping the pulse time constant? |
| A. | increase |
| B. | decrease |
| C. | decrease and increase |
| D. | none of the mentioned |
| Answer» A. increase | |
| Explanation: by keeping pulse time constant and increasing current, crater size also increases. | |
| 206. |
What happens to the crater size if we decrease the pulse time keeping the current constant? |
| A. | increase |
| B. | decrease |
| C. | increase and decrease |
| D. | none of the mentioned |
| Answer» B. decrease | |
| Explanation: by decreasing pulse time and keeping current constant, crater size also decreases | |
| 207. |
On which of the following factors do the craters depend? |
| A. | physical properties |
| B. | mechanical properties |
| C. | composition of medium |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: in edm, craters depend on the physical and mechanical properties of material and composition of medium. | |
| 208. |
The maximum depth of damaged layer is how many times that of average surface roughness? |
| A. | 1.5 time |
| B. | 2 times |
| C. | 2.5 times |
| D. | 3 times |
| Answer» C. 2.5 times | |
| Explanation: depth of damaged layer is two and half times the average surface roughness value. | |
| 209. |
What happens to the surface roughness values if the MRR increases in EDM? |
| A. | increases |
| B. | decreases |
| C. | decrease and increase |
| D. | none of the mentioned |
| Answer» A. increases | |
| Explanation: in edm, the surface roughness values increases linearly with increase in the material removal rates. | |
| 210. |
In Electro discharge machining, what happens to the surface finish if the pulse energy is decreased? |
| A. | reduces |
| B. | decreases |
| C. | improves |
| D. | none of the mentioned |
| Answer» C. improves | |
| Explanation: in electro discharge machining, the surface finish improves if the pulse energy is decreased. | |
| 211. |
Using of a mate electrode in Electro discharge machining the surface roughness of material. |
| A. | increases |
| B. | decreases |
| C. | enhances |
| D. | none of the mentioned |
| Answer» B. decreases | |
| Explanation: by using a mate electrode in electro discharge machining, the surface roughness values are decreased. | |
| 212. |
What happens to the surface roughness if oxygen gas is introduced in the gap? |
| A. | increases |
| B. | decreases |
| C. | decrease and then increase |
| D. | all of the mentioned |
| Answer» B. decreases | |
| Explanation: in edm, surface roughness increases with the supply of oxygen gas in gaps. | |
| 213. |
What are the tolerance values obtained by machining using EDM? |
| A. | ± 10 mm |
| B. | ± 15 mm |
| C. | ± 25 mm |
| D. | ± 40 mm |
| Answer» C. ± 25 mm | |
| Explanation: the tolerance values of ± 25 mm are obtained when we machine components using edm. | |
| 214. |
How much extra tolerances are achieved when we choose proper variables? |
| A. | ± 5 mm |
| B. | ± 10 mm |
| C. | ± 15 mm |
| D. | ± 20 mm |
| Answer» A. ± 5 mm | |
| Explanation: extra tolerances of ± 5 mm are obtained with a proper choice of process variables | |
| 215. |
What is the value of thickness of recast layer obtained when power of 5 µJ is given? |
| A. | 1 µm |
| B. | 3 µm |
| C. | 5 µm |
| D. | 7 µm |
| Answer» A. 1 µm | |
| Explanation: when a power of 5 µj is given, recast layer thickness of 1 µm is obtained. | |
| 216. |
The depth of the annealed surface is to the amount of power used in machining operation. |
| A. | directly proportional |
| B. | inversely proportional |
| C. | exponential |
| D. | all of the mentioned |
| Answer» A. directly proportional | |
| Explanation: the depth of annealed surface in edm is proportional to the amount of power used. | |
| 217. |
In EDM, choosing electrodes that produce which type of machining reduces the annealing effect? |
| A. | stable |
| B. | unstable |
| C. | uneven |
| D. | all of the mentioned |
| Answer» A. stable | |
| Explanation: in electro discharge machining, choosing the electrodes which produce more stable machining reduces the annealing effect. | |
| 218. |
What happens to the fatigue strength of alloys if altered surfaces are produced in Electro discharge machining? |
| A. | increases |
| B. | reduces |
| C. | enhances |
| D. | improves |
| Answer» B. reduces | |
| Explanation: the altered surface layers that are produced in electro discharge machining, significantly reduces the fatigue strength of alloys. | |
| 219. |
The altered layers formed during the process of EDM consists of which of the following? |
| A. | tempered layers |
| B. | heat affected zones |
| C. | intergranular precipitates |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: altered layers consists of recast layers, tempered layers, hazs and intergranular precipitates in edm. | |
| 220. |
During roughing process through Electro discharge machining, what is the thickness of layer formed? |
| A. | <0.075 mm |
| B. | <0.125 mm |
| C. | <0.500 mm |
| D. | <0.750 mm |
| Answer» B. <0.125 mm | |
| Explanation: the thickness of layer obtained after machining is <0.127 mm in edm. | |
| 221. |
During finishing process through Electro discharge machining, what is the value thickness of layer formed? |
| A. | <0.075 mm |
| B. | <0.125 mm |
| C. | <0.500 mm |
| D. | <0.750 mm |
| Answer» A. <0.075 mm | |
| Explanation: the thickness of layer obtained during edm finishing is <0.075 mm. | |
| 222. |
Which of the following processes can be used for restoration of fatigue properties? |
| A. | low-stress grinding |
| B. | chemical machining |
| C. | reheat treatment |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: for removal of altered layers processes such as low-stress grinding, chemical machining, reheat treatment, metallurgical type coating and application of shot peening. | |
| 223. |
State whether the following statement is true or false regarding the HAZ in EDM. “In EDM, post treatment to recover fatigue strength is not recommended.” |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: after machining using edm, post treatment to restore the fatigue strength is recommended. | |
| 224. |
Which of the following shapes can be produced using Electro discharge machining? |
| A. | complex shapes |
| B. | simple shapes |
| C. | all of the mentioned |
| D. | none of the mentioned |
| Answer» C. all of the mentioned | |
| Explanation: electro discharge machining is used to machine complex shapes to a high degree of accuracy. | |
| 225. |
Which of the following materials can be machined using Electro discharge machining? |
| A. | heat resistant alloys |
| B. | super alloys |
| C. | carbides |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: edm is used to machine materials such as carbides, heat resistant and super alloys which are difficult-to-machine materials. | |
| 226. |
Which of the following are the applications of Electro discharge machining? |
| A. | holes |
| B. | slots |
| C. | texturing |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: micromachining of holes, slots, dies, texturing, milling, surface modification and mechanical pulsing are some typical applications of electro discharge machining. | |
| 227. |
Which type of electrode is used for drilling in Electro discharge machining? |
| A. | flat electrode |
| B. | cuboidal electrode |
| C. | tubular electrode |
| D. | spherical electrode |
| Answer» C. tubular electrode | |
| Explanation: tubular electrode is mostly preferred in electro discharge machining, for drilling purpose. | |
| 228. |
The dielectric fluid is flushed in thorough which part of the electrode in drilling in EDM? |
| A. | interior hole |
| B. | side gaps |
| C. | all of the mentioned |
| D. | none of the mentioned |
| Answer» A. interior hole | |
| Explanation: edm drilling uses a tubular electrode which flushes the dielectric thorough the interior holes for removing debris. | |
| 229. |
Which type of holes can be produced through drilling using Electro discharge machining? |
| A. | irregular |
| B. | curved |
| C. | tapered |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: drilling of work piece using edm produced holes which can be irregular, curved, tapered as well as inclined holes. | |
| 230. |
What are the values of general feed rates used for drilling in EDM? |
| A. | 0.1 mm/min |
| B. | 0.3 m/min |
| C. | 0.5 mm/min |
| D. | 0.7 mm/min |
| Answer» A. 0.1 mm/min | |
| Explanation: usually a feed rate of 0.10 mm/min is used for drilling the work piece using electro discharge machining. | |
| 231. |
10 to 0.50 mm. |
| A. | 0.01 to 0.05 mm |
| B. | 0.1 to 0.5 mm |
| C. | 1 to 5 mm |
| D. | 10 to 15 mm |
| Answer» A. 0.01 to 0.05 mm | |
| Explanation: overcut values from 0.01 to 0.05 mm are obtained after the drilling process in edm. | |
| 232. |
Electro discharge sawing is an application of EDM which employs as tool material. |
| A. | steel band |
| B. | disc |
| C. | steel band & disc |
| D. | none of the mentioned |
| Answer» C. steel band & disc | |
| Explanation: electro discharge sawing is an application of edm which employs either steel band or disc as tool. | |
| 233. |
When compared to the conventional abrasive sawing, how many times faster is the MRR? |
| A. | twice |
| B. | thrice |
| C. | four |
| D. | five |
| Answer» A. twice | |
| Explanation: electro discharge sawing cuts the work piece material at the rates which are twice that of conventional abrasive sawing method. | |
| 234. |
How much amount of burr is produce while machined using Electro discharge sawing? |
| A. | 10% |
| B. | 20% |
| C. | 50% |
| D. | no burr |
| Answer» D. no burr | |
| Explanation: the cuts produced in electro discharge sawing have smaller kerf widths which hav no burrs in it. | |
| 235. |
3 to 10 µm when machined using Electro discharge sawing. |
| A. | 0.001 to 0.022 mm |
| B. | 0.025 to 0.130 mm |
| C. | 0.236 to 0.352 mm |
| D. | 0.432 to 0.568 mm |
| Answer» B. 0.025 to 0.130 mm | |
| Explanation: the recast layer thickness values obtained from ed sawing range from 0.025 to | |
| 236. |
Which of the following electrodes are used for machining spherical surfaces in Electro discharge machining? |
| A. | tubular electrodes |
| B. | flat electrodes |
| C. | cuboidal electrodes |
| D. | all of the mentioned |
| Answer» A. tubular electrodes | |
| Explanation: simple tubular electrodes are used to machine convex and concave spherical surfaces. | |
| 237. |
What are the values of dimensional accuracy obtained while machining spherical surfaces? |
| A. | ± 1 µm |
| B. | ± 3 µm |
| C. | ± 5 µm |
| D. | ± 7 µm |
| Answer» A. ± 1 µm | |
| Explanation: dimensional accuracy of ± 1 µm is obtained while machining spherical surfaces using edm. | |
| 238. |
What are the surface roughness values obtained while machining spherical surfaces using Electro discharge machining? |
| A. | <0.1 µm |
| B. | <0.3 µm |
| C. | <0.5 µm |
| D. | <0.7 µm |
| Answer» A. <0.1 µm | |
| Explanation: the surface roughness values obtained while machining of spherical surfaces are <0.1 µm in electro discharge machining. | |
| 239. |
Which motion of tool is used for machining spherical surfaces in Electro discharge machining? |
| A. | oscillatory |
| B. | vibratory |
| C. | rotary |
| D. | all of the mentioned |
| Answer» C. rotary | |
| Explanation: the rotary motion tool is used for machining spherical surfaces of conducting ceramic materials in edm. | |
| 240. |
Which type of electrodes are used for milling application in Electro discharge machining process? |
| A. | tubular type electrodes |
| B. | cylindrical type electrodes |
| C. | flat type electrodes |
| D. | spherical type electrodes |
| Answer» B. cylindrical type electrodes | |
| Explanation: standard cylindrical electrodes are used for milling application in edm process. | |
| 241. |
Which type of cavities can be machined using milling process by Electro discharge machining? |
| A. | complex cavities |
| B. | simple cavities |
| C. | simple & complex cavities |
| D. | none of the mentioned |
| Answer» C. simple & complex cavities | |
| Explanation: simple cavities and complex cavities are machined by successive nc sweeps of electrode over the desired path. | |
| 242. |
The simple electrodes are rotated at which speed for milling of work pieces in Electro discharge machining? |
| A. | very low |
| B. | low |
| C. | medium |
| D. | high |
| Answer» D. high | |
| Explanation: simple electrodes are rotated at high speeds for milling in electro discharge machining same as that of conventional milling. | |
| 243. |
What happens to the dielectric flushing while milling tool is rotated at a high speed in EDM? |
| A. | improved |
| B. | worsen |
| C. | reduced |
| D. | all of the mentioned |
| Answer» A. improved | |
| Explanation: milling by electro discharge machining enhances the dielectric flushing due to high speed rotation of tool. | |
| 244. |
Which of the following are the steps included in the die sinking process of EDM? |
| A. | cad of electrode |
| B. | electrode manufacturing |
| C. | programming for die sinking |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: designing of electrode, then manufacturing, and programming of die sinking are the steps to be followed for die sinking process in edm. | |
| 245. |
Which path of the components in wire EDM determines the path to be machined? |
| A. | horizontal worktable movement |
| B. | vertical worktable movement |
| C. | horizontal & vertical worktable movement |
| D. | none of the mentioned |
| Answer» A. horizontal worktable movement | |
| Explanation: horizontal movement of the work table determines the path to be machined in wire electro discharge machining. | |
| 246. |
Which of the following materials are machined using Wire Electro discharge machining? |
| A. | polycrystalline diamond |
| B. | cubic boronitride |
| C. | matrix composites |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: polycrystalline diamond (pcd), cubic boron nitride (cbn) and other matrix composites are the material than can be machined using wire edm. | |
| 247. |
How much amount of burr is produce when we use Wire Electro discharge machining for machining of work pieces? |
| A. | 10% |
| B. | 20% |
| C. | no burr |
| D. | small amount |
| Answer» C. no burr | |
| Explanation: in wire electro discharge machining no burr is produced without any distortion while machining work pieces. | |
| 248. |
Which of the following industries use wire EDM for different applications? |
| A. | chemical industry |
| B. | aerospace industry |
| C. | automobile industry |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: industries such as chemical, aerospace, automobile, nuclear etc.., use wire edm for a wide variety of applications in their industries | |
| 249. |
While machining insulating ceramic materials using EDM, where is the sheet metal placed? |
| A. | over material |
| B. | below material |
| C. | under material |
| D. | none of the mentioned |
| Answer» A. over material | |
| Explanation: sheet metal is placed over the material in machining of insulating materials using edm. | |
| 250. |
Sparks occur between which of the following components? |
| A. | work piece and sheet metal |
| B. | tool electrode and sheet metal |
| C. | work piece and electrode |
| D. | none of the mentioned |
| Answer» B. tool electrode and sheet metal | |
| Explanation: sparks occur between sheet metal and tool electrode for macining insulating ceramics. | |
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