Download Assignment _03

Manufacturing Process Technology part-2
Assignment – 03
1. Which of the following statements are true for Electro-Chemical Machining (ECM)?
1. ECM is capable of machining metals and alloys irrespective of their strength and
hardness
2. No cutting forces are involved in ECM process
3. ECM process consumes very high power
4. Very small space is required to set up ECM process
a. (1), (2) and (3)
b. (2), (3) and (4)
c. (1), (3) and (4)
d. (1), (2) and (4)
2. Electrochemically machined surfaces have
(a) High residual stresses and improved fatigue strength
(b) High residual stress and reduced fatigue strength
(c) Insignificant residual stress and reduced fatigue strength
(d) Insignificant residual stress and improved fatigue strength
3. Desirable properties of electrolyte used in ECM are:
(a) high electrical conductivity
(b) high thermal conductivity
(c) low specific heat
(d) high specific heat
4. Which of the following are true for an ECM process? (One or more may be correct). Where
m = Mass of the machined material M, A= Gram equivalent weight of M, ρ= Density of
M, Z= Valency state of the ion M, ε = Gram equivalent weight of M, F= Faraday constant,
Q = Material removal rate.
(a) m= AI/ZF (b) dm/dt = AI/ZF (c) Q= AI/ρZF
(d) m = Itε/F
5. In electrochemical machining (ECM) removal of metal from the work piece takes place
(a) anodic dissolution
(b) abrasive action
(c) thermal melting
(d) erosion
6. ECM cannot be used for processing of
(a) steel
(b) Nickel based super alloy
(c) Al2O3
(d) Titanium alloy
MOOC course under NPTEL (July 2016)
IIT Kanpur
Manufacturing Process Technology part-2
Assignment – 03
7. Which statement is/are true?
(a) Electrolyte is not consumed in ECM. Type of electrolyte used during ECM, therefore,
has no effect on MRR.
(b) Electrochemically ground surface requires deburring.
(c) Theoretically tool wear rate during ECM is zero.
(d) Inter electrode gap during ECM is usually in range of 1-3 mm.
8. In an electrolytic cell the electrode at which the electrons enter the solution is called the
______; the chemical change that occurs at this electrode is called _______.
(a) anode, oxidation
(b) anode, reduction
(c) cathode, oxidation
(d) cathode, reduction
(e) cannot tell unless we know the species being oxidized and reduced.
9. Which of the following statements is FALSE?
(a) Oxidation and reduction half-reactions occur at electrodes in electrochemical cells.
(b) All electrochemical reactions involve the transfer of electrons.
(c) Reduction occurs at the cathode.
(d) Oxidation occurs at the anode.
(e) All voltaic (galvanic) cells involve the use of electricity to initiate nonspontaneous
chemical reactions.
10. Which of the following statements is(are) true for all voltaic (or galvanic) cells?
(I) Reduction occurs at the cathode.
(II) The anode gains mass during discharge (note: this means operation of the cell.)
(III) The voltage is less than or equal to zero.
(a) only III
(b) only II
(c) only I
(d) II and III
(e) I, II, and III
11. For a galvanic cell, which of the following statements is never true?
a) The potential of the cathode is higher than that of the anode.
b) The electrons flow in the external circuit from the anode to the cathode.
c) Reduction takes place at the cathode.
d) Oxidation takes place at the anode.
MOOC course under NPTEL (July 2016)
IIT Kanpur