61. The function of interpolator in a CNC machine controller is to

1. 1. control spindle speed

   
   
   

   2. coordinate feed rates of axes

   
   
   

   3. control tool rapid approach speed

   
   
   

   4. perform Miscellaneous (M) functions (tool change, coolant control etc.)

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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62. In an ultrasonic machining (USM) process, the material removal rate (MRR) is plotted as a function of the feed force of the USM tool. With increasing feed force, the MRR exhibits the following behavior:

1. 1. increases linearly

   
   
   

   2. decreases linearly

   
   
   

   3. does not change

   
   
   

   4. first increases and then decreases

   
   
   

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1. View Hint View Answer Discuss in Forum

   

   Correct Option: D

   

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63. Which one of the following statements is TRUE for the ultrasonic machining (USM) process?

1. 1. In USM, the tool vibrates at subsonic frequency.

   
   
   

   2. USM does not employ magnetostrictive transducer.

   
   
   

   3. USM is an excellent process for machining ductile materials.

   
   
   

   4. USM often uses a slurry comprising abrasive-particles and water.

   
   
   

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1. View Hint View Answer Discuss in Forum

   USM uses an abrasive slurry which transfers the impact load provided by the vibrating tool to the work piece.

   Correct Option: D

   USM uses an abrasive slurry which transfers the impact load provided by the vibrating tool to the work piece.

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64. An electrochemical machining (ECM) is to be used to cut a through hole into a 12 mm thick aluminium plate. The hole has a rectangular cross- section, 10 mm × 30 mm. The ECM operation will be accomplished in 2 minutes, with efficiency of 90%. Assuming specific removal rate for aluminium as 3.44 × 10^–2 mm³/ (A s), the current (in A) required is _____ (correct to two decimal places).

1. 1. 988

   
   
   

   2. 962

   
   
   

   3. 968.992

   
   
   

   4. 868

   
   
   

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1. View Hint View Answer Discuss in Forum

   Volume of metal to be removed.
   = (10 × 30) × 12 mm³ = 3600 mm³
   Ideal energy required.
   

   =	3600 mm³	= 104651.163 As.
   	3.44 × 10-2 mm³/as.

   
   

   Actual energy required =	104651.163	As.
   	120

   
   = 116279.07 As.
   Time is 2 min = 120 s
   

   ∴ Current =	116279.07	= 968.992 A.
   	120

   Correct Option: C

   Volume of metal to be removed.
   = (10 × 30) × 12 mm³ = 3600 mm³
   Ideal energy required.
   

   =	3600 mm³	= 104651.163 As.
   	3.44 × 10-2 mm³/as.

   
   

   Actual energy required =	104651.163	As.
   	120

   
   = 116279.07 As.
   Time is 2 min = 120 s
   

   ∴ Current =	116279.07	= 968.992 A.
   	120

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65. Match the following
    List-I
    A. ECM
    B. USM
    C. EDM
    D. LBM
    List-II
    1. Erosion
    2. Fusion and vaporization
    3. Vaporization and ablation
    4. lon displacement

1. 1. A–1, B–3, C–2, D–4

   
   
   

   2. A–3, B–1, C–2, D–4

   
   
   

   3. A–4, B–1, C–2, D–3

   
   
   

   4. A–4, B–1, C–3, D–2

   
   
   

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1. View Hint View Answer Discuss in Forum

   A–4, B–1, C–2, D–3
   Erosion – USM
   Fusion and vapoirization – EDM
   Vaporization and ablation – LBM
   Ion Displacement – ECM

   Correct Option: C

   A–4, B–1, C–2, D–3
   Erosion – USM
   Fusion and vapoirization – EDM
   Vaporization and ablation – LBM
   Ion Displacement – ECM

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