356. Better surface finish is obtained with a large rake angle because

1. 1. the area of shear plane decreases resulting in the decrease in shear force and cutting force

   
   
   

   2. the tool becomes thinner and the cutting force is reduced

   
   
   

   3. less heat is accumulated in the cutting zone

   
   
   

   4. the friction between the chip and the tool is less

   
   
   

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1. View Hint View Answer Discuss in Forum

   As rake angle increase shear plane decreases so smaller force one required so smooth machining operation
   

   tan Φ =	r cos α	Favourable machining
   	1 - r sin α

   
   condition Φ ↑α↑r↑

   Correct Option: A

   As rake angle increase shear plane decreases so smaller force one required so smooth machining operation
   

   tan Φ =	r cos α	Favourable machining
   	1 - r sin α

   
   condition Φ ↑α↑r↑

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357. Two separate slab milling operations, 1 and 2, are performed with identical milling cutters. The depth of cut in operation 2 is twice that in operation 1. The other cutting parameters are identical. The ratio of maximum uncut chip thicknesses in operations 1 and 2 is

1. 1. 0.707

   
   
   

   2. 0.767

   
   
   

   3. 0.807

   
   
   

   4. 0.709

   
   
   

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1. View Hint View Answer Discuss in Forum

   Ratio of 1 and 2 is
   

   Correct Option: A

   Ratio of 1 and 2 is
   

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358. Cutting tool is much harder than the work piece. Yet the tool wears out during the tool-work interaction, because

1. 1. extra hardness is imparted to the work piece due to coolant used

   
   
   

   2. oxide layers on the work piece surface impart extra hardness to it

   
   
   

   3. extra hardness is imparted to the work piece due to severe rate of strain

   
   
   

   4. vibration of induced in the machine tool

   
   
   

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1. View Hint View Answer Discuss in Forum

   Metal cutting takes place in plastic deformation zone where work hardening takes place as chip get strained.

   Correct Option: C

   Metal cutting takes place in plastic deformation zone where work hardening takes place as chip get strained.

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359. A straight turning operation is carried out using a single point cutting tool on an AIS 1020 steel rod. The feed is 0.2 mm/rev and the depth of cut is 0.5 mm. The tool has a side cutting edge angle of 60°. The uncut chip thickness (in mm) is _____.

1. 1. 0.1 mm

   
   
   

   2. 0.3 mm

   
   
   

   3. 0.4 mm

   
   
   

   4. 0.2 mm

   
   
   

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1. View Hint View Answer Discuss in Forum

   t₁ = f cos θ
   = 0.2 × cos 60
   t₁ = 0.1 mm
   where t₁ =uncut chip thickness

   Correct Option: A

   t₁ = f cos θ
   = 0.2 × cos 60
   t₁ = 0.1 mm
   where t₁ =uncut chip thickness

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360. Under optimal conditions of the process the temperatures experienced by a copper work piece in fusion welding, brazing and soldering are such that

1. 1. T_welding > T_soldering > T_brazing

   
   
   

   2. T_soldering > T_welding > T_brazing

   
   
   

   3. T_brazing > T_welding > T_soldering

   
   
   

   4. T_welding > T_brazing > T_soldering

   
   
   

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1. View Hint View Answer Discuss in Forum

   Temp of Brazing > 450°C
   Temp of soldering < 450°C

   Correct Option: D

   Temp of Brazing > 450°C
   Temp of soldering < 450°C

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