GATE Mechanical Engineering Production Engg Set 1

1) Which of following is a solid state joining process?
A) Gas tungsten arc welding
B) Resistance spot welding
C) Friction welding
D) Submerged arc welding

ANS: B) Resistance spot welding; For all other welding processes the heat is added to have localized melting of material to achieve welding.

2) Which  type of motor is NOT used in axis or spindle drives of CNC machine tools?
A) Induction Motor
B) DC Servo Motor
C) Stepper Motor
D) Linear Servo Motor

ANS:  A) Induction Motor

3) In Electro-Discharge machining (EDM), if thermal conductivity of tool is high and specific heat of work piece is low, then tool wear rate and material removal rate are expected to be

A) High and High
B) Low and Low
C) High and Low
D) Low and High

ANS: D) Low and High; As thermal conductivity of tool is high it will conduct heat faster and the rise in temperature is less hence tool will erode Slowly; AND specific heat of work piece is low hence the heat required to increase temperature is less hence temperature will quickly increase and material will be easily removed.