Question

In electro discharge machining ,if the thermal conductivity of tool is high

Answer 1

Which of the following is/are used as low wearing tool material(s) in electric discharge machining?   

(a) Copper and brass

(b) Aluminium and graphite

(c) Silver tungsten and copper tungsten

(d) Cast iron

Answer




2. The mechanism of material removal in EDM process is               

(a) Melting and Evaporation

(b) Melting and Corrosion

(c) Erosion and Cavitation

(d) Cavitation and Evaporation

Answer

3. As tool and work are not in contact in EDM process    

(a) no relative motion occurs between them

(b) no water of tool occurs

(c) no power is consumed during metal cutting

(d) no force between tool and work occurs

Answer

4. In Electro-Discharge Machining (EDM), the tool is made of   

(a) Copper

(b) High Speed Steel

(c) Cast Iron

(d) Plain Carbon Steel

Answer

5. Assertion (A): In ECM, the shape of the cavity is the .mirror image of the tool, but unlike EDM, the tool wear in ECM is less. 
Reason (R): The tool in ECM is a cathode. 

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R arc true but R is NOT the correct explanation of A

(c) A is true but R is false

(d) A is false but R is true

Answer

6. In electro discharge machining (EDM), if the thermal conductivity of tool is high and the specific heat of work piece is low, then the tool wear rate and material removal rate are expected to be respectively   

(a) high and high

(b) low and low

(c) high and low

(d) low and high