## Mechanical Objective Question 1. The purpose of jigs and fixtures is to

a. Increased production rate

b. Increased machining accuracy

c. Facilitate interchangeable manufacturing

d. Enable employ less skilled operators

e. All of the above

All of the above

a. Hobbing

b. Casting

c. Punching

d. Milling

e. Broaching

Hobbing

## Mechanical Objective Question 3. Tool life of the cutting tool is most affected by

a. Cutting speed

b. Tool geometry

c. Cutting feed and depth

d. Microstructure of material being cut

e. Not using coolant and lubricant

Cutting speed

## Mechanical Objective Question 4. Metal in machining operation is removed by

a. Tearing chips

b. Distortion of metal

c. Shearing the metal across a zone

d. Cutting the metal across a zone

e. Pushing the metal with tool

Shearing the metal across a zone

## Mechanical Objective Question 5. A feeler gauge is used to check

b. Screw pitch

c. Surface roughness

d. Unsymmetrical shape

e. Thickness of clearance

Thickness of clearance

## Mechanical Objective Question 6. Interpolator in a CNC machine

B. coordinates axes movements

C. operates tool changer

D. commands canned cycle

Coordinates axes movements

Solution

As interpolator provides two functions:

1. It computes individual axis velocities to drive the tool along the programmed path
at given feed rate.
2. It generates intermediate coordinate positions along the programmed path.

## Mechanical Objective Question 7. For an Oldham coupling used between two shafts, which among the following statements are correct?

I. Torsional load is transferred along shaft axis.

II. A velocity ratio of 1:2 between shafts is obtained without using gears

III. Bending load is transferred transverse to shaft axis.

IV. Rotation is transferred along shaft axis.

A. I and II

B. I and IV

C. II and III

D. II and IV

I and IV

Solution

Oldham’s coupling is used to transmit power between two shafts having small angular misalignment. There is no bending load or reduction/increase of speed criterion. Hence only I and IV statements are correct.

## 8. In an arc welding process, welding speed is doubled. Assuming all other process parameters to be constant, the cross sectional area of the weld bead will

A. Increase by 25%

B. Increase by 50%

C. Reduce by 25%

D. Reduce by 50%

Reduce by 50%

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

(A) Twelding > Tsoldering > Tbrazing

(B) Tsoldering > Twelding > Tbrazing

(C) Tbrazing > Twelding > Tsoldering

(D) Twelding > Tbrazing > Tsoldering

Twelding > Tbrazing > Tsoldering

Solution

Under the optimal conditions temperature of different processes experienced by a copper work piece is given by Twelding > Tbrazing > Tsoldering

## 10. The part of a gating system which regulates the rate of pouring of molten metal is

(A) pouring basin

(B) runner

(C) choke

(D) ingate

Choke

Solution

Rate of poring molten metal is regulated by choke. As, the choke area is the minimum area of the gating system, which decide the gating will be pressurized and unpressurised [Or turbulence will occur or not]. Hence, choke is the part which regulates the rate of pouring.

## 11. The non-traditional machining process that essentially requires vacuum is

(A) electron beam machining

(D) electro discharge machining

Electron beam machining

Solution

In electron- beam machining, vacuum conditions are created/required for material removal, because electrons move efficiently in vacuum.

## 12. For flow of viscous fluid over a flat plate, if the fluid temperature is the same as the plate temperature, the thermal boundary layer is

(A) thinner than the velocity boundary layer

(B) thicker than the velocity boundary layer

(C) of the same thickness as the velocity boundary layer

(D) not formed at all