# Theory of Metal Cutting | Production Engineering | GATE MCQs (solved)

## GATE ME Questions on Metal cutting (Production Engineering)

Question #1

Using the Taylor’s tool life equation with exponent n=0.5, if the cutting speed is reduced by 50%, the ratio of new tool life to original tool life is
(A) 4
(B) 2
(C) 1
(D) 0.5

[GATE 2018 Set 1, 1 mark]

Question #2

An orthogonal cutting operation is being carried out in which uncut thickness is 0.010 mm, cutting speed is 130 m/min, rake angle is 15 and width of cut is 6 mm. It is observed that the chip thickness is 0.015 mm, the cutting force is 60 N and the thrust force is 25 N. The ratio of friction energy to total energy is __________
(correct to two decimal places)

[GATE 2018 Set 1, 2 marks]

Question #3

Two cutting tools with tool life equations given below are being compared:
Tool 1: $VT^{0.1} =150$
Tool 2: $VT^{0.3} =300$
Where V is cutting speed in m/minute and T is tool life in minutes. The breakeven cutting speed beyond which Tool 2 will have a higher tool life is ________ m/minute.

[GATE 2017 Set 1, 2 marks]

Question #4

During the turning of a 20mm-diameter steel bar at a spindle speed of 400 rpm, a tool life of 20 minute is obtained. When the same bar is turned at 200 rpm, the tool life becomes 60 minute. Assume that Taylor‟s tool life equation is valid. When the bar is turned at 300 rpm, the tool life (in minute) is approximately.

(A) 25
(B) 32
(C) 40
(D) 50

[GATE 2017 Set 2, 2 marks]

Question #5

In an orthogonal machining with a tool of 9° orthogonal rake angle, the uncut chip thickness is 0.2mm. The chip thickness fluctuates between 0.25 mm and 0.4 mm. The ratio of the maximum shear angle to the minimum shear angle during machining is ___________

[GATE 2017 Set 2, 2 marks]

Question #6

In an orthogonal cutting process the tool used has rake angle of zero degree. The measured cutting force and thrust force are 500 N and 250 N, respectively. The coefficient of friction between the tool and the chip is _________

[GATE 2016 Set 1, 1 mark]

Question #7

The tool life equation for HSS tool is $VT^{0.4}f^{0.7}d^{0.4}=Constant$. The tool life (T) of 30 min is obtained using the following cutting conditions:
V = 45 m/min, f = 0.35 mm, d = 2.0 mm.If speed (V), feed (f) and depth of cut (d) are increased individually by 25%, the tool life (in min) is

(A) 0.15

(B) 1.06

(C) 22. 50

(D) 30.0

[GATE 2016 Set 1, 2 marks]

Question #8

For a certain job, the cost of metal cutting is Rs. 18 C/V and the cost of tooling is Rs. 270 C/(TV), where C is a constant, V is the cutting speed in m/min and T is the tool life in minutes. The Taylor’s tool life equation is $VT^{0.25}=150$. The cutting speed (in m/min) for the minimum total cost is _______

[GATE 2016 Set 2, 2 marks]

Question #9

For an orthogonal cu9tting operation, tool material is HSS, rake angle is 22 o, chip thickness is 0.8 mm, speed is 48 m/min and feed is 0.4 mm/rev. The shear plane angle (in degrees) is

(A) 19.24

(B) 29.70

(C) 56.00

(D) 68.75

[GATE 2016 Set 3, 2 marks]

Question #10

In a single point turning operation with cemented carbide tool and steel work piece, it is found that the Taylor’s exponent is 0.25. If the cutting speed is reduced by 50% then the tool life changes by ______ times

[GATE 2016 Set 3, 2 marks]

Question #11

Under certain cutting conditions, doubling the cutting speed reduces the tool life to (1/16)th of the original. Taylor’s tool life index (n) for this tool-workpiece combination will be _______

[GATE 2015 Set 1, 1 mark]

Question #12

An orthogonal turning operation is carried out under the following conditions: rake angle = 5º; spindle rotational speed = 400 rpm; axial feed = 0.4 m/min and radial depth of cut = 5 mm. The chip thickness, tc, is found to be 3 mm. The shear angle (in degrees) in this turning process is_____

[GATE 2015 Set 1, 2 marks]

Question #13

A single point cutting tool with 0° rake angle is used in an orthogonal machining process. At a cutting speed of 180 m/min, the thrust force is 490 N. If the coefficient of friction between the tool and the chip is 0.7, then the power consumption (in kW) for the machining operation is ________

[GATE 2015 Set 2, 2 marks]

Question #14

Orthogonal turning of a mild steel tube with a tool of rake angle 10° is carried out at a feed of 0.14 mm/rev. If the thickness of the chip produced is 0.28 mm, the values of shear angle and shear strain will be respectively
(A) 28°20′ and 2.19
(B) 22°20′ and 3.53
(C) 24°30′ and 4.19
(D) 37°20′ and 5.19

[GATE 2015 Set 3, 2 marks]

Practice other topics from Production Engineering:

Machining

Casting

Welding