1

GATE PI 2003

MCQ (Single Correct Answer)

+5

-1.5

The following data refers to an orthogonal machining of mild steel with a single point $$HSS$$ tool. Rake angle of tool $$ = {10^ \circ },$$ uncut chip thickness $$=0.3mm,$$ width of cut $$=2.0mm,$$ single plane shear angle $$ = {36^ \circ },$$ shear strength of mild steel $$=450$$ $$MPa,$$ using Merchants analysis

The coefficient of friction between the chip and tool will be

2

GATE PI 2003

MCQ (Single Correct Answer)

+5

-1.5

The following data refers to an orthogonal machining of mild steel with a single point $$HSS$$ tool. Rake angle of tool $$ = {10^ \circ },$$ uncut chip thickness $$=0.3mm,$$ width of cut $$=2.0mm,$$ single plane shear angle $$ = {36^ \circ },$$ shear strength of mild steel $$=450$$ $$MPa,$$ using Merchants analysis

The shear force in cutting will be

3

GATE PI 2002

Subjective

+5

-0

A cutting tool is designated in 'Orthogonal Rake System' as:
$$${0^ \circ } - {0^ \circ } - {6^ \circ } - {6^ \circ } - {25^ \circ } - {75^ \circ } - 0.8\,\,mm.$$$

The following data were given

$${S_0} = $$ feed $$=0.12$$ $$mm/rev$$

$$T=$$ depth of cut $$=2.0$$ $$mm$$

$${a_2} = $$ chip thickness $$=0.22$$ $$mm$$

$${V_f} = $$ chip velocity $$=52.6$$ $$m/min$$

$${\tau _s} = $$ dynamic yield shear strength $$=400$$ $$MPa$$

$${P_z} = $$ main cutting force $$ = {S_0}\,t\,{\tau _s}\left( {\zeta \,\sec y - \tan \gamma + 1} \right)$$

The following data were given

$${S_0} = $$ feed $$=0.12$$ $$mm/rev$$

$$T=$$ depth of cut $$=2.0$$ $$mm$$

$${a_2} = $$ chip thickness $$=0.22$$ $$mm$$

$${V_f} = $$ chip velocity $$=52.6$$ $$m/min$$

$${\tau _s} = $$ dynamic yield shear strength $$=400$$ $$MPa$$

$${P_z} = $$ main cutting force $$ = {S_0}\,t\,{\tau _s}\left( {\zeta \,\sec y - \tan \gamma + 1} \right)$$

Where $$\zeta = $$ chip reduction coefficient and $$\gamma = $$ orthogonal rake.

The main cutting force $$\left( {{P_z}} \right)$$ and cutting power assuming orthogonal machining are

4

GATE PI 2001

Subjective

+5

-0

In certain machining operation with a cutting speed of $$50$$ $$m/min,$$ tool life of $$45$$ minutes was observed, when the cutting speed was increased to $$100$$ $$m/min,$$ the tool life decreased to $$10$$ minutes. The cutting speed for maximum productivity, if tool change time is $$2$$ minutes is

Questions Asked from Metal Cutting (Marks 5)

Number in Brackets after Paper Indicates No. of Questions

GATE PI Subjects

Fluid Mechanics

Metrology

Theory of Machines

Engineering Mathematics

Machine Tools and Machining

Industrial Engineering

Engineering Mechanics

Strength of Materials

Thermodynamics

Machine Design

Casting

Joining of Materials

Metal Forming