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

Where $$\zeta =$$ chip reduction coefficient and $$\gamma =$$ orthogonal rake.
The main cutting force $$\left( {{P_z}} \right)$$ and cutting power assuming orthogonal machining are

2
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
3
GATE PI 2001
Subjective
+5
-0
Tool life in drilling steel using $$HSS$$ drill is expressed as $${T^{0.2}} = 9.8\,\,{D^{0.4}}\,\,/\,\,V\,{s^{0.5}}$$ where $$D$$ is the drill diameter (in $$mm$$), $$T$$ is the tool life (in minutes), $$V$$ is the cutting speed (in $$m/min$$) and $$s$$ is the feed ($$mm/rev$$). The feed is set at maximum possible value of $$0.4$$ $$mm/rev$$ for a given drill diameter of $$30mm.$$ The length of drilling is $$50mm.$$ The machine hour rate Rs $$60$$ and the cost of drill is Rs. $$400.$$

$$i)$$ For the given conditions, the tailor's exponent and constant are .............
$$ii)$$ The optimum cutting speed, $${V_{opt}},$$ neglecting the work-piece and tool changing times is

4
GATE PI 1995
+5
-1.5
In an orthogonal machining experiment using a tool having $${6^ \circ }.$$ Rake angle, the following data were collected. Cutting speed $$0.5$$ $$m/sec,$$ width of cut $$3$$ $$mm,$$ depth of cut $$1mn,$$ chip thickness $$1.5mm.$$ Assuming that shearing takes place under minimum energy condition,

The coefficient of friction between the chip tool interfaces will be

A
$$0.235$$
B
$$0.339$$
C
$$0.467$$
D
none
GATE PI Subjects
Engineering Mechanics
Strength of Materials
Theory of Machines
Engineering Mathematics
Machine Design
Fluid Mechanics
Heat Transfer
Thermodynamics
Casting
Joining of Materials
Metal Forming
Machine Tools and Machining
Metrology
Industrial Engineering
EXAM MAP
Joint Entrance Examination