1
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
2
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

3
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
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,

Area of shear plane is

A
$$3m{m^2}$$
B
$$4m{m^2}$$
C
$$5.2m{m^2}$$
D
$$7.1m{m^2}$$
GATE PI Subjects
Fluid Mechanics
Metrology
Theory of Machines
Machine Tools and Machining
Industrial Engineering
Engineering Mechanics
Thermodynamics
Machine Design
Casting
Joining of Materials
Metal Forming
EXAM MAP
Medical
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