Machine Tools Multiple Choice Questions on “Cutting Parameters of Drill”.
1. Which of the following are the cutting parameters used in drill?
a) cutting speed
b) feed
c) depth of cut
d) all of the mentioned
Answer: d
Clarification: All are the cutting parameters used in drill. Apart from these parameters, machining time, metal removal rate are also cutting parameters which are used in drill.
2. Which of the following is considered as the peripheral speed of the drill?
a) cutting speed
b) feed
c) depth of cut
d) none of the mentioned
Answer: a
Clarification: This is the definition of cutting speed. If you know the diameter of the drill and rpm of the drill, you can easily calculate the cutting speed.
3. Cutting speed generally express in_____
a) meter
b) meter/minute
c) meter*minute
d) none of the mentioned
Answer: b
Clarification: Cutting speed is simply a speed. So, its unit should be match with speed’s unit.
4. Formula for cutting speed is______
d=diameter of drill in mm, n=rpm of drill.
a) (d*n)/1000
b) (3.14*d*n)/1000
c) 3.14*d*n
d) none of the mentioned
Answer: b
Clarification: Though cutting speed is peripheral speed the distance covered through it must be equal to 3.14*d. N is rpm and 1000 is there as we are measuring it in mm.
5. The ______ of a drill is the distance the drill moves into the work at each revolution of the spindle.
a) depth of cut
b) feed
c) cutting speed
d) none of the mentioned
Answer: b
Clarification: This is the definition of feed. It is a distance/revolution.
6. The feed may be expressed in______
a) mm/revolution
b) mm*revolution
c) mm
d) none of the mentioned
Answer: a
Clarification: As per its definition, feed is the distance per revolution. So its unit should be match with this formula..
7. ______ is equal to half the diameter of the drill used.
a) feed
b) depth of cut
c) machining time
d) none of the mentioned
Answer: b
Clarification: This is the definition of depth of cut. Its simply a distance. Here one point is there, we always talk in terms of diameter in drill, never in terms of radius.
8. Depth of cut can be expressed in______
a) mm
b) mm/revolution
c) mm/minute
d) none of the mentioned
Answer: a
Clarification: It is simply a distance and so its unit should be match with distance’s unit.
9. The formula for depth of cut is______
d=diameter of the drill.
a) d/4
b) d/2
c) d
d) 2d
Answer: b
Clarification: Depth of cut is equal to half the diameter of the drill used. So if d is the diameter of drill then its formula must be equal to d/2..
10. If s2=feed per revolution, s1=feed per minute, n=rpm.
Which of the following is mathematically right?
a) s1=s2*n
b) s2=s1*n
c) s1*s2=n
d) none of the mentioned
Answer: a
Clarification: It can be solved by equating units both sides. Left side unit = feed/minute and Right side unit = feed / revolution * revolution/minute. So overall unit of right side = feed/minute. So, left side unit=right side unit.
11. Machining time is expressed in______
a) mm/minute
b) minute*minute
c) minute
d) none of the mentioned
Answer: c
Clarification: Machining time is simply a time. So its unit must be match with time’s unit.
12. If l=length of travel of the drill in mm, n=rpm of the drill, s= feed per revolution of the drill in mm. Then machining time can be given as_____
a) (l*n)/s
b) (l*s)/n
c) l/(n*s)
d) none of the mentioned
Answer: c
Clarification: L/(n*s)- This is the right formula for calculating machining time. Here l is expressed in mm, n is revolution/minute and s is expressed in mm. So by putting these all units in machining time’s formula we get the unit of the whole expression as minute. So our formula is right.
13. Metal removal rate can be given as_____
a) (mm*mm*mm)/min
b) (mm*mm*m)/revolution
c) mm/revolution
d) mm/minute
Answer: a
Clarification:
Metal removal rate = area of metal removed*rpm*feed/revolution and it equal to (3.14*d^2/4)*n*feed/revolution. From this, we can easily derive the expression.