Machine Tools Multiple Choice Questions on “Drilling Operation-2”.
1. A hole is being drilled with 1.5mm drill at a feed of 0.3 mm/revolution and rpm is 70. Calculate the metal removal rate in mm3/minute.
a) 18.5
b) 37
c) 74
d) 148
Answer: b
Clarification: Metal removal rate means the rate at which the metal is removed during the operation. From the formula, m= ( 3.14*d*d*f*n) / 4, we can easily calculate metal removal rate.
2. If drill is 2 mm, feed is 0.2 mm/revolution and metal removal rate is 50 mm^/minute. Then find out the value of rpm.
a) 318.4
b) 159.2
c) 79.6
d) 39.8
Answer: c
Clarification: From the formula, m= ( 3.14*d*d*f*n) / 4. Put all the given values with their respective units in the above equation and you will get the value of n as 79.6 .
3. If drill is 3.15 mm, metal removal rate is 55 mm3/minute and rpm is 170.Then find the value of feed in mm/revolution.
a) 0.02
b) 0.2
c) 0.04
d) 0.4
Answer: c
Clarification: During each revolution of spindle drill moves into the work. That distance is known as the feed.From the formula, m= ( 3.14*d*d*f*n) / 4.
4. If metal removal rate is 100 mm3/minute, rpm is 165 and feed is 0.01 mm/revolution. Then find the value of drill in mm.
a) 8.78
b) 4.41
c) 19.3
d) 77.8
Answer: a
Clarification: From the formula, m= ( 3.14*d*d*f*n) / 4. By substituting all the given values in the above equation, we can easily get the value of drill.
5. If diameter of the drill is 20 mm. Then find the value of depth of cut in mm.
a) 20
b) 10
c) 40
d) none of the mentioned
Answer: b
Clarification: Depth of cut=diameter/2. Depth of cut is equal to half the diameter of the drill used.
6. The diameter of the drill is 20 mm and rpm of drill is 10. Find the value of cutting speed in meter/minute.
a) 0.628
b) 628
c) 0.2
d) 200
Answer: a
Clarification: From the formula, cs = (3.14*d*n) /1000. Cutting speed in a drilling operation is taken as the peripheral speed of the drill.
7. Feed per minute (f1) is 10 and feed per revolution (f2) is 5. Then find the value of rpm.
a) 2
b) 4
c) 1
d) 0.5
Answer: a
Clarification: Rpm = f1/f2. Here, f1=10 and f2=5. We can easily get the value of rpm as 2.
8. If the depth of cut (d1) is 10mm, then find the value of the diameter of the drill (d2).
a) 5
b) 10
c) 20
d) none of the mentioned
Answer: c
Clarification: From the formula, d1= d2/2. Here d1=10. So, d2 sholud be 5.
9. If l=10mm, n=2 rpm and s=5 mm. Then find the value of t. t=machining time in minute, l=length of travel of the drill in mm, n= rpm of the drill and s=feed per revolution of the drill in mm.
a) 0.5
b) 1
c) 2
d) none of the mentioned
Answer: b
Clarification: From the formula, t= l / (n*s). By putting all the given values in the above equation, we can easily get the value of machining time as 1 minute.
10. If l=10mm, n=2 rpm and t=0.5 minute. Then find the value of s. t=machining time in minute, l=length of travel of the drill in mm, n= rpm of the drill and s=feed per revolution of the drill in mm.
a) 5
b) 10
c) 20
d) none of the mentioned
Answer: b
Clarification: From the formula, t= l / (n*s), we can calculate the feed per revolution. Feed per revolution may be defined as the axial distance moved by the drill into the work per revolution.
11. If l=20 mm, t=2 minute and s=5 mm. Then find the value of t. t=machining time in minute, l=length of travel of the drill in mm, n= rpm of the drill and s=feed per revolution of the drill in mm.
a) 0.5
b) 1
c) 2
d) none of the mentioned
Answer: c
Clarification: From the formula, t= l / (n*s). Substitute all the given values in the above equation and you can get the value of t as 2.
12. If d=1, n=1 and f=4. Then find the value of m. d= diameter of drill in mm, n=rpm, f=feed per revolution in mm and m=metal removal rate in mm3/minute.
a) 0.08
b) 1
c) 0.3184
d) none of the mentioned
Answer: c
Clarification: From the formula, m= (3.14*d*d*n*f) / 4. Here d,n and f are given. Substitute these values in above equation, you will easily get value of m as 0.3184 .
13. If d=2, n=4 and f=1. Then find the value of m. d= diameter of drill in mm, n=rpm, f=feed per revolution in mm and m=metal removal rate in mm3/minute.
a) 0.798
b) 1
c) 0.6369
d) none of the mentioned
Answer: a
Clarification: From the formula, m= (3.14*d*d*n*f) / 4. Substitute all tyhe given values in the above equation and you will easily get the value.
14. If cs=1 and n=40, then find the value of d. d=diameter of drill in mm, n=rpm and cs=cutting speed in mm/minute.
a) 7.96
b) 3.98
c) 15.92
d) none of the mentioned
Answer: a
Clarification: From the formula, cs = (3.14*d*n) /1000. Substitute all tyhe given values in the above equation and you will easily get the value of d.