ANSWER KEY
Academic Year:
2012-2013
Teacher: Eng. Rahma Najjar
Section: 12.52-12.55 AEE
Applied Engineering
(Mechanical)
Subject :
Module :
Name:
CNC Turning
Content
organization Language
Knowledge
End date for
submission
Date of
submission
Total
mark
Question 1:
Fill in the table with the coordinates of the points shown on the 2-D Cartesian coordinate
system shown below.
a
b
c
d
X
80
-60
-40
20
Y
60
40
-50
-20
Question 2:
Use the coordinates table below, to locate the points "a" through "d" on the 2-D Cartesian
coordinate system shown in the figure.
a
b
c
d
X
10
-80
40
-30
Y
20
-30
-70
50
Question 3:
Enter the Cartesian coordinates of the points "a" to "g" in the table.
Determine the corresponding diameter values of the X-coordinates.
a
b
c
d
X
0
40
40
80
Z
140
140
100
100
e
f
g
80
110
110
50
50
0
Question 4:
Write (T) for true and (F) for false following statements:
a) ( F )Moving on a turning machine on the X-axis from the center of the workpiece to the end
is a positive direction.
b) (F)Workpiece zero point is defined by the manufacturer and cannot be changed.
c) (F) In incremental dimensioning all measurements are taken from workpiece zero point.
d) (F) Moving on a turning machine towards the chuck on the Z-axis is positive direction.
Question 5:
Enter the Cartesian coordinates of the points "a" to "d" in the table.
Determine the corresponding diameter values of the X-coordinates.
a
b
c
d
X
40
40
70
70
Z
0
-60
-60
-85
Question 6:
Calculate the rotational speed, if a 15mm diameter workpiece made of Bronze is to be
machined (rough cut). the cutting tool is HSS.
𝑛=
𝐶𝑠
𝜋. 𝑑
Cs = 27 m/min (for Bronze rough cut, from the table)
d = 15mm
n=
15
1000
27
3.14 x 0.015
= 0.015 m
= 573.24 RPM
Question 7:
Calculate the rotational speed, if a 1.6 cm diameter workpiece made of cast iron is to be
machined (finish cut). The cutting tool is made of HSS
𝑛=
𝐶𝑠
𝜋. 𝑑
Cs = 24 m/min (for cast iron finish cut, from the table)
1.6
d = 1.6 cm
n=
100
= 0.016 m
24
3.14 x 0.016
= 477.71 RPM
Question 8:
Calculate the rotational speed required to rough turn a 40 mm diameter piece of
machine steel, the cutting tool is made of HSS.
𝑛=
𝐶𝑠
𝜋. 𝑑
Cs = 27 m/min (for Machine steel rough cut, from the table)
d = 40mm
n=
40
1000
27
3.14 x 0.04
= 0.04 m
= 214.97 RPM
Question 9:
If a work piece with the radius of 7mm is to be machined (rough cut) using a HSS cutting
tool, the workpiece has a rotational speed of 477.71 RPM.
1. Calculate the cutting speed.
2. What is the material of the workpiece?
𝑛=
𝐶𝑠
𝜋. 𝑑
Cs = unknown
r = 7mm
7
1000
= 0.007 m
diameter = 2 x r = 2 x 0.007 = 0.014 m
477.71 =
Cs
3.14 x 0.014
Cs = 477.71 x 3.14 x 0.014
Cs = 21 m/min
2. From the table
for the rough cut, and the cutting speed is 21 m/min
The material of the work piece is tool steel