Lecture Notes for Civil Engineering Students.

1. CEME 352 ENGINEERING MANAGEMENT II
(LECTURE SERIES 8)
1
TOPIC: Project Costs & Valuation(s)-Line Balancing
Lecturer: Mr. Herod Malo
School of Engineering (Civil)
Papua New Guinea University of Technology
Reference:
Malo, H. “Project Costs & Valuations- Line Balancing”. Papua New Guinea
University of Technology, August 07, 2020 Lecture.
BEng (Civil) Semester II
© 2020 School of Engineering (Civil), Papua New Guinea University of Technology

2. Determine:
1. Make precedence diagram and
determine the Cycle Time (CT)
2. Using the longest operation time
heuristic determine the most efficient
production time
3. Determine the line efficiency and the
Smoothing Index (SI)
Line of Balance in Practice
Process Process Time
Seconds
Predecessor
A 90
B 30
C 70 A
D 10 A,B
E 30 C,D
F 60 D
G 50 E
H 50 E,F,G
Sum 390
Example
A company wants to produce 360 parts in a 10 hours/shift in a day.
The production itself has 8 different process. With such
information:

3. LB-Step by step process
1
Draw Precedence diagram
2
Calculate Cycle Time (CT)
3
Determine number of work
station
4
Make line of Balance
5
Determine the efficiency-
Smoothing Index (SI)

4. Draw precedence diagram
1
Process Process Time
seconds
Predecessor
A 90
B 30
C 70 A
D 10 A,B
E 30 C,D
F 60 D
G 50 E
H 50 E,F,G
Sum 390
A
B
C
D
E
G
F
H

5. Calculate Cycle Time (CT)
2
Example
A company wants to produce 360 parts in a 10
hours/shift in a day. The production itself has 8
different process. With such information:
Known:
Number of products: 360 units
Production time per day: 10 hours/ (10 hours x 60 mins x 60
secs =36000 secs)
Production time per day
Number of product
CT=
36,000
360
CT=
100 seconds
CT=

6. Determine the number of
workstation(NT)
3
Sum of Process Time (T)
Cycle Time (CT)
NT=
390
100 seconds
NT=
3. 9 Work stations
NT=
Process Process Time
seconds
Predecessor
A 90
B 30
C 70 A
D 10 A,B
E 30 C,D
F 60 D
G 50 E
H 50 E,F,G
Sum 390
4 Work stations rounded
NT=
100 seconds
CT=

7. 4
Proc
ess
Process
Time
seconds
Predece
ssor
A 90
B 30
C 70 A
D 10 A,B
E 30 C,D
F 60 D
G 50 E
H 50 E,F,G
Sum 390
A
B
C
D
E
G
F
H
Work
station
Time Remaining
(seconds)
Eligible Will fit Assign
(Task time)
Remaining
time
Idle
Time
1 100 A,B A,B A (90) 10 (=100-90)
10 B,C None 10 10
2 100 B,C B,C C (70) 30 (=100-70)
30 B,D B,D B (30) 0 (=30-30)
3 100 D,E D,E E (30) 70 (=100-70)
70 D,F D,F F (60) 10 (=70-60)
10 D,G D D (10) 0 (=10-10)
4 100 G,H G,H G (50) 50 (=100-50)
50 H H H (50) 0 (=50-50)
Rule: Assign task according to the greatest number of following tasks. In case of a
tie, use the tie breaker of assigning the task with the longest processing time first.
Workstation
1 (A)
Workstation
2 (C,B)
Workstation
3 (E,F,D)
Workstation
4 (G,H)
Line Balancing
Longest Operation Time heuristic

8. Calculate the Idle time and
efficiency
5
10
4 x 100
Idle Time=
10
400
Idle Time=
0.025
Idle Time=
Efficiency % = 100 x (1-0.025)
Efficiency % =97.5%