The document discusses assembly line balancing. It provides examples of unbalanced toy train and chocolate assembly lines that have bottlenecks or low utilization. The key points of line balancing are to understand when a line is balanced or unbalanced, calculate takt time which is the maximum time a workpiece can spend at each station, and identify methods to balance lines such as adding workers, combining stations, or automating processes. The goal of line balancing is to eliminate waiting times and have a smooth flow of work from one station to the next.

1. Assembly Line Balancing

2. Objective of this line balancing training
• Understanding the concept of line balancing
• Know to identify when the line is balanced or unbalanced
• Know how to optimises the balancing line from unbalanced lines
• Know how to calculate the line balancing simplest formula
• Know when to apply line balancing or not

3. Why line balancing is important ?
• The exploded view shows the assembly of toy train.
• In the next slides, videos of the toy assembly are shown

4. Why line balancing is important ?

5. • In the next video, you can see one of the comedy shorts of chocolate assembly
line
Why line balancing is important ?

6. Why line balancing is important ?

7. Quiz 1
•Is the assembly line in both videos is balanced ? Why ?
Why line balancing is important ?

8. • The first video of toy train assembly, the line is not balanced because during at
the wheel assembly station, it takes longer time and causing bottleneck to the
subsequent stations
• The second video of chocolate assembly, the line is not balanced because the
output demand is high but it only have 2 workers to wrap the chocolates in the
assembly line
• The major downside is as you can see in above videos are more defects will
occurred in unbalanced assembly line
• Examples: Screws are not tightened enough / slanting positions on tyres causing
tyres to falloff
• Chocolates not wrapping correctly / not hygienic
Why line balancing is important ?

9. Time Concepts
• Most basic unit of time is seconds
Quiz 2:
• 1 minute : _____ seconds
• 1 hour : _____ minutes => _____ seconds
• 1 day : _____ hours => _____ minutes => _____ seconds
• Extra
• * 1 week : _____ days => _____ hours => _____minutes => _____seconds
• * 1 year :_____weeks => _____ days => _____hours => _____minutes =>
_____ seconds

10. Line Balancing Case Study
• A factory which are assembling Nokia 3310 phones are having difficulties of
meeting the production capacity issues. Here are the simplified exploded view of
the whole assembly processes and process flow
A: Install battery
pack to back cover
(Cycle time:
4 seconds)
B: Install PCB assembly to back
cover & fasten (X4) screws
(Cycle time: 16 seconds)
C: Install volume
button to back cover
(Cycle time:
8 seconds)
D: Apply glue to
keypad button
(Cycle time:
5 seconds)
E: Install keypad
button to back cover
(Cycle time:
2 seconds)
F: Weld speaker unit to PCB Assembly
(Cycle time:22 seconds)
G: Install front cover to
back cover
(Cycle time: 3 seconds)

11. Takt Time
• Cycle time is the time spent on one piece on one station
• Takt time is the maximum allowed time of a work piece spent on a station
• How to calculate Takt time
• Takt time = (Forecast Demands)
(Available Time)

12. • Based on the phone assembly example just now, calculate the takt time of the
phone assembly
• Example 1
• The work order requires 100,000 phones to be ready in 14 days. What is takt
time required ?
• 100,000 units/week ÷ 14 days= 7,142.86 units/day ≈ 7,143 units/day
• 7,143 units/day ÷ 2 shifts = 3571.5 units/shift ≈ 3572 units/shift
• 3572 units/shift ÷ 10 hours/shift = 357.2 units/hour ≈ 358 units/hour
• 358 units/hour ÷ 60 minutes/hour = 5.97 units/minutes ≈ 6 units/minute(1/6)*60
seconds= 10 seconds
Takt Time

13. Takt Time
• The goal of this line balancing example is to reduce cycle time to equal or
lower than the takt time

14. Line Balancing Case Study
Quiz 1
•Bottleneck = The stations which consumes the most cycle time
•Identify which stations are the bottleneck in the whole assembly process ? Station
_____
• Low utilization = The station which had the lowest cycle time and the preceding
stations have the longest cycle time
•Identify which stations are having low utilization in the whole assembly process ?
•Station _____ and station _____
•Therefore the line above is considered unbalanced because
(i) _______________________________
(ii) _______________________________

15. Line Balancing Case Study
• Therefore based on the assembly lines , there are a few methods to balance the
assembly lines
(i)Assign one or more people in the stations that require more cycle time: Station
_____________________________
(ii)Combine two process stations into single stations if the 2 stations have low
utilizations: Station ___________________
(iii)Automate the process to shorten cycle time :
Station _____________________________
(iv)Select and train the correct operator
(v)Cutting down on transport/movement by moving the essential stuffs within the
hand reaches (See next slides)

17. Takt Time
• How to calculate Takt time (Refresher)
Example 2
• Customer order 100,000 units of 828 mini pens to be ready in 1 week time.
Calculate the cycle time (per minute) needed
• 100,000 units/week ÷ 6 days(why?) = 16666.6667 units/day ≈ 16667 units/day
• 16667 units/day ÷ 2 shifts = 8333.33 units/shift ≈ 8334 units/shift
• 8334 units/shift ÷ 10 hours/shift = 833.4 units/hour ≈ 834 units/hour
• 834 units/hour ÷ 60 minutes/hour = 13.9 units/minutes ≈ 14 units/minute(what?)
• (1/14)*60 seconds= 4.29 seconds(what?)

18. Takt Time
Quiz 3
•Customer order 650,000 units of 828 mini pens to be ready in 3 week time.
Calculate the takt time (per minute) needed

19. Cycle Time
• Remember this ?
A: Install battery
pack to back cover
(Cycle time:
4 seconds)
B: Install PCB assembly to back
cover & fasten (X4) screws
(Cycle time: 16 seconds)
C: Install volume
button to back cover
(Cycle time:
8 seconds)
D: Apply glue to
keypad button
(Cycle time:
5 seconds)
E: Install keypad
button to back cover
(Cycle time:
2 seconds)
F: Weld speaker unit to PCB Assembly
(Cycle time:22 seconds)
G: Install front cover to
back cover
(Cycle time: 3 seconds)

20. Cycle Time
Process Time To Produce 1
Pcs (seconds)
What is our target ? (In 1 Hour)
A
B
C
D
E
F
G
Based on the slide before, fill in the time taken to produce 1 pieces and our target
of productions in 1 hour
Hints: Recall how many seconds are there in 1 hour

21. Cycle Time
Process Time To Produce 1
Pcs (seconds)
What is our target ? (In 1 Hour)
A 4 3600/4 = 900
B 16 3600/16 = 225
C 8 3600/8 = 450
D 5 3600/5 = 720
E 2 3600 /2 = 1800
F 22 3600/22 = 163
G 3 3600/3 = 1200
Here is the answer …
What is your interpretations of the figure ?

22. • However , do you see any issues?
• The target output between each stations can vary as much as 10 times especially
station E, F and G
• From station E to F is overproductions/oversupply
• From F to G is underproduction/starvation
Cycle Time
STATION
E
STATION
F
STATION
F
STATION
G

23. • Cycle time is determined by
(a) No. of workstations in the assembly line
(b) Workstation with the slowest cycle time
Cycle Time

24. Real exercises
• A customer have ordered 50k of pens to be shipped in 8 days.
• Calculate takt time
• Based on the infos given, calculate the cycle times

25. Conclusions
• Balanced assembly line ultimate target is to reduce to bare minimum / eliminate
waiting time
• Balancing assembly line in some cases will reduce the defects greatly compared
to unbalanced line balancing
• Target of line balancing is so that output of one workstations become the input
of the next workstations or known as “One Piece Flow”
• It is NEVER THE INTENTION to use line balancing to:
• - Meet the sales commitments
• - Minimises costs
• - Maximises operating efficiency