The document discusses line balancing of a rear cushion production line. It identifies bottlenecks in the current process with cycle times over the takt time of 10.1 seconds. By adding additional labor to two bottleneck stations, manual sub-assembly processes, the cycle times are reduced. This increases the minimum and maximum output capacities of the line to meet and exceed current and future demand. Line balancing the process eliminates idle time and improves productivity.

1. SUBMITTED BY:
WAJAHAT ALI (BS IE, 4TH YEAR)
SHAH FAISAL (BS IE 3RD YEAR
ZAHOORULLAH (BS IE 3RD YEAR)
MOHAMMAD IMRAN (BS ME 3RD YEAR)
ADEEL KHALID (BS EE 3RD YEAR)
ASIF NAWAZ( BS ME 2ND YEAR)
LINE BALANCING OF REAR CUSHION
LINE

2. LINE BALANCING
Line balancing is the process of assigning tasks to
workstations, so that workstations have
approximately equal time requirements. We use line
balancing to
- minimize idle time
- balance bottlenecks

3. BOTTLENECK
Neck of the Bottle never has the same capacity as the base.
In product layouts, when we want to improve productivity, we
need to find and improve
critical operations, known as bottlenecks. Productivity
improvements to any non-bottleneck operation will NOT
improve productivity of the system.

4. THE CUSHION SHOP
The cushion shop has two lines operating:
Front Fork
Rear Cushion

5. CUSHION SHOP
Total demand per shift= 2850
Total time Available= 575 min –
Lunch Break= 30 min
Prayer Break= 20 min
Tea break= 20 min
5% tolerance time= 25.25
Total time for production=28785 sec= 480 min=8 hrs.

6. TAKT TIME
Takt time= Production time available/Total demand per shift
Takt time= 28785 sec/ 2850= 10.1 sec
Thus one unit of product should spent a maximum of 10.1
sec in the line for producing 28750 units of production
Total workstation are 11 and total man hours are 88.

7. REAR CUSHION
All processes and their
Cycle times in seconds

8. 3
Manual
Sub-
Assembly
4.1
Manual
Sub
assembly
Riveting
Oil seal
press
Rod
Guide
Press
Caulking Stacking
Sub-
assy
Sub-
assy
Sub -
assy
Metal
Tightenin
g
Metal
tightening
1
6
Inspectio
n
1
6.
3
8.
5
3.6
10.
18
7.9
Sub-assy 10.
5
6.0
18
2.3
5
3.1
1
6.0

9. TABLE FOR CPM DIAGRAM
Activity Alphabet Time
Manual Sub Assy A 4.1
Manual sub Assy B 3.6
Manual sub assy+riveting C 8.5
Oil filling +rod guide press D 10.18
Stacking E 7.9
Manual sub assy+Caulking F 10.5
Manual sub assy G 6.018
Manual sub assy H 3.11
Manual sub assy I 2.35
Metal tightening (2 machines) J 8.1
Inspection k 6.032

10. CPM DIAGRAM
A
B
C D E F
G
H
IJK

11. GRAPH
0
2
4
6
8
10
12
Manual Sub
assy
Manual Sub
assy
Manual sub
assy
+riveting
Oil filing+rod
guide press
Stacking Manual sub
assy +
caulking
Manual Sub
assy
Manual Sub
assy
Manual Sub
assy
Metal
Tighteining
Inspection
Time(sec)

12. THE BOTTLE NECK
From the above data, it has been found that two processes in
the line have appeared as Bottlenecks.
The Combined process of oil filling and rod guide press are
having the cycle times 10.18sec and 10.5 sec respectively.
Thus the minimum cycle time of the line comes out to be 10.5
sec which is more than the takt time i.e. 10.1 sec.

13. OUTPUT CAPACITY
Thus, maximum output capacity of line= Operating time /Min
cycle time
=28785/10.5= 2741 units
The lead time or flow time of the line is 78.49 sec, which is
also the maximum cycle time.
Minimum output capacity of line=
Operating time/ Max cycle time
= 28785/78.49= 367 units

14. OUTPUT CAPACITY
Thus the output capacity of current line can range from 367
units to 2741 units.
But the requirement of line is 2850 units and even the max
output capacity of line is not matching the demand and thus
the workers of rear cushion are compelled to work in their
lunch break and line’s speed is also increased at times.
Thus the rear cushion line needs to be balanced.

15. ISSUES IN THE LINE
At the combined process of oil filing+ rod guide process, the
processing time is 10.18 sec. The product has to wait 2.4 sec
on avg at the machine during the process.
At the combined process of Caulking+ Manual sub assy, the
processing time is 10.5 and the product has to wait 3.01 sec
on avg at the machine during the process.

16. LINE BALANCING
The bottleneck’s time should be reduced by increasing either
machines or manpower.
As both the bottlenecks include manual sub-assy, thus one
more person should be added to these process.
It will increase the workstations from 11 to 13.
The processing time of both bottlenecks would be reduced
by, one half.

17. TABLE FOR NEW CPM
DIAGRAM
Activity Alphabet Time
Manual sub assy A 4.1
Manual sub assy B 3.6
Manual Sub assy+ Riveting C 8.5
Oil Filling+ Rod guide press D 5.09
Stacking E 7.9
Manual sub assy+ caulking F 5.25
Manual sub assy G 6.018
Manual sub assy H 3.1
Manual sub assy I 2.35
Metal Tightening( 2 Machines) J 16.2
Inspection k 6.032

18. A
B
C D E F
G
H
IJK

19. GRAPH
0
1
2
3
4
5
6
7
8
9
Manual Sub
assy
Manual Sub
assy
Manual sub
assy +riveting
Oil filing+rod
guide press
Stacking Manual sub
assy +
caulking
Manual Sub
assy
Manual Sub
assy
Manual Sub
assy
Metal
Tighteining
Inspection
Time(sec)

20. PROCESS
IMPROVEMENT
Thus, the part waiting at the two bottlenecks processes is
nullified now.
The oil filling and rod guide process and caulking+ manual
sub assy have the processing times 5.09 and 5.25
respectively.
Now the min cycle time of the line is 8.5 sec which is the time
of riveting+ manual sub assy, which is less than the takt time
and thus the line is more balanced.

21. CAPACITY
CALCULATION
Now the maximum output capacity = Operating time/ min
cycle time= 28785/8.5=3386 units
The lead time or flow time of the line is 68.15sec, which is
also the maximum cycle time.
Minimum output capacity of line=
Operating time/ Max cycle time
= 28785/68.15= 422 units

22. ADVANTAGE
Thus by balancing the line in this way, the line has the
capacity to produce the parts in the range of 422 units to
3386 units and thus it has crossed the 2850 parts, daily
requirement.

23. FUTURE USEFULNESS
As currently the main frame line at the main plant is
producing 1130 bikes everyday and the requirement from
cushion shop is 2850.
But with the installation of new line at the mainframe
assembly, the requirement from cushion shop will rise.

24. CALCULATIONS
1130 bikes = 2850 cushions
1 bike= 2850/1130 cushions
1250 bikes= 2850/1130*1250
=3153 cushions.

25. CONCLUSION
But if, the line will be balanced in the suggested way, then the
maximum output capacity will be 3386 cushions and thus the
cushion shop will not have to worry a lot on increase in
demand from the mainframe assembly.

26. THANK YOU