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

LINE BALANCINGLine 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

BOTTLENECKNeck 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 improvecritical operations, known as bottlenecks. Productivity improvements to any non-bottleneck operation will NOT improve productivity of the system.

THE CUSHION SHOPThe cushion shop has two lines operating:

Front Fork Rear Cushion

CUSHION SHOPTotal demand per shift= 2850Total time Available= 575 min –Lunch Break= 30 minPrayer Break= 20 minTea break= 20 min5% tolerance time= 25.25Total time for production=28785 sec= 480 min=8 hrs.

TAKT TIMETakt time= Production time available/Total demand per shiftTakt time= 28785 sec/ 2850= 10.1 secThus 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.

REAR CUSHIONAll processes and their Cycle times in seconds

3Manual

Sub-Assembly4.1

Manual Sub

assembly

RivetingOil seal press

Rod Guide Press

Caulking Stacking

Sub-assy

Sub-assySub -assy

Metal Tightenin

g

Metal tightening1

6

Inspection

16.3

8.53.6

10.18

7.9Sub-assy 10.

5

6.018

2.35

3.11

6.02

TABLE FOR CPM DIAGRAMActivity Alphabet TimeManual 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

CPM DIAGRAM

A

B

C D E F

G

H

IJK

GRAPH

Manual

Sub as

sy

Manual

Sub as

sy

Manual

sub assy

+rive

ting

Oil filin

g+rod gu

ide pres

s

Stacki

ng

Manual

sub assy

+ cau

lking

Manual

Sub as

sy

Manual

Sub as

sy

Manual

Sub as

sy

Metal T

ightei

ning

Inspecti

on0

2

4

6

8

10

12

Time(sec)Series1

THE BOTTLE NECKFrom 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.

OUTPUT CAPACITYThus, maximum output capacity of line= Operating time /Min cycle time=28785/10.5= 2741 unitsThe 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

OUTPUT CAPACITYThus 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.

ISSUES IN THE LINEAt 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.

LINE BALANCINGThe 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.

TABLE FOR NEW CPM DIAGRAMActivity Alphabet TimeManual 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

A

B

C D E F

G

H

IJK

GRAPH

Manual

Sub as

sy

Manual

Sub as

sy

Manual

sub assy

+rive

ting

Oil filin

g+rod gu

ide pres

s

Stacki

ng

Manual

sub assy

+ cau

lking

Manual

Sub as

sy

Manual

Sub as

sy

Manual

Sub as

sy

Metal T

ightei

ning

Inspecti

on0

1

2

3

4

5

6

7

8

9

Time(sec)Series1

PROCESS IMPROVEMENTThus, 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.

CAPACITY CALCULATIONNow the maximum output capacity = Operating time/ min cycle time= 28785/8.5=3386 unitsThe 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

ADVANTAGEThus 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.

FUTURE USEFULNESSAs 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.

CALCULATIONS1130 bikes = 2850 cushions1 bike= 2850/1130 cushions1250 bikes= 2850/1130*1250=3153 cushions.

CONCLUSIONBut 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.

THANK YOU