LINE BALANCING AND PERFORMANCE: A STUDY OF SELECTED ...

International Journal of Business and Management Review

Vol.3, No.8, pp.29-43, September 2015

___Published by European Centre for Research Training and Development UK (www.eajournals.org)

29 ISSN: 2052-6393(Print), ISSN: 2052-6407(Online)

LINE BALANCING AND PERFORMANCE: A STUDY OF SELECTED BREWERIES

IN ANAMBRA STATE, NIGERIA.

DR. Ikon, M.A and Nwankwo Catherine Nkechi

Department of Business Administration, Nnamdi Azikwe University, Awka, Nigeria

ABSTRACT: This study presents a heuristic procedure for improving performance in breweries

companies. A study of SABMiller (Intafact beverages) Ltd and Life Continental Plc, Anambra State

was adopted. The objective of this study is to balance the Production line and improve

performance of Hero beer and life beer. In this study, a new heuristic approach, the Rank

Positional Weight (RPW) method was used in designing the new production line. Data collected

for this research is based on primary information. The finding of the research shows that after line

balancing the cost of labour decreased by 1.3 per cent for Hero beer and 6.24 per cent for Life

beer and production line efficiency was found to have increased by 18.9 per cent for Hero beer

and 10 per cent for Life beer. The study recommends that companies should adopt the new

production line and empty inspection light should also be replaced with a new one for higher

performances.

KEYWORDS: Assembly Line Balancing (ALB), Balancing Techniques, Idle Time, Line

Efficiency, Task Time, Cycle Time and Bottleneck.

INTRODUCTION

Quality product and the capability to cope with customers’ demands are important aspects that

should be take in to account especially for small and medium industry. Management systems also

contribute to planning, controlling and measuring parameters related to the performance of the

sectors. Companies should realize that performance depends on how well the production line is in

term of output. Line Balancing means balancing the production line, or any assembly line. The

main objective of line balancing is to distribute the task evenly over the work station so that idle

time of man of machine can be minimized. Line balancing primary focus is on minimizing waste

related to over production, inventory, defects, transportation, motion, waiting. Assembly line exists

when we assemble or handle any device or product in a planned, sequential manner with two or

more operators performing tasks of repetitive work at established workstation (Milas, 1990). When

the products have many operations and the demand is high the process of balancing the line

becomes more difficult.

Statement of the Problems

The production line of Life lager and Hero lager was experiencing a technical problem of high idle

time, high labour cost and low line efficiency. This problem is as a result of imperfect allocation

of work along various workstations. This uneven work distribution indicated that the production

line of Life and Hero Lager Beer is unbalanced and inefficient, which will tend to reduce the

productivity of the company.

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Objectives of the Study

The overall objective of this paper is to improve performance of Hero and Life lager through line

balancing by minimizing both labour and idle times on the production line.

This paper intends to investigate and evaluate the line balancing problem in a production line of

Hero lager Beer and Life lager Beer .The paper seeks to:

i. To identify the idle time at each workstations and how it can be reduced.

ii. To assign tasks to workstations on the production lines in order to minimize number of

stations while satisfying cycle time, precedence, location, and station-type constraints.

REVIEW OF RELATED LITERATURE

Fleszar and Hindi (2003) present a work on enumerative heuristic and reduction methods for the

assembly line balancing problem. They presented a new heuristic algorithm and new reduction

techniques for the type 1 assembly line balancing problem. The new heuristic was based on the

Hoffmann heuristic and builds solutions from both sides of the precedence network to choose the

best. The reduction techniques aimed at augmenting precedence, conjoining tasks and increasing

operation times. A test was carried out on a well-known benchmark set of problem instances;

testify to the efficacy of the combined algorithm, in terms of both solution quality and optimality

verification, as well as to its computational efficiency.

Kilincci, (2011) worked on firing sequences backward algorithm for simple assembly line

balancing problem of type 1 and published their work on the same. The objective of simple

assembly line balancing problem type-1 (SALBP-1) was to minimize the number of workstations

on an assembly line for a given cycle time. A new heuristic algorithm was presented to solve the

problem. The presented algorithm makes an order of firing sequence of transitions from Petri net

model. Task was assigned to a workstation using this order and backward procedure

METHODOLOGY

The Ranked Positional Weight Heuristic was used in this study to design the proposed model for

Hero and Life lager beer production line. It was introduced by Helgeson and Birnie in 1961. In

this method, a Ranked Positional Weight value (RPW) is computed for each element. The RPW

takes into account both the Tek value and its position in the precedence diagram. Specially, RPWk

is calculated by summing Tek and all other times for elements that follow Tek in the arrow chain

of the precedence diagram.

Data Presentation and Analysis of Data

The work elements (or tasks) that make up the production line of Hero and Life lager beer are

Carrying pallets of hero and life lager beer from the store by the forklift to Carrying a pallet to the

store by forklift and it is represented by 1 to 12






This figure below shows the Precedence diagram of Hero and Life lager beer production

line:

Source: Author’s Design

2

3

4

6

7

8

9

10

5

11

12

13

16

17 18 19

15

20 21 22

14

1






In this study all times are in seconds. The time study top sheet was conducted on one pallet of 60cl

bottle of Hero and Life Lager Beer. One pallet contains 48 crates, which contains 12 bottles each.

Therefore, the total number of bottles in one pallet is 576 bottles. The time study top sheet reveals

the observed time, basic time, number of work elements, numbers of workstations, numbers of

workers, production volume, and production time. The existing production line of Hero Lager Beer

has 9 workstation, 22 work elements, 480 units production volume, 8 hours shift production time

14 numbers of workers on the production line, Life Lager Beer has 9 workstation, 22 work

elements, 400 units production volume, 12 hours shift production time 15 workers excluding one

supervisor on the production line. The production line comprises machines and workers. The

production line was monitored and operation of the line was analyzed in this research paper.( see

Appendix 1 and 2)

The production line of Hero lager beer is operational for 12 hours in seconds daily.

Cycle time = Available time per day in seconds

Desirable production output

= 3600 x 12 = 108

400

The production line of Life lager beer is operational for 12 hours in seconds daily.

Cycle time = Available time per day in seconds

Desirable production output

= 3600 x 8 = 60

480

Sample Calculation of the existing Production Line:

Idle time per day (Hero Beer) = Total idle time per station

One hour in seconds

= 697 = 0.2 hours

3600

Idle time per day (Life Beer) = Total idle time per station

One hour in seconds

= 249 = 0.07

3600






Line efficiency (Hero Beer) = Total Station time x 100%

Cycle time x no of workstation

= 275 x 100%

108 x 9

= 28.3%

Line efficiency ( Life Beer) = Total station time x 100%

Cycle time x no. of workstation

= 291 x 100%

60 x 9

= 53.9% or 54%

Balance Delay (BD) = Idle time of all workstations

Available working time for all stations

BD = (100 – LE)

= (100 -28.3) %

= 71.7%

Balance delay (BD) = Idle time of all workstations

= Available working time for all stations

BD = (100-LE)

= (100-54)%

= 46%

Balance Efficiency (Hero beer) = Theoretical minimum no. of workers

Actual no. of workers

Theoretical minimum no. of worker = ΣT

CT

Since, Total time, ΣT = W1T1 + W2T2 + W3T3 +…………+ WyTy = 3 x 29 + 1 x 16 + 2 x 28 +

2 x 22 + 1 x 108 + 2 x 24 + 1 x 16 + 1 x 17 + 2 x 15 = 885 seconds






Theoretical minimum no. of worker = 885 = 8.2

108

Balance Efficiency = 8.2 x 100%

15

= 55%

Balance Efficiency (Life beer) = Theoretical minimum no. of workers

Actual no. of workers

Theoretical minimum no. of worker = ΣT

CT

Since, Total time, ΣT = W1T1 + W2T2 + W3T3 +…………+ WyTy = 2 x 19+ 1 x 15+ 2 x 37 +

2 x 43 + 1 x 60 + 2 x 36 + 1 x 16 + 1 x 16 + 2 x 49 = 938 seconds

Theoretical minimum no. of worker = 938 = 16

60

Balance Efficiency = 16 x 100%

14

= 114%

Balancing of Hero and Life lager beer Production line as to minimize the number of work stations.

Originally, the production line of Hero and Life brewery has 9 workstations. In an attempt to

balance the line, the new number of workstations is calculated as follows:

Theoretical minimum = [Total work content (Time) per unit] [Desire number of units per day]

Total productive time available per day

Number of workstation

= 275 x 400 291 x 480

43200 28800

= 2.55 = 4.89

= 3 stations = 5 stations






To balance the production line Life and Hero lager beer, the tasks or elements would be assigned

to at least 3 workstations and 5 workstation respectively, following the precedence relationship of

the elements. The performance times assigned to each station cannot exceed 108 seconds cycle

time for Hero beer and 60 seconds cycle time for Life beer. To minimize idle time, the line for

Life and hero beer should now have 3 workstations and 10 workers, and 5 workstations and 12

workers instead of the previous 9 workstations, 15 and 14 workers respectively. (See Appendix3

and 4)

Table 1 Step1 using Ranked Positional Weights Method (RPW)

Work

element

RPW

(Hero beer)

Task

Time

Immediate

predecessor

RPW

(Life

beer)

Task time Immediate

predecessor

1 270 5 - 287 6 -

2 265 6 1 281 6 1

3 259 6 2 275 7 2

4 258 12 3,5 272 11 3,5

6 241 11 4 257 12 4

7 230 23 6 245 20 6

8 207 5 7 225 5 7

9 202 5 8 220 4 8

10 197 13 9 216 34 9

11 184 4 10 182 5 10

12 180 108 11 177 60 11

13 72 6 12 117 6 12

14 66 4 13 111 5 13

15 62 14 14 106 25 14

5 53 5 4 85 4 4

16 48 5 15,5 81 6 15,5

17 43 11 16 75 10 16

18 32 5 17 65 5 17

19 27 12 18 60 11 18

20 15 4 19 49 19 19

21 11 6 20 30 25 20

22 5 5 21 5 5 21

Source: Field Survey 2015






Table 2: Step 2 Work Element assigned to stations (Hero beer)

Workstation

Number of

workers

work

element

Task times

(sec)

Time per

station (sec)

Idle time Per

station (sec)

1 5 1

2

3

4

6

7

8

9

10

11

5

6

6

12

11

23

5

5

13

4

95

13

2 1 12 108 108 0

3 4 13

14

15

5

16

17

18

19

20

21

22

6

4

14

5

5

11

5

12

4

6

5

72 36

TOTAL 275 49







Table 3: Work Element assigned to stations (Life beer)

Workstation

Number of

workers

work

element

Task

times (sec)

Time per

station (sec)

Idle time Per

station (sec)

1 4 1

2

3

4

6

8

9

11

6

6

7

11

12

5

4

5

56 4

2 2 7

10

13

20

34

6

60 0

3 1 12 60 60 0

4 3 14

15

5

16

17

18

5

25

4

6

10

5

55 5

5 2 19

20

21

22

11

19

25

5

60 0

TOTAL 291 9


Sample Calculation of the New Production line ( Hero)

New idle time per day = Idle time cycle

One hour in seconds

= 49 = 0.14 hour

3600






Sample Calculation of the New Production line (Life beer)

New idle time per day = Idle time cycle

One hour in seconds

= 9 = 0.003 hour

3600

The new idle time per day is 0.14 hours compared to the former 0.2 hours

New Line efficiency (Hero beer) = Total station time x 100%


275 84.9%

108 x 9

New Balance Delay (BD) = (100 – LE)

= (100 – 84.9) %

= 15.1%

New Balance Efficiency = Theoretical minimum no. of workers x 100

Reduced no. of workers

= 8.2 x 100%

10

= 82%

The new idle time per day is 0.003 hours compared to the former 0.07 hours

New Line efficiency (Life beer) = Total station time x 100%


291 54%

60 x 9

New Balance Delay (BD) = (100 – LE)

= (100 – 54) %

= 46%






New Balance Efficiency = Theoretical minimum no. of workers x 100

Reduced no. of workers

= 16 x 100%

12

= 133.3%

Cost analysis and comparison

The table 7 below shows the cost analysis and comparison of Hero and Life lager beer

Production line respectively.

Hero Lager beer before line balancing

Station

number

No. of workers of the

existing production

line

01 3

02 1

03 2

04 2

05 1

06 2

07 1

08 1

09 2

TOTAL 15

Life Lager beer before line balancing


Station number


existing production

line

01 5

02 1

03 4

TOTAL 10

Station

number

No. of workers

of the existing

production line

01 4

02 2

03 1

04 3

05 2

TOTAL 12

Station

number


existing production

line

01 2

02 1

03 2

04 2

05 1

06 2

07 1

08 1

09 2

TOTAL 14

Hero Lager beer after line balancing

Life Lager beer after line balancing






Hero lager Beer and Life lager Beer Labour cost before Line Balancing

COMPANY DAILY LABOUR

COST

WEEKLY

LABOUR COST

MONTHLY

HERO LAGER

BEER

N 22,500.00 N 135,000.00 N 585,000.00

LIFE LAGER

BEER

N 19,600.00 N 117,600.00 N 509,600.00


Hero lager Beer and Life lager Beer Labour cost after Line Balancing

COMPANY DAILY LABOUR

COST

WEEKLY

LABOUR COST

MONTHLY

HERO LAGER

BEER

N 15,000.00 N 90,000.00 N 390,000.00

LIFE LAGER

BEER

N 16,800.00 N 100,800.00 N 436,800.00


The modify production line of Hero and Life, reveals that the company spent N 390,000.00 and N

436,800.00 per month for workers salary. By comparison, the new production line will improve

the productivity of the company by minimizing the labour cost in the production line. The

difference between the previous and the new production line of the labour cost per month is N

585,000 – N 390,000 = N 195,000 for Hero beer and N 509,600 – N 436,800 = N 72,800 for Life

beer. Therefore, it would be now easy to realize that, it would be more profitable to modify

production line, because it minimizes the labour cost per month of the production line by N

195,000 and N 72,800 respectively.

SUMMARY OF FINDINGS

Summary result of Hero and Life lager beer Production line:

S/n Sample Calculation Before line balancing After Line Balancing

1 Idle time per day( hours) Life

beer

0.07 0.003

2 Idle time per day( hours) Hero

beer

0.2 0.04

3 Line efficiency (%) Life beer 53.9 54

4 Line efficiency (%) Hero beer 28.3 84.9

5 Balance delay (%) Life beer 46 46

6 Balance delay (%) Hero beer 71.7 15.1

7 Balance efficiency (%) Life

beer

114 133






In summary, Life and Hero lager beer production line was balanced using rank positional Weight

(RPW). The idle and workstations was minimized to improve performance. A modified or new

production line of 3 workstations and 10 workers for Hero beer and 5 workstations and 12 workers

for Life beer was introduced instead of the previous 9 workstations and 15 workers and 9

workstations and 14 workers. It was discovered that the worker responsible for task 2 (i.e

depalletizing) could also take care of task 3. Also, the worker responsible for task 12 (i.e. filling

the bottle with beer and crowning) could also take care of task 13 and the worker responsible for

task 14, could also take care task 15 and finally, worker responsible for task 20, and could also

take care of task 21 and 22. This led to the reduction of workers from 15 to 10 workers. As a result

of this, the labour utilization or line efficiency increased from 28.3% to 84.9%, the idle time or

balance delay reduced from 17.7% to 15.1 %( Hero beer) and it remain the same 46% the balance

efficiency increased from 55% to 82 %.(Hero beer) and 54% to 54% (Life beer). Consequently,

daily labour hour idle reduced from 0.2 hours to 0.14 hours (Hero beer) and from 0.07 hour to

0.003 hour ( Life beer) and labour cost per month of Hero lager beer production line reduced

from ₦585,000.00 to ₦390,000.00. and that of Life lager beer reduced from ₦509,600 to ₦436,800

CONCLUSIONS

The cycle time used and the precedence diagrams used were based on the result of this study.

Normally, it took 12856 seconds for Intafact Beverages plant to produce one pallet of 60cl bottles

of Hero lager beer and 13935 seconds for life Continental Brewery plant to produce one pallet of

60cl bottles of Life lager beer. The production line runs 12 hours and 8 hours respectively and the

maximum daily output is 400 crates ( 4800 bottles) and 480crates ( 57600 bottles) . The production

line consists of 9 workstations and 15 workers excluding one supervisor in Hero Brewery and 9

workstations and 14 workers in Life Beverages. Before the production line was balance, the line

was not efficient. The line efficiency was 28.3%, the idle time was 17.7%, the balance efficiency

was 55% and the daily idle time was 0.2 hours. For Life beer and the line efficiency was 53.9%,

the idle time was 46%, the balance efficiency was 114% and the daily idle time was 0.07 hours for

Life beer. As a result of assembly line balancing, the line efficiency increased from 28.3% to

84.9%, the balance delay decreased from 17.7% to 15.1%, the balance efficiency increased from

53% to 82%, and the daily idle time reduced from 0.2 hours to 0.14 hours. Through the study of

the total costs, it had been shown that ₦195,000.00 could be saved every month. Although the

output remains the same but the number of workstations reduced from 9 to 3 workstations and the

number of workers reduced from 15 to 10 workers including one supervisor. Hence, the same

amount of product (Hero lager beer) is produced at less cost. The line efficiency still remain 53.9%,

the balance delay remain 46%, the balance efficiency still remain 114% to 133%, and the daily

idle time reduced from 0.07 hours to 0.003 hours. The study shown that, the total costs ₦195,000.00

for Hero beer and ₦72,800 for Life beer could be saved every month. Although the output remains

8 Balance efficiency (%) Hero

beer

55 82

9 Labour cost per month (N) Life

beer

509,600 436,800

10 Labour cost per month (N)

Hero beer

585,000 390,000






the same but the number of workstations reduced from 9 to 3 and 9 to 5 respectively and the

number of workers reduced from 15 to 10 and 14 to 12 excluding one supervisor. Hence, the same

amount of product (Life and Hero lager beer) is produced at less cost.

RECOMMENDATIONS

On Life and Hero lager beer production line, task 12 is the bottleneck operation. The companies

should create an efficient pathways linking pasturizer to the labeler. The empty inspection light

should also be replaced with a new one for higher performances. Lastly, the speed of the conveyor

belt should be increased for efficient drive.

SUGGESTIONS FOR FURTHER STUDY

This paper covered extent of activities on the production line, for further studies, work

measurement and assembly line balancing should be carried out on other sectors of the industries.

The other sectors include placement of orders of raw material before getting to the production line,

storage and before and after sale services. Also, other heuristic techniques for production line

balancing should also be used for further studies.

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Hamta, N., F., Ghomi, S.M.T., Jolai, F., & Bahalke, U. (2013). Bi-criteria assembly line balancing

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Journal of Researches in Engineering Mechanical and Mechanics Engineering Volume 12

Issue 3 Version 1.0 Publisher: Global Journals Inc. (USA)


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