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Proceedings of the 2016 International Conference on Industrial Engineering and Operations Management Kuala Lumpur, Malaysia, March 8-10, 2016

Motion and Time Study: Measurement of Workstation for Piston Assembly Line Considering Anthropometric for

Indonesian People T.Yuri M. Zagloel

Department of Industrial Engineering Universitas Indonesia

Depok , 16424, Indonesia [email protected]

Inaki Maulida Hakim Department of Industrial Engineering

Universitas Indonesia Depok , 16424, Indonesia

[email protected], [email protected]

Rieke Adyartie Department of Industrial Engineering

Universitas Indonesia Depok , 16424, Indonesia [email protected]

Abstract - This research was conducted on an artificial piston assembly line of Toyota cars on a laboratory scale. The piston assembly line consists of four workstations where each workstation has tasks carried out by the workers respectively. Fatigue issue was known to occur frequently – causing problems for operators of those workstations – due to the design of the work table which did not comply with anthropometric measurements of the operators. This matter caused longer cycle time and decreased productivity. In order to tackle the issue, this research focused on analyzing workspace factors needed to produce design and to conduct simulation to create an assembly line with reference to anthropometric measurements of Indonesian people. Thorough anthropometric data collecting and analysis were required to design the assembly line. The collected data were tested using adequacy test, homogeneity test, and normality test, where later on was used as reference in proposing the design. Anthropometric data were obtained from 12 operators, male and female, which represent Indonesian anthropometric measurements. The result of normality test shows that the data were normal, while the homogeneity test shows similarities in each dataset, which should let the data pass the qualification. Yet, adequacy test for male operators indicates that there was not enough men, so additional measuring elements were added to make the test samples to be enough. Using the required data, this study proposes anthropometric measurements needed to design workstation fitted for Indonesians which should be able to be implemented on a larger scale.

Keywords— piston workstation, fatigue, anthropometric measurement

I. INTRODUCTION

The development of manufacturing industry in Indonesia is so fast, as seen from the increase in sales of products from manufacturing industry. Such growth cannot be achieved without improvements in working facilities and great skills of the operators to support the increase in productivity. Workstation is one component that must be considered with respect to the progressive increase in labor productivity. Working conditions that do not pay attention to comfort, safety, and satisfaction will certainly affect the productivity of human labor in a bad way. Manufacturing industry nowadays needs workstation that takes into account the interaction between human, machine, and the physical environment of work to ensure comfort, safety, and satisfaction for workers. For this purpose, ergonomic approach is needed for the focus of ergonomics is human beings and their interaction with the products and tools.

This study discusses workstations design on piston assembly line on a laboratory scale, where the focus of this research is the anthropometric aspects of the workstation and the posture of operator during work. Anthropometrics is the study of the human body dimensions (size, weight, volume, etc.) and the specific characteristics of the body such as grip range.

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Anthropometric measurements may vary for each different region, as those measurements correspond to the physical condition of the human majority in the region or the country.

Anthropometric measurements are used for various purposes, such as the design of workstations, working facilities, and the design of products in order to obtain the appropriate and feasible measures with respect to the dimensions of human limbs that will use it. Anthropometric measurements are often used to get a good human-centered design of workstations in order to increase work productivity. If workers find that doing their tasks easily makes them tired, or the distance to get a workpiece on a workstation is too far, or the comfort and safety are not guaranteed, there may be a big mismatch between the workers and the work environment. This situation is due to the design of workstations which usually do not pay attention to anthropometric measurements of the workers who work on the workstations.

The ideal workstation should be adjusted to the role and the basic functions of the system components which involve human, machine, and the physical environment of work. The role of humans in this regard will be based on the capabilities and limitations related to aspects of observation, cognitive, physical, or psychological. The role of machine is to support certain work activities carried out by workers. While the physical work environment has the role to keep workers feel comfortable so that they will not be distressed by their workload. Designing workstation with respect to anthropometrics should help in adjusting roles and functions of the three components.

II. METHODOLOGY

In this study, the data of anthropometric measurements were collected using samples from 12 operators – 8 men and 4 women. The data consist of 10 anthropometric measurements associated with the posture and activities performed during work. The samples were randomly chosen to represent different body dimensions for Indonesians so that the data should cover all measurements range of Indonesians. Stages of research following the steps of data collecting are illustrated in Fig. 1 below.

Fig. 1 Data collecting and processing steps

III. RESULT

All anthropometrics data in this research are measured in centimeters. Table 1 shows the anthropometric measurements results. After conducting measurements, data were tested using normality test, homogeneity test, and adequacy test to ensure that the collected data are valid and can be used on a larger scale. In addition, data percentiles were also calculated to determine extreme value which should apply for a certain percentage of people who have measurements beyond or below normal people.

A. Normality TestNormality test is commonly used to test whether the acquired data are distributed normally so that the data can be used in

statistiparametrics The method used in testing the normality of anthropometrics data here were Shapiro-Wilk. Calculations were done using SPSS software. The decision in this normality test is based on statements below.

• If sig. (significance) or probability value < 0.05, then the data are not distributed normally• If sig. (significance) or probability value > 0.05, then the data are distributed normally

The results of normality test are shown in Table 2. Test results show that three anthropometric data of men were not qualified: eye height, stature height – head height, and elbow height.

Measuring body dimensions

Testing data uniformity

Testing data adequacy

Calculating mean and standard deviation

Calculating percentiles for extreme data

Creating anthropometrics table based on calculation



B. Homogeneity Test

Homogeneity test is used to ensure that data within the dataset have certain similarities to each other. In this study, homogeneity test determine whether a dataset is qualified to be used as valid anthropometric measurements. The test results for homogeneity test of anthropometric measurements data set show no meaningful variety that could make the data invalid. Tests were executed using SPSS software. C. Adequacy Test

Adequacy test objectively tests whether the collected data are adequate or not. If data are not adequate, additional data will be needed in order to make the data valid. The formula for adequacy test is shown below.

(1) If N’ < N, then the data for the calculated category is adequate, and if N’ > N, then the data is not adequate yet. In this

research, data are assumed to be adequate although the test results show that they are not adequate yet. The test results are shown in Table 3 and Table 4.

TABLE I

DATA SAMPLES OF ANTHROPOMETRIC MEASUREMENTS FOR MALE AND FEMALE INDONESIAN

Equipment Measurement Female Male

1 2 3 4 Average 5 6 7 8 9 10 11 12 Average

Anthropometer Type-I (Large)

Elbow-fingertip length 24.5 25 25.6 28.6 25.925 26.5 27.3 28 28 28.6 30 30 31 28.675

Anthropometer Type-II (Small)

Chest depth 17.1 14.1 13.9 20 16.275 19.8 22.5 17.7 19 18 23 18 15.3 191.625

Tape measure/ruler

Eye height 135 148 146 156 146.25 158 157 160 156 163 161 161 174 161.25

Stature 149 161 157 170 159.25 174 170 175 166 176 172 173 187 174.125

Shoulder height 120 133 126 143 130.5 142 138 141 136 146 140 141 152 142

Span 147 164 159 175 161.25 175 173 180 169 186 181 178 190 179

Stature height - head height

127 136 138 150 137.75 149 150 151 145 152 149 150 165 151.375

Elbow height 94 98 95 105 98 104 100 102 102 110 101 103 113 104.375

Forward grip reach 63.2 75 67 80 71.3 85 79 75 79 88 81 87 91 83.125

TABLE II NORMALITY TEST RESULTS OF ANTHROPOMETRIC MEASUREMENTS

Measurement Female Male

Mean SD AD P-Value Normality Mean SD AD P-Value Normality

Elbow-fingertip length

28.675 1.533 0.253 0.626 Normal 25.925 1.839 0.420 0.150 Normal

Chest depth 191.625 2.565 0.339 0.398 Normal 16.275 2.883 0.319 0.318 Normal

Eye height 161.250 5.651 0.697 0.041 Abnormal 146.250 8.655 0.222 0.596 Normal

Stature 174.125 6.081 0.472 0.173 Normal 159.250 8.732 0.167 0.831 Normal

Shoulder height

142.000 4.986 0.410 0.257 Normal 130.500 9.883 0.175 0.798 Normal

Span 179.000 6.845 0.131 0.966 Normal 161.250 11.615 0.170 0.820 Normal


151.375 5.878 1.007 0.006 Abnormal 137.750 9.465 0.225 0.585 Normal

Elbow height 104.375 4.627 0.692 0.043

Abnormal 98.000 4.967 0.340 0.274 Normal

Forward grip reach

83.125 5.463 0.226 0.727 Normal 71.300 7.604 0.210 0.647 Normal



D. Anthropometric Data Percentile The percentiles for male and female anthropometric measurements are calculated separately to obtain the extreme value for each male and female measurements. Number of samples for female measurements is 4, and therefore P5 = (5(4+1))/100 = 0.25 while P95 =(95(4+1)/100 = 4.75. It can be concluded that to calculate 5th percentile for female we use the first data and to calculate the 95th percentile we use the fourth data. The value for the 5th and 95th can be obtained from the following equation.

Q5 = X1 + 0.55 * X1 (2)

TABLE III ADEQUACY TEST RESULTS FOR FEMALE INDONESIAN ANTHROPOMETRIC MEASUREMENTS

N=4 Female

∑xi (∑xi)2 ∑xi2 N' Description


103.70 10753.69 2698.57 4.110 Adequate

Chest depth

65.10 4238.01 1084.43 25.622 Adequate

Eye height 585 342225 85781 2.861 Inadequate

Stature 637 405769 101671 2.456 Inadequate

Shoulder height

522 272484 68414 4.684 Adequate

Span 645 416025 104411 4.238 Adequate

Stature height -

head height 551 303601 76169 3.856 Inadequate

Elbow height

392 153664 38490 2.098 Adequate

Forward grip reach

285.20 81339.04 20508.24 9.290 Adequate

Q95 = X4 + 0.45 * X4 (3) 8 samples were used to collect anthropometric data of male Indonesian. Therefore P5 = (5(8+1))/100 = 0.45 and P95 = (95(8+1))/100 = 8.55. It can be concluded that to calculate 5th percentile for female we use the first data and to calculate the 95th

percentile we use the eighth data. The value for the 5th and 95th can be obtained from the following equation.

Q5 = X1 + 0.55 * X1 (4) Q95 = X8 + 0.55 * X1 (5)

The calculation results for data percentile are shown in Table 5.

TABLE IV ADEQUACY TEST RESULTS FOR MALE INDONESIAN ANTHROPOMETRIC MEASUREMENTS

N=8 Male



229.40 52624.36 6594.56 2.723 Adequate

Chest depth

153.30 23500.89 2893.67 17.085 Inadequate

Stature 1393 1940449 242815 1.162 Adequate

Shoulder height

1136 1290496 161486 1.175 Adequate



N=8 Male


Span 1432 2050624 256656 1.393 Adequate

Stature height -

head height 1211 1466521 183557 1.437 Adequate

Elbow height

835 697225 87303 1.873 Adequate

Forward grip reach

665 442225 55487 4.115 Adequate

TABLE V

ADEQUACY TEST RESULTS FOR MALE INDONESIAN ANTHROPOMETRIC MEASUREMENTS

Measurements Female Male

Q5 Q50 Q95 Q5 Q50 Q95


24,57 26,30 28,15 26,78 28,30 30,65

Chest depth 13,93 18,50 19,56 16,14 18,60 22,85

Eye height 136,65 152,51 154,80 161,67 177,21 183,15

Stature 150,2 163,50 168,65 167,40 171,52 183,15

Shoulder height 120,90 140 141,50 136,70 142 149,90

Span 148,80 160 173,35 170,40 176,13 188,60


128,35 131,20 148,20 146,40 154,23 160,45

Elbow height 94,15 100,30 103,95 110,52 111 113,46

Forward grip reach

63,77 71,12 79,25 76,40 83,24 89,95

IV. DISCUSSION

According to the results of anthropometric measurements, we found that the current workstation design was not suited to the body dimensions of Indonesian majority. As the workstation is adopted from Toyota’s piston assembly line, it means that this problem most probably occurs to Toyota Motor Manufacturing Indonesia as well. The same thing might happen to other manufacturing plants in Indonesia for several industries, such as automotive industry, belong to the same corporate group, and so they share the same facilities design or use the same contactors for building their facilities.

Considering that workstation design does not take into account the importance of ergonomics and conformity of anthropometric measurements, there is a big chance that accidents happen in the work place. This may lead to workers feel discomfort and demotivated. Another downside of inappropriate workstation design is decreased productivity. Time spent to reach a workpiece or tool due to distance longer than arms span, line stop due to fatigue, longer cycle time due to unnecessary movements, etc. are waste caused by inappropriate design that should be eliminated in order to achieve higher productivity.

To create a better workstation, redesign based on the anthropometric measurements shown in this research is urgently needed. In the case of the artificial piston assembly line in this research, improvements should be done on tools and workpiece placement to make them easier to reach considering the height and grip range of most Indonesian.

V. CONCLUSION

In this study, we investigated an artificial piston assembly line adopted from Toyota Lean Production System facility on a laboratory scale and find out that the workstation design was not suitable to be used by Indonesian. This research justifies that anthropometric measurements should be paid attention to in order to design the appropriate workstation that can make operator feels safe, comfortable, and satisfied with the work environment. In addition, percentile for the extreme should be noted as well so that the design of the workstation shall be able to cover all Indonesian, even the extreme ones who have measurements beyond or below the average people.



Further research will be conducted to validate the safety, health, and work environment aspects considering the suitability between anthropometric measurements and workstation design after improvement has been carried out. Future research may also be conducted on the artificial piston assembly line to further investigate the ergonomic aspects of the workstation using different perspectives and methods.

ACKNOWLEDGMENT

The authors would like to express their gratitude and appreciation to Universitas Indonesia for financing this research through Multidisciplinary Research Grant.

REFERENCES

[1] Bimal Das, Julia Wimpee, Bijon Das, Ergonomic evaluation and redesign of a hospital meal cart, Appied Ergomomics 33,( 2002), 309-318.

[2] Chan, H.,Jiao,Y.,Development of an antropometric data base for Hongkong Chinese CAD operators., Journal of Human Ergology 25(1), (1996),38-43

[3] Das B, Sengupta, Inustrial workstation design : A systematic ergomoic approach, Applied Ergonomics, (1996), 157-163. [4] Das B, Shikdar, Winters.T, Workstation redesign for repetitive drill press operation : a combined work design and ergonomics

approach, Human Factors in Manufacturing 17, (2007), 395-410. [5] Hunting W, Grandjean E, Maeda K, Contrained postures in accounting machine operators, 1980, Apllied Ergonomics 11, 145-149. [6] Jinky Leilanie Del Prado_Lu, Anthropomtetric Measurement of Filipino Manufacturing Workers, International Journal od Industrial

Ergonomics 37(2007), 497-503. [7] Lin R.T, Chan C.C, Effectiveness of workstation design on reducing musculeskeletal risk factors and symptoms among semiconductor

fabrication room workers, International Jounal od Industrial Ergonomics 37, (2007), 35-42. [8] McLeod.D, The Ergonomics Edge : Improving Safety, Quality and Productivity, John Willey, New York (1995). [9] Rungtai Lin , Yen Yu Kang, Ergomic Design of desk anf chair for primary school students in Taiwan, International Journal of

Innovation Management and Technology 4 ,1 (2013). [10] Shikdar A, Das. B, Hall.R, Ergomoics and worker productivity : A Study with repetitive manufacturing task, International Journal of

industrial and Systems Engineering, 2, 4 (1997), 336-374 [11] T.K. Chuan, M. Hartono, and N. Kumar, Anthropometry of the Singaporean and Indonesian populations, International Journal of

Industrial Ergonomics, 2010, pp. 757 – 766. [12] T. Yuri Zagloel, Inaki M Hakim, Syarafi Mukmin, Pre Elimanary Design Adjustable Workstation For piston assembly line

considering anthropmetic for Indonesian People, International Conference World Academia, Bali (2015)

BIOGRAPHY

T. Yuri M Zagloel is Professor in Department of Industrial Engineering. He is also as head of Manufacturing System Laboratory. He obtaine his Bachelor Degree in Machine Engineering, Universitas Indonesia. He countied his study in Industrial and Management , University of New South Wales. He get Phd in Faculty of Engineering, Universitas Indonesia. As a researcher, he has released several publications focused in the field of Logistic Maritime, Manufacturing, Total Quality Management, Ergonomics, Quality and Supply Chain Management. He is also active as a lecturer at Industrial Engineering Department Universitas Indonesia. His research interests include manufacturing, manufacturing, logistics, supply chain, productivity, ergonomics and lean concept. He can be contacted through his email [email protected]. Inaki M Hakim is a researcher of Manufacturing System Laboratory. She obtained her Bachelor Degree in Industrial Engineering, Universitas Sebelas Maret (UNS). She continued her study in Industrial Engineering and Management, Institut Teknologi Bandung (ITB). As a researcher, she has released several publications focused in the field of Logistic and Supply Chain Management. She is also active as a lecturer at Industrial Engineering Department Universitas Indonesia. Her research interests include manufacturing, simulation, optimization, reliability, ergonomics, productivity, scheduling, manufacturing, logistics, supply chain, sustainable, renewable and lean concept. She can be contacted through her email [email protected], [email protected]. Rieke Adyartie is laboratory assitant of Manufacturing System Laboratory. She obtained her Bachelor Degree in Industrial Engineering, Universitas Indonesia She continued her study in Fast Track Program in Departement of Industrial Engineering Universitas Indonesia. As a assistant laboratory , she has released several publications focused in the field of Manufactruing, Logistics and Ergonomy. She can be contacted through her email [email protected].


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