Human Activity Analysis Using DELMIA Ergonomics In JKTP Machining Technology Laboratory (Lathe).

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UNIVERSITI TEKNIKAL MALAYSIA MELAKA

HUMAN ACTIVITY ANALYSIS USING DELMIA

ERGONOMICS IN JTKP MACHINING TECHNOLOGY

LABORATORY (LATHE)

This report is submitted in accordance with the requirement of Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor of Manufacturing Engineering

Technology (Product Design) with Honours

by

TAN JIA ZHEN B071210071 920611-01-5060

FACULTY OF ENGINEERING TECHNOLOGY 2015


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DECLARATION

I hereby, declare that this thesis entitled “Human Activity Analysis using DELMIA Ergonomics in JTKP Machining Technology Laboratory (Lathe)” is the result of my

own research except as cited in references.

Signature : ………

Name : ………


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APPROVAL

This report is submitted to the Faculty of Engineering Technology of UTeM as one of the requirements for the award of Bachelor of Manufacturing Engineering Technology (Product Design) with Honours. The member of the supervisory is as

follow:

……… (Supervisor)


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ABSTRAK

Projek ini bertujuan untuk mengkaji dan mensimulasi beberapa tugas manusia yang berkaitan dengan keupayaannya semasa mereka menggunakan mesin larik di JTKP Makmal Teknologi Pemesinan. Pemerhatian akan dijalankan pada 3 orang lelaki pelajar dan 3 orang perempuan pelajar Fakulti Teknologi Kejuruteraan (FTK) dengan kategori ketinggian pada tinggi, sederhana dan pendek. Postur kerja mereka semasa melakukan set-up prosedur pada mesin pelarik akan direkodkan dan diambil gambar. Berdasarkan pemerhatian, susun atur kerja di makmal mesin pelarik akan direka bentuk menggunakan software CATIA V6. Satu manikin akan dimasukkan dan diedit berdasarkan data antropometri yang dikumpulkan daripada responden pelajar. Selepas itu, analisis aktiviti manusia akan disimulasi dengan menggunakan analisis DELMIA Ergonomik. Postur kerja responden akan dianalisis dan dijustifikasi dengan menggunakan kaedah Rapid Upper Limb Penilaian (RULA). Berdasarkan skor RULA, postur kerja yang tersesuai semasa menggunakan mesin pelarik akan dicadangkan untuk mengurangkan risiko daripada mengalami Musculoskeletal Disorders (MSD). MSD adalah salah satu penyakit yang disebabkan oleh manual pengendalian tugas seperti mengangkat, menolak dan menarik. Operasi menggunakan mesin pelarik telah dikenal-pasti melibatkan beberapa jenis aktiviti pengendalian manual.


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ABSTRACT

This project aims to study and simulate several human’s task related to human capabilities while using lathe machine in JTKP Machining Technology Laboratory. Observation has been conducted on three males and three females students group of Faculty of Engineering Technology (FTK) with the height category in tall, medium and short. The respondents working postures while doing set-up procedures on lathe machine had been recorded and photographed. Based on the observation, the working layout in lathe machine laboratory was designed using CATIA V6 software. A lifelike manikin was inserted and edited based on the anthropometric data collected from the respondents. Then, the human activity analysis was simulated by using DELMIA Ergonomics analysis. The respondents working postures was then analyzed and justified by using Rapid Upper Limb Assessment (RULA) method. Based on the RULA scores, the ideal working postures while working on lathe machine was proposed to minimize the risk from suffer Musculoskeletal Disorders (MSD). MSD is one of the sicknesses caused by manual handling task such as holding, lifting, carrying, pushing and pulling. Lathe machine operations has been identified involve several kinds of manual handling activities.


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DEDICATION

To my beloved parents Tan Say and Thong Gek Choo Raise me to become who I am


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ACKNOWLEDGEMENT

I would like to express my gratitude to my supervisor, Encik Mohd. Faiz bin Wahid who guides me through completing this project. He gave me a lot of advice, ideas and confidence to complete this project. Besides, I would like to thank Faculty of Engineering Technology of University Teknikal Malaysia Melaka (UTeM) for helping me in preparing formal documentations and guidelines for my project report. Not to forget, my families and friends for their support and blessing.


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TABLE OF CONTENTS

ABSTRAK ...i

ABSTRACT ... ii

DEDICATION ... iii

ACKNOWLEDGEMENT ...iv

TABLE OF CONTENTS ...v

LIST OF TABLES ... viii

LIST OF FIGURES...ix

LIST OF ABBREVATIONS, SYMBOLS AND NOMENCLATURES ... xiii

CHAPTER 1: INTRODUCTION ...1

1.1 Background ...1

1.2 Problem Statement ...2

1.3 Objectives...3

1.4 Scope of the study ...3

CHAPTER 2: LITERATURE REVIEW ...4

2.1 Introduction ...4

2.2 Workplace Evaluation...4

2.2.1 Working Postures ...4

2.2.2 Working Layout...6

2.2.3 Musculoskeletal Disorders (MSD) ...8

2.3 Ergonomics in the Lathe Laboratory ...10

2.3.1 Lathe Machine ...12

2.4 Methods for Ergonomics Assessment...14

2.4.1 RULA (Rapid Upper Limb Assessment) ...14

2.4.2 REBA (Rapid Entire Body Assessment) ...18


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2.5 DELMIA Ergonomics based on CATIA Version 6 (V6) ...26

CHAPTER 3: METHODOLOGY ...29

3.1 Identifying the Study Problem ...30

3.2 Library Research ...30

3.3 Identification of Human Activity ...30

3.4 Human Activity Analysis...32

3.5 Data and Result Analysis ...35

3.6 Report Writing and Compilation ...35

CHAPTER 4: RESULT AND DISCUSSION ...36

4.1 Simulation Machine Layout and Manikin Edition...37

4.2 RULA Analysis...40

4.2.1 Respondent 1 ...40

4.2.2 Respondent 2 ...43

4.2.3 Respondent 3 ...46

4.2.4 Respondent 4 ...49

4.2.5 Respondent 5 ...51

4.2.6 Respondent 6 ...54

4.3 Best Details Score ...57

4.3.1 Upper Arm ...58

4.3.2 Forearm...59

4.3.3 Wrist ...61

4.3.4 Neck and Trunk ...62

4.3.5 Final Score ...63

4.4 Discussion ...66

4.5 Improvement Result ...68


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4.5.2 Male Manikin ...72

CHAPTER 5: CONCLUSION ...75

5.1 Conclusion ...75

5.2 Recommendation for Future Work ...76

APPENDIX A ...77

APPENDIX B...78

APPENDIX C ...79

APPENDIX D ...81


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LIST OF TABLES

Table 2.1: The categorization of risk level under RULA...17 Table 2.2: The categorization of risk level under REBA. ...17 Table 2.3: The standardization of the categorization of RULA and REBA methods. .21 Table 2.4: Distribution of sampled postures. ...24 Table 2.5: Distribution of action category/level for 301 postures by three methods. ..24 Table 2.6: Coincidence rate of evaluation results between the three methods (%). ....25 Table 4.1: The anthropometric data of 6 respondents (Three male and three female).36 Table 4.2: The scores of the Level of MSD Risk by RULA analysis tool...57 Table 4.3: RULA score for the upper arm of six respondents on both sides of body to move the carriage table toward x-axis and z-axis. ...58 Table 4.4: RULA score for the forearm of six respondents on both sides of body to move the carriage table toward x-axis and z-axis. ...59 Table 4.5: RULA score for the wrist of six respondents on both sides of body to move the machining table toward x-axis and z-axis. ...61 Table 4.6: RULA score for the neck and the trunk of six respondents to move the carriage table toward x-axis and z-axis. ...62 Table 4.7: The scoring for final score of RULA analysis in Table C of RULA

Employee Assessment worksheet. ...63 Table 4.8: RULA score for the final score of six respondents to move the carriage table toward x-axis. ...64 Table 4.9: RULA score for the final score of six respondents to move the carriage table toward z-axis. ...65 Table 4.10: The actual and automatic dimensions of acromion-radiale length and radiale-stylion length of three male respondents...66 Table 4.11: The average and automatic anthropometric data of both male and female manikins. ...69


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LIST OF FIGURES

Figure 2.1: The risk factors of awkward working postures Source: Safety in

Manufacturing, 2000]. ...5 Figure 2.2: Descriptions of Neutral Postures Midpoints for the Body Joints [Source: Ergonomics, 2009]. ...6 Figure 2.3: Horizontal and vertical reach zones of a worker in a workstation [Source: Lista making workspace work, 2012]. ...7 Figure 2.4: Musculoskeletal disorders (MSDs) affected body parts [Source: Spine Place: Empowering Ordinary People with Extraordinary Health, 2014]...9 Figure 2.5: Conceptual model of the relationship between trunk postures and Lower Back Pain [Source: Nico J. D., 2004]. ...11 Figure 2.6: The basic components part of a lathe machine [Source: Terminology, 2013]...12 Figure 2.7: The standard lathe machine coordinate system [Source: Positioning, 2015]...13 Figure 2.8: Scores of the level of Musculoskeletal Disorders (MSDs) risk by RULA [Source: Ergonomics Plus, (n.d.). A Step-by-Step Guide to the RULA Assessment Tool] ...14 Figure 2.9: Snapshots from video on the workers body postures while doing their jobs [Source: Ansari N. A., 2014]. ...15 Figure 2.10: The RULA score according to position of body parts by using

ErgointeligenceTM software [Source: Ansari N. A., 2014]. ...16

Figure 2.11: The REBA score according to position of body parts by using

ErgointeligenceTM software [Source: Ansari N. A., 2014]. ...16 Figure 2.12: Scores of the level of Musculoskeletal Disorders (MSDs) risk by REBA [Source: Ergonomics Plus, (n.d.). A Step-by-Step Guide to the REBA Assessment Tool]. ...18 Figure 2.13: Frequencies Distribution: scores RULA [Source: Fernanda D.de.S., 2006]...20 Figure 2.14: Frequencies Distribution: scores REBA [Source: Fernanda D.de.S., 2006]...20


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Figure 2.15: Comparison of the postural analysis results: RULA and REBA [Source: Fernanda D.de.S., 2006]. ...21 Figure 2.16: Posture classification and codes for different body parts of OWAS system [Source: Waldemar K., 2003]. ...23 Figure 2.17: Percentage distribution of action category/level for 301 postures by three methods [Source: Kee D., 2007] ...25 Figure 2.18: DELMIA Ergonomics Analysis (EGA) analyze and predict human safety, comfort and performance directly within the 3D virtual environment [Source: DELMIA, 2002]. ...26 Figure 2.19: The human model interaction with arm strength gymnastic device in CATIA V6 software [Source: Ye Z. H., 2013]. ...28 Figure 3.1: Process flow chart of Bachelor Degree Project. ...29 Figure 3.2: Observation of students while using lathe machine in Machining

Technology Laboratory. ...31 Figure 3.3: Process flow chart of Human Activity Analysis...32 Figure 3.4: The lathe machine working layout was inserted in CATIA V6 software..33 Figure 3.5: The example of a manikin was inserted together in the lathe machine working layout...33 Figure 3.6: The collected anthropometric data was edited to the manikin by using the human measurement editor in CATIA V6 software. ...34 Figure 3.7: The working postures of manikin while using lathe machine was adjusted and set...34 Figure 3.8: The human activity was simulated by using RULA Analysis. ...35 Figure 4.1: The lathe machine layout with the machining table move towards x-axis and y-axis. ...37 Figure 4.2: The Human Measurement Editor of the manikin. ...38 Figure 4.3: The population and percentile setting of the manikin. ...39 Figure 4.4: The working posture and RULA analysis score of Respondent 1 brings the carriage table towards x-axis (Right side of body)...40 Figure 4.5: The working posture and RULA analysis score of Respondent 1 brings the carriage table towards x-axis (Left side of body). ...41 Figure 4.6: The working posture and RULA analysis score of Respondent 1 brings the carriage table towards z-axis (Right side of body). ...42


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Figure 4.7: The working posture and RULA analysis score of Respondent 1 brings the carriage table towards z-axis (Left side of body). ...42 Figure 4.8: The working posture and RULA analysis score of Respondent 2 brings the carriage table towards x-axis (Right side of body)...43 Figure 4.9: The working posture and RULA analysis score of Respondent 2 brings the carriage table towards x-axis (Left side of body). ...44 Figure 4.10: The working posture and RULA analysis score of Respondent 2 brings the carriage table towards z-axis (Right side of body). ...44 Figure 4.11: The working posture and RULA analysis score of Respondent 2 brings the carriage table towards z-axis (Left side of body). ...45 Figure 4.12: The working posture and RULA analysis score of Respondent 3 brings the carriage table towards x-axis (Right side of body)...46 Figure 4.13: The working posture and RULA analysis score of Respondent 3 brings the carriage table towards x-axis (Left side of body). ...47 Figure 4.14: The working posture and RULA analysis score of Respondent 3 brings the carriage table towards z-axis (Right side of body). ...47 Figure 4.15: The working posture and RULA analysis score of Respondent 3 brings the carriage table towards z-axis (Left side of body). ...48 Figure 4.16: The working posture and RULA analysis score of Respondent 4 brings the carriage table towards x-axis (Right side of body)...49 Figure 4.17: The working posture and RULA analysis score of Respondent 4 brings the carriage table towards x-axis (Left side of body). ...50 Figure 4.18: The working posture and RULA analysis score of Respondent 4 brings the carriage table towards z-axis (Right side of body). ...50 Figure 4.19: The working posture and RULA analysis score of Respondent 4 brings the carriage table towards z-axis (Left side of body). ...51 Figure 4.20: The working posture and RULA analysis score of Respondent 5 brings the carriage table towards x-axis (Right side of body)...52 Figure 4.21: The working posture and RULA analysis score of Respondent 5 brings the carriage table towards x-axis (Left side of body). ...52 Figure 4.22: The working posture and RULA analysis score of Respondent 5 brings the carriage table towards z-axis (Right side of body). ...53


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Figure 4.23: The working posture and RULA analysis score of Respondent 5 brings the carriage table towards z-axis (Left side of body). ...54 Figure 4.24: The working posture and RULA analysis score of Respondent 6 brings the carriage table towards x-axis (Right side of body)...55 Figure 4.25: The working posture and RULA analysis score of Respondent 6 brings the carriage table towards x-axis (Left side of body). ...55 Figure 4.26: The working posture and RULA analysis score of Respondent 6 brings the carriage table towards z-axis (Right side of body). ...56 Figure 4.27: The working posture and RULA analysis score of Respondent 6 brings the carriage table towards z-axis (Left side of body). ...56 Figure 4.28: The example of the Muscle score of Respondent 1. ...68 Figure 4.29: The working posture and RULA analysis score of Female manikin brings the carriage table towards x-axis (Right side of body)...69 Figure 4.30: The working posture and RULA analysis score of Female manikin brings the carriage table towards x-axis (Left side of body). ...70 Figure 4.31: The working posture and RULA analysis score of Female manikin brings the carriage table towards z-axis (Right side of body)...71 Figure 4.32: The working posture and RULA analysis score of Female manikin brings the carriage table towards z-axis (Left side of body). ...72 Figure 4.33: The working posture and RULA analysis score of Male manikin brings the carriage table towards x-axis (Right side of body)...72 Figure 4.34: The working posture and RULA analysis score of Male manikin brings the carriage table towards x-axis (Left side of body). ...73 Figure 4.35: The working posture and RULA analysis score of Male manikin brings the carriage table towards z-axis (Right side of body). ...73 Figure 4.36: The working posture and RULA analysis score of Male manikin brings the carriage table towards z-axis (Left side of body). ...74


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LIST OF ABBREVATIONS, SYMBOLS AND

NOMENCLATURES

BDP - Bachelor Degree Project

CATIA V6 - CATIA Version 6

EGA - DELMIA Ergonomics Analysis

EGE - DELMIA Ergonomics Evaluation

FTK - Faculty of Engineering Technology

HAA - Human Action Analysis

HBR - Human Builder

HME - Human Measurement Edit

HPA - Human Posture Analysis

LBP - Lower Back Pain

MSD - Musculoskeletal Disorders

NIOSH - National Institute for Occupational Safety and

Health

OWAS - Ovako Working Postures Assessment System

REBA - Rapid Entire Body Assessment


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CHAP TER 1

INTRODUCTION

1.1 Background

First of all, ergonomics is the study of human in the working environment. Ergonomics also concerned with the comfort, health and safety, and productivity. Nowadays, ergonomics is very important in any subject of field because it provides us a way to analyze our body postures when our body is under any ergonomics risk factors. All of this risk factors will contribute to Musculoskeletal disorders (MSD) are the disorders where the human body gets traumatized over a period of time. Many industry always overpass these types of disorders where it tend to cause the sickness slowly appeared within the workers body. In fact, this problem can be foreseeable when time passed by. Therefore, ergonomic analysis should be done to overcome this kind of diseases so that everyone has a healthy and comfort posture when doing their job every time.

This project is mainly focused on the human activity analysis using DELMIA V6 Ergonomics. The ergonomics human activity analysis for this project is aimed to focus on various working postures of students while they are using lathe machine in JTKP Machining Technology Laboratory. Since ergonomics is a study of human’s activity with workspace, the working layout in lathe machine laboratory has an indirectly influences on the analysis. The study was not only concentrated on the working postures of students while using lathe machine. The movements of students while taking materials from the tool room and referring working procedures at work table had been focused too. Then, the study had paid full attention on the hand


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actions while processing the lathe machine. Vertical and horizontal reaches of upper parts of body as well as position of visual display was taken in consideration too.

The approach that was used to perform the human activity analysis is by using the DASSAULT SYSTEMES software, CATIA V6. This software allows users to do the DELMIA Ergonomics analysis. A 3D virtual environment and lifelike manikins can be created to perform the working tasks. Users can analyze and predict the comfort or safety scoring of the working postures by observing color coding of Rapid Upper Limb Assessment (RULA) analysis. RULA is a method for analyzing risk factors to the upper limb of the user-defined manikin or human in an actual physical environment. The RULA analysis can measures several risk factors such as body movements, static work load, force, working posture and time worked without a break.

1.2 Problem Statement

This study was focused on the human activity analysis while students using lathe machine in laboratory, which can carry out several machine procedures. From several research studied, many lathe machine workers suffering MSD on the neck, shoulders, trunk, and lower back region. All these disorders are mostly causes from prolonged unhealthy postures while working, lower back support is inadequate and poor ergonomics workstation set up. Since there are no specific ergonomics guidelines and assessment implemented in JTKP Machining Technology Laboratory, therefore the student’s activities when operating the lathe machine will be observed and analyzed using anthropometric data gathered from a specific group of students.


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1.3 Objectives

The main objectives in this project are:

i. To study and simulate several human’s task related to human capabilities while using lathe machine in JTKP Machining Technology Laboratory. ii. To identify and propose the ideal working posture while working on lathe

machine to minimize the risk from suffer MSD.

iii. To identify relevant collected anthropometric dimensions in human-machine interaction that could be related to awkward working postures.

1.4 Scope of the study

The scope on this project covers on:

i. Using DELMIA V6 Ergonomics software to study and simulate human activity.

ii. Observe and analyze the laboratory work on lathe machine.

iii. Rapid Upper Limb Assessment (RULA) ergonomics analysis will be used based on recommendations from National Institute for Occupational Safety and Health (NIOSH).

iv. Observe on 3 male and 3 female students group of Faculty of Engineering Technology (FTK) with the categories of height in tall, medium and short while doing set-up procedures on lathe machine.


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CHAP TER 2

LITERATURE REVIEW

2.1 Introduction

For further process of this research project, literature review makes an important key of it. The sources of literature survey are obtained from the books, journals and also electronic resources. All of the information was based on the past studies related to ergonomics fields. Therefore, it had covers on the study of workplace evaluation, ergonomics in the lathe laboratory, ergonomics assessment tools and DELMIA Ergonomics based on CATIA V6.

2.2 Workplace Evaluation

2.2.1 Working Postures

Working posture can be defined as the posture of an individual required to perform a job. Work posture in the workplace is determined by the interaction of many factors, including working method, workstation layout and equipment design. In addition, the body-size characteristics of a worker interact with all the workplace factors determines specific postures used to perform a job. Awkward working postures occur when there was a mismatch between a worker’s body size and the job requirements [1]. Figure 2.1 showed the risk factors of awkward working postures.


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Figure 2.1: The risk factors of awkward working postures Source: Safety in Manufacturing, 2000].

Awkward working postures are caused by the joints position of body that is not moving in neutral range of postures. Movement of joints such as bending the neck forward more than 30 degrees, raising the elbow above the shoulder, bending the back forward greater than 45 degrees and squatting will lead to extreme awkward postures. To avoid awkward working postures, the joints of body should maintain in a neutral range of postures. Postures within the neutral range can contribute in high force production or control of body and reduce the stress apply on the tissues, muscle, nerves and bones. Figure 2.2 showed the descriptions of neutral postures midpoints


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Figure 2.2: Descriptions of Neutral Postures Midpoints for the Body Joints [Source: Ergonomics, 2009].

2.2.2 Working Layout

The design of workstation was one of the important ergonomics approach in manufacturing industry but this approach can be easily ignored by people. With a little consideration to the anthropometric measurements of the anticipated user, the manufacturing workstation was often designed in an arbitrary manner. A slightly change in the dimension of workstation can bring the impact to worker health, safety and also effect on industry productivity.


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There were many guidelines and principles in the design of workstation. One of it was apply the anthropometric data to workspace design. This mean the dimension for workstation design is determine according to the anthropometric data while doing industrial tasks such as reaching, sitting, standing and sit-stand positions. The populations for male and female workers consist of 5th, 50th and 95th percentiles

based on the existing anthropometric data. The design of reaching limits and clearance requirements were based on the smaller (5th percentile) and larger (95th

percentile) dimensions of individual worker. The zones for reaching and clearance were shown in Figure 2.3.

Figure 2.3: Horizontal and ve rtical reach zones of a worke r in a workstation [Source: Lista making workspace work, 2012].


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Besides that, to solve the workstation design problems, Ernest J. McCormick had stated out four principles of rational workspace layout, which are [5]:

 Importance principle: The most important items should be in the most accessible locations.

 Frequency of use principle: The most frequently used items should be in the most accessible locations.

 Function principle: Items with similar functions should be grouped together.  Sequence of use principle: Items that are commonly used in sequence should be

laid out in the same sequence.

2.2.3 Musculoskeletal Disorders (MSD)

The term of musculoskeletal disorders (MSD) donate to the disease or damage of the muscles, tissues, nerves, joints or tendons at the body part of neck, upper limb and the back. MSD are consequences from the mismatch between the health capacities of worker and the job requirements. According to a study, it pointed that manual material handling is one of the factors that causes MSD occur [6]. Activities such as holding, lifting, carrying, pushing and pulling are all covered in manual handling tasks. Figure 2.4 showed the body parts affect by MSD.


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3 1.3 Objectives

The main objectives in this project are:

i. To study and simulate several human’s task related to human capabilities while using lathe machine in JTKP Machining Technology Laboratory. ii. To identify and propose the ideal working posture while working on lathe

machine to minimize the risk from suffer MSD.

iii. To identify relevant collected anthropometric dimensions in human-machine interaction that could be related to awkward working postures.

1.4 Scope of the study

The scope on this project covers on:

i. Using DELMIA V6 Ergonomics software to study and simulate human activity.

ii. Observe and analyze the laboratory work on lathe machine.

iii. Rapid Upper Limb Assessment (RULA) ergonomics analysis will be used based on recommendations from National Institute for Occupational Safety and Health (NIOSH).

iv. Observe on 3 male and 3 female students group of Faculty of Engineering Technology (FTK) with the categories of height in tall, medium and short while doing set-up procedures on lathe machine.


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CHAP TER 2

LITERATURE REVIEW

2.1 Introduction

For further process of this research project, literature review makes an important key of it. The sources of literature survey are obtained from the books, journals and also electronic resources. All of the information was based on the past studies related to ergonomics fields. Therefore, it had covers on the study of workplace evaluation, ergonomics in the lathe laboratory, ergonomics assessment tools and DELMIA Ergonomics based on CATIA V6.

2.2 Workplace Evaluation

2.2.1 Working Postures

Working posture can be defined as the posture of an individual required to perform a job. Work posture in the workplace is determined by the interaction of many factors, including working method, workstation layout and equipment design. In addition, the body-size characteristics of a worker interact with all the workplace factors determines specific postures used to perform a job. Awkward working postures occur when there was a mismatch between a worker’s body size and the job requirements [1]. Figure 2.1 showed the risk factors of awkward working postures.


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Figure 2.1: The risk factors of awkward working postures Source: Safety in Manufacturing, 2000].

Awkward working postures are caused by the joints position of body that is not moving in neutral range of postures. Movement of joints such as bending the neck forward more than 30 degrees, raising the elbow above the shoulder, bending the back forward greater than 45 degrees and squatting will lead to extreme awkward postures. To avoid awkward working postures, the joints of body should maintain in a neutral range of postures. Postures within the neutral range can contribute in high force production or control of body and reduce the stress apply on the tissues, muscle, nerves and bones. Figure 2.2 showed the descriptions of neutral postures midpoints


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Figure 2.2: Descriptions of Neutral Postures Midpoints for the Body Joints [Source: Ergonomics, 2009].

2.2.2 Working Layout

The design of workstation was one of the important ergonomics approach in manufacturing industry but this approach can be easily ignored by people. With a little consideration to the anthropometric measurements of the anticipated user, the manufacturing workstation was often designed in an arbitrary manner. A slightly change in the dimension of workstation can bring the impact to worker health, safety and also effect on industry productivity.


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There were many guidelines and principles in the design of workstation. One of it was apply the anthropometric data to workspace design. This mean the dimension for workstation design is determine according to the anthropometric data while doing industrial tasks such as reaching, sitting, standing and sit-stand positions. The populations for male and female workers consist of 5th, 50th and 95th percentiles based on the existing anthropometric data. The design of reaching limits and clearance requirements were based on the smaller (5th percentile) and larger (95th percentile) dimensions of individual worker. The zones for reaching and clearance were shown in Figure 2.3.

Figure 2.3: Horizontal and ve rtical reach zones of a worke r in a workstation [Source: Lista making workspace work, 2012].


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Besides that, to solve the workstation design problems, Ernest J. McCormick had stated out four principles of rational workspace layout, which are [5]:

 Importance principle: The most important items should be in the most accessible locations.

 Frequency of use principle: The most frequently used items should be in the most accessible locations.

 Function principle: Items with similar functions should be grouped together.  Sequence of use principle: Items that are commonly used in sequence should be

laid out in the same sequence.

2.2.3 Musculoskeletal Disorders (MSD)

The term of musculoskeletal disorders (MSD) donate to the disease or damage of the muscles, tissues, nerves, joints or tendons at the body part of neck, upper limb and the back. MSD are consequences from the mismatch between the health capacities of worker and the job requirements. According to a study, it pointed that manual material handling is one of the factors that causes MSD occur [6]. Activities such as holding, lifting, carrying, pushing and pulling are all covered in manual handling tasks. Figure 2.4 showed the body parts affect by MSD.