CHAPTER 1
INTRODUCTION
1.1 Background study
Ergonomics applies information about human behavior, abilities
and limitations and other characteristics to the design of tools,
machines, tasks, jobs and environments for productive, safe,
comfortable and effective human use (McCormick and Saunders 1993).
In order to improve the standard of the workspace and to enhance
the workers productivity, the science of ergonomics concerns with
the degrees of workspace design.
From previous study, the researchers have identified s lot of
types of ergonomic factors such as awkward postures, forceful
exertion, localized contract stress, restless and repetitive
motions in the working environment, especially in manufacturing
based company.
Studies in the car assembly industry found the ergonomics issues
caused poor workmanship that lead to poor product quality (Eklund
(1995, 1999). While Lim and Hoffmann (1997) conducted an experiment
on hacksaw assembly and found that improved layout of the workplace
improved productivity of the workers through more economical use of
hand movement.
It is crystal-clear proved that ergonomic interventions by
alteration in the arrangement or equipment of the workplace
exercise, rest break and training able to reduce musculoskeletal
symptoms in the workplace. A study conducted in office work
(Mehrparvar A.H, 2014) found a beneficial short-term effect for
both ergonomic modifications and stretching work-place exercises on
reducing musculoskeletal pain in office workers.
1.2 Problem Statement
The careful thought about ergonomics to put into practice in can
generally be regarded as a means to maintain companys workforce and
its competitiveness. This is particularly true in automotive
manufacturer, where the workers in the shop floor have to fulfill
physical and strenuous task. The stress load, if sustained over
time and depending on the individual resources, can produce adverse
effects, such as health and safety problems and lack of
performance.
The problem here is, even though the importance of ergonomics
seems evident, the implementation status can be described as rather
poor in many companies. So, it is important to implement the
ergonomic interventions in the work place and at the same time to
identify the effectiveness of the interventions towards the works
safety and health.
1.3 Objectives
The objective of this study is to identify ergonomic risk
factors and to implement ergonomics interventions in order to
improve human performance in an automotive factory.
1.4 Scope of Research
For this study, the scholar already chosen to embark on
ergonomics studies in real life factory environments in Malaysia,
which is an automotive parts factory, Autokeen Sdn. Bhd. This
factory is a private limited company specializing in metal parts
manufacturing and assembly specifically for the automotive
industry, among a host of other products and services offered. The
research study was focused on the whole department in the company
plant.
The research had undergone numbers of processes to obtain the
result related to this topic. There are four methods that had been
applied in completing this study which are Subjective Assessment,
Direct Observation, Retrieved of Archival Record, and Intervention
Study. For Subjective Assessment, the questionnaire was prepared to
obtain overview feedbacks from the respondent.
1.5 Significance of ResearchThis research will give the
information about the risk factors of ergonomics and the effect of
them towards human body. From the obtained result, the company can
come up with better methods or tools in order to ensure the workers
health and safety.
Besides, the workers performance will improve; hence, it will
increase the productivity of the company. Last but not least, the
findings of this research also can be used for the further related
research.
CHAPTER 2
LITERATURE REVIEW
2.1 Basics of ergonomicsThe transition from classical job shop
production to mass production in large-scale manufacturing systems,
which took place in the course of the industrial revolution, lead
to an emphasis on aspects such as standardization, productivity,
and efficiency in operations. As major consequences of the
continued division of labor and the aim of rising productivity was
the maximization of workforce utilization as the predominant
management goal without considering possible consequences for the
employees (Murell, 1967).
The increased complexity of machines and growing demand for
higher operation speeds in the course of World War II lead to the
first specific scientific investigations on performance limits and
physical capacity of humans, and therewith to the emergence of
ergonomics as a scientific discipline. The term ergonomics is
composed of the Greek words. ergon (work) and nomos (rule, law)
(Murrell, 1971). Today, the scientific disciplines of ergonomics
can be divided in three major areas: physical, cognitive, and
organizational ergonomics. Physical ergonomics deals with anatomic,
anthropometric, and physiologic aspects of job design (Karwowski
and Rodrick, 2001). Cognitive ergonomics examines mental processes
such as information processing, apperception, reaction and
coordination (Vicente, 1999). In organizational ergonomics, also
known as macro-ergonomics, the emphasis is put on structures,
methods and processes of socio-technical systems (Karwowski,
2005).
2.2 Occupational injuries and illness in the industry.According
to Shameem et al. (2001), industrial workers in Malaysia
experienced little work freedom and relaxation and significant
overtime work. They did not complain strongly about poor work
conditions, such as background stressors i.e., noise, heat stress
due to poor air conditioning, limited working space and poor vision
due to low lighting levels. Most of these workers were poorly
educated and were ignorant of the various work environmental
standards. These workers had the idea that work conditions were
what they had to adapt to. In fact, in the 1980s, most
multinational companies in Malaysia had put ergonomics as low
priority, as application of the knowledge of ergonomics was
perceived as a costly and burdensome expenditure (Yeow and Sen,
2002) rather than a rewarding investment. This was also due to the
abundance of replaceable cheap labour and low government regulation
of labour health and safety issues.
Figure 2.1: Occupational Accidents by Sector until June
2014According to the Department of Occupational Safety and Health
(DOSH), Malaysia report on Occupational Accidents by Sector until
June 2014, the highest accidents were reported by the manufacturing
sector with 964 cases, 24 cases were reported in death category, 74
cases in Permanent Disability category and 866 cases in Non-
Permanent Disability (NPD) category. Agriculture, Forestry, Logging
and Fishing with 224 cases was the second highest. However, the
highest accident for death category was reported by construction
sector, with 35 cases while manufacturing lead in Non- Permanent
Disability (NPD) category.For the Occupational Accidents by State
until June 2014, Perak led with 255 occupational accidents, 238
cases in Non- Permanent Disability (NPD) category, 8 cases in death
category and 9 cases in Permanent Disability category. Negeri
Sembilan recorded as the second highest state that reported the
occupational accidents with 197 cases followed by Pulau Pinang with
190 cases.
Figure 2.2: Occupational Accidents by State until June 2014
2.3 Ergonomics risk factorsStress-related organizational aspects
such as time pressure, work times and shift changes or the
necessity to highly concentrate for long periods of time might have
negative impact on an employees performance and therefore critical
issues in terms of cognitive ergonomics. Moreover, surrounding
conditions such as noise, temperature, contact with chemicals, or
vibration emitting noise tasks could hamper employees conducting
their job and might have a negative influence on workers health in
the long run.Common risk factors that can be seen at the workplace
are overexertion force, awkward posture, repetition task,
environment and vibration.
2.3.1 ForceThere are three types of force, the static force
required to lift and hold a load, the kinetic force required to
move an object (push or pull) and grip force. Force is the exertion
on internalized bodily tissues, including vertebral disc
compression from lifting a heavy box, or tension within a muscles
during a pinch grip. Forceful muscular exertions place high loads
on the muscles, tendons, joints, and discs, and are therefore
associated with most musculoskeletal disorders. Muscles fatigue
with increased muscular exertion, and the time needed to recover
increases. If recovery time is limited, soft tissue injury is more
likely to occur. Where other risk factors are present, especially
frequent repetitions of exertions, awkward postures or static
postures, they add to the force required to accomplish the
exertion. Generally the larger the force the higher the injury
risk, so it is always beneficial to reduce the weight of the object
to be handled.
2.3.2 PosturePosture is the position the body is in while
completing the movement. Muscles and tendons are strongest in
neutral positions, so any deviation reduces stability and strength.
With prolonged awkward postures, muscles can be strained and
tendons and nerves stretched or pinched. Tasks that involve long
reaches require considerably more force to accomplish than tasks
that can be performed closer to the body.Common injuries involving
repetitive awkward postures include carpal tunnel syndrome in the
wrist and impingement syndrome in the shoulder. To avoid injuries
caused by awkward postures, avoid lifting objects from overhead,
use an ergonomic computer mouse and avoid far reaches with the
upper body. Table below shows postures that accompany higher injury
risks.
Table 2.3.2.1: Postures that accompany higher injury risksBody
PartsPostures
Wrist: flexion and extension (bending up and down) ulnar/radial
deviation (side bending)
Shoulder: abduction/flexion (upper arm out to the side or above
shoulder level) hands at or above shoulder height
Neck: flexion/extension (bending neck backwards and forwards)
side bending
Low Back: bending at the waist twisting bending while
twisting
2.3.3 RepetitionRepetition is described as the number of times
the same movement/task is completed within a given time. Highly
repetitive tasks are of concern because they work the same muscles,
tendons, and ligaments repeatedly, rarely allowing for adequate
recovery. With time, the effort to maintain the repetitive
movements continually increases. When the work activity is
continued, in spite of the developing fatigue, injuries occur.2.3.4
EnvironmentWhen the environment is too cold, blood flow is diverted
from the extremities, to the core to maintain body temperature.
Decreased blood flow results in lower muscle power and early onset
of fatigue, as well as reduced sensation in extremities.
Consequently, when the work area is too hot, blood flow increases
to the skin to dissipate the heat, again reducing blood flow to
skeletal muscle. Decreases in strength and early onset of fatigue
as well as increased need for recovery time are all consequences of
hot work environments.2.3.5 VibrationVibration causes reduced blood
flow to the fingers and hands, resulting in localized numbness.
Prolonged and repeated exposure to vibration can permanently damage
blood vessels leading to White finger syndrome or even Reynauds
Disease. Hand Arm Vibration also interferes with sensory receptor
feedback, leading to tighter gripping of hand tools.All of the
above mentioned the risk factors (out of the categories task,
organizational aspects, and surrounding conditions) have in common
that they hamper workers to unfold their full potential and that
they contribute to harmful manufacturing environments (Xiao et al.
2004).Today, production systems, especially in the automotive
industries are oftentimes characterized by a large number of
various processes in highly automated environments (Ohno, 2005).
This has severe consequences for the number and nature of tasks
performed by shop floor employees. Harmful in this context are
simple, monotonous, and highly repetitive tasks (Kume and Sato,
1999; Xiao et al. 2004). These lead to one-sided strains and can
therefore be identified as the main reason for diseases of the
muscular-skeleton system such as Repetitive Strain Injuries or
Cumulative Trauma Disorders (Fathallah et al. 1998)2.4
Musculoskeletal injuries (MSIs)
An MSI, defined by the Occupational Health and Safety
Regulation, is an injury or disorder of the muscles, tendons,
ligaments, joints, nerves, blood vessels or related soft tissue
including a sprain, strain and inflammation, that may be caused or
aggravated by work.
Figure 2.3: MSD in the upper extremities of body.
The risk factors for MSI are related to the physical demands of
a task and include force, repetition, work posture, working
heights, and local contact stress. The most common type of MSI is
back strain, followed by other strains and tendinitis. MSIs are
most commonly reported among workers in the retail industry, with
3,352 claims submitted between 2005 and 2009.
2.5 Laboratory Workbenches
Figure 2.4: Workbench DesignWhen used inappropriately,
laboratory workbenches can expose researchers to a variety of
hazardous conditions or ergonomic risk factors depending on the
laboratory procedure being used. Most workbenches at the University
are of fixed heights and cannot be modified (raised or lowered). In
general they are the same height and were designed for light to
slightly heavy work. Using a laboratory workbench as a computer
workstation is an example of inappropriate use, since it forces the
worker to assume a variety of awkward postures and may increase the
likelihood of acquiring MSD.
If workbench height is above elbow height, between 37and 43
inches, use for precision work. If workbench height is just below
elbow height, between 34 and 37 inches, use for light work. If
workbench height is below elbow, between 28 and 35 inches, use for
heavy work.
2.6 Rapid Entire Body Assessment worksheet (REBA)
The basic idea of REBA is: positions of individual body segments
will be observed and the more there is deviation from the neutral
posture the higher will the score of each body part be. Group A
includes trunk and neck, and legs and group B upper arms, lower
arms, and wrists. These groups are combined and the 144 posture
combinations are transformed to a general postural score ("'grand
score"). Additional items observed and scored are the load handled,
coupling with the load handled, and physical activity. The scores
are summed up to have one score for each observation. These scores
are compared to tables stating risk on five levels and actions
needed.
Figure 2.6.1: REBA worksheet
The static captured pictures of the workers working posture will
be selected and then by using the REBA worksheet, a score will
assigned for each of the body regions.
Figure 2.6.2: REBA worksheet Score
After the data for each region is collected and scored, tables
on the form are then used to compile the risk factor variables,
after the final score is generate, that score represents the level
of MSD risk.
Figure 2.6.3: Proper lifting techniques
CHAPTER 3
METHODOLOGY
3.1 Methods and TechniquesThe methodologies used in this project
have been categorized into 3 groups.I. The general methods used
were: Direct observations in the field consisting of human
recording such as scored assessments (REBA) and walkthroughs
Indirect observations in the field via questionnaires and
subjective ratings Standards and recommendations that were enforced
via the intervention
II. To collect information about the workers the following
methods were used: Physical measurements such as how individuals
performed body movements Subjective assessment via
questionnaires.
III. For the analysis and design the following methods were
used: Expert analysis often involving, walkthroughs and scored
assessments Intervention studies4. To evaluate human performance
the following methods were used: Physical assessment by using Rapid
Entire Body Assessment worksheet (REBA) Subjective assessment by
means of questionnaires and ratings5. To evaluate the demands on
the workers the following methods were used: Job and work attitudes
measurements of by means of rating scales in questionnaires.
3.2 Research FlowchartStart
Scope of ProjectProblem StatementLiterature Review
Research and Development
Intervention StudiesDirect Observation
Subjective Assessment
Ergonomic Interventions
Retrieved of Archival RecordSubjective Assessment
Data Collection
Report Writing
End
Figure 3.2.1: Research flowchart3.3 Research Stages and its
details3.3.1 Research and DevelopmentIn this phase, the problem
statement and the objective of the study were narrowed down in
order to focus more on the purpose of the research. As for the
literature review, the sources of all the information and data
mostly based on journals, come from article and few from books.
3.3.2 Ergonomic InterventionsDuring this phase, the data
collection was gathered from quantitative and qualitative analysis.
A few methods have been done in this phase such as;3.3.2.1
Subjective Assessment The subjective assessment is a set of
questionnaire that consisted of several sections such as
demographics and relevant questions due to the issue regarding to
ergonomic study. Thirty sets of questionnaires were distributed to
the respondent in the working plant. The respondents were the
operators from several departments in the Autokeen which are
Production, Machining and Finishing. The data gained from the
subjective Assessment was analyzed and interpreted into the table
and graph.3.3.2.2 Direct ObservationPictures and video were taken
during this stage to confirming the finding of Subjective
Assessment and the pictures and videos taken were used for Rapid
Entire Body Assessment (REBA) scores.
3.3.3 Ergonomic InterventionsBased on the data from Subjective
Assessment and REBA Scores, Some interventions such as packing
blocks, modified adjustable table and rubber mat are introduced as
the interventions to improve human work performance. All of the
interventions were implemented one at a time. Packing block was
implemented in CNC machine, rubber mat was placed on floor in the
production line and the adjustable table was not in a fixed
workstation since the table was attached to the pallet jack.
CHAPTER 4
RESULTS AND DATA ANALYSIS
The data was collected from all the methods that were explained
in the chapter 3 (Methodology). All the data collected was gaining
from all of the methods that were explained in the Methodology
Chapter. All the data and results are was analyzed and interpreted
in the following sub topics.
4.1 QuestionnairesThirty sets of questionnaires were distributed
to the respondent in the automotive power plant. Mostly the
operators are come from Bangladesh, a few from Pakistan and only
one Malay respondent. All of them are the operators from several
departments in the Autokeen which are Production, Machining and
Finishing.
The demographic details such as age, height, weight, working
experience, working days per week, working hours per day and
working hours per day spent standing (Section A and B) were
tabulated in Table 4.1.Table 4.1: Demographic Details.Categorical
variables (N=30)Categorical VariablesCategoryn (%)
Age (Years)21-3031-40
17 (57)13 (43)
Body SizeSMLXL
2(7)10(33)11(37)7(23)
Department
ProductionMachining Finishing
18(60)1(3)11(37)
Work experience (months)1-56-1011-15
20(67)10(33)0
Working hours per day (hour/day)81012
8(27)12(40)10(33)
Maximum standing hours per day0-23-45-67-8
4(13)8(27)12(40)6(20)
Figure 4.1: Percentage of respondent opinion about occupational
safety and health problemsFrom the figure 4.1 above, 60% which is
18 respondents from 30 number of respondent that facing with safety
and health problems due to work are from production department.
While the other 35% (11 respondents) and 5% (1 respondent) from
Finishing and Machining department. Most of them also agreed the
accidents occurred due to less safety procedure took place during
the machining operation. The worst case had been reported during
scholar internship was one of the machining operators lost his
thumb because hes ignoring the safety procedure when handling the
lathe machine.
Figure 4.2: One of safety label in the working plantWork
ActivitiesStrenousMonotonousFatigueBoring
No of respondents12292311
Table 4.2: Respondent's opinion about their working
condition
Figure 4.3: The graph of respondent's opinion about their
working conditionFrom figure 4.3 above, almost all of the
respondents agreed their work is monotonous which is repeated. 29
from 30 respondents said that they keep working on same thing every
day, for 8-10 hours in standing work position which 77% of the
respondent agreed the conditions lead to fatigue. Because of the
repetitiveness, 11 respondents found their work is boring.
Figure 4.4: Respondent opinion about their work station
condition
Based on the data that had been interpreted into the Figure 4.4
above, about 70% (21) respondents agreed they had enough working
space and dont have any problem working in it. However, only 27%
respondent answered they were comfortable with their conveyer
height. Most of the respondents complaining about their conveyor
height are too low, especially theres a few of the operators in
Finishing Department, which they dont have fixed workstations.
Figure 4.5: A picture of a few workers from finishing
departmentFigure above shows the operators improper work station
which makes them feel discomfort when working. The working table
was not provided, and the chair that they are using to sit also is
not properly design which is the custom made chair made from scrap.
Because of the uncomfortable work station, they complained having a
back ache after working hours.
Figure 4.6: Respondents comfortability in their working
environment
Due to the company-based nature in producing stamping products,
noisy working environment was the most selected as their main
disturbance during working time. From the Figure 4.6 above, 23 from
30 respondents agreed the noise from stamping operation give them
discomfort as the sound produced from the stamping machine was too
loud. Even they wear the ears protection; they still can hear the
sound clearly. However, 100% respondent admits they are satisfied
with the lighting in their working environment since the working
plant had proper illumination. Theres less complains about dirty
environment because the company applied 5S. The operators doing
cleaning task 15 minutes before they start working and 15 minutes
before they finish their working hour.
Figure 4.7: Body diagram with labels
In one of the questionnaire question, the respondents were ask
to scale to which their body region that they feel discomfort
during their job by referring to the figure 4.7 above. The scale of
the levels of discomfort was divided with five categorical which
are non-discomfort, discomfort, mild discomfort, moderate
discomfort and severe discomfort. The Non- Discomfort category is
means for none body region that having pain or injury that
influenced by their daily work routine. As for the Discomfort
category, it is means that the respondent feels that their specific
body region is bit disturbed their movement for doing their job.
Mild Discomfort category is represented for uneasy feeling that
probably makes the respondent out of their focus while working. For
Moderate Discomfort category, it is means that the pain or injury
in their specific body region makes them feel uneasy and to reduce
the sickness they have to consume a medicine. Meanwhile Severe
Discomfort category is represent for the uneasiness of the specific
body region is the main reason for the respondent medical leave or
being hospitalized.From the data that had been obtained, the result
was interpreted into the table and figure below.Table 4.3:
Percentage of level discomfort of specific body regionBody
RegionsNon-Discomfortn(%)Discomfortn(%)Mild Discomfortn(%)Moderate
Discomfortn(%)Severe Discomfortn(%)
Waist15(50)12(40)2(7)1(3)1(3)
Neck13(43)13(43)4(13)
Right Shoulder15(50)8(27)7(23)
Left Shoulder20(67)6(20)4(13)
Right Upper Arm10(33)12(40)5(17)3(10)
Left Upper Arm16(53)10(33)3(10)1(3)
Right Forearm16(53)11(37)1(3)2(7)
Left Forearm19(63)8(27)2(7)1(3)
Right Hand9(30)3(10)15(50)3(10)
Left Hand12(40)14(47)3(10)1(3)
Right Wrist21(70)3(10)6(20)
Left Wrist23(77)4(13)2(7)1(3)
Right Thigh23(77)6(20)1(3)
Left Thigh25(83)3(10)1(3)1(3)
Right Knee21(70)5(17)2(7)2(7)
Left Knee23(77)4(13)2(7)1(3)
Right Calf22(73)6(20)1(3)1(3)
Left Calf24(80)6(20)1(3)1(3)
Right Ankle15(50)10(33)3(10)2(7)
Left Ankle15(50)12(40)2(7)1(3)
Right Foot20(67)5(17)2(7)3(10)
Left Foot20(67)5(17)2(7)3(10)
Referring to the Table 4.3, the highest percentage of level
discomfort of specific body region is at hand with 70%. Discomfort
recorded with 10% only while highest is mild discomfort with 50%.
The rest 10% was complained as moderate discomfort. There were also
reported that they feel severe discomfort on some parts that are on
their waist, and left thigh. However the percentage is too low with
3%. From the table 4.3 it can be observe most of them that report
having pain symptoms in previous question were saying that the pain
level is at mild discomfort.
Figure 4.8: Discomfort of the specific body region of
respondent
From the overall result, it shows that upper extremities of body
region specifically from shoulder to hand were the most discomfort
part of body region that the respondent chose. There is also a
complains about the discomfort at the respondent lower extremities
of body region, which at their ankle and foot mostly because of
their long standing working posture. The highest body part was
recorded as discomfort is hand and the lowest part is thigh.
Figure 4.9: Problem encounters during works
Based on the data that had been collected from question 23,
question 24, question 25, and question 26, the results was compiled
and interpreted into the Figure 4.9 above. From the analyzed data,
30 out of 30 respondents faced the same problem during their works
activities. Which is means that 100% of the respondents experienced
turning waist while working. The respondents admit by turning their
waist during working, they can minimize their movement but they did
not realize how it can bring the negative impact to their body.Out
of 30 respondents, 90% agreed they experienced long-term standing
working posture. This is due to their work nature that forced them
to work by standing. Meanwhile 83% respondents experienced bend
down during works. This situation was unavoidable since their part
or material box are placed on floor. So, they have to bend down to
reach it with no compromise
Figure 5.0: Respondent response over training before conduct the
machine
The percentage result from the question 28 of the questionnaire
was significantly led to the negative answer. About 83% respondents
admit that they didnt have sufficient training before conducting
the machine. This is because most of the operators in the plant are
from an agency, so the agency just put them randomly into the
company without giving them the training before work. Only a few of
the respondents have sufficient training to conduct the machine b
due to their previous work experience. The result was supported
with the company record of high value of defect products per day.
4.2 Direct Observation and REBA EvaluationFrom the walk through
observation, workings operator body postures were observed and
captured. Ten pictures were selected, and the results of the
posture evaluation were tabulated on the table below. In the case
of the operation of finishing line, which is drilling (situation
1-3), the risk of exposure to MSD's was high (AC 4) which requires
investigation and implement changes. For other activities in
operation line (Situation 4-10), the average risk of MSD's is
classified as high too, which is AC 4. The high level was due to
the need to maintain a stable upright posture while working, tilt
the body, especially for the collection of the part from the box,
and a high involvement of the upper limbs in the performance of the
task.The most vulnerable segments of the body to injuries arising
were the thorax, which was usually tilted heavily forward, or
twisted to the side. The other segment is legs; this is due to the
standing nature of the work. Last but not least is the arms, which
is most were at a greater distance from the axis of the body,
elevated at the shoulder joint, and frequently bent and twisted
wrists.Only four working positions were rated as medium, which are
position 3, position 4, position 6 and position 8 (AC 3) that need
further investigation and changes soon.Table5.1: REBA Scores based
on 10 selected working posturesSituationsScoresFinal REBA
scores
Table AForce/LoadTable BCouplingTable CActivity
170619110
25061819
34031415
42041617
55053819
65031516
75052819
81051617
960629110
1050819110
Table 5.2: REBA scores with description of working
posturesBil
Static pictures with REBA scoreDescription of Working
Posture
1.REBA SCORE: 10The trunk position is deviated about 45o to
90ofrom the neutral posture. Wrist is bent from midline within 0o
to 15o, while neck in extension. The position is maintained for
longer than 1 minute and repeated. The operator work in standing
position about 8-10 hours per day.
2.REBA SCORE: 9Neck and trunk are flexed about 20o from neutral
posture. Upper arm is abducted about 45o to 90o, lower arm raised
about 0o to 60o, wrist are bent within 0o to 15o in radial and
ulnar deviation. The operator work in standing position about 8-10
hours per day and small range action repeated more than 4 times per
minute.
REBA SCORE: 5Neck and trunk are flexed about 20o from neutral
posture. Upper arm is abducted about 20o to 45o, lower arm lowered
about 0o to 10o. The operator work in standing position about 8-10
hours per day and small range action repeated more than 4 times per
minute.
REBA SCORE: 7Upper arm is abducted about 45o to 90o, lower arm
raised about 0o to 60o, and shoulder is raised. Wrist is bent
within 0o to 15o in radial and ulnar deviation. Twisting at the
waist. The operator work in standing position about 8-10 hours per
day and small range action repeated more than 4 times per
minute.
REBA SCORE: 9The trunk position is deviated about 45o to 90ofrom
the neutral posture. Upper arm is abducted about 20o to 45o, lower
arm raised about 0o to 10o, and shoulder is raised while neck in
extension. The position is maintained for longer than 1 minute and
repeated.
REBA SCORE: 6Neck and trunk are flexed about 20o from neutral
posture. Lower arm is abducted about 60o to 100o, wrist are bent
within 0o to 15o in radial and ulnar deviation, and twisted. The
operator work in standing position about 8-10 hours per day and
small range action repeated more than 4 times per minute.
REBA SCORE: 9Neck and trunk are in extension about 20o from
neutral posture. The waist is bending. Upper arm is abducted about
90o or above, lower arm raised about 60o to 100o, wrist are bent
and twisted within 0o to 15o in radial and ulnar deviation. The
operator work in standing position about 8-10 hours per day and
small range action repeated more than 4 times per minute.
REBA SCORE: 7Neck and trunk are flexed about 0o to 20o from
neutral posture. Upper arm is abducted about 90o while lower arm is
abducted about 60o to 100o, wrist are bent within 0o to 15o in
radial and ulnar deviation, and twisted. The operator work in
standing position about 8-10 hours per day and small range action
repeated more than 4 times per minute.
REBA SCORE: 10Neck and trunk in extension about 20o from neutral
posture. Upper arm is abducted within 45o to 90o and lower arm is
abducted about 60o to 100o. Wrist are bent and twisted within 0o to
15o in radial and ulnar deviation. Waist is bending and twisted.
The operator work in standing position about 8-10 hours per day and
small range action repeated more than 4 times per minute.
REBA SCORE: 10Upper arm is abducted about 90o and above, while
lower arm abducted about 90o to 100o, and shoulder is raised. Wrist
is bent within 0o to 15o in radial and ulnar deviation and twisted.
Twisting at the waist. The operator work in standing position about
8-10 hours per day and the body posture are held for longer than 1
minute.
CHAPTER 5
ERGONOMIC INTERVENTION
The interventions have been implemented after 2 months from the
process of the data collected and analyzed. For this study, the
scholar implemented three ergonomic interventions in the plant one
at a time. This is to make sure that each of the intervention
really did some changes or improvements. Besides, one at a time
implementation provides the easier way for data collection process.
Based on the results, the scholar implemented three ergonomic
interventions in the plant which included packing blocks, modified
adjustable table and rubber mat. These interventions were
implemented in different workstations. Packing block was
implemented in the CNC machine, while rubber mat was placed on
floor in the production line. And lastly, the adjustable table was
not in a fixed workstation since the table was attached to the
pallet jack.5.1 Adjustable TableSince the operators at the working
floor had same difficulties with their work bench, the scholar
decide to design a new working table which its height can be
adjusted and can be easily moved. With the help of the technician
in the working floor, a custom made table had been made by using
the ready material in the company. The table then was attached to
the pallet jack as shown in the Figure 5.1.1 below.
Figure 5.1.1: Final product of Modified adjustable tableBecause
of the table will be attached to the pallet jack, the dimension of
the table must be accurate so that there is no problem occurred
during the attachment of the table and the pallet jack. So, the
process of measuring the pallet jacks dimension was took place
before designing the drawing. The design drawing was created by
using AutoCAD software in the company with the help of the designer
in the design house. The flow of the process of this intervention
had been simplified into the Figure 5.2 below.
Figure 5.1.2: Process flow of the intervention
Figure 5.1.3: Spraying process of the table.
Figure 5.1.4: The height of the table that can be adjusted.
5.2 Packing BlocksThe second intervention is focusing on the
operation in the Machining Department which is mainly at the CNC
machine. A questionnaire was distributed to the CNC operator and
the data had been analyzed. To add some details, the Retrieved of
Archival Record method was used. From the data obtained, the
operator spend about one month, 29-31 days to finish their given
task. Since there is no changes can be made related to the CNC
machining process and timing, then the only thing that we can
modified is the activities that doesnt related with the CNC
machine. So, removal of rust on the dies activities (finishing
process) is selected. In order to reduce the overall production
time, the scholar altogether with the supervisor discussed and come
up with the idea of using the packing blocks in the CNC
machine.
Figure 5.2.1: The packing blocks that are designed in different
sizes
As we can see from Figure 5.2.1 above, the packing blocks are
designed in different sizes due to the shape and the design of the
dies are varies. The packing blocks are functioning as the divider
between the dies and the CNC machine so that there is no direct
attachment between those two.
Figure 5.2.2: The usage of the packing blocks in the CNC
Machine
Figure 5.2.2 above shows how the packing blocks are used in the
CNC machine. Because the company is practically use coolant that
mix up with the water, these combination of both fluid expose the
surface of the die to the development of corrosion. From previous
record, process of rust removal from the surface of the dies
somehow took 2 days from the overall production time since the
operator doing it manually.The intervention was implemented a week
after the first intervention. For this intervention, it took longer
times due to the production process for these packing blocks were
made in different company. To withstand the weight of the dies and
to avoid the corrosion happen to the packing blocks, a lot of
thought was put into the selection of the material. After doing
some research, material SKD 11 (alloy tool steel) has been
selected. SKD11 is a High-Carbon High-Chromium alloy steel with
high hardness (appropriate toughness) and tempering hardening
effect.
Figure 5.2.3: Drawing and 3D model sample of the packing
blocks
There are four design of the packing blocks were created. One of
the design is the one that shown in the Figure 5.2.3 above. All the
drawings were sent to the other company that able to make the
custom made products. The cost was fully sponsored by the Autokeen
Sdn Bhd.
5.3 Rubber MatsBased on the Direct Observation and Subjective
Assessment data gain, the biggest issues is about the respondent
long-term standing. From previous research, the effects of
long-term standing on hard surfaces are not comfortable due leg
muscles become static and continuously flexed to ensure the body in
an upright position.
Figure 5.3.1: Standing for long periods reduces the natural flow
of oxygen and blood back to the heart, which can cause fatigue and
blood pooling in lower extremities
As for the solution, the scholar came up with an idea to propose
the intervention of rubber mat in the production line. Based on the
environment of the department, the vibration that caused by the
stamping machine can be one of the ergonomic risk factors.
Prolonged and repeated exposure of human body to vibration caused
reduced blood flow and lead to permanent blood vessels damage.This
intervention mat is a Neoprene rubber- based material. Neoprene is
a synthetic rubber produced by polymerization of chloroprene and
used in weather-resistant products, adhesives, shoe soles,
sportswear, paints, and rocket fuels. Neoprene polychloroprene was
originally used as an oil-resistant replacement for natural
rubber.
Boots insole rubberNeoprene rubber
Figure 5.3.2: Custom made rubber mat that had been implement
The Figure 5.3.2 above shows the picture of the rubber mat.
There are two different materials for this mat which are Neoprene
and the rubber for shoes insole. Both of the materials are used to
isolate noise and high frequency vibration generated by mechanical
equipment. The idea to make this mat was based on the Kinetics
Model RD Neoprene Isolation technology.This 6cm mat is made up from
two layer of Neoprene rubber on the side, and the insole rubber was
placed at the middle of the mat. These rubbers were attached
together by using the special glue for the rubber material. It took
a week before the glue completely dried up. And the intervention
was placed at the production line, which is at the stamping
machine.
Figure 5.3.3: The operator standing on the rubber mat during
stamping operation
CHAPTER 6
CONCLUSION
6.1 DiscussionAfter three months of the implementation,
Subjective Assessment, Direct Observation and Retrieved of Archival
Record method had been carried out in order to determine the
effectiveness of each of the interventions. The same questionnaire
was distributed to the same person who is being the subjects of the
interventions.
Table 6.1.1: Percentage of level discomfort of specific body
region before the interventionBody
RegionsNon-Discomfortn(%)Discomfortn(%)Mild Discomfortn(%)Moderate
Discomfortn(%)Severe Discomfortn(%)
Waist15(50)12(40)2(7)1(3)1(3)
Neck13(43)13(43)4(13)
Right Shoulder15(50)8(27)7(23)
Left Shoulder20(67)6(20)4(13)
Right Upper Arm10(33)12(40)5(17)3(10)
Left Upper Arm16(53)10(33)3(10)1(3)
Right Forearm16(53)11(37)1(3)2(7)
Left Forearm19(63)8(27)2(7)1(3)
Right Hand9(30)3(10)15(50)3(10)
Left Hand12(40)14(47)3(10)1(3)
Right Wrist21(70)3(10)6(20)
Left Wrist23(77)4(13)2(7)1(3)
Right Thigh23(77)6(20)1(3)
Left Thigh25(83)3(10)1(3)1(3)
Right Knee21(70)5(17)2(7)2(7)
Left Knee23(77)4(13)2(7)1(3)
Right Calf22(73)6(20)1(3)1(3)
Left Calf24(80)6(20)1(3)1(3)
Right Ankle15(50)10(33)3(10)2(7)
Left Ankle15(50)12(40)2(7)1(3)
Right Foot20(67)5(17)2(7)3(10)
Left Foot20(67)5(17)2(7)3(10)
In the Table 6.1.1 above, it shows that upper extremities of
body region specifically from shoulder to hand were the most
discomfort part of body region that the respondent chose. There is
also a complains about the discomfort at the respondent lower
extremities of body region, which at their ankle and foot mostly
because of their long standing working posture. The same set of
questionnaire was distributed to the same person who is being the
subjects of the interventions. There was a slightly reduction in
musculoskeletal complaints after the interventions. Figures 6.1.1
below show the changes in the frequency of musculoskeletal
complaints in different parts of the body. Figure 6.1.1: The
comparison graph of discomfort in specific body region of the
respondent before and after the intervention
The highest reduction complains recorded is 2 which at the
waist, calf, shoulder, thigh and knee body region. There is not
much improvement since the interventions did not focus on person by
person. But, one reduction of foot and one reduction of calf
complains in discomfort of specific body region was come from the
subject of rubber mat intervention. Additionally, the respondent in
Machining Department, which is where packing blocks are
implemented, also report that there is less pain in his thigh and
waist body region since he dont have to spend a lot of time sitting
and bending to clean the die.
Besides, the operators in the production department gave a
positive feedback regarding the intervention of adjustable table.
The respondents agreed about the usage if adjustable table improve
their work performance. Since the table is movable and its height
is adjustable, the operator use less working energy and they dont
have to bend down to reach their product. Figure below shows the
operator using the table to place his part. However, he did not
lift up the table to the maximum height so that the height is more
ergonomic to him.
Figure 6.1.2: The intervention usage in the production line
While for the second intervention, which are packing blocks,
there are some improvements in the machining department. A
production time for the latest TATA project from Miyazu was
recorded faster than previous production overall time. The operator
saved 2 days for rust removing activities since there is less
corrosion development on the surface of the dies. This study had
some limitations. Regarding ergonomic modifications, the scholar
could change the arrangement of workstation and some non-ergonomic
equipment but the production activities in the plant cant be stop.
The strongest improvements can be done, but some of these
modifications are costly. At first, the scholar decided to
implement anti-vibration in the work plant, but the idea need to be
cancelled since the cost for the mat is out of budget.
5.2 RecommendationsIn order to reduce working injury and to
preserve workers health and safety, corrective actions should be
carried out soon. Ergonomic intervention should be related to
reorganization of workstations, and redesign of working
methods.
Figure 5.2.1: The Basics of Neutral Working Postures
By referring to the basic of neutral working postures above, the
ergonomic interventions at the work station can be done by:
Figure 5.2.2: Designing the job to allow the worker to keep the
arms low and the elbows close to the body.
Figure 5.2.3: A chair, footrest, a mat to stand on, and an
adjustable work surface are essential components for a standing
workstation
5.3 Conclusion For the conclusion, based on the evaluations of
this study, the workers in the unorganized and manufacturing
sectors are compelled to maximum amount of work but minimum amount
of safety. As the result, the operators had to perform strenuous
manual tasks for prolonged period and suffer from injury and pain
afflicting different body parts. The best way to prevent Work
related Musculoskeletal Disorders (WMDs), is to implement ergonomic
intervention. In this study the scholar found a beneficial
short-term effect for the ergonomic interventions.
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