ERGONOMICS ASSESSMENT OF SHEET METAL
CUTTERS
AZIMI B AB RASHID
B050810032
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
ERGONOMICS ASSESSMENT OF SHEET METAL CUTTERS
This report submitted in accordance with requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing
Engineering (Manufacturing Management) with Honours.
by
AZIMI B AB RASHID
B050810032
DECLARATION
I hereby declare that this report entitled “Ergonomics Assessment of Sheet Metal Cutters” is the result of my own research except as cited in the references.
Signature :
Author’s Name : AZIMI B AB RASHID
APPROVAL
This report is submitted to the Faculty of Manufacturing Engineering of UTeM as a partial fulfilment of the requirements for the degree of Bachelor of Manufacturing Engineering (Manufacturing Management) with Honours. The members of the supervisory committee are as follow:
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ABSTRAK
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ABSTRACT
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ACKNOWLEDGEMENT
First and foremost, I would like to thank my parents and family for the endless encouragement and undying support for me complete this report especially to my father, AB RASHID B MAMAT and my mum CHE ARIAH BINTI MAT ZAIN. They have been my inspiration to bring out the best of me in completing this study.
I also wish to thank all of lecturer in Management Department of Manufacturing Engineering Faculty Universiti Teknikal Malaysia Melaka ( UTeM). In addition, thanks and apologies to others whose contributions I may have forgotten to acknowledge.
I also would like to express my sincere thank to my friends in 4BMFU. Their idea and moral support have helped me during this project. I wish them achieve their goal successfully.
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1.1 Background Study of Sheet Metal Cutters 1
1.2 Problem Statement 3
2.2 Repetitive Motion Injuries of the Upper Limb 6
2.3 Hand Tools Ergonomics 7
v 2.5 Methods and Techniques Used in Evaluating Hand Tools Ergonomics 9 2.5.1 Several Considerations Regarding Hand Tool Ergonomics 10
2.5.1.1 Design of Grip 10
2.5.1.2 Effectives Weight of Tools 10
2.5.1.3 Grip span and Handle Length 11
2.5.1.4 Duration and Repetitiveness of Use 11
2.5.1.5 Users Consideration 12
2.6 Comparison of Methods and Technique 12
2.7 Evaluation Sheet Metal Cutters (Tools and Technique) 13
2.7.1 Questionnaire Survey 13
2.8 Literature Review Summary Journal 15
3. CHAPTER 3: METHODOLOGY
3.4.2 Usability Survey Questionnaire 19
3.4.3 Comfort Survey Questionnaire 20
3.4.4 Actual Testing of Tools 20
3.4.5 Straight Cutting 20
3.4.6 Curved Cutting 21
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3.6 Laboratory Testing of Sheet Metal Cutting 22
3.6.1 Subjective Grip Force Assessment for Sheet Metal Cutting Tasks 23
3.6.2 Tool Specifications 24
3.8.3 Design and Development Stage 29
3.8.4 Analysis Stage 29
4. CHAPTER 4: RESULTS AND DISCUSSION
4.1 Tin Snips Data Analysis 30
4.2 Overall Score Result 32
4.2.1 Pre and Post Estimate Force Score for Tin snips 33
4.2.2 Tin Snips Grip Force Score 34
4.3 Pre Estimate and Post Estimate Results 35
4.4 Tin Snips Ergonomics Factors Survey Results 38
4.4.1 Ergonomics Factors 39
4.5 Tin Snips Usability Factor Survey Results 48
4.5.1 Usability Factors 49
4.6 Additional Hand Tools Evaluation 55
4.6.1 Hand Tools Design Consideration 55
4.6.2 Hand Grip 55
4.6.2.1 Comparison Tin Snips Hand Grip 55
4.6.3 Handle Length 56
4.6.3.1 Comparison Tin Snips Handle Length 57
4.6.4 Handle Size 58
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4.6.5 Handle Material 59
4.6.5.1 Comparison Tin snips Handle Material 59
4.6.6 Weight of the Tools 60
4.6.6.1 Comparison Tin Snips Weight of Tools 61
4.6.7 Handle Shape 62
4.6.7.1 Comparison Tin Snips Handle Shape 62
4.7 Testing Limitation 63
5. CHAPTER 5: CONCLUSION & RECOMMENDATION
5.1 Conclusion 64
5.2 Recommendation 66
REFERENCES 67
APPENDICES A - Tin Snips Questionnaire Data & Calculation
APPENDICES B - Pre Estimate and Post Estimate Questionnaire Form
APPENDICES C - Tin Snips Ergonomics and Usability Questionnaire Form
APPENDICES D – Overall Results Ergonomics and Usability Questionnaire
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LIST OF TABLES
2.8 Literature Review Summary Journal 15
3.6.2 Tin snips tool specification 24
4.1 Overall score, pre and post estimate grip force for tin snips 31 4.2.1 Pre and post estimate force data for tin snips 34
4.2.2(a) Tin Snips 1 grip force Average score 34
4.2.2(b) Tin Snips 2 grip force Average score 34
4.2.2(c) Tin Snip 3grip force average score 34
4.3 Pre estimate and post estimate grip force result for tin snips 35
4.4 Ergonomic rating for tin snips 38
4.5 Usability rating for tin snips 48
4.6.2.1 Comparison tin snips hand grip 56
4.6.3.1 Comparison tin snips handle length 57
4.6.4.1 Tin snips comparison of handle size 58
4.6.5.1 Comparison tin snips handle material 60
4.6.6.1 Tin snips comparison for weight 61
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3.8 Flow chart of the overall project process 28
4.2 Overall score result for tin snips 32
4.3 Pre estimate and post estimate force result for tin snips 36 4.3(b) Participants cutting tasks using tin snip 1 37
4.4.1(a) Tin snips 1 rectangle shape 39
4.4.1(b) Tin snip 2 curve shape 39
x 4.4.1(f) Feeling numb agrees percentages for tin snips 43 4.4.1(g) The tool will promote a comfortable hand posture agree
percentage for tin snips 44
4.4.1(h) Feeling slippery at handle agrees percentage for tin snips 44 4.4.1(i) Needs low hand grip force supply for tin snips 45
4.5.1(c) Using this tool in my job would increase my productivity for
tin snips 51
4.5.1(d) Learning to operate this tool would be easy to me for tin snips 52 4.5.1(e) 1 would find it easy to perform cutting task for tin snips 52 4.5.1(f) 1 would find this tool easy to use for tin snips 53 4.5.1(g) Using this tool would enhance my effectiveness on the job for
tin snips 53
4.5.1(h) Using tool would make it more difficult to do my job for tin snip 54
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LIST OF ABBREVIATION
CM - Centimeter
CTS - Carpel Tunnel Syndrome
EMG - Electromyography
F - Female
FYP 1 - Final Year Project 1
FYP 2 - Final Year Project 2
KG - Kilogram
M - Male
P1-P11 - Participant 1 to Participant 11
Q1-Q16 - Question1 to Question 16
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CHAPTER 1
INTRODUCTION
1.1 Background Study of Sheet Metal Cutters
Using of hand tools lead to feeling of comfort and discomfort factor. These feeling of discomfort can reduce efficiency and satisfaction of workers. Using hand tools can also cause musculoskeletal disorders for the long term. Comfortable hand tools can reduce the occupational injury for the workers. Design of hand tools very important for discomfort user and provide worker satisfaction. Comfort is considered for construct of a subjectively defined personal nature, affected by factors of various nature (physical, physiological, psychological) and reaction to environment.
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The idea of comfort in hand tools would also extend to sheet metal cutters. The design of sheet metal cutters can highly influence comfort for users, as well as reducing the risk of upper limb musculoskeletal disorders. Sheet metal cutting may cause neck and upper limb disorder. The force, posture and frequency of movement of the hand, forearm, and wrist posture, high torque forces, high repetition, friction and shoulder has been associated with such disorder. Interaction between user and hand tool posture and muscles, irritation and pain hand fingers, irritation hand surface and handle characteristic.
Ergonomic sheet metal cutting tools expose factors are the following hand tools user considerations. Firstly in sheet metal cutting design of grip, weight, duration frequency use and gloves using would influence hand tool comfort. Worker characteristic such as left and right handed, gender and age, strength, technique, body size and posture profoundly influence both risk of injury and productivity in work with hand tool for user consideration.
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1.2 Problem Statement
Poor design and excessive use of sheet metal cutting may be associated with increased incidence chronic disorders of the hand, wrist and forearm. Dissatisfaction using the sheet metal cutting for the long time because discomfort factor.
Short term fatigue and discomfort has been considered risk factors for musculoskeletal syndromes and have therefore been used been used as criteria in ergonomic guidelines and standard. Type of tools, the majority of injury is inflicted by non power hand tools due to the widespread use of non powered hand tools. Sheet metal cutter is a non powered hand tools. Therefore this project will focus on the evaluation and improving the design of sheet metal cutting.
1.3 Objectives of Study
The main objectives this project is to conduct an ergonomics evaluation of sheet metal cutters. This project can improve the sheet metal cutters more comfort and less comfort for users during their job. To achieve the main objectives, these sub objectives are described:
To perform a hand tool ergonomics assessment for sheet metal cutters. To conduct a usability assessment of sheet metal cutters.
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1.4 Scope of Project
This project focuses to sheet metal cutting hand tools about comfort and discomfort factors, related from ergonomic sheet metal cutting design. Focus to the musculoskeletal disorder and injury factors from the type of sheet metal cutting design. Comparison and evaluate good design of sheet metal cutting from different types of tools user. Scopes in sheet metal cutters laboratory testing is curved and straight cutting only with material plate thickness 0.8 mm. Subjective of grip force testing focus for right handed users only.
1.5 Potential/Benefit of Project.
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CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
This chapters contains the literature review of the study relates to the scope of the study. Design aspect very important for develop ergonomic sheet metal cutters tools. Using hand tools must be comfort to workers for the job satisfaction.
Design of comfortable sheet metal cutters can be reduce the risk of occupational injury. Basic ergonomic principles of hand tools design have been known for several decades, limited attention has been paid these principles in designed widely used industrial tools. Guidelines has been general, lacking specify and frequently conflicting.
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2.2 Repetitive Motion Injuries of the Upper Limb
The concept repetitive work refers to similar tasks performed again and again. Repetitive work of the upper extremity implies motor component, which can defined in terms of time and force. Repetitive work of the upper extremity is considered one of several physical work load factor, associated with symptoms and injuries of the musculoskeletal system. Other important factors are static loads, posture, and exertion of external forces. Static load occurs when muscles are kept motionless for a long time and this is undesirable in any work situation, especially while using hand tools. The muscles become more vulnerable to fatigue and future injury.
Body posture is an effect of posture on torque exertion capability was studied in detail Mital (1986) and Mital and Channaveeriah (1988). Body posture influence using the hand tools because prevention from the awkward posture, wrist posture and effected to the musculoskeletal injuries and repetitive motion injuries.
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2.3 Hand Tools Ergonomics
Using hand tools that require awkward and forceful hand exertions can cause (carpal tunnel syndrome, tendinitis, muscle strain, and other problems).
Carpal Tunnel Syndrome (CTS) is associated by symptoms and signs, which are caused by compression of the median nerve travelling through the carpal tunnel. Carpal Tunnel Syndrome affects the hands since it is an upper limb neuropathy that results in motor and sensory disturbance of the median nerve.
Tendinitis meaning inflammation of a type of tendinopathy often confused with the more common tendinitis, which has similar symptoms but requires different treatment. The term tendinitis should be reserved for tendon injuries that involve larger-scale acute injuries accompanied by inflammation. Generally tendinitis is referred to by the body part involved, such as Achilles tendinitis (affecting the Achilles tendon), or patellar tendinitis (jumper's knee, affecting the patellar tendon).
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2.4 Recent Studies on Hand Tool Ergonomics.
There have been a number of studies on the ergonomic evaluation of hand tools. One such study involved Groenesteijn et al (2004) where the authors evaluated pliers in a laboratory setting and in a field study. 3 different plier designs were evaluated. The subjects in the field study consisted of industrial workers and in the laboratory study it consisted of students. The results of the study showed that the multitask plier appeared to result in more comfort during working, more relaxed working and more satisfaction. No differences in productivity were found. Groenesteijn et al (2004) concluded that the multitask pliers can replace the originally used pliers and were suitable for more tasks than the original pliers.
Studies in an EU company from de Jong and Vink (2002) showed a high physical workload among employee. Awkward posture , heavy lifting and repetitive handling are often seen. This problem not occurs in one company and increase each of years. Awkward postures are postures that when used repetitively or for prolonged periods result in increased risk of fatigue, pain or injury. These postures are sustained either actively by muscle contractions or passively by compressive or tensile loads on bones, muscles, tendons, ligaments,etc. (Chaffin et al., 1984). Which the type of musculoskeletel disorder case is a neck and upper limb disorders.
