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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. Manufacturers recognize comfort as a major selling point, as it is thought to play an
increasingly important role in product buying decisions. Therefore, they pay more attention to the design of comfortable hand tools, which reduce the risk of occupational
injury and result in high product quality for customers, and of course, comfort for users. The major question here is, how to design hand tools that are characterized by much
comfort for the user .Therefore, a clear definition of the concept of comfort is important to the designer, as well as knowledge about which factors contribute to the comfort of
the end user. Comfort and discomfort have been as two discrete state Hertzberg, 1972; Branton, 1962, as two opposites on a continuous scale and as two separate entities
underlied by different factors Zhang et al.,1996.
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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.
Ergonomic sheet metal cutting important for avoid feeling of discomfort during the job and reduce musculoskeletal disorder on a long term. Hand tools design must be
ergonomic and comfortable for workers because related with productivity. Discomfort
may also reduce job satisfaction and avoid to the workers from give high performance during using the hand tool especially sheet metal cutting tools. Poor design and
discomfort sheet metal cutting tools can increase the incident of chronic musculoskeletal problem disorders for hand.
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1.2 Problem Statement