CHAPTER 1: INTRODUCTION
Assembly lines are manufacturing processes which are of great importance in the industrial production of high quantity and even low volume production of customized products. In an assembly line, two or more different tasks are fitted together in a sequential manner to form a new finished product. An assembly line is a flow-oriented production system, where the operations on the workpieces are performed in the designed stations. The workpieces are moved along the stations in a line usually by some kind of transportation system, for example a conveyor belt, transfer lines or cranes. Henry Ford, the founder of the Ford Motor Company, is the father of modern assembly lines by introducing the use of assembly lines. This revolutionary assembly line was for the mass production of the Model-T automobile in 1908–1915 (Uddin et al., 2011).
Assembly lines were basically introduced and designed for a cost-efficient mass production of standardized products, also exploiting a high specialization of labour. In modern manufacturing system however, product requirements and its production systems have changed dramatically, mainly because of customer needs. Manufacturing companies have to allow for an individualization of their products, come up with more complex manufacturing strategies and assembly systems (Uddin et al., 2011). Designing and configuring assembly lines in modern era requires high capital investments, thus has attracted the attention of researchers, to solve assembly lines’ problem and optimize its efficiency in terms of productivity and cost (Boysen et al., 2006).
1.1 Background of the Study
There are many types of assembly line that are being designed and implemented in modern manufacturing. The designs of line vary widely according to the suitability to produce certain products, and this creates many kinds physical production floor layout. This includes Straight, Parallel, U-Shaped and Two-Sided lines, which are generally applied in modern assembly lines (Grzechca, 2011).
The products or work units are processed according to its set of tasks and they are performed at each station during a fixed period. This is widely known as cycle time of an assembly line, which is predetermined by a desired production rate. Related to that, the time the operators at each workstation take to complete a task is known as the process time. The production rate is very important so that the desired amount of finished products is produced within a certain time period. The total processing times at each workstation must not exceed the stations’ predetermined cycle time; otherwise the line will not be able to maintain the target production rate. The other critical term in all types of assembly line is idle (delay) time. Idle time is said to be present at a workstation, if the cycle time is more than the sum of the processing times within that station (Grzechca, 2011).
One of the indicators of a well-designed assembly line is the efficiency of...