Lean manufacturing is a systematic approach to identify and eliminate wastes. Adopting the lean manufacturing concepts has become inevitable. It can lead to many advantages including higher efficiency, better responsiveness and flexibility, shorter lead times, and lower rework and defect rates. This ultimately reduces the production costs, and is appropriate for current business environment where it is required to produce a portfolio of products with suitable production capacity.
This paper describes the process of transforming an assembly line to work with lean concepts. A methodology has been developed and used as a framework to utilize various lean manufacturing tools in analyzing the configuration and performance of the assembly line and identify the present forms of waste and their causes. Wastes included high levels of work-in-process that led to high defect rates, frequent inability to meet production targets within regular capacity, lack of flexibility and expensive change over between models were identified. Simulation models of the modified (lean) assembly lines were built and used as management decision support tools to investigate further modifications to the lean system.
Converting the assembly line into a lean production system led to cutting off work-in-process by about 82%, reducing the cycle time by 30%, and decreasing the model changeover time from 127.5 min to 11.5 min, in addition, splitting the assembly line into two parallel assembly lines to produce two models concurrently.