Development of a work instruction system based on analysis of learning processes for cellular manufacturing

Cellular manufacturing systems are well known as flexible manufacturing systems for assembly processes. Single workers carry out all assembly processes of products in the typical cellular manufacturing systems. The cellular manufacturing systems are required to cope with dynamic changes of product mix and production volumes. The workers are not able to be trained by repeating same assembly processes. The objective of this study is to propose a work instruction system for workers to understand the assembly processes quickly and reduce their assembly times of products without repeating same assembly processes. According to the learning curve of workers, it is important that the assembly time should be reduced from the first time the workers assemble the products in order to increase the productivity of cellular manufacturing systems. This study firstly records workers' assembly processes by using video equipment and analyzes the learning processes of the workers in order to propose an effective strategy for the workers to reduce the assembly processes in the cellular manufacturing systems. According to the proposed strategy, a prototype of a work instruction system is developed for an assembly cell. The prototype system provides a graphical user interface explaining the information of assembly processes for the workers to facilitate understanding the assembly processes. Some experiments are carried out for assembling a toy car built with Lego blocks in order to evaluate the effectiveness of the developed work instruction system. Experimental results of the proposed work instruction system are compared with the ones of a simple work instruction system. Through the comparison, it is recognized that the proposed work instruction system is superior to the simple work instruction system from the viewpoint of the reduction of assembly times.