Balancing mixed-model parallel two-sided assembly lines

Mass customization plays a significant role for customer satisfaction and for reaching global markets in today's highly competitive changing world. However, customization brings companies extra costs because of the different tasks and scheduling and/or manufacturing issues of model variations. Companies in the manufacturing industry are in a pursuit of reducing their costs whilst increasing their profits and customer satisfaction level. There is a trade-off between these conflicting objectives. Mixed-model assembly lines provide companies with greater flexibility and capacity to respond to different market demands, allowing them to cope with the extra costs caused by customized demands. This study investigates model variations for parallel two-sided assembly lines, which are widely used in the production of high-volume large-sized products like automobiles, trucks, or buses. The proposed system is introduced in a view of balancing approach with a summary of the relevant literature, which is given in tables in appendices. Two well-known test problems from the literature are also combined and illustrated as an example. It is obvious that mixed-model parallel two-sided assembly lines help to minimize operator requirements while improving line efficiency and communication between operators and increasing resource utilization when demand is high enough. To the best of our knowledge, this is the first study which addresses mixed-model parallel two-sided assembly line balancing problem in the relevant literature. The result that can be drawn from this research is that, this is a promising area which needs attention from both academia and industry.