Influence of task time variation in adopting Walking Worker assembly systems: a design approach

Unlike traditional Fixed Worker (FW) assembly systems, in which an operator remains in the same workstation performing repetitive tasks, in the Walking Worker (WW) ones the operators travel along the line stations to produce the finished product. Interestingly, such a configuration enables to achieve a greater level of production volume flexibility, without changing the assembly system layout, parts disposition, and tools assignment. The basic requirement of a WW is to be cross-trained and able to fully assemble the product from beginning to end. The WW travel activity, which increases when the number of stations increases, negatively impacts on the system performance. On the other hand, the possibility to have extra-stations, i.e., a greater number of stations compared with the number of operators, makes the WW system able to dynamically balance the work overload differences between the operators.