The simple assembly line balancing problem with parallel workstations - A simulated annealing approach

This work presents a new mathematical programming model for the simple assembly line balancing problem with parallel workstations that allows the user to control the way workstations are 'parallelised'. As in the conventional procedures the user can limit the number of replicas allowed for each workstation, but in this novel approach the user can also define a minimum task time to trigger the replication of the workstations. Another important characteristic of the model is that it simultaneously minimises the number of workstation and smoothes the workload among them. Due to the model complexity a simulated annealing approach is proposed to solve it. An example is used for illustration and computational experience is provided. The computational tests show that the performance of the proposed procedure is quite good, taking into account the problem complexity.Significance: Assembly lines are employed for high volumes of output, so the global savings that result from a small reduction in unit costs, fostered by a correctly balanced line, can be important, The proposed model introduces a more realistic approach to assembly line balancing than previous ones.