In a recent paper of Lapierre, S.D. et al., the authors considered the balancing of a PCB assembly line consisting of several pick-and-place machines. The authors claimed that, for the particular machine type they considered, the component placement time is independent of the placement sequence of the components and then concentrated on allocating component types to machines and configuring the feeders on each machine to balance the line. We show that the placement time is actually dependent on the placement sequence and thus, it needs to be accounted for if a more accurate line balance is looked for.
