Figure 6 presents the results for different PCB types (single
sided, double sided, multilayer). Multilayer PCB have a
stronger influence on the lead time of the job compared to
single or double sided PCB and it increases significantly with
the number of layers. The processing time per unit however is
significantly higher for multilayer PCB but not very much
affected by the number of layers. An explanation for the
increase in lead time for higher numbers of layers could be
found in longer waiting times at bottle neck processes.