Anautomotive sheet-metal press line is an excellent example of an automatedmanufacturing system with time dependent complex control functions. The PLCcontrol functions include not only discrete events and supervisory control, butalso analogue feedback and motion control. Furthermore, most press line tuningmethods today are on-line and highly empirical, depending on individualoperators. Thus, there is a need of an objective off-line parameter tuningmethod. This paper presents an off-line parameter tuning of an automotivesheet-metal press line. Improved production performances have been reached,both in terms of increased production rate and smoother robot motions, comparedto today’s industrial on-line method. Two suitable optimisation algorithms havebeen implemented and evaluated. The challenge is to handle highly non-linearfunctions, considerable number of parameters, and long evaluation times in thesimulation. The utilised off-line method is a combination of simulation basedoptimisation and time synchronised hardware-in-the-loop simulation, i.e. avirtual manufacturing system including real PLCs. This method provides adistinct advantage, since it describes all complex control functions byexecuting the same PLC control code used in the manufacturing plant. A furtherbenefit is that all tuned process parameters can be directly transferred to themanufacturing plant.