We are interested in Discrete Event Dynamic Systems and especially in Flexi
ble Manufacturing Systems (FMS) and their production management. In order t
o master the combinatorial complexity, ive adopt steady, repetitive and det
erministic schedule. We have already determined an approach to compute this
cyclic schedule (which corresponds to the steady state) while optimizing q
uantitative and qualitative performance criteria: cycle time (throughput),
Work In Process, simplicity of the schedule. In order to apply this schedul
e ive consider and compute the transient periods to start and end the produ
ction. In a previous paper [9], ive gave a preliminary study of the transie
nt states. We computed upper and lower bounds for the transient state, the
steady state and the makespan then we established a method to optimize the
makespan. In this paper, we recall some necessary assumptions and definitio
ns for the study of the transient states then we give a heuristic for the c
omputation and optimization of the makespan.