Flow Lines with Random Processing Times
A "Flow Line" comprises work stations with random processing times. This is usually the case if human workers perform manual operations. For example, the final assembly of televisions is usually done by humen workers.
Besides the average processing time for each station also variation - usually quantified with the parameter "coefficient of variation" (=standard deviation/average) - to account for the amount of randomness of the processing time must be specified.
This type of flow production system can also be used to model a system with deterministic processing times, but with a mix of different products fed into the line in a random order. At each station, each product may have a specific processing time. If an external observer loks at the sequence of different workpieces with specific processing times arriving at a station, this basically is equivalent to a sequence of identical workpieces but with random processing times.
The work stations are decoupled with the help of buffers of limited size.