This model represents an electronic assembly and test system.
Two types of parts (A and B) arrive to the system, and need to be pre-processed.
After that, the components are assembled and inserted in a case, which is sealed (sealer process).
The 91% of the parts pass the inspection, and are shipped.
The rest need to be reworked. After the rework process, the 20% of the parts are scrapped, while the rest are salvaged and shipped.