CHARACTERIZING THE OUTPUT PROCESS OF A CONWIP LINE WITH DETERMINISTICPROCESSING AND RANDOM OUTAGES

We model a CONWIP (CONstant Work-in-Process) production line with dete rministic processing times and exponential failure and repair times as a closed queueing network. We derive an approximation for the mean an d variance of the output during a specified interval and give computab le conditions under which this approximation performs well. We show th rough empirical tests that the approximation is robust and illustrate its usefulness as the basis for a procedure for selecting an economic production quota and a card count for a CONWIP line.