M.Sc Student | Miri Gilenson-Zalevsky |
---|---|

Subject | Yield vs. Cycle Time Trade-off Analysis |

Department | Department of Industrial Engineering and Management |

Supervisor | Dr. Yedidsion Liron |

Full Thesis text |

Control limits in use in quality monitoring operations are traditionally set by yield requirements. Since deviations from these limits usually trigger production station stoppage, the monitor design has a direct impact on the availability of the station, and thus on the cycle time (CT). We first develop a bi-criteria trade-off formulation between the expected CT and the die yield at a single station based on the impact of the control limits in a system monitored by inspection stations on both performance measures. We then extend our result by formulating the Pareto-Optimal set for an entire flow-shop network rather than just for a single station.

We consider a
multi-step flow-shop network of *m=1,?,M* stations, each of which is
immediately followed by an imperfect inspection operation. We assume production
stations afflicted by a two-state particle deposition process whose rate can be
either low or high. If the inspection indicates high deposition rate, the
production is stopped for repair, which guarantees machine recalibration.

We explore the
impact of the upper control limit of inspection operation *m*, (*UCL _{m}*),
on the expected yield and CT of production station

Once *yield _{m}*
and

To extend our
result to a flow-shop network, we present an optimal greedy algorithm that
recommends a set of * UCL _{m}*
values for each point on the CT to yield Pareto-Optimal curve for the entire
line. The CT of the line is approximated using an acceptable
G/G/1 queuing network approximation technique. This technique allows us to
construct the CT to yield Pareto-Optimal set for the entire network in a
polynomial time.