Factory Explorer® v2.4
Technical Alert #22

Lot-Splitting Within Rework Loops

Summary: Factory Explorer's capacity analysis engine does not capture the effect of lot-splitting within rework loops, leading to an underestimate for the load on tools and operators found in these split-lot regions. There is no workaround for this problem, other than avoiding lot-splitting within rework loops. This problem is fixed in Factory Explorer v2.5 beta 5.

Details: In a model that specifies lot-splitting, Factory Explorer examines the flow and size distribution of lots into the split-lot step, and using the split-lot size, calculates the resulting flow and size distribution of split-lots into the split-lot region. The current release of Factory Explorer, however, only performs this calculation for non-rework lots. Thus, if lot-splitting is nested within a rework loop, the flow of rework lots effectively disappears as it enters the split-lot region, and reappears after the unsplit step. Within the split-lot region, the load on tools and operators is underestimated. This problem only affects capacity analysis results - simulation results are not affected.

Workaround: There is no workaround for this problem, other than avoiding split-lot regions within rework loops.

Techalert tafx22-9811

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