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Both Activities and Conveyors can simulate situations were equipment or people work with less then 100% efficiency.

Note that Efficiency relates to machine breakdown rates, not loss of product in process in the from of scrap. This should be dealt with using a Routing Out option in the work Center. Typically a percent rule is appropriate.

Click the Efficiency button in either the Conveyor or Activity dialog to specify the efficiency rate.


Simply set the efficiency value (in % terms). If you wish you can also specify a typical time it takes to repair the stoppage. If you leave this field as a ? then SIMUL8 will automatically “repair” the Activity at a speed that appears compatible with the rate at that it is working.

With efficiency set to “AUTO” SIMUL8 calculates automatically mean-time-between-failure figures and uses negative exponential distributions for mean-time-between-failure and Erlang 2 distributions for repair time.


Time Between Breakdowns can be based on:

MTBF: Mean Time Between Failures. By default based on Clock time this option stops a machine working at intervals based on the distributions used. The default in SIMUL8 is to breakdown an Activity based on the elapsed time since the end of repair for the previous breakdown. This means that machines can breakdown even if they have not been working. Only Count Busy Time restricts the time since the last breakdown to count only to machine running time.

MCBF: Mean Cycles Between Failure. The number of machine cycles, or items processed, between the end of repair and the next breakdown.

To be able to select breakdown distributions yourself click the DETAIL button on the efficiency dialog.

Select the Work Items option to control the action on the current Work Item during Down Time.

SIMUL8 allows an additional Resource to be required for the duration of a breakdown, by selecting the Time to Repair option and then the Resources button.

More Information on Detailed Efficiency Options

Visual Logic

Visual Logic can be triggered at the start of Breakdown, at the start of Repair time and at the end of Repair time.

See Also