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eddie0527 avatar image
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eddie0527 asked Jason Lightfoot commented

First Failure Time and Uptime

OMISLINE with OEE.fsm
Hello Flexsim Answers Group,

I am doing a personalised juice simulation and I am quite new to Flexsim. I have attached the simulation model below above.


I am currently trying to induce downtime for one of the station using MTBF/MTTR. The problem I am facing right now is I do not know what function I should use for the uptime and first failure time in the function tab. The downtime I am using the normal distribution with my desired mean and std ev, but for the uptime, I want it to like will have a probability of 20 percent the downtime will happen when an object reaches the station. As for the first failure time, can I put negative value if I do not want to set the downtime happen at a certain time, I hope it will follow the probability once the production run. So, I hope you can really help me, thank you very much in advanced!

1681012656763.png

FlexSim 23.0.5
mtbf mttr
1681012656763.png (38.9 KiB)
omisline-with-oee.fsm (11.4 MiB)
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Jeanette F avatar image Jeanette F ♦♦ commented ·

Hi @eddie0527, was Jason Lightfoot's answer helpful? If so, please click the "Accept" button at the bottom of their answer. Or if you still have questions, add a comment and we'll continue the conversation.

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Karan avatar image Karan commented ·

Hi @Eddie0527,


Were you able to achieve "for the uptime, I want it to like will have a probability of 20 percent the downtime will happen when an object reaches the station"? If so, could you share how?
I am looking to do something similar

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Jason Lightfoot avatar image Jason Lightfoot ♦♦ Karan commented ·

Just make the average/expected uptime 4x the average/expected downtime, and then if you want it to happen only when an item is present change the states that apply to the interval:

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1 Answer

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Jason Lightfoot answered Jason Lightfoot edited

If your up time distribution has no memory then you can put that in the first failure field too.

Otherwise you should, in an ideal world, come up with a distrubution for the first failure time. In the past I've sampled a timeline of generated uptime events to then fit a distribution for the first failure.

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