First Failure Time and Uptime

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question

eddie0527 asked Apr 9, '23 Jason Lightfoot commented Nov 28, '23

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!

Software Version:

FlexSim 23.0.5

mtbf mttr

1681012656763.png (38.9 KiB)

omisline-with-oee.fsm (11.4 MiB)

· 3

Jeanette F ♦♦ commented · Apr 12, 2023 at 05:41 PM

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.

If we haven't heard back from you within 3 business days we'll auto-accept an answer, but you can always unaccept and comment back to reopen your question.

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Karan commented · Nov 28, 2023 at 02:45 PM

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 ♦ Karan commented · Nov 28, 2023 at 03:15 PM

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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1701184473863.png (12.0 KiB)

Answer 1 · 2023-04-09T12:51:00Z

Jason Lightfoot answered Apr 9, '23 Jason Lightfoot edited Apr 9, '23

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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