Simulation two processes, batch size should remain same?

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John B10 asked Dec 31, '21 Felix Möhlmann answered Jan 3, '22

Simulation two processes, batch size should remain same?

Hi could anybody help me and tell me if my conclusions about the follwing simulation is right?:
I have simulated a process with 2 machines.
I have used the experimenter. I am simulating the process with a batch size from 9-13.

I have inserted two different process times. Once process time is mean_old:20 and std_old:8
and mean_new:16 and std_new:16
As result i get this values.

At a batch size of 12 we see that the average WIP is increasing high.

Now I want to know if the delivery batch size should remain the same? If I see this right we can have also a higher batch size because we can reach also a higher throughput. I am not sure if my decision is right.

Or which batch size is the best to choose?

simulation.fsm

Software Version:

FlexSim 22.0.0

case study

pic.png (107.4 KiB)

simulation.fsm (381.4 KiB)

· 2

Jason Lightfoot ♦ commented · Dec 31, 2021 at 03:25 PM

I think it helps if you name your scenarios:

simulation_jl.fsm

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1640964270294.png (21.2 KiB)

simulation-jl.fsm (506.7 KiB)

Jason Lightfoot ♦ Jason Lightfoot ♦ commented · Dec 31, 2021 at 03:27 PM

Also your std dev. value in the scenarios tab is 18, not 16.

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1640964374592.png (23.1 KiB)

Answer 1 · 2022-01-03T07:23:52Z

Felix Möhlmann answered Jan 3, '22

The rising average WIP shows you that items are accumulating in the queues because the processors can't keep up with the input. The same can be seen in the Throughput statistic. For a batch size from 9 to 11 the throughput increases linearly. Going up to a batch size of 12, the throughput increases less compared to the previous step and not at all when raising the batch size further.

The "optimal" batch size (max utilization of processors without increasing backlog) would thus lie somewhere between 11 and 12.

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