I have a simulation in which there are multiple workers behaving badly.
Problem: Invariably, the simulation run stalls when attempting to move an MU between two different workstations that are not connected. This happens at different times, but always happens on other side of one of the five WIP buffers.
Note: The above figures are from different simulation runs.
Any assistance would be greatly appreciated.
Solved! Go to Solution.
as you can read in the error message, there is a footpath missing between OD_wip2 and pree11.
I just added this footpath as you will see in the screenshot and the model was running without any error.
Hope this helps.
That makes the model run, but not according to the correct process. Connecting those two workstations bypasses the buffer. What I can't understand is why the simulation wants the MUs to move from offloading from these WIP (buffer) stations operators to putting the MUs at the buffer infeed.
I understood the error message wanting a connector between wOD_wip1 and pre21, for example, but I can't find in the methods and exit controls where that instruction is given.
Additionally, with this fix, the offloading worker regularly blocks the onloading worker, and one worker stops working after less than an hour and returns to the worker pool. Indeed, the first Frame (MU) to be completed embarks upon a senseless journey:
I have tried this fix (#5 in my original post) and it leads to further bad behaviour.
Any ideas on why an MU at buffer offload would want to circle back through that material flow element? This tanks throughput and is not representative of the process.
part SL:43 is carried by worker pre:1 to station OD_wp2.
Buffer OD_wp2 is full so the worker cannot drop the part there and the worker is waiting.
At this point in time, there is a shift event fromobject clock and worker pre:1 carries the part to buffer preShEnd.
The exit control of preShEnd moves part SL:43 to station OD_wp2 without modifying the destination of the part. Therefore when exiting station OD_wp2, the part wants to be carried to pre11 again.
Alterantive 1: define a new destination for the parts in the exit control of preShEnd
Alternative 2: define 'Carry part away' as exit strategy for preShEnd and set a high priority. After starting the shift again, the worker first will carry away the parts from preShEnd before carrying parts from Prefoam1.
Hope this will help.