Flexsim job shop problem

[a9080109]

[ FlexSim 22.0.16 ]

I'm currently building a model for gig production and I'm not sure why my model is having issues. But what I can provide is some preliminary information on modeling.

1. I have 20 orders but my production order is randomly generated.

2. My processing time wants to be set to evenly distribute 1,100, but I am wondering if I can give him a processing time label at the beginning, and then the machine will process according to the processing time label on the item.

But now it seems that my model is not processed as I thought.

random.fsm

[moehlmann_fe]

You need to return a specific number in the Send to Port field of the queue, so it can 'know' that the item was pushed to list and correctly listen for a pull to release it. Use the "Push to List" option in the Send to Port field instead of Process Flow to get this to work easily.

You also have a "Pull from List" expression in the process time field of processor2. That's probably not supposed to be there.

[a9080109]

spt0501.fsm

but its look happend some problems!

[moehlmann_fe]

That's the same model you uploaded before (?). I'm aware that there are issues in the model. I told you what you need to change. (Push to list in Send to Port option and process time field of processor2).

The pull query is also missing an expression that matches the processor station number and station label on the item.

spt0501-fm.fsm

[a9080109]

Hello, I tried to do it in my own way but found that it did not work smoothly. I would like to ask why?

[a9080109]

@Felix Möhlmann

I have a new question now. I think the current processing method is my ideal method, but I want to ask about the input of my machine. There are several arrows. I want to ask whether the ordering of the arrows will affect the overall priority? as the picture shows

Assuming that both q13 and q12 have items that need to be fetched, will q13 be fetched first because it is above q12?

Now I want to set the order of some StationAssignments in my model to 0, which means early completion of processing. How should I set it. My current setting is that StationAssignments must have five steps, and the sixth step is 0, so it will enter the sink. But now I want to set this rule to maybe only two or three steps like this0501q5.fsm

[moehlmann_fe]

Any item whose next station assignment is a 0 is send to the sink by the processors' "Send to Port" setting. It does not matter how many steps the item went through previous to that (though it needs at least one or it would never enter a processor).

Yes, the connection ranks do matter. When pulling the next item the processors will check the queues for available items in that order.

You could use a single queue like in the model I attached previously, if you don't want that.

[a9080109]

But your model seems to have not completed the priority part??

Because my model send to port classifies item.step, the larger the step, the more priority I will grab, but your model doesn’t seem to have this problem??

[a9080109]

But if I use step to classify when station=0, it will only stay in q and will not enter sink or other actions.

[moehlmann_fe]

In my model I kept the ordering by "processtime" which you added to the model you uploaded before that. You can of course change this to "step".

And you are right, I must have looked at a different version of the model. In your latest one the items only enter the sink after having completed 5 steps. You could connect the queues to the sink as well and have the sink pull items with a "station" value of 0, like how the processors are each pulling items with their respective station number.

[a9080109]

I don't quite understand what you mean by setting it here?

[a9080109]

Can you provide me with a sample?

[moehlmann_fe]

Leave the Pull Strategy as 'Any Port' and use the same code the processors use in the Pull Requirement, requiring the next station to be "0".

Or, since the item has this value assigned as a label as well, you could just use "return item.station == 0"

Pull Strategy: Where something is pulled from
Pull Requirement: What can be pulled
When pulling from a list the Pull Requirement is not used though. Instead you then use a WHERE clause in the pull query.

[a9080109]

I have an idea now. I currently have a model with five machines, but I want to turn the problem into a model with 20 machines, but my inputs have to be pulled one by one. I feel a little stupid. Is there a faster way to do this? I increase the size of my model.20m20o.fsm

[Jeanette_Fullmer]

Hi @mark zhen , was Felix Möhlmann'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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