decision point conveyor according to child id

[larissa_r2]

[ FlexSim 19.2.4 ]

I am working on a warehouse model, where orders arrive between 16 to 16 seconds. Each order has 4 boxes to be picked. This model has an order picking system by box, which means that I have 1 operator at each aisle picking the boxes and sending them to a conveyor.

At the end of the conveyor, I have an operator (picker 4) that should pick the items according to the orders and place them in the pallets. I have two issues in my model that I am trying to solve:

First, I created 3 decision points. I need that the boxes that go out the decision points are from the same child id. I don't know how to create this condition in my model.

scenario 3_ pick to box_23SKUs_VS3.fsm

The second issue that I have in my model is that my operator (picker 4) is grabbing all items in the conveyor, and he should grab only items from the same id (maximum 4 items at a time) at the end of the conveyor.

I hope someone can help me solving this issues, I read about parent/child tokens at the manual, but I still don't know how to solve these.

[brenton_king]

@Larissa R2

For issue 1, you are talking about a 3 to 1 merge. I think I understand that you would like your items to stay together on the conveyor if they are from the same order. Is that correct? Would each item need to stop and be scanned to make sure it continues on? If this is the case, I think your merge point needs a process flow that controls which item comes next. This would be done by pushing every item to a list when it hits the merge point, stopping the item, then having the merge point pull items off of the list in the order you would like. The other issue becomes having some sort of label on each item that groups them together. Process flow can write labels on associated items. I'm just trying to make my best guess at what you are talking about with childID. I would just write this childID on each item.

As for issue 2, it is very similar to issue 1. You need to have a process flow for that operator that represents his brain and which item he is going to pull next. When items arrive in the removal area they push themselves to a list. The operator has a loop that pulls the best/desired item off of the list.

[larissa_r2]

@Brenton King, "I think I understand that you would like your items to stay together on the conveyor if they are from the same order. Is that correct? " Yes, this is exactly what I need.

"This would be done by pushing every item to a list when it hits the merge point, stopping the item, then having the merge point pull items off of the list in the order you would like. " I am not sure how to merge items from the same order to a list, and I don't know either how to check if the items are from the same list on the decision point.

[larissa_r2]

@Benjamin W2 @tanner.p, any suggestions?

[tanner_p]

@Larissa R2,

What defines an item "list"? Is it referencing a table value or something? If so, you can just parse through that list and check to see if the current item is included. I'm not sure exactly what you mean with your second question.

[larissa_r2]

A list should be composed by 4 SKU items. The activity 'do order picking' makes pickers grab items according to the list. I don't know how to check if the items that arrive in decision points are from the same list. Also, picker 4 should grab only the 4 items at the end of the conveyor line.

[tanner_p]

Okay, I think I'm understanding a bit better now. So the "list" is the four items in the array on the token label as shown below?

And then you need to match the items at the decision points with the items referenced on the token?

[larissa_r2]

@tanner.p, yes, this is exactly what I need! 🙂

[tanner_p · Accepted solution]

@Larissa R2,

I decided to batch the items as they're dropped off at their respective conveyors and then release them one by one as they arrive at the decision points. The Zone makes sure that only one "list" of items is handled at a time. It's important that we aggregate the labels at the batch activity so that we know what the last item is that should cross DP1. The Wait for Event listens for that last item to cross the DP1.

Here's the model: scenario-3-pick-to-box-23skus-vs3 (2)_1.fsm

Let me know if it helps.

[brenton_king]

@Larissa R2

The main order token needs to have a unique label on it. Let's say OrderID. This label then needs to be on all of the items as well. You can add the label whenever it is added to the order. This is how that would look when executed properly:

After you have the labels, you need to create a merge controller. This can be a simple process flow where each item on the conveyor gets stopped, adds itself to a list, and waits to be pulled off of the list by the controller. The controller tries to pull a matching order item if there is one available, if not it will start the next order. Here is an example of what I mean:

I didn't actually implement this in your model but hopefully this helps.

[brenton_king]

There are almost always multiple ways of doing something though. I see that Tanner responded as well with a different method. Just do whatever makes sense to you.

[larissa_r2]

@tanner.p and @Brenton King, thanks very much for helping me to solve these issues. It really helped, I appreciate your help 🙂