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Claire Krupp avatar image
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Claire Krupp asked Claire Krupp commented

How to pull from Item List by batches based on item.Type

This problem seems so simple - but no matter what I do the pulling processor pulls in the wrong part type, or else won't pull anything at all!

I have items arriving in batches controlled by an Arrival Schedule on the source. I then pull them into Kitting by batch using an Item List. It works perfectly here because they enter the list in batch order and so it is just FIFO pulling them out of the list.

Further down, I want to do the same thing, but one type of part has a different routing and so individual parts enter the queue/list out of sequence. This then triggers multiple changeovers on the downstream processor.

I have tried using partitions, but then I need to tell the processor which partition to pull from, and that will vary depending on whether there are more items for the current batch, or else it should look for a new Type.

I tried putting a label on the processor and updating in when an item enters the queue/list, but I don't want to change it in the middle of batch.

I tried adding a queue to batch the interrupting items before they enter the queue/list, but it does not solve the problem, and the batch quantity needs to be variable/label, which it will not allow me to enter in the "quantity" field.

I tried "ORDER BY item.Type" but if you are running a batch of "3"s and then a "1" arrives it interrupts the batch.

These lists are so powerful I know there has to be a simple answer that I just can't see!

This is a rough cut model with a very tight deadline. I really hope it does not require huge amounts of programming code!

(I have looked at similar questions, but I don't think they really apply to this situation.)

I am attaching a simplified version of the model where the list is partitioned, but the processor will only pull one Type.

batch-pull-from-list.fsm

FlexSim 19.0.0
item listbatch order picking
5 |100000

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Joshua S avatar image
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Joshua S answered Claire Krupp commented

Take a look at this model. It grabs an item off the list, but leaves it on the list, takes the Type it is, then checks the list for all items with that Type and processes those until nothing is left in the list of that Type, then it grabs another item and does the same thing.17673-batch-pull-from-list.fsm


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Claire Krupp avatar image Claire Krupp commented ·

I'll take a look, thanks!

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Claire Krupp avatar image Claire Krupp Claire Krupp commented ·

Thanks @Joshua S, that is a simple but very effective method!

Another wrinkle: sometimes when the queue is almost empty, the batch with the different routing has not completed at the previous operation and it leaves a few "orphans" behind since they are not detected in the list yet. (Since my "Target Batch Size" cannot be changed to reflect the actual batch quantity.) Can I have the items enter the list at an earlier location, but not allow them to be physically moved until they have entered the correct queue?

I'm thinking another "Wait for Event" would need to be placed before the "Move Object" activity?

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Claire Krupp avatar image Claire Krupp Claire Krupp commented ·

Ok just found out "(Since my "Target Batch Size" cannot be changed to reflect the actual batch quantity.)" is not true!

Just found out how to do this from another post :)

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