Push/pull strategy for items on pallet

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question

Artur K asked Jan 14, '20 Artur K edited Jan 14, '20

Push/pull strategy for items on pallet

Hello, I am trying to use lists to simulate my model. I need to unload by the robot items from pallet (18 items) which comes onto Conveyor1 and load them singly onto new pallet on Conveyor 2. I 've got problem, because Robot loads every second box (starting from box no.2) not from the Conveyor1 but from the pallet on Conveyor2 (it takes box that has been recently loaded on the target pallet). Where I made a mistake or what should I add to get correct solution?

pushpullproblem.fsm

Software Version:

FlexSim 19.2.4

push and pull list

pushpullproblem.fsm (59.3 KiB)

Answer 1 · 2020-01-14T21:33:22Z

tannerp answered Jan 14, '20 Artur K commented Jan 14, '20

Hi @Artur K,

I simplified your push logic in this model to just be a single bit of code in the Custom Code activity. Let me know if you have any questions about the highlighted portion I added:

As for the unloading logic, you can add in stop/start logic for the conveyor station with Custom Code activities similar to what you had in the other Process Flow. Adding those allowed the loading/unloading to be handled properly as you described. Hopefully this helps.

push-pull-problem-updated.fsm

custom-push-to-list.png (30.5 KiB)

stop-resume-custom-code.png (10.6 KiB)

push-pull-problem-updated.fsm (55.7 KiB)

· 1

Artur K commented · Jan 14, 2020 at 10:11 PM

Hi @tanner.p,

evreything is clear for me, thanks a lot for your time and help!

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Answer 2 · 2020-01-14T21:42:54Z

Regan Blackett answered Jan 14, '20 Artur K edited Jan 14, '20

I think all you would need to do to get your model working they way you want is to do the following three things:

1) change the push value from:

token.paleta.first

to

token.paleta.subnodes.toArray()

That will push all the boxes in the pallet to the list.

2) go to your list properties and add an expression field named 'Rank' that says:

value.rank

This will tell you where boxes are located within the pallet, lower ranks at the bottom of the pallet.

3) change your Pull from List Query to say:

ORDER BY Rank DESC

This will tell the robot to pull boxes starting from the top and working its way down. This will also allow you to eliminate the Decide activity in your process flow, as the token won't leave the Push to List activity until the pallet has it's last box pulled.

· 1

Artur K commented · Jan 14, 2020 at 10:16 PM

Hi @Regan Blackett,

your solution also meets my expectations - thanks a lot!

I've just implemented your suggestions and my model works fine!

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