Problem stacking pallets in Rack

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question

Sebastián Cañas asked Oct 18, '22 Jason Lightfoot edited Jan 20, '23

Problem stacking pallets in Rack

Hi all,

If I store boxes in a rack, it will fit properly considering x-y-z dimensions:

When I use Totes, it will do as well as with boxes:

This is not the case if I use pallets, it seems that the Rack is only considering the z height of the pallet and not the whole z height considering the products packed within it:

Is this a bug?

Stacking_Pallets.fsm

Software Version:

FlexSim 22.0.8

racks pallet bounding box stack pallets pallet contents

1666133433332.png (199.8 KiB)

1666133513062.png (502.6 KiB)

1666133598411.png (538.9 KiB)

stacking-pallets.fsm (52.4 KiB)

Answer 1 · 2022-10-18T23:45:37Z

Jason Lightfoot answered Oct 18, '22 Jason Lightfoot edited Jan 20, '23

The stacking doesn't consider the content of the item being stored - so totes only appear to stack correctly - if the contents exceed the tote dimensions that is not considered - it just uses the tote bounding box. It not a bug, it's more of an over-simplification which needs rectifying.

Attached is a model with a new pallet in the flow item bin that uses the simple packing method to stack inside, like the tote, and additionally changes the pallet bounding box size when you pack/unpack items (using the pallet's OnReceive and OnSend behaviors), while preserving the pallet visual.

stacking-pallets_jl.fsm

Here's a library containing the pallet for easy loading into your model.

AutoSizingPallet.fsl

Here's an example of pallets being packed,stored, unpacked and re-stored in a rack based on the available space:

PalletSpaceExample.fsm

1666178956931.png (140.7 KiB)

1666178984469.png (129.0 KiB)

1666179042779.png (122.4 KiB)

1666179069636.png (143.9 KiB)

stacking-pallets-jl.fsm (53.3 KiB)

autosizingpallet.fsl (1.2 KiB)

palletspaceexample.fsm (65.5 KiB)

autosizingpallet.fsl (1.2 KiB)

palletspaceexample.fsm (66.0 KiB)

· 4

Joerg Vogel commented · Oct 19, 2022 at 07:28 AM

@Sebastián Cañas , please highlight a container item. You will notice, that a pallet is framed in its outer limits just like a tote. But a tote stores items inside and a pallet outside of this frame. If you stack such objects then stacking Methode evaluates just the dimension of those yellow frames.

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Sebastián Cañas commented · Oct 19, 2022 at 01:43 PM

Thanks @Jason Lightfoot for the explanation!

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Joerg Vogel commented · Jan 20, 2023 at 04:24 PM

I discussed a dynamic pallet before, unfortunately such pallets behave a bit strange, if they are inside of a queue and their content changes or their height differ.

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Jason Lightfoot ♦ Joerg Vogel commented · Jan 20, 2023 at 04:34 PM

I think that issue is one of restacking without removing pallets - I don't think there are many examples where people take from a bottom pallet without removing the upper pallets.

Note this method doesn't use drawsurrogates or dummy objects - the pallet and item tree is exactly as you'd expect and can be virtualised and restored as any normal pallet.

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