In Flexsim 18.2, How to control the number of flow items on a flow rack

[don_c2]

[ FlexSim 18.2.3 ]

I have a model that I am using an operator to load cartons onto a flow rack. that is 5 items deep by 6 items wide for 30 items a shelf, 3 shelfs for 90 total flow items. The problem I am have is that, the operator keeps loads items in the last row filed. and does not stop loading cartons. What steps are needed to limit the number of items that can be placed in the flow rack? Notes I have adjusted the "Maximum Content" and that does not appear to be working on the flow racks.

unload-plt-to-rack.fsm

[regan_blackett · Accepted solution]

@Don C2

In 19.2 there are some better ways to do what you are looking for, but for your version we can take an approach where a List is used to control the availability of cells in your racks.

The attached model includes a Fixed Resource process flow that is attached to a rack like your CMA Flow objects. It uses tokens to represent each Bay/Level combination for the rack and pushes them to a List to signal their availability.The tokens are a assigned a capacity from a label on the Rack.This assumes that all cells will have the same number of items in them.When a cell’s capacity is reached it goes to a Decide activity that just holds the token until its content is less than its capacity.

The Incoming Items section of the process flow creates a token for a pallet ready to be unloaded into the rack, and then creates child tokens for each item in the pallet.Those child tokens then search for an available cell preferring the highest level first then the lowest bay.When a cell for the item is found, it is recorded by Bay/Level into labels on the item. A task executer is acquired, and it transports to the box to the Rack.The Rack reads the Bay/Level labels to know where to place it.

The Outgoing Items section monitors when a flowitem leaves the Rack, updating cell contents and releasing the cell token back to the list if needed.

Have a look and see if this is what you are looking for and let me know if you have questions about it.

Edit: Mistake in the uploaded model. Fixed Model here:

listcontrolledrack-2.fsm

[don_c2]

I see what the model is doing. it looks as if it fixes the problem of the operator loading more flow-items (cartons) then what the rack is designed to hold. The problem that I now have with this model is that I can only load items into the 2nd 3rd and 4th levels if the rack, leaving the 1st level (floor level) open as the rack is configured and built in such a way as it would be imposable to place or pick material there.

[braydn_t]

@Don C2 Can you send a photo of this behavior or clarify what you mean? This is what I see when I run the model, and it looks like the floor is filled.

[don_c2]

20170905-094633.jpg

I have attached a photo of one of the rack location that I am trying to replicate. the ground level is not accessable by the pick operator.

[tanner_p]

Hi @Don C2,

Thanks for uploading the picture to help us understand. If the ground level is not a functional level of the rack, then I wouldn't include it as a level in FlexSim. You essentially use 3 levels of the rack based on your description and attached picture. If you still want to create the visual of having the lowest level 12" or so off the ground, you can adjust the Z-height of the level in the property shown below:

I've updated and attached Regan's model to include a 3 level rack with the adjusted level location. The result is shown in the image below. Hopefully this helps.

listcontrolledrack-updated.fsm

[don_c2]

This will fix the issue that I was having. Thanks