Apple Packhouse simulation

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question

Mihnea V2 asked Jan 31, '22 Jeanette F commented Feb 11, '22

Apple Packhouse simulation

Hi all,

I have been tasked with simulating the packing process in an apple packhouse. The first part of this process involves a bin of around 5000 apples being emptied onto a conveyor belt.

I was thinking of using a mass flow conveyor to simulate the objects but I am unsure how to go about creating the apple bins with 5000 apple in them and then have them emptied onto the mass flow. How can I create a bin containing a specified number of objects then having that exact number of objects emptied onto the mass flow?

Furthermore, I have noticed that the mass flow conveyor would simulate the apples as a fluid flow as opposed to discrete objects. Is there a way to convert every apple into a discrete object after it is finished on the mass conveyor so I can assign labels to each apples and sort them into appropriate packlanes based on these labels?

Would really appreciate the help!

Software Version:

FlexSim 22.0.0

massflowconveyor

· 1

Jeanette F ♦♦ commented · Feb 11, 2022 at 10:18 PM

Hi @Mihnea V2, was one of Jason Lightfoot's or Kenny Macleod's answers helpful? If so, please click the "Accept" button at the bottom of the one that best answers your question. Or if you still have questions, add a comment and we'll continue the conversation.

If we haven't heard back from you within 3 business days we'll auto-accept an answer, but you can always unaccept and comment back to reopen your question.

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Answer 1 · 2022-01-31T13:19:01Z

Jason Lightfoot answered Jan 31, '22 Jason Lightfoot edited Feb 8, '22

On the entry transfer you can say how many apples to create from one flexSim item:

Then on the exit transfer you just tell it to use one per item:

And on a photoeye or entry of the belt conveyor you can set labels as usual and route to exit transfers or decision points as usual.

Model attached.ApplePackHouse.fsm

1643632782595.png (42.7 KiB)

1643634951287.png (3.0 KiB)

1643635028560.png (280.5 KiB)

applepackhouse.fsm (45.6 KiB)

· 13

Kenny Macleod commented · Feb 01, 2022 at 02:49 AM

MMmm. My comment disappeared, maybe I didn't save it. This may be asked twice.

Thanks Jason, the normal conveyors retain information on the objects so they can be packaged or routed accordingly. However, the MFC doesn't retain any info.
Your trigger allocates a random product type, which would work if there's some form of selector/grader at the end of the MFC to automatically choose what happens to individual apples next. But what if they are already graded as a homogeneous batch, all allocated to a particular bin? And that product type/routing has already been decided and sitting on a label in the crate/hopper that feeds the MFC?
Would you use Felix's example or do you have a better way?

KM

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Jason Lightfoot ♦ Kenny Macleod commented · Feb 01, 2022 at 09:58 AM

The original poster wasn't asking for labels to be retained within the mass flow section, so I didn't address that.

The problem you are describing is one of 'composition' and the events surrounding changes to that. Currently there's no easy way to track composition other than ensuring batches are separated and comprise only one type; or building your own objects to do what the mass flow conveyor does at the event level (easier without the graphics). Ideally they would support defining composition at entry (list of attributes and the percentage of occurance in the flow) and the conveyors would manage changes to the composition as the flows merge and divide so that you could reconstruct labels in the correct proportions when they exit the mass flow. When the item mapping at the exit is not 1:1, say 100 apples in this case, the composition would need to be an attribute on the new item that represents 100 apples and the percentage (from my example model) expected to be type1, 2 or 3 within that 100.

The answer by @anthony.johnson in the post to which you linked, already suggests that the developers will consider it in the future. It's just extra information needed at the change in density events that are already being created and managed by the objects and a new event to track the flow of composition as it travels through accumulations (since the density change is absorbed at that point). The other challenge will be defining to the user how it should be set up and what to expect from the behaviour.

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Mihnea V2 commented · Feb 01, 2022 at 08:31 PM

Hi Jason,

Thanks for that. That's exactly the logic I was looking for. Just some further questions on the model you've attached:

When I bring up the properties of the source and I want to look in the output section, it is completely blank and nothing comes up. Is this supposed to be happening.

Also, I cannot seem to see you port connections between objects. Have you used A-connects and hidden them or is there another way you have connected the objects?

Thanks!

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Jason Lightfoot ♦ Mihnea V2 commented · Feb 01, 2022 at 08:39 PM

The output sections of both source objects should look something like this both in the popup (double click) and in the quick properties.

The connections are just disabled and reenabled in the view's Properties (click anywhere on the background)

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1643747701096.png (4.9 KiB)

1643747785090.png (5.5 KiB)

Mihnea V2 Jason Lightfoot ♦ commented · Feb 02, 2022 at 04:47 AM

Thanks Jason,

I have been working on the model a little bit and I have managed to get some of the conveyors arranged to represent the start of the pack house. I am experiencing some issues with the blue mass conveyors in my model (model attached) as the apples are only visible on the center conveyor and are not showing up on the two outer conveyors. There's also some funny things going on with the black coneyor belts feeding into the center blue MFC. Any idea why this may be happening?

Also, I get some exceptions thrown when I connect the 3 blue mass conveyors to the larger green mass conveyor saying that the green conveyor has multiple modes of input. Is it not possible to have 3 separate, smaller mass conveyors all flowing into one larger one?

Would really appreciate the help again!

Apple Packhouse.fsm

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apple-packhouse.fsm (66.5 KiB)

Show more comments

Jeanette F ♦♦ Mihnea V2 commented · Feb 01, 2022 at 08:44 PM

Hello @Mihnea V2 ,

I am able to see the output section in properties of the source. Is this a continual problem that you are able to replicate? A possible solution would be updating to our most current bug fix which is 22.0.1.

The connections are turned off in the models properties. To turn it back on, select the model floor and check your properties panel for the following and check show connections.

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1643748096497.png (15.7 KiB)

1643748248214.png (51.7 KiB)

Answer 2 · 2022-01-31T05:57:27Z

Kenny Macleod answered Jan 31, '22

Hi Mhinea
I think that your view that Mass Flow Conveyor is more like a fluid resource is correct. It was designed for a specific purpose and is still in its infancy.
Check out an earlier post that put up, to help me understand for a project I was working on.
I wanted a label to be retained for further down the line. There's no in-built functionality to do that but there is a workaround by @Felix Möhlmann.

https://answers.flexsim.com/questions/110957/passing-paramaters-and-lables-through-mass-conveyo.html

The example model retains a product type in a separate resource for it to be picked up again later. Doing it for individual apples is more of a challenge. I got around my issue by simply running a normal conveyor. This was possible because the small items were only at that individual level for a short time, so there were not too many in the model at once. This is possible by moving your boxes of apples around as individual boxes, with nothing inside apart from sufficient data to generate the number of items it contains (along with any labels you need), then packing them back into a carton or pallet - again making sure you destroy the content as you go.

The official line is that you would not pass labels or details through a FMC in real-life, but use some control system around it. While I agree with that concept, we're in the business of faking something enough for it to replicate enough of a reality for us to solve a solution. Building the model is not the solution so cheating a bit by attaching data to items in the MFC is quite legitimate.

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