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#1
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Help with material flow in a facility
Hi everyone,
Our problem seems a little more complex than the usual problem so I am going to try to explain it to you as clear and simple as I can. Here is an explanation for the problem: My goal is to simulate part of a facility. The facility has 9 different cells (a cell is a group of machines that can complete a piece without the need of the piece leaving the cell). The facility has about 175 different types of pieces and each one is assigned to a specific cell (Global table_arrival schedule shows the code for each piece (ItemName), the cell they are suppose to be send to (ItemType) and the batch size quantity (quantity), also the arrival time (but that one does not matter much) . The pieces sit outside the factory (top left in the model) as raw material placed inside bins. The bins have a maximum number of pieces they can hold (do not have a table for this, but it is basically 25 pieces per bin), so when it is time to move the batche, more than one trip has to be made. Also, cells only have enough space for an input and an output bin, so the trips have to wait for the input bin to be empty and removed by a truck driver. The idea is that once a batch of pieces has been produced (remember this could be several trips since one batch is not the same as bin) to call for the next piece type on the list. Since there are 9 cells, the truck driver has to be able to tell that if a cell does not has input (let's say cell 2), he has to pick the next item on the table for cell 2. The problem that I am having with the simulation is that there is only one truck driver moving the bins, I have no idea how to code or programmed for him to always be looking out (or receiving a call) when a cell needs input. The simulation would probably have a lot more steps, but right now I am only concentrating on getting the right material, when needed, to the right cells with only one fork lift truck. A few questions that might help in providing an answer are: 1) Is it better to have 1 queue or 9 queue feeding the trucker? (same question with sources) 2) How do I combine a bin and 25 pieces? Remember that once the pieces arrive to the cells, they would be removed one by one , but the bin would stay there preventing the next bin to arrive until removed. Something that might clarify why I am removing piece by piece is becomes I have the run times for every machine for every piece type (not included yet, but will look into that later) 3) How to create the right tasksequence? or is it easier to avoid tasksequence on this process? Currently i am able to create the nine different item types(175 products total), but i can't seem to send the to their respective queue. also i tried using combiners and separators but they didn't do what i wanted. Thank you Andres Last edited by Andres Gomez; 11-10-2011 at 01:57 PM. |
#3
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Hi Andres,
think your model and all things to understand are very big. Would need much time, that I don´t got, to work in. But maybe I can give you some small hints. 1st of your Questions: I think it´s a goog solution to use one Source and 9 queues. For your problem with sending Items by Itemtype to different Queues. I solved it with just trying again the option "By Expression" in Flow Tab. Don´t know if there had been any other Query in it, and if yes there had been the mistake. I attached model with solved problem. Another point with creating Flowitems is, that you only should create as much as you need. Because the more objects you´ve got in model, the slower everything works. So maybe create some less at beginning of your simulation run to increase speed. 2nd of your Questions: Why you can´t use Combiner for this task?
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Hemmi |
#4
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Hey sebastian,
Thanks for the help, i dont know why i could not get it to work. Regarding the separators, i tryed seting them up but i was not able, but it is no necessary. Now all i have to do is set up the forklift dirver to deliver batches to each cell and then have the operator process those items one by one. do you have any hint on which way would it be easiest to do this? |
#6
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Help
Hi everyone,
I been working on the model, and it is looking much better, but there are still a few little things that I need to get through. #1 and most important. I got a table with the name of the pieces as the rows headers, and 1 column of the processing time right next to the row headers. I know I have to use the table lookup, but I have trouble calling the function because my row headers are strings and the functions ask for numbers. If you can get me one example of this (for one machine, and let me know which machine) I should be able to do the rest. Less important, but if you know the way please help. I was wondering if I could created a queue somewhere in the facility to take material from the outside into the inside without directly sending them to the in pallets of the cells. In other words, I would have a queue as a central port between the raw material queue and the cell in (separator looking like a pallet). secon, is there a way to set a one time setup time for a set of pieces with the same name? take in consideration, there might be two batches of the same piece (same name) so, I need something that reads when there is a new piece, and before running the first one, the operators waits for a given time (setup time). Like the process time, I do have the same format of numbers, but I did not include it. The combiners outside the facility produce everything perfect except the last one, since the pieces do not leave until the bin is completed, and since the last bin is never complete, they do not leave. Also, is there a way to only allow a certain name at a bin based on the first piece that entered the bin? Last, can the fork lift truck carry 2 bins of different itemtype/itemname?? Thank you again for all the support, |
#7
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For your first question I think Excel could help. Just insert data in a new sheet and change from string to number data.
But because it is not only number as data it would be only possible, with setting a number key for every different string.
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Hemmi |
Tags |
facility planning, material flow, material handling |
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