Variable process time

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Antonio R8 asked Jul 22, '19 Matthew Gillespie commented Jul 24, '19

Variable process time

Hi there,

I've got a model with 3 different processors. There are 72 items to process and they can be of two different types, type A and type B. The time of each process depends of the volume of each item. I know the process output rate ie. m3/h for each type. So, my first question is:

- Is it possible to specify the volume of each item, and also make each Processor to work out the processing time based on the type and the volume?

My second question is the following. There are only 7 hours available per shift. The third process has to start and finished within the same shift, so if there is not enough time available, it should not start until the following day. Is it possible to do this?

Thanks a lot in advance.

Software Version:

FlexSim 19.0.2

labels arrival schedule process time by case

· 1

Matthew Gillespie ♦♦ commented · Jul 22, 2019 at 09:38 PM

Please ask your second question as a separate question.

0 ·

Answer 1 · 2019-07-22T23:55:25Z

Matthew Gillespie answered Jul 22, '19 Matthew Gillespie commented Jul 24, '19

You can assign whatever label values you want to an item and then read those values off at later points.

volume.fsm

In the attached model I create items of two different types (distinguished by color). I give them a random size and then set the Volume label on the item to be equal to their x size * y size * z size (mostly just so the bigger items naturally get a bigger label value).

I then used the Values by Case pickoption to use two different formulas for the processing time depending on the item's type. Both formulas multiply the item's Volume label by some arbitrary number.

timebycase.png (5.9 KiB)

volume.fsm (19.0 KiB)

· 4

Antonio R8 commented · Jul 23, 2019 at 11:39 AM

piles-concrete-simulation.fsm

01.jpg

Thank you so much Matthew for your quick response.

So, if I know the order of the items that have to be processed. How do I set up the sequence? Do I just go into my source and set up an arrival sequence with two labels specifying the type and volume of each item?

See model attached.

0 ·

piles-concrete-simulation.fsm (22.2 KiB)

01.jpg (146.4 KiB)

Matthew Gillespie ♦♦ Antonio R8 commented · Jul 23, 2019 at 09:50 PM

Yes, the Arrival Sequence with label columns is a great way to do that.

You're getting errors in the model because you put

Item.Volume

instead of

item.Volume

in the Values by Case popups.

fixed.fsm

0 ·

fixed.fsm (19.1 KiB)

Antonio R8 Matthew Gillespie ♦♦ commented · Jul 24, 2019 at 12:03 PM

piles-concrete-rev2.fsm

@ Matthew Gillespie

You are star!!!! Thank you so much, it works great now.

Can I ask you two more things?

I want to work out the number of days that it'd take to process 12 items, bearing in mind that there are only 7 hours available per day. I've put a text with the date and the time but the model takes 24h per day. Is there a way to specify each day is only 7h?

And also, the third processor is only supposed to start the process if there is enough time available within the day to finish the process, otherwise it has to start the following day. Is it possible to introduce somehow this constraint?

See model attached.

0 ·

piles-concrete-rev2.fsm (203.7 KiB)

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