PiM example for change of units within a process

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Kai Neumann (#1) has provided a description of the model with the iMODELER Presenter.

Description

The challenge behind this model was to collect units in a box and to take them from the boxes again. There are probably other ways to model this but this was my first idea.

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assembly

final product

worker

delivery of boxes with parts type 1

prepared parts type 1

preparation of parts type 1

material

boxes

forklift truck

delivered boxes

capacity of box

amount from box needed per unit

available boxes

box space available

total of boxes

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Comments (3)

Kai Neumann replies Dirk Schink

Hi Dirk
The model is just a little exercise I did to help a customer. The challenge was to run a process step until it reaches a certain amount, and then shift (in my example by explicit transportation) that amount to the next process step. That step then uses each of the units of the previous step but as easy as this sounds it is quite a challenge to get the proper results. You could define that the first step stops when the amount is reached and that the following process starts only when the amount is available, but then you would use the whole amount from step 1 for just one unit of step 2. Or you use the priorities so that step 1 always comes first. To let step 2 wait for step 1 they would then have to share a resource.
So, this model shows the solution to let step 1 stop, when the amount is reached, and let step 2 start when the amount is reached but not take the whole of it for just one unit of step 2, but the fraction of it, one unit of step 1.
More concrete: the box is full if there are 20 units in it. The next step then starts when a full (hence 'integer') box arrives and uses 1/20 of it until it is empty.
Hmm, I sound very complicated although this is really simple. The only trick was to use 1/20 of the box. Therefore the challenge is to find a solution for boxes that are not full. I have several ideas for that but maybe you and others find smarter ones?

Dirk Schink

Hi Kai, honestly I have not grasped the intention of this model. Collecting units in boxes is OK - next step is assembly of full boxes ending up in final products. Looks like a 2-step-picking mechanism. Could you please explain in more detail?!

Kai Neumann

This is just one of many possible ways to model it. Here is another: http://www.imodeler.info/ro?key=CxB2C8sDFZ4QpQ1O-FFImbQ
BTW: can anyone think of an idea on how to model boxes that do no have to wait to be fully filled, e.g. because a job is done?