Maybe fun question?

[dw027]

Greetings, I am trying to understand material resource usage for reusable material. My made up project is brew 3 batches of beer with 100 reusable beer bottles. Each batch needs 50 so when batch one is done the bottles start being emptied at the rate of 10 per week. Obviously batch two can start at any time.. how do you show the usage of 10 per week and then see the available of 50? It seems easy in my thinking, just cannot figure how to show in MS Project.

Liken this to having 100 tooling machines that are released from assembly line at the rate of 10 per week to be retooled and used on another assembly.

Thanks ... and Cheers

 

[SkipVought]

hi,

Do some research in MRP practices, for instance . Your posed question is really a demand/supply problem, that has sheduling as an aspect of the problem, not just a scheduling problem.

http://www.apics.org/

Skip,

_{Just traded in my old subtlety...
for a NUANCE!}

 

[dw027]

Thanks Skip,

It looked like i could use a hammer.. so it must have been a nail.

Your redirect is appreciated.

David

 

[SkipVought]

It's interesting, too, that classroom problems usually have simple assumptions that illustrate an aspect of real-world problems. In reality, your bottles or tools do not return at a steady rate and so the signal points are based in trigger criteria, that ought to be parameters in the MRP control database, that indicate what kind of order policy you are using for this particular resource and hwo the reorder-point is triggered to create an order in the system. Of course, you also need to know, first and foremost, what the demand is, and this usually cones from a firm customer order, or some sort of forecast.

Skip,

_{Just traded in my old subtlety...
for a NUANCE!}

 

[SkipVought]

You also did not state your capacity for a batch of 50 bottles. How long does that take?

Skip,

_{Just traded in my old subtlety...
for a NUANCE!}

 

[SkipVought]

The line of balance schedule might look something like this...

............initial | 1    2   3   4   5   6   7
demand      150     | 100  50                   0 
supply       50     |  50  50                  50
bottle ret   10     |          10  10  10  10  10
on hand     100     |  50   0  10  20  30  40   0

Skip,

_{Just traded in my old subtlety...
for a NUANCE!}

 

[JulieInMaine]

Just to jump in for anyone looking at this thread in the future. Microsoft Project does has material resource type - however it will not calculate "demand" only usage. To see if you have enough bottles, they would have to be work resources in Project.

 

[SkipVought]

Julie, are you saying that Project can do this kind of allocation if the properties are appropriately assigned? I am a Project dummy, and know just about enought to be dangerous.

Skip,

_{Just traded in my old subtlety...
for a NUANCE!}

 

[JulieInMaine]

You can set a max units for bottles - in this circumstances - 100. Create the Batch task with the duration and assign 50 to the batch. Your bottle Percent Allocation is now 50% - you have half of the bottles in use with the other half available. You still need to account for the "returns" and I would do that with tasks with the "in use" bottles assigned. So week one you are still "using" all 50, week two using 40, and so on.

Julie