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Daily change in individual capacity for a work center

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Daily change in individual capacity for a work center

Postby yaelb » Thu Nov 01, 2012 8:32 am

Hello,

We have a work center for manual assembly. Sometimes 5 people work there, sometimes 13 people work there, etc...
If 13 people work instead of 5, they will produce more items per day.

Maybe someone has an idea how to handle this situation?

Best regards,
Yael.
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Re: Daily change in individual capacity for a work center

Postby Ramarao » Fri Nov 02, 2012 3:59 pm

To answer your question, every work center - actually within the work center at a capacity category level, there is an interval of available capacity that you can define to indicate day by day loads - normally we don't have to use it so granularly but you seem to need it for your scenario.

How soon before do you know that the capacity is going to change - and what do you want to use this capacity in calculations for? Are you actually checking capacity planning in anyway?
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Re: Daily change in individual capacity for a work center

Postby yaelb » Sun Nov 04, 2012 8:07 am

Hello,

Thanks for the quick answer, it helped me.
But now I want to undersatnd how can I affect the calculation of time for a production order.
For example: This week I have 3 people, Next week I have 10 people. In general, if I had 1 person I could do 30 pieces in 24 hours.
I know that there are formulas in the work center, but I cannot find a way to take an individual into consideration.

Thanks a lot,
Yael.
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Re: Daily change in individual capacity for a work center

Postby Ramarao » Mon Nov 05, 2012 4:44 pm

If you use the standard SAP formulas they do take the individual capacities into consideration:

Example - if you have to machine a part, routing has base quantity = 12 pieces and the processing time in the routing = 2hrs (processing time = 10 minutes per part). Assuming setup time = zero for simplicity.

You have 5 individual capacities in the work center (they could be machines or men) - for simplicity assume one capacity category.

Suppose you want to make 100 pieces in a production order operation

For this example you'd use scheduling formulas:

execution time = processing time * operation quantity/ (base quantity * no. of individual capacities)
= 120* 100 / (12 * 5) = 200 minutes.

Whereas for capacity calculation the formula is different:

executing time = processing time * operation quantity/base quantity (note: required capacity doesn't change whether you use one machine or 5)
= 120 * 100/12 = 1000 minutes.

your total requirements = 1000 minutes processing time for 5 individual capacities. But for scheduling purposes, if you use 5 individual capacities, 200 minutes to complete the job.

When you consider setup time, this picture gets more complex, and it might actually be a different work center (person) with different hourly rate for setup.

Hope this helps, check SAP help under PP basic data --> work centers --> formulas for more details.
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Re: Daily change in individual capacity for a work center

Postby yaelb » Mon Nov 12, 2012 7:45 am

Hello,

Thank you very much for the detailed information regarding the scheduling formula.
I created a new work center in which the capacity category is 002 (person) instead of the regular we have 001 (machine).
In "Capacities" tab I entered our old formula, which is (Processing time*Operation qty)/Base qty, in "Scheduling" tab I entered the new one you've mentioned, which is (Processing time*Operation time)/(base qty*no.of ind.cap.), because I want the work order to be shorter if there is more than 1 person, in "Costing" tab I assumed I need to enter the old formula, because I need to take into consideration all the time that was "invested" in the work order (for example if the work order took 2 hours because there were 2 persons and could take 4 hours with 1 person, for costing I assume we should take the 4 hours into consideration).
I defined for a certain material that 12 EA are done in 2 H
I created a production order for 48 EA, meaning it should take 8 hours.
I changed in the work center "capacities" tab that I have 2 ind.capacities.
I created another work order for 48 EA and assume that for scheduling it will be 4 hours, but when I look on the dates+time, I can see it still take 8 hours.

I don't understand why, can you help me figure it out?

Thanks a lot,
Yael.
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Re: Daily change in individual capacity for a work center

Postby Ramarao » Mon Nov 12, 2012 1:57 pm

You're right... Capacity and Costing use the same formula whereas scheduling use the other formula -- in fact, if you use a wrong formula in any one of the tabs, the system should tell you it is not expected, for standard SAP formulas.

In your case, your expectation is correct, scheduling with 2 capacities should take 4 hours. Wonder why it shows 8 hrs for you still.. couple of thoughts...

Are you using a routing? If so, changes to the workcenter are not automatically considered in routings and therefore the production orders. You may have to delete the routing operation (or at least the workcenter) and re enter it. Alternatively, you may delete the operation in the PP order, and enter a manual operation directly in there (therefore not using the routing) - it may help.
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Re: Daily change in individual capacity for a work center

Postby yaelb » Wed Nov 14, 2012 3:02 am

Hello,

Thanks again for the quick answer.
We found the problems:
1. In the parameter defenition, for no. of ind.cap, I should have written "1" in "standard value" field.
2. In the formula for execution time, I should put brackets, like ()/(), otherwise, the calculation is wrong.

I saw that I have to define the scheduling with "capacity category" = 002 and it is defined automatically also for capacity tab. Should I use also capacity category 001 for any reason in this case?

Thanks a lot,
Yael.
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Re: Daily change in individual capacity for a work center

Postby Ramarao » Wed Nov 14, 2012 5:56 pm

Good to know it worked for you.

You may have any number of capacity categories and validate capacity planning on different dimensions. However, scheduling has to be by one of them, in order to be unambiguous. Normally, you'd enter the most "bottleneck" capacity category (be in personnel, or machines) that is likely to be least available, for scheduling purposes. The assumption is when this capacity category is available, rest would be too.

If your purpose is to schedule it accurately only - and not plan capacities against requirements, then there is no need for you define additional capacity categories - like 001 in your case.

Hope this makes sense.
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Re: Daily change in individual capacity for a work center

Postby yaelb » Wed Nov 28, 2012 8:08 am

Hello again,

I changed the formula for scheduling, so it will take the number of individual capacity into consideration, and when I test the formula through the work center it looks ok.
I opened a production order and expect that the time at the "dates" paragraph will be changed if I changed the number of individual capacities from 1 to 2, will be shorter, but nothing has changed.
Maybe you have an idea why?

Best Regards,
Yael.
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Re: Daily change in individual capacity for a work center

Postby Ramarao » Fri Nov 30, 2012 5:24 pm

"where" did you change the number of individual capacities? In the work center?
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Re: Daily change in individual capacity for a work center

Postby yaelb » Sun Dec 02, 2012 1:34 am

Yes, I changed the number of individual capacities in the work center, when I double click the "capacity category" field, under paragraph- "standard available capacity".
yaelb
 
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Re: Daily change in individual capacity for a work center

Postby yaelb » Sun Dec 02, 2012 7:13 am

Hello,

Yes, I changed the number of individual capacities in the work center, when I double click the "capacity category" field, under paragraph- "standard available capacity". the dates of the order were not changed based on that, I have no idea why? maybe it's because of the capacity category which is defined as "person" (002)?
I also tried to dispatch the production order through CM25 and got weird messages ("Error on conversion of internal units of time: 00000000 000000
"- CY709,"Order 000000450627 operation 0010: Planning step was undone (UNDO)"- CY763,"All rescheduling was undone (UNDO)"- CY765), maybe it is connected to the same problem?

Best Regards,
Yael.
yaelb
 
Posts: 37
Joined: Wed Nov 03, 2004 10:42 am

Re: Daily change in individual capacity for a work center

Postby Ramarao » Sun Dec 02, 2012 6:09 pm

I am not sure if this is because new changes in master data may not be updating already exisitng orders. Did you try to create a new order and see how it is?

Other errors you mentioned do not seem like related to your capacity category issue to me.
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