MRP and capacity

[Former Member]

Hi,

Just a quick question. Does MRP take into account capacities? I understand MRP is all about ensuring the material availability striking a balance between optimial service and costs. It matches the sales orders (requirements) with stock and generates planned orders or purchase requisitions orstock transfer requisitions based on type of prourement.

But in this flow, does it consider the capacities of it's resources?

Thank you.

[Former Member · Accepted solution]

Not in the true sense of the word (assuming you are talking about the generic MRP and not any specific system)

MRP is just a(n) (information)system to calculate the requirements of dependant demand inventories by ordering and scheduling

it is supposed to answer the following Q: what is needed, how much is needed,

and when is it needed

MRP-I does not have to do with Capacity. But you can give the system a feedback(or close the loop) tor set up constraints that will change this calculation (typically this is done by MRP - II along with a few other things)

[Former Member · Accepted solution]

Hai Harish,

Thanks for the reply. Do you mean that capacity is not checked in MRP? Pardon my ignorance but how is the capacity leveling handled in PP then? I don't know about MRPI but MRP II is the principle the Heuristics work on, i.e., it does infinite planning.

Can you refer to any links where I can read more about this?

Thanks.

[Former Member · Accepted solution]

What i mentioned was definition of the terms - MRP and MRP II

What each software does and each process is named in it is not necessarily related to this

MRP in R3 for example will do what the definition says

SNP heiristics will do the same by infinite planning(assuming no lotsizing etc..)

But when you add on capacity levelling you have now gone into the MRPII definition area

So you will have to match what the definition is vis-a-visa what the System calls it and has under it

some basic link here.

http://www.answers.com/topic/material-requirements-planning

check the APICS definition - materials management - tony arnold should have some

will post some more if i come across any

[Former Member · Accepted solution]

Hi Harish,

Thanks for the replies. I found the answers. I should have done a little more search outside help.sap.com on MRP and MRPII.

Here it is in <a href="http://en.wikipedia.org/wiki/MRP_II">Wiki</a>

"MRP: based production planning and inventory control system used to manage manufacturing processes.

The other major drawback of MRP is that takes no account of capacity in its calculations. This means it will give results that are impossible to implement due to manpower or machine or suppler capacity constraints. However this is largely dealt with by MRP II."

When I was reading through Heuristics, it says it is run based on MRPII (infinite planning). That confuses me now as SAP academy material and wiki seems to contradict each other. Can you clarify this for me please?

Thanks.

[Former Member · Accepted solution]

AFAIK Heuristics is not simple MRP but has a lot of rules (as the name indicates) built into it which are feedback to the system to calculate taking into consideration a lot of other factors than just a simple calculation

So if you run heuristics without any rules and just use it to arrive at just a number for requirement and a date on it and the source of supply it does what MRP is supposed to do

If you add in capacity levelling and lot sizing and transportation lane constraints and other rules it tends towards being MRP II.

But if the reading you mentioned here said MRPII is Infinite planning then it probably is not the mainstream understanding of the term.