MRP Suggestions by Reorder Cycle

Running latest version of NAV

MRP is making unrealistic suggestions

It seems it is treating all purchase orders as un-released when in reality that are released

examples, Assume MRP Run OCT 1 for ease of conversation

Assume reorder cycle is 7 days- (The term period refers to one reorder cycle)

Example 1,

A PO was placed for 200 parts 60 days ago due Oct 15

Sales order demand was moved from OCT 15 to Oct 14 (period 3 to period 2)

MRP suggest “cancel” Current PO and Suggest a NEW PO for period 2. MRP “should’ Reschedule the current PO

Example 2,

A PO Was placed for 100 parts 30 days ago and is due in period 1 let’s say tomorrow

Demand has increased from 100 to 115 in period 1

MRP suggest increase QTY on current PO due tomorrow , MRP should suggest placing a NEW PO for the increased QTY.

Example 3

PO Placed for a long leadtime item, The planning Flexibility for that order is set to “NONE”

The reorder cycle is 30 days

The PO is due Oct 21

When MRP runs it sees the Flexibility = None and suggest a NEW PO Like it should if it finds demand prior to this PO’s schedules date. BUT, the system sees demand prior to the scheduled date and it then looks at ALL demand for the reorder cycle of 30 days and suggest a NEW PO for the whole demand. In this example there is a demand of 200 prior to OCT 21 and a demand for 500 after Oct 21. MRP suggest a NEW PO for 700 in error. The NEW Sugg PO Should be for 200. Using the current suggested PO will result in 500 excess parts as the current PO covers demand after the OCT 21 date.


MRP is assuming it can make any change needed to any PO regardless of leadtime or when it was ordered

“MAIN ISSUE” MRP is planning within each “reorder cycle” and if there is a demand in a different “period” it suggest cancel the current order and placing a new PO for the other period. What the system should do is reschedule the current PO. It “seems like” it only reschedules “IF” the supply is within the “same” period.

The site went live within the last 90 days, I do operational consulting and assist businesses in improving MRP performance and was just recently engaged. I am assuming that there is something the dealer did not setup correctly or that there is a bug that needs to be addressed as the suggestions are unrealistic and do not reflect normal MRP suggestions.

Appreciate any suggestions

Feel free to call if you know what it is or what needs done (I am in EST)

Dave Mowrey

Cell- 603-867-1523

It has been a long time, but I will assume not much has changed in the fundamentals.

So, are you using SKU’s?

Which Reordering Policy are you talking about? Fixed Reorder?

The site uses both Lot for Lot and Fixed Order Qty

I do not believe those ploicies should make a difference based on my examples above?

I ran numerious test In the test company. One of those test was to shifted ALL order policies to lot for lot and in another all to fixed reorder, the messages and responses from the system were very similar - the differences were QTY related based on policy as expected.

I have verified that the are running NAV 2009

You did not answer the most critical question - are they using SKU’s? Stock Keeping Units?

This is my guess.

  1. You are not using SKU’s

  2. The field “Components at Location” in the Manufacturing Setup file is BLANK.

This would cause the symptoms you describe.

Solution - put your main warehouse in the “Components at Location” field, if you do not have a main one put anything in there. Blank is the issue as you have not told NAV the main planning warehouse, so it treats a movement like this completely independently.

The reason for the question on the reordering policies was to conclude whether the reorder cycle would be called. It would be with those, assuming the end date is beyong the final demand.

I do appreciate the effort; hope any prior reply did not come across in any way that did not imply the same.

I am at a different client site this week, I do not implement NAV software just try to aid in understanding and determining IF this is how NAV works, is it a bug do they need a custom program or if it is setup. I hope setup

Yes there are using SKU Cards

I have them checking the Components at Location fields right now

No the reply was fine. If they are using SKU’s the components at location is not relevant but where were the settings you describe? Make sure they are on the SKU card. If they are using manufacturing check the planning flexibility on the order. What is the manufacturing policy if they do? The final one is did they modify it in any way?

Hello, I am new to this site and not totally familiar with how it works please forgive my ignorance.

I to am having these same issues. Was this question every fully answered? I am using both the sku card and reorder policy. I am getting hundreds of messages to sort through similar to what was mentioned previously. Is there a solution to this issue? I leave flexibility open as we often mover orders around so I do need to be able to expedite orders.

Thanks you for your time I appreciate it.