New coverage groups have been created recently to manage DDMRP method into D365. Globally these new coverage groups are great and it is nice to have these options. However negative days are not considered by DDMRP model.
DDMRP FAQ - Supply Chain Management | Dynamics 365 | Microsoft Learn
Here is our business case:
Let's say we've got an item with no stock. Sales orders (SO) are placed and confirmed for next week. There are purchase orders (PO) to cover the requirements. Unfortunately , according to POs confirmed delivery dates, POs are coming next month. So it is much to late to respect the confirmed shipping date of SOs.
When I'm running MRP, the projected stock for the next couple of days is negative.
Historically, by using a requirement coverage group with few negative days (2 days for example), then MRP would have created new planned purchase orders on the very short term to avoid the shortage due to late deliveries.
Unfortunately, this is not the case with DDMRP coverage group: MRP will create planned purchase order to reach min, max and reorder point but if current purchase orders permit to reach this level, no new planned purchase orders will be created on the short term even if POs are very very very late.
Would it be possible to consider negative days by DDMRP method? is it in your roadmap?
Thank you
Beatriz Nebot Gracia (administrator) on 6/13/2023 2:52:09 PM
Thanks for your input. Negative days are intentionally not considered in DDMRP.
This is due to the fact that the goal with DDMRP is always to maintain a stock buffer of the product so that stockouts do not occur. And in case that the net flow is below the reorder point, indicating that the buffer should be refilled, then an order will be created. The order will come a lead time into the future, so it is true that it is expected to come at that point in time, and if it comes later, it can result in a stockout and in the situarion that is on your business case:
"Let's say we've got an item with no stock. Sales orders (SO) are placed and confirmed for next week. There are purchase orders (PO) to cover the requirements. Unfortunately , according to POs confirmed delivery dates, POs are coming next month. So it is much to late to respect the confirmed shipping date of SOs.
When I'm running MRP, the projected stock for the next couple of days is negative."
It is expected that you update the lead times to be realistic lead times, so the case mentioned above is the exception and not the rule. Or another option, if you have very variable parameters, is that you create more frequent planned purchase orders for replenishing the buffer - which is achieved by adjusting the lead time parameter (on the coverage group) for the buffers needed. By lowering the parameter, the buffer zones will be affected (red and green, according to the formulas) by being diminished, and resulting in that you order more often.