Hi Yassine,

PDP (MPS in English) and CBN (MRP in English) are basically the same processing.
But usually you don't use them the same way.

The theory would recommend:

- to use MPS for long term (for instance based on forecast only while neglecting the current stock and firm sales with a monthly bucket for the next 18 months). The output will be usefull to have some activity forecast for the year(s) to come.

- to use MRP for short and medium term (for instance based on firm sales only and obviously taking into account the current stock level with usually a bucket size mixing days and weeks on a total horizon of 6 months). The output will be usefull to take the decision what, when and how much to produce/purchase.

=> In this configuration, both processes are used on the same products.

However, quite often you can have a need to manage reording quite differently between puchase and produced goods (for instance the bucket size). In that case, it also possible to dedicate the MRP to puchased products and MPS to manufactured products. Doing so you are losing the ability to have the long term usage...

There's a lot of info out there on MRP vs MPS. Basically in X3, MRP can explode the BOM when creating work order suggestions depending on how the reorder policy is set up. MPS doesn't explode the BOM. Just really depends on your environment for which is more useful.

MPS stands for Master Planning Schedule. As the name suggested, it's meant be used for scheduling production based on your sales demand. So it would take your sales orders/forecast, do BOM explosion in the case of multi-level BOM, and suggest work orders in the end. Since MPS does NOT consider production capacity, it's up to the planner to adjust MPS suggestions and finalize their schedule after MPS run. 

MRP stands for Material Requirements Planning. It's meant to be used to figure out the material you need to SUPPORT your finalized schedule after MPS run. It use the same logic as MPS. It takes your Work Orders as demand, do BOM explosion, and suggest Purchase orders for material. 

So the easy way to say it is that MPS is for Work orders, and MRP is for purchase orders. However, strictly speaking, MPS should be run down to where you may have bottleneck in your manufacturing process. This way, you can adjust your schedule to even out the load at your bottleneck work center, and then run MRP to generate sub-assembly work orders and Purchase orders to support that schedule.

A good example of this would be in an assemble-to-order environment. The manufacturers would produce and stock common modules, and assemble them to final products based on sales orders. In that case, the main focus of the production is really for the common modules. So a common practice would be run MPS down to the common modules, and the planner would focus on the stock level and schedule for the modules. Once the schedule is finalized, they would run MRP to create Work orders for subassembly and PO for materials.

Mike I think you said it very well.  In most of the manufacturing environments I deal with MPS is used to manage the work order schedule and MRP for the intermediate and raw material schedule.    This delineation is especially helpful in environments where the scheduling profile of the finished good work orders doesn't exactly parallel the demand profile of the sales orders.  This could be due to a variety of reasons to include supply chain/factory constraints.  MPS in these environments allows for the production planners to analyze the demand profile (sales orders, contracts, forecasts, safety stock) and then make a determination on what demand will be satisfied in the planning period with work orders.  Then once those work orders (master production schedule) is in place MRP is executed to identify what intermediate work orders and purchase orders need to be generated to satisfy these specific needs.  In these environments usually I will tailor the MRP section of the Requirements Parameters to look only at the demand from the firm/planned work orders.

Good stuff guys. Check out ASCM.org - If MRP/MPS is your work world they are a really good resource. Used to be APICS before the name change.

Just for the record, in Sage X3 the MPS will explode the BOM.