Master Planning/Planned order generation

Hello! I’m having a problem with ‘approved’ planned purchase orders being replaced by new MPO’s.


When processing an order, engineering will create a BOM and ensure that the parameters for each item are correct. Planned production orders are not an issue as each project moves from engineering directly to routing, and routing firms the planned production orders into actual production orders. Planned purchase orders are approved by engineering, and purchasing will act on the planned orders according to requirement date. Often times, the order is processed long before the due date, and we must rely on the notion that any approved planned purchase orders will not be affected by master planning. We do experience(all too often) situations in which individual engineers are failing to set the proper purchase/inventory lead times.

Additional Details:

1.) We currently use a default production order scheduling principle of ‘backward’.

2.) We do not use any delivery date control on the Sales Order form(delivery date control = none)

3.) We do not have any capacity set for any work centers.


When the order is processed, the requirement date for the main(level 0) item has an ‘order date’ and a ‘requirement date’ on the master plan generated planned production order. My understanding is that the requirement date is derived via the confirmed ship date from the sales order form. Generally, I will set an inventory lead time of 14 days for each main assembly, which would generate an order date of 14 days prior to the requirement date. When I finish processing the order it is forwarded to routing. At this point in the process all planned purchase orders have been approved, and routing need only to act on planned production orders. It is my understanding that the requirement date for any planned order is driven via the order date from the parent [planned]production order, or the sales order if it is the ‘level 0’ item(which is driving all subsequent demand). I feel that this is an issue as it is engineering that is approving any necessary planned purchase orders which are created via master planning, using the ‘order date’ from the parent production order. Utilizing the ‘backward’ scheduling principle nullifies any lead time because when job scheduling is run, the system generates a new ‘order’ date for the production order by calculating the routed time. As such, the production order for the main assembly(level 0) item which is driving all subsequent demand now has a new order date, which is generally the same date as the requirement date as the routed time is generally <4 hrs. This new ‘order’ date is later than the date that was originally generated via master planning and inventory lead time. Additionally, production management will manually modify the dates on these production orders to start earlier than the scheduled date, and many times it is earlier than the ‘order’ date(which dictated the requirement date of all subsequent orders) that was on the original planned production order. Ultimately, the original planned purchase orders(that were approved by engineering) are disappearing and being replaced by new MPO’s with dates that differ from the originals(default status is ‘unprocessed’) understandably, as the dates on the parent production orders have changed.

The end result of these happenings is that after a shipment meeting, the explosion for the production order is reexamined and found to have multiple planned purchase orders that are ‘unprocessed’. Generally, these are not caught in time to get parts on order that have a lead time > 2 weeks.


How does job scheduling affect planned orders, if at all?

How does job scheduling differ from master scheduling?

If the requirement date for the original ‘approved’ planned order is later than the ‘order’ date for the parent production order, does the system automatically replace said planned order with a new MPO that has an earlier requirement date?

I believe that this is only occurring with planned orders for items of item type ‘BOM’, with ‘stop explosion’ checked in the item details form(to generate planned purchase in lieu of planned production order).

Any advice is greatly appreciated!

Apologies I kept getting lost in the extensive post

Job scheduling defines times, so working backwards from your defined receipt time (defaults at 10.00) it will plan on capacity backwards and potentially define an earlier start date - when is your planned receipt time from a planning perspective?

Job scheduling defines the capacity only, master scheduling looks at the capacity and materials, it drives the job scehduling. You can run job scheduling without a care about stock availabilty if you want. Ultimately you can run teh Job scheduling as much as you want it will not suggest planned orders.

With regards to the requirement date this depends on many of the planning settings. The answer is Yes and No depending upon your settings. I would suggest looking at your coverage group settings and plan settings for requirement and future dates.