Changing the Production order BOM (Prod-BOM) - a few remarks

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Manufacturing industries of the make-to-order or engineer-to-order variety will often have the need to modify the Production order BOM.

The most common reason is a new engineering revision. When my production order is in "created" status, there is no problem, simply modify the Prod-BOM or copy the most accurate BOM to the Production order.

When using MRP, production orders are typically in status "scheduled" or further. Making any changes in the Prod-BOM will trigger a re-estimate and re-schedule. The recently added items will behave like any other BOM line-item.

What if we have to delete an item from the Prod-BOM? Unless my order is in status "created", the system will not allow this but a simple work-around is to change the quantity to zero. No problem.

Now what about reservations? What if I have my reservation parameter set to "start" (reserve materials at the last possible moment to remain as flexible as possible regarding priority of orders when there is material shortage)?

And what if my order has already started when an ECO comes through that requires me to add items to the Prod-BOM?

As opposed to "estimate" and "schedule", the "start" transaction is a one-time deal. We cannot "restart" an order. The quantity field will be blank if I start an order for the second time, which means no transaction can possibly happen.

So we have the following situation: the order is started and the Prod-BOM line items are now reserved. But I have added one or more additional items to the Prod-BOM. How to get them reserved?

METHOD 1: Manual reservation.

METHOD 2: Reset the order status and restart, only acceptable when no transactions have posted yet

METHOD 3: Modify the reservation parameter to "estimate" first, then add the new items to the Prod-BOM. Upon saving, the system will prompt for a re-estimate and re-schedule and the new items will be reserved.

The picklist will contain these new items as if they had always been on the BOM. Success!! (PS no sense in changing the reservation parameter back to "start" again.  New orders will pick up the "start" reservation from the parameters)


What if the BOM-changes are too dramatic to simply add or remove a few line items in the Prod-BOM?

Here we face a dilemma. We can only copy the latest BOM to the production order when it is in status "created".

SOLUTION 1: reset the order status and do the copy (only acceptable when no actual postings have taken place)

SOLUTION 2: change the code so it does allow a BOM-copy to the production order in statuses other then "created". One can argue the design is unnecessarily strict in this area. When the order is "started", we would like to get a warning when attempting to do a BOM-copy. The other statuses should be fine.

SOLUTION 3: create a new production order.

I have seen all three solutions being used in real life. Solution 2 turned out to be a very moderate programming effort and was very well received. We were facing a situation where the Prod-BOM had to be updated multiple times, because of engineering changes. Yet the order had to be on the schedule for capacity planning purposes.



  • This lesson learned is equally valid in all Dynamics AX versions.