Question:
How to constraint the optimizer (DS) to respect dependent demand requirement dates?
Abstract:
How can I change order priority in APO for planned order create in R3? Is it possible to change orders priorities manually ?
Context:
We actually try to improve our scheduling ability at Pratt & Whitney Canada (PWC) by implementing an APO-PPDS pilot cell. This pilot is done in order to "proof the concept" that detailed scheduling with APO-PPDS can improve our business performances.
The pilot cell is a job shop environment that counts approximately 20
machines and process near 10 different parts. Each part has a different routing with approximately 40 operations. In our cell, 75 order will be process by month.
The project scope:
Actually, all the orders produce by PWC manufacturing unit are plan and schedule using the SAP MRP planning run. We want to continue to use the MRP to plan and schedule production at PWC except for the pilot cell parts. The parts produce by the pilot cell has a low-level code of 2. That means that we want to manage level 0 and 1 part with the MRP (This constraint is mandatory for this project).
The problem:
When we try to use the optimizer in order to schedule the pilot cell
orders, the solution found by the optimizer for minimizing lateness (maximum delay, average delay) is useless. The optimizer only push the level 2 requirement dates and the level 1 planned orders in the future. This way, the levels 2 parts are never delay (if we compare requirements dates and planned orders dates) but our level 1 parts are always delay. With this optimization strategy, our objective function equals zero, but the solution is useless. How can we introduce the upper level planned orders date as soft constraint?
Actually the optimizer behave like if moving upper level date and delay upper level orders have no cost.
The problem found appear when we do a 30 minutes optimization with a follow up phase. Our test problem only includes 2 orders and plenty of capacity.
The cause:
We think that the cause of our problem is because planned order create by R3 don't have a priority. This imply that delay an R3 order don't impact the objective function.
The solution:
How can we give to an R3 planned order a priority in APO? How can I change order priority in APO ?
_________________
Marko BLAIS
Answer:
Marko
APO gives planned orders priorities based on the product priority maintained on the SNP2 tab of the product/location record.
So if you maintain the priority here, delete your current planned orders then re-run the heuristics, they should then take the new priority.
APO will also automatically take the product priority from Sales Orders.
Then re-try your optimisation.
Hope this helps
Regards
Parksy
Answer:
Parksy,
Thank you for your fast answer. I think that your solution is good. But my problem still continue to occur because I don't want to have higher BOM level planned orders create in APO. This point is essential because I don't want to maintain higher level part PPM in APO.
_________________
Marko BLAIS
Answer:
Marko
If you "fix" the orders created for the R/3 MRP planned orders in APO (usually via the heuristic run with fixing function).
Then in the optimiser settings on the "order processing" tab check the "Observe latest start/end dates".
This effectively will make the dates on fixed orders a hard constraint.
This may help. Hope so
Regards
Parksy
Answer:
I read something similar in the APO help. I did not found the function/heuristic name fix operation in the function/heuristic list that I can access from the production planning run (/SAPAPO/CDPSD0).
I found a function name firm objects is it the one you refer to ? If you found the fix operation function in your production planning run, let me know. Maybe my support team miss an APO update.
Thank you for your answer,
_________________
Marko BLAIS
Answer:
Marko
Yes my system also calls it "firm objects", but the help and other documentation refer to it as "Fix Objects".
All I can say is try it and see
Let me know how you get on. Good Luck
Regards
Parksy
Answer:
Parksy,
This approach did not work. I was unable to use the firm function in the planning run on the high level product (plan with R3). Maybe because the PPM are not availaible in APO meaning that APO can't fix operation.
After a trial in the planning run, I firm the order manually using the product view lock. The firming work but this trial diden't work. The firm order dates where push by the optimizer without cost.
Thank you for your comment.
_________________
Marko BLAIS
Answer:
Marko
As for the optimizer ignoring these firmed orders. I would check with OSS on this. According to the help it should see these dates as a hard constraint.
I have had a fair few problems with the optimizer on my current project and OSS have made a few corrections over the past few months. It is not a widely used part of APO as of yet and as such a lot of areas have not had much testing.
It's always worth a quick OSS message to see if there is a problem or not. It could save you a few weeks research.
Good Luck
Parksy
Answer:
Parsky,
Thank you for your help.
_________________
Marko BLAIS