PPDS Heuristic for Constrained/Finite planning

Question

Hello PPDS Experts,
I am trying to setup PPDS Heuristcs for a client to achieve a feasible plan for the following scenario:
1) 7 BOM Levels to be planned in APO
2) PPDS Heuristic run must be constrained by material availability at all levels
3) PPDS Heuristic must run in Finite capacity mode at all BOM Levels
With CTM, we can achieve all this in one go;
With PPDS Heuristic, i think we have to use multiple planning steps to achieve this; I tried the following steps until now;
1) Step 1 -> Determine Low Level codes
2) Step 2 -> Un-Constrained MRP Heuristic
3) Bottom - Up Multi Level heuristic
1) Step 1 -> Determine Low Level codes
2) Step 2 -> Un-Constrained MRP Heuristic
3) Step 3- Stable forward scheduling
1) Step 1 -> Determine Low Level codes
2) Step 2 -> Un-Constrained MRP Heuristic
3) Step 3-> Stable backward scheduling
Even after trying all these approaches, my planning result is still wrong; I want to achieve a feasible plan that is constrained by material at all levels and capacity at all levels.
Is there a general PPDS Heuristic sequence that i have to use to achieve this feasible plan.
thanks
swathi

Answer 1

Hi,
I will suggest to go with following approch
1. Infinite Planning run.
2. Finite planning with find slot backward/forward direction for first level BOM.
3. Run bottom up heuristic to adjust planning accordingly.
This may lead to constraint violation at  upper level.
4. Finite planning with find slot i forward direction for next level of BOM. Direction backward is not used  so that there will not be problem of material availability.
You can carry on like this for further BOM levels.
Still planning with above steps may not give desirable results as some times larger lot sizes maynot find suitable slots and there can be poor utilisation of resources.
For somewhat better results after first level of planning some manual intervention will be required.
I will like to aske few questions-:
1. Is your rough cut/mid term plan is balanced considering these constraints.
2. What is approximate lead time at each level?
3. What is total lead time.
4. Duration of shortterm planning horizon at each level(PPDS horizon)
5. Purpose of above questions is in case of multilevel planning genrally short term planning as you to higher bom levels depends on  inventory already available in stock.
Regards,
Santosh