Rube Goldberg’s Self-Operating Napkin
I love SAP! The Production Planning (PP) process is very logical and straightforward and actually quite fun to do! So why do companies mess with it and create a Rube Goldberg machine to plan their production?
From Wikipedia: A Rube Goldberg machine, named after American cartoonist Rube Goldberg, is a machine intentionally designed to perform a simple task in an indirect and overly complicated way. Usually, these machines consist of a series of simple unrelated devices; the action of each triggers the initiation of the next, eventually resulting in achieving a stated goal.
In this blog I discuss each Production Planning step using business language. Why do we execute each step? What is the business outcome? Then I show you one of the many Rube Goldberg machines I’ve encountered in my 20+ years of SAP PP consulting. Finally, I surmise how clients end up with these “machines”.
The standard Production Planning Process
Here is a schematic of the standard SAP Production Planning process. My discussion focuses on Operative planning starting with Demand Management, step 1 and ending with Production Order Execution, steps 7 and 8.
SAP Production Planning Process
Here is the detail for each step:
|1||Demand Management is the starting point of operative planning. Once you have a consensus plan in Sales & Operations Planning or Long Term Planning you move the plan to demand management. Depending on your industry (planning strategy) the sales from customers might influence the total demand. So will safety stock set in the material master.||You have a total demand plan.|
|2||The purpose of Material Requirements Planning is to create/change supply elements (purchase requisitions for buy-materials and planned orders for make-materials) to meet the total demand. If the planner has firmed some of the supply elements, the MRP run will create exception messages to advise the planner what she must do.||You have a total supply plan that needs corrections.|
|3||Planners perform Exception Monitoring after the MRP run to re-balance supply with demand. Because MRP could not change firm elements such as purchase orders and production orders it is the job of the planner to manually reschedule these.|| |
You have a re-balanced supply plan.
Supply matches Demand
In Capacity Evaluation the planner ensures that no work centers’ capacity is overloaded within the capacity planning period, for example the next 9 weeks. This plan is accurate to the WEEK.
If capacity overloads exist, she does one of these things to resolve the problem:
She then re-runs the MRP program for this slightly revised plan.
The production plan is feasible from a work center capacity point of view (weekly buckets).
Your buyers can trust this plan and buy components for it.
|5||In Dispatching using the Graphical Planning Table, the planner schedules the near term planned orders (say, for the next 2 weeks). During this scheduling she can make use of sequencing functionality so that planned orders with the same/similar setup are scheduled together. This ensures that the shop floor spends less time cleaning/setting up and more time producing. This plan is accurate to the HOUR.|| |
The production plan is feasible from a work center capacity point of view (hourly buckets).
AND, the planned orders are sequenced in the order the Production Supervisor wants them!
|6||The Available to Promise (ATP) program is run on the planned orders in the dispatched period to commit components to these planned orders. The rule for this commitment is not strict; it will consider scheduled elements (e.g. purchase orders) as a source of supply. If this ATP check fails the planner:|