Production planning/detailed scheduling

Need Identification Manufacturing Decision Basic Chemistry Detailed Chemistry Task Identification Unit Operations Basic Plant Engineering Detailed Engineering Vendor Specifications Component Acquisition Construction Plan and Schedule Plant Construction Operating Procedures Commissioning and Start>up Production Plan and Schedule... 

The short-term planning process is dealt with in the Production Planning and Detailed Scheduling module within SAP APO. PP/DS considers a horizon of two to three months. In contrast to SNP planning, there is no cross-location planning in PP/DS. 

The requirements for short-term planning, especially with regard to campaignhandling as well as the need to consider sequence-dependent setup and finite resource capacities on most resources lead to the selection of the PP/DS optimizer as the most suitable planning method. In addition to the optimizer, PP/DS offers numerous heuristics for automating production planning and detailed scheduling tasks. 

The main focus of the optimization process in PP/DS is the determination of production campaigns. On the basis of the results determined in SNP optimization, a detailed schedule which considers additional resources and products is created. This schedule is fully executable and there is no need for manual planner intervention, even though manual replanning and adjustments are fully supported within the PP/DS module. An executable plan can only be ensured by considering additional complex constraints in PP/DS optimization. These additional constraints include ... 

Integration of Supply Network Planning and Production Planning and Detailed Scheduling... 

Production planning has to determine on the detailed level which production step (operation) has to be carried out at which time and on which resource. For this purpose a resource allocation problem has to be solved (this is denoted as a scheduling problem in mathematical theory). It is natural to desire this allocation to be optimal in a certain sense (minimal number of setups and/or violations of requirements dates, etc.). 

A system in such an environment has to create high-level production plans as weU as more and more detailed scheduling plans. The timing of the generation of these detailed schedules depends on the urgency or the importance of the jobs in question. 

While the production plan lays out what mix and quantity of products the company is expected to produce over a certain time horizon, the schedule describes the detailed execution of this plan, giving a step-by-step work list in the form of a dispatch list or a specification of the times at which every operation should start and end. In contrast to the production plan, whose focus is on independent... 

Pure simulation approaches are proposed by Pitty et al. (2008) and Adhitya and Srini-vasan (2010). Pitty et al. (2008) propose a discrete-event simulation model for a refinery supply chain. Operational decisions such as unloading schedules and production planning are made based on simple priority rules. Various configurations of the modelled SC are studied and compared to reveal optimization potentials. This approach explicitly considers some details of ship and pipeline transports. Adhitya and Srinivasan (2010) describe a discrete-event simulation model for an SC producing and distributing lubricant additives. Here, batch production is modelled. Again, operational production decisions are made by priority rules and a scenario analysis is conducted to evaluate the effects of other priority... 

This module produces the detailed schedule, indicating which order must be released in production and when, based on the master production schedule and the associated material plan. The short-range scheduling works with finite capacity constraints. 

The master production schedule (MPS) is the detailed production plan for the end items to be produced by the plant or firm. It is constrained by the production plan. For example, if the production plan calls for 1,000 two-liter size bottles of soda to be produced in January, then the MPS is the detailed plan to produce all the different types of two-liter size bottles of soda produced in January. This may mean that 250 two-liter bottles of cherry cola are produced in week 1 250 bottles of diet cola in week 2 250 bottles of sugar cola in week... 

The system safety program plan generally includes detailed information about system safety personnel (responsibilities, qualifications, and level of effort), procedures (tasks to be performed and techniques to be used), and products (format and schedule). 

Audits Product safety programs work well when there are planned and scheduled reviews of for aU aspects. There should be periodic audits to assure that participants meet all program details. 

As we discussed earlier, aggregate production planning is a tactical decision in supply chain management. Production scheduling is an operational decision. It is important to understand the key differences between the two, with respect to the time horizon and the level of detail in the production plan. 

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