Production Planning and Scheduling

Production Planning and Production Scheduling Concepts


Let us first look at some definitions from APICS (American Production and Inventory Control Society) Dictionary.

Production Planning A process to develop tactical plans based on setting the overall level of manufacturing output (production plan) and other activities to best satisfy the current planned levels of sales (sales plan or forecasts), while meeting general business objectives of profitability, productivity, competitive customer lead times, and so on, as expressed in the overall business plan. The sales and production capabilities are compared, and a business strategy that includes a sales plan, a production plan, budgets, pro forma financial statements, and supporting plans for materials and workforce requirements, and so on, is developed.

One of its primary purposes is to establish production rates that will achieve management’s objective of satisfying customer demand by maintaining, raising, or lowering inventories or backlogs, while usually attempting to keep the workforce relatively stable. Because this plan affects many company functions, it is normally prepared with information from marketing and coordinated with the functions of manufacturing, sales, engineering, finance, materials, and so on.

Production Scheduling The process of developing the production schedule – A plan that authorizes the factory to manufacture a certain quantity of a specific item. It is usually initiated by the production planning department.

Capacity Planning The process of determining the amount of capacity required to produce in the future. This process may be performed at an aggregate or product-line level (resource requirements planning), at the master-scheduling level (rough-cut capacity planning), and at the material requirements planning level (capacity requirements planning).

Infinite Loading or Infinite Scheduling Calculation of the capacity required at work centres in the time periods required regardless of the capacity available to perform this work.

Finite Loading or Finite Scheduling Assigning no more work to a work centre than the work centre can be expected to execute in a given time period. The specific term usually refers to a computer technique that involves calculating shop priority revisions in order to level load operation by operation.

Drum-Buffer-Rope (DBR) The theory of constraints method for scheduling and managing operations that have an internal constraint or capacity-constrained resource.

Forward Scheduling A scheduling technique where the scheduler proceeds from a known start date and computes the completion date for an order, usually proceeding from the first operation to the last. Dates generated by this technique are generally the earliest start dates for operations.

Backward Scheduling A technique for calculating operation start dates and due dates. The schedule is computed starting with the due date for the order and working backward to determine the required start date and/or due dates for each operation.

Advanced Planning and Scheduling (APS) Techniques that deal with analysis and planning of logistics and manufacturing during short, intermediate and long-term time periods. APS describes any computer program that uses advanced mathematical algorithms or logic to perform optimization or simulation on finite capacity scheduling, sourcing, capital planning, resource planning, forecasting, demand management, and others. These techniques simultaneously consider a range of constraints and business rules to provide real-time planning and scheduling, decision support, available-to-promise, and capable-to-promise capabilities. APS often generates and evaluates multiple scenarios. Management then selects one scenario to use as the official plan. The five main components of APS systems are
  • Demand Planning
  • Production Planning
  • Production Scheduling
  • Distribution Planning
  • Transportation Planning


Our Solutions for Production Planning and Scheduling

Supply Chain Business Solutions offers Preactor Advanced Planning and Scheduling software for Production Planning and Production Scheduling.

Preactor Advanced Planning System helps in effective scheduling of production helping manufacturing companies to minimise work in progress inventories and reduce manufacturing costs. Preactor is a constraints-based production scheduling solution that will help manufacturing businesses schedule production to best meet customer demands while achieving business objectives such as minimise work in process inventories, minimise costs by doing things such as minimise changeovers or optimising schedules in other ways.

So successful has Preactor’s breakthrough technology been that the number of companies using the product recently reached the 4,500 marks, more than any of our competitors. These companies are a mix of small and medium-sized as well as large corporations located in 88 countries.

Preactor can be configured as constraints-based detailed production scheduling software as well as a production planning software.

Detailed Scheduling software is an important tool for many companies where it can have a major impact on the productivity of a process. In manufacturing, the purpose of scheduling is to minimize the production time and costs, by telling a production facility what to make, when, with which staff, and on which equipment. Production scheduling aims to maximize the efficiency of the operation and reduce costs.

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The basic difference between planning software and scheduling software is that planning systems are ‚bucketed (monthly, weekly, daily) and cannot preserve operation sequences within the time bucket. True scheduling systems are bucketless, preserving sequencing, and capable of generating work-to or dispatch lists. Assignment of operation to a resource is a key function to achieve operational efficiency and optimizing performance.

Detailed scheduling uses a shorter time horizon and a much more detailed process route than a planning system.‚ Typically the input would be manufacturing orders which have a process route associated with each defining the operation steps to make the product.‚ The user then can load the orders onto individual resources using scheduling rules and interact with the schedule using the Gantt charts and plots that are generated.‚ A typical output would be a dispatch list for each resource.

An important feature of any scheduling tool is the ability to customise it to meet the unique needs of each application.‚ Templates can help to get the user to 80% of the requirements but to get the last 20% it's important to be able to tailor the tool to fit.

Planning Software

Preactor takes a breakthrough approach to the planning process. Whereas most planning systems use a spreadsheet type grid to calculate the production load with some simple load leveling to push overloads from one week to the next, Preactor s uses its detailed scheduling roots to search for available capacity.

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When used in a long term planning system, Preactor is set up with a high-level model of the process. The forecast demand is usually planned at SKU (finished product) level and the processing capacity is typically represented as weekly or daily ‚buckets of capacity, with the resources representing departments, cells, plants or entire factories. The inputs to the planning system are the forecast demand, initial stock, and the target stock level required at the end of each day or week. The target stock levels can either be entered as a number of items, e.g. 10,000 cases or in Days of Cover (DoC), e.g. 14 DoC, in which case Preactor analyses the forecast and real demand over the next DoC period to determine the required stock level.

The available capacity is also entered through a calendar system set up in either daily or weekly mode for each resource, where resources may be departments, cells, plants or entire factories.

Typically the production load is backward scheduled, so Preactor will start by trying to load the demand onto the available resources into the week or day it is ideally required.‚ Preactor also includes the concept of a Make Window. The Make Window defines how early you are prepared to make the product because there may be shelf life issues to take into account. If capacity cannot be found within the Make Window, then alternative resources will be considered.

The planner can then use the system to change planning parameters and capacity in each period to see the impact on deliveries, stock levels, and capacity utilization over the planning horizon.

Please CLICK HERE to review more information on Preactor Advanced Planning and Scheduling System.