production schedulingthe detailed planning of PRODUCTION so as to achieve production targets within specified timetables and avoid production bottlenecks, while making effective use of labour resources and ensuring a high rate of machine utilization. Production scheduling is generally undertaken by the production planning department and will be based upon orders received for products or forecasts of product demand. Where a firm schedules its production on the basis of making to order then it will plan its production in response to customers' specific orders and promised delivery dates. On the other hand, where a firm schedules its production on the basis of making for stock it will plan its production to maintain adequate STOCK levels of finished products from which it can, in turn, satisfy customer orders.
Production scheduling in BATCH PRODUCTION is concerned with fitting new orders into the spaces available in the manufacturing programmes. This requires knowledge of:
- the production operations required for the manufacture of each product, the order in which these operations must be undertaken and the machine or work stations at which operations will be performed;
- the available capacity of machines or work stations;
- the relative priorities of existing jobs;
- available labour and materials;
- the required delivery or completion date for the job.
Almost all production scheduling in batch production involves the successive subtraction of operation times from the required completion date. This is known as due date or reverse scheduling. The principal problem in due date scheduling is to decide what allowances shall be made for idle or waiting time. Operation times are known sufficiently accurately, but waiting times between operations are variable. Production schedules of this type are usually depicted upon bar charts (see GANTT CHART). The advantage of this type of presentation is that the load on any machine or on any department is clear at a glance, and available or spare capacity is easily identified. It will also indicate which resources are overloaded so that activities can be rescheduled or some of the work subcontracted.
Production scheduling in MASS PRODUCTION is more straightforward since usually a much more limited number of products is involved, sequences of production operations are predetermined and production is generally for stock rather than in response to direct customer orders.
Once production schedules have been established then PRODUCTION CONTROL will be concerned to ensure that products are manufactured according to the previously-determined production plan. See PRODUCT SPECIFICATION, MASTER PRODUCTION SCHEDULE, LINE OF BALANCE CHART, BACKLOG, ACTIVITY CHART, JUST-IN-TIME (JIT) SYSTEM, MATERIALS FLOW MANAGEMENT, DISPATCH, BACKWARD SCHEDULING.