Rate Planning

JIT uses online rate planning techniques to plan supply and demand in a uniform, flow-like fashion for JIT parts. To better reflect the nature of a flow environment, rate planning in MAC-PAC uses flow authorizations rather than production orders. Flow authorizations state part production, and flow requirements state component demand. Both are defined as daily rates between a pair of dates. Flow requirements can be offset to reflect the lead time for filling the production pipeline.  When a flow authorization for a parent part is established, component flow requirements are calculated based on the bill of material for the parent part, plus a specified scrap quantity.

The Master Scheduling and Requirements Planning modules both contain rate planning logic to analyze demand and develop supply rates for JIT-designated parts. Both modules use planning intervals to establish optimal production rates for a part in its main production center.  These planning intervals, called flow intervals, can be weeks, months, or user-defined periods.  If you want to modify or simulate changes to the rates produced by Master Scheduling or Requirements Planning, or if you wish to schedule a part in an alternative production center, you can do so in JIT.

As Just-in-time productivity improvements are made, most environments will operate in a mixed JIT/MRPII manner. This affects requirements planning in several ways. First, some components of JIT-designated parts may be unique and best treated with MRPII production orders. Similarly, some JIT components may be used in batch processes. MAC-PAC supports all combinations of planning within the bill of material to meet the needs of the mixed environment.

In a mixed JIT and MRPII environment, a variety of MRPII independent demand may exist with flow dependent and MRPII dependent demand. The Master Scheduling and Requirements Planning modules will plan supply rates for JIT-designated parts in their main production centers.  However, you may want to check capacity at each cell in the Just-in-Time module. Through a single simulation/maintenance screen, you can control the exact profile of a cell and specify the best production mix for an interval. As the demand for the JIT-designated part becomes more flow-like, user intervention may taper off completely.

Once the material plan is created, it can be executed in either of two ways. One method is through a production schedule, which is characteristic of the traditional push method. This method emphasizes working to a schedule, regardless of changes in production priorities downstream. The other method, CONBON, is a pull production system, which produces parts only to replenish those the using cells have consumed. (Refer to the CONBON User Manual for further explanation.)