Description

The Just-in-Time (JIT) module provides a comprehensive set of tools for planning and controlling production for repetitive or JIT processes.  JIT uses online rate planning techniques to plan supply and demand in a uniform, flow-like fashion for parts defined as JIT-produced.  The resulting plan is orderless and smooth, facilitating execution by a pull production system.  With pull production, actual part consumption drives replenishment production with no direct tie to the material plan.  The Just-in-Time module has two major functions:  Just-in-Time Planning and Just-in-Time Control.

Just-in-Time Planning involves definition of production rates and maintenance of production schedules.  For JIT parts, MAC-PAC plans production by rates instead of by manufacturing orders.  The JIT supply and demand planning process uses a rate record called a flow authorization (FA) to establish and store rate data.  Flow authorizations state part production, and flow requirements (FR) state component demand.

To help plan flow authorizations, the system maintains user-defined planning periods called flow intervals.  The system initially plans flow authorizations and flow requirements by flow intervals, but the user may adjust the flow intervals to span any desired number of days greater than or equal to one week.

Users can change supply rates by part within a particular cell in either daily or weekly quantities by using the Daily/Weekly Production Schedule Maintenance conversation.  Each screen displays multiple parts that may be made at the cell and their supply rates.  An over/under bucket is displayed on the Detail screen of this conversation to show either past-due production (indicated by an asterisk (*)) or over-production for each part since the cell's last synch date.  The synch date indicates the date on which flow authorizations and flow requirements were last synchronized.  The synchronization processing closes all FAs and FRs for a cell that begin before the current date, and splits and re-adds any FAs and FRs that end on or after the current date.  This processing may be activated by pressing a command key and updating the schedule.  Availability, load, and capacity rates are also displayed for each part in each bucket on the screen.

Users may also change supply rates by cell for a particular part in the Part Production Schedule Maintenance conversation.  This conversation makes it easy for users to schedule a part in multiple production centers at once.  The Detail screen of this program also shows an over/under bucket for past-due or over production since that cell's last synch date.  The synch date indicates the date on which flow authorizations and flow requirements were last synchronized.  You may synchronize a part in this conversation.  The synchronization processing closes all FAs and FRs for a cell that begin before the current date, and splits and re-adds any FAs and FRs that end on or after the current date.  This processing may be activated by pressing a command key and updating the schedule.  For each daily bucket, supply quantities, run units, and availability rates are also displayed.  Total load for the part on the production center may also be viewed by pressing a command key.

Both of these conversations serve as tools to modify production rates to keep within a cell's capacity.  They also act as a simulation or a worksheet to provide "what if" analysis for a cell or a part within multiple cells.  These conversations are necessary to schedule a part in a production center other than the main production center defined on the Part Master File.  Master Scheduling and Requirements Planning will only schedule a part in its main production center.  Therefore, if the user wishes to schedule a part in an alternative cell, production must manually be decreased in the main cell and added to the alternative cell.  These conversations aid in determining supply rate changes and their effect on total load and availability without affecting the data base.  When a final schedule is determined, the data base is updated.

Once schedules are modified for a part, the system automatically generates component requirements (flow requirements).  When these requirements are modified, their impact on the load at a particular cell is automatically updated.

Just-in-Time Control involves reporting production to the MAC-PAC system.  JIT production receipts and time recording transactions are reported by part rather than by order.  Only a minimal amount of information is needed.  However, these transactions provide all the information needed to calculate variances in Inventory Accounting.