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MRP Processing You run the MRP engine through the Process MRP program. After the demand requirements are defined, the MRP engine generates the job, transfer order, and purchase suggestions to satisfy the requirements. The MRP engine uses several calculations to generate job, transfer order, and purchase suggestions. These calculations take into account all the demand requirements currently placed within your database. The demands included in the calculations are defined by a beginning date (Scheduled Start Date) and a final date (Cut Off Date). Any demand requirements that occur on or between these two dates are evaluated by the MRP engine. The MRP engine always uses the base inventory unit of measure assigned to the part in the Primary UOMs - Inventory field when performing these calculations. If the Track Multiple UOMs check box has been selected for a part, it first converts quantities and units of measure entered into transactional programs to the base unit of measure for the part before performing MRP calculations and generating suggested jobs, transfers or purchase orders. All quantity values it uses that are defined in the part master file (for example, Min On Hand, Max On Hand, Min Lot Size are specified in the base unit of measure. Before you run the MRP calculations, make sure that the application reflects the production workflow within your manufacturing center. Each part needs an accurate method of manufacturing and a complete set of plant details; demand is generated against all levels within a method. You should also verify that the stock quantities currently recorded within inventory are correct. Your plants must also be linked to production calendars that accurately define the days and hours per day during which work will be performed. When all of the required information is entered, you are ready to run the MRP engine. The engine handles demand requirements that originate from these sources: •Forecasts •Master Production Schedules •Sales Orders •Transfer Order Suggestions •Inventory Restock Quantities •Material Requirements on Jobs •Recurring Purchase Order Quantities The MRP engine calculates the total demand required during the defined date range for each manufactured and purchased part handled by your company. It then performs a series of calculations to determine how much supply is available to satisfy the demand. The MRP supply logic asks these questions: •What quantities of a part are coming in from different locations? The MRP engine calculates supply quantities from the following sources: • urchase Orders •Other Jobs •Transfer Orders •Receipts from Inspection •If this is a stock part, what quantities can be used from inventory? The MRP engine calculates these supply quantities using the following considerations: •The Total On-Hand Quantity available in all warehouses that stock the part. •The Minimum On-Hand Quantity required to be kept within stock. •The Safety Stock Quantity required to be kept in stock for emergency situations. •What quantities are being manufactured? The MRP engine calculates these supply quantities from the jobs that are currently manufacturing part quantities. •What quantities are needed each day? When the available supply quantities do not equal the required demand quantities on a specific date, the MRP engine creates job, transfer order, and purchase suggestions. The MRP engine calculates the quantities required on these suggestions using the following methods: •If this is a non-stock part, create a job or purchase suggestion for the demand. •If this is a stock part, calculate the amount of supply available on a specific day and then create the job or purchase suggestion. •If this is a stock part, is the On-Hand Quantity under the Minimum On-Hand Quantity? If so, create a suggestion for the demand. •If the Re-Stock to Max check box is selected, the job or purchase suggestion will use the quantity defined within the Part-Plant detail’s Maximum On-Hand Quantity. •If this is a stock part, is the On-Hand Quantity under the Safety Stock Quantity? If so, create a suggestion for the demand. •If the Re-Stock to Max check box is selected, this job or purchase suggestion will use the quantity defined within the Part-Plant detail’s Maximum On-Hand Quantity. By default, the MRP engine will create an unfirm job if it can find a valid method of manufacturing linked to the part. However, if the MRP engine cannot locate a valid part method, it instead generates a job suggestion. You can convert the job suggestions to firm jobs within the Job Manager program. •Even though you can convert an unfirm job or job suggestion into a firm job, these jobs will continue to be modified each time the MRP engine is run. This is also true for open purchase orders that were originally generated by MRP. The MRP engine will generate suggested changes to open jobs and purchase orders, which you can choose to act on. •Note that the MRP engine will use the Unfirm Job Prefix value to indicate which jobs were generated by the MRP calculations, and that these job numbers are generated in sequence. You can review the jobs within the Job Entry program. As long as the job has an Unfirm status, it can be deleted by the MRP engine and regenerated as a new unfirm job. If the MRP engine is run against a firm job, you can limit the suggestions placed against it. You can freeze a firm job’s Due Date or Quantity by selecting the appropriate Lock check box. The MRP engine cannot make suggestions against locked values. Locked values, however, are still evaluated as part of the MRP calculations in order to determine the total supply available against the current demand requirements. Similar logic is used for purchase orders. After a PO is created from a purchase suggestion, its status is set to Open and suggestions can be placed against it each time the MRP engine is run. You can pull these suggestions into the PO record, updating its releases with the new results. To prevent a release from being changed, however, you can freeze each release’s Due Date and Quantity by selecting the appropriate Lock check box. After you lock the PO, the MRP engine will no longer create suggestions for it. However, the engine will still consider this purchase order during its calculations. After you close a PO, the MRP engine no longer counts this purchase order during its calculations. |