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Mrp present
- 3. MRP
- 4. MRP Overview
- 5. Uses of MRP
- 8. Planning Run
- 9. Planning Run - Types
- 10. MRP - Control Parameters
- 12. Planning in Planning Horizon
- 13. Planning Run - Single Item
- 15. Single-Level MRP
- 16. Multi-Level MRP
- 17. Total Planning
- 18. MRP Procedure
- 19. Single Item - Multi-Level MRP
- 27. Safety Stock
- 28. Coverage Profile
- 29. Coverage Profile
- 30. Coverage Profile
- 31. Receipt Range of Coverage
- 32. Safety Time
- 33. Safety Time in Production
- 35. Lot Sizing - Overview
- 37. Period Lot - Sizing Procedure
- 39. Long Term Lot Sizing
- 40. Other Lot Sizing Features
- 41. Lot Size Rounding Profiles
- 43. Layout of MRP List
- 44. Stock Req. List - Layout
- 45. MRP List - Collective Display
- 46. MRP List - Functions
- 49. Old / New Exception Message
- 50. Planned New Exception Message Order Conversion
- 51. Material Supply for Production
- 53. Search in Individual List
- 54. Current List - Functions
- 56. Order Report
- 59. Scheduling in PP
- 60. Scheduling - Basic Dates
- 61. Scheduling - Production Time
- 62. MRP Customizing
Notas del editor
- In MRP, all existing requirements and receipts with quantities and dates are taken into account as well as stocks. Requirements such as sales orders, planned independent requirements, material reservations and dependent requirements are used as the basis of the planning run. The existing receipt elements such as planned orders or production orders, purchase requisitions, purchase orders, schedule lines and so on are compared with the requirements.
- In net change planning, the system only plans materials with the appropriate indicator. The planning file entry contains the following information: Ÿ the low-level code of the material Ÿ whether the change refers to an element within the planning period whether the BOM has to be re-exploded
- To improve the performance of the planning run, you can limit the planning horizon. This means that the system will only create receipt elements for the requirements that lie in the planning horizon. Note that as time passes, requirements that are not yet covered by receipts may move into the planning time fence. If no other changes relevant to planning occur, these requirements will not be covered until you carry out a planning run over the total time axis using the control indicator NETCH. Therefore, you should carry out this planning run at regular intervals.
- In the single-item, multi-level planning run, the materials planned using MRP techniques are planned according to the structure of the bill of materials. The MRP controller can view the planning results of assemblies or components during the multi-level planning run and can make manual changes before the system continues the planning run. In the single-item, single-level planning run, dependent requirements are created for materials in the next lower BOM level. The planning results of the single-item, single and multi-level planning runs can be processed interactively. The MRP controller can create, change, delete and reschedule order proposals.
- A comparison of firmed receipts and requirements takes place along the time axis. If a material shortage occurs, the system calculates a net requirement. The lot-size calculation is carried out on the basis of the net requirements.
- You can define the available part of the safety stock in the MRP group. A new order proposal is not created until stock levels have fallen below the available portion of the safety stock. This order proposal replenishes stock (at least) back up to the safety stock level. Advantage: no order proposals are created for very small material shortages. This reduces the administrative effort and planning is more stable.
- The planning run makes sure that the available quantity does not fall below the minimum stock. If necessary, it is replenished up to the target stock. If the stock level exceeds the maximum stock level (by firmed receipts), the system issues an exception message.
- In Customizing, you define the periodicity (week, month or planning calendar period) and the number of periods to be used for calculating the average stock consumption. The average daily requirements are calculated for each period. Multiplying these values with the values you specified in Customizing for the minimum, target and maximum range of coverage (days’ supply) result in the minimum, target and maximum stock.
- You can define up to three validity periods each with different values for the minimum, target and maximum range of coverage (days’ supply).
- The receipt range of coverage informs you when the material supply for production is low if only certain firmed receipts are delivered which are not sufficient to cover requirements. The selection of the firmed receipts is made in Customizing for the plant.
- The safety time is used to avoid material shortages caused, for example, by an unreliable vendor. The order proposals are brought forward by the number of workdays specified in the safety time. The safety time is defined in the material master record.
- If a safety time has been defined at finished product level and also at assembly level, these two times are added together when planning the assemblies. This may not be necessary. Therefore, you can define per material whether the safety time is valid for all independent requirements or only for certain independent requirements (such as sales orders).
- The net requirements are used in the lot-size calculation to determine the quantities of the inividual order proposals. For period or optimum lot-sizing procedures, several net requirements are grouped together into one lot. Moreover, you also have the option of restricting the lot size as follows: you can define a maximum lot size or a minimum lot size you can specify that the system is to round up/down the lot size according to a preset rounding value
- When maintaining the material master record, you can define a minimum and a maximum lot size which the system uses when calculating lot sizes.
- In the static lot-sizing procedure, future material shortages are not taken into account, that is, when a material shortage occurs, the system simply creates an order proposal for the amount defined in the static lot size. No check is made to see when a future material shortage exists. In the lot-for-lot order quantity, the system creates an order proposal for the amount of the material shortage. If on a particular day, several issues cannot be covered, the system will still only create one order proposal for the total shortage quantity on this day. In the fixed order quantity, the system creates an order proposal for the quantity determined as the fixed lot size. If this quantity does not cover the complete requirement quantity, the system creates several order proposals for the same date. In replenishment up to maximum stock level, the system creates an order proposal for the quantity necessary to bring the stock level up to the maximum stock level.
- In the period lot-sizing procedures, all the requirements within a predefined period are grouped together into one lot. The resulting receipt can be set to the start of the period, the end of the period or to the date of the first requirement.
- Dynamic lot-sizing procedures optimize the total costs resulting from order and storage costs. On the basis of various costing criteria, the requirements are grouped together into a lot in such a way as to optimize the total costs.
- The MRP list displays the results of the last planning run. Changes to the stocks, requirements or receipts cannot be seen until after the next planning run.
- The current stock/reqmts list displays the most up-to-date information on stocks, requirements and receipts. Changes to stocks, requirements or receipts can be seen immediately.
- The MRP controller can use the collective display of the MRP list to select materials specifically assigned to the controller. Using this display it is possible, for example, to only select materials with exceptional situations that have not yet been processed.
- The planning run will not automatically displace firmed receipts. Instead, if a firmed receipt should be rescheduled out, the system will create an exception message to this effect. Note that the system will only do this if the date to be rescheduled lies in the rescheduling horizon. Otherwise, no exception message will be created. Firmed receipts in the rescheduling horizon for which no requirements exist any more are flagged with a reversal proposal You can use the rescheduling period to avoid the system from using receipts that lie in the distant future to cover requirements in the near future. Within the rescheduling period, the system only searches for firmed receipts that can be brought forward. To reduce the number of exception messages, you can set tolerance values for rescheduling in and out. Then, the system will only create an exception message when the difference between the current date of the receipt and the rescheduling date exceeds the tolerance value.
- In the planning run, the system compares the exception messages in the new MRP list with the exception messages in the old list. If one exception messages appears in both lists, it is indicated an ‘old’ exception message. In the collective list display, you can select lists with new exception messages only. In the individual display of the MRP list, you can search specifically for new or old exception messages.
- In the collective conversion, the MRP controller can select the planned orders for the materials for which he is responsible and convert them collectively into production orders, process orders or purchase requisitions. The opening period is the interval between the opening date and the start date in the planned order. It represents the processing time required by the MRP controller to convert the planned orders. Therefore, for collective conversion, the system selects the planned orders using the opening date. It is also possible to select planned orders with opening dates in the past.
- The two types of scheduling in production planning are used in different ways. Production orders are scheduled using lead time scheduling on operations. You can also use lead time scheduling to calculate capacity requirements for planned orders in material requirements planning. The production order always uses both pairs of dates (basic and target dates). The target dates are the dates relevant to production .
- Material Requirements Planning explodes a material’s BOM, generates planned orders for the components to be procured and calculates basic order dates . Basic order dates (planned dates) are calculated using the in-house production time or the planned delivery time in the material master. The in-house production time for a material can be calculated using lead time scheduling of a routing without an order and is then copied to the material master. The floats before and after production are defined using a scheduling margin key. The scheduling margin key is assigned in the material master.
- You maintain the in-house production time in the material master. To calculate basic dates correctly in requirements planning, it is very important that the in-house production time in the material master agrees with the results of lead time scheduling using a routing .
- Distributing the work to several application servers. This significantly improves the performance of the planning run.