Material Requirements Planning
Material Requirement Planning ( MRP) is the English term for since about 1960 standard MRP.
Since the early 1970s it was part of the production planning and control systems (PPS ) systems, the concept of which was described in detail as Communications Oriented Information and Control System ( COPICS ). The PPS systems follow a phase-related successive planning concept. Starting from the planning of the production program, which is derived from a marketing program, these primary needs are resolved with the help of BOMs in the dependent requirements (see needs assessment ). The production program consists of already known customer orders, the results of the demand forecast and planned warehouse orders. With the help of disposition parameters ( lot sizes, Heats, safety stocks, etc. ) of the material requirements currently required is then determined.
The steps in detail were the BOM explosion with the help of so-called bill of processors ( DBOMP IBM UNIBORS of Sperry and others). The result of the BOM explosion was the need for individual parts, sub-assemblies and assemblies for the products to be manufactured. On each step of the disposition generally multilevel BOM structure, the determined gross demand was compared to the stock, then summarized the remaining net demand ( net requirements calculation) to the planned construction contracts (lots) and further resolved. Before further resolution, the dates were roughly with the help of lead times of production orders or purchase orders calculated ( termination). This scheduling of material requirements based on the assumption of unlimited capacity to carry out the production orders.
The so roughly scheduled construction contracts were subsequently terminated detailed work schedules. This time scheduling delivered simultaneously the capacity requirements for each planning period ( see Production Planning and Control). This scheduling of material requirements as the termination was based on the BOM on the assumption of unlimited capacity for execution of production orders.
End of the 1970s, the above procedure was followed by an capacity scheduling, among other things, with the aim of avoiding congested capacity in individual planning periods to obtain realistic dates for the planned production orders. This is now called MRP I.
A further development and extension of MRP Manufacturing Resources Planning is the abbreviation MRP II
Due to the weaknesses of MRP - II the advanced planning system was developed around the year 2000, which is divided into individual modules that communicate with each other, and thus differs from the successive method of MRP II.