Material requirements planning

Material requirements planning (MRP) is a production planning, scheduling, and inventory control system used to managemanufacturing processes. Most MRP systems are software-based, but it is possible to conduct MRP by hand as well.

An MRP system is intended to simultaneously meet three objectives:

• Ensure raw materials are available for production and products are available for delivery to customers.
• Maintain the lowest possible material and product levels in store
• Plan manufacturing activities, delivery schedules and purchasing activities.

Prior to MRP, and before computers dominated industry, reorder point (ROP)/reorder-quantity (ROQ) type methods like EOQ (economic order quantity) had been used in manufacturing and inventory management.^[1] MRP was computerized by the aero engine makers Rolls-Royce and General Electric in the early 1950s but not commercialized by them. It was then 'reinvented' to supply the Polaris program and then, in 1964, as a response to the Toyota Manufacturing Program, Joseph Orlicky developed material requirements planning (MRP).

Early MRP users in the 1960s and 1970s included Black & Decker, Twin Disc, Markem, Steelcase, and American Sterilizer.^[2] The first company was Black and Decker in 1964, with Dick Alban as project leader. Orlicky's 1975 book Material Requirements Planning has the subtitle The New Way of Life in Production and Inventory Management.^[3] By 1975, MRP was implemented in 700 companies. This number had grown to about 8,000 by 1981.

En 1983, Oliver Wight desarrolló MRP en planificación de recursos de fabricación (MRP II). ^{[ 4 ] [ 2 ]} En la década de 1980, el MRP de Joe Orlicky evolucionó a la planificación de recursos de fabricación (MRP II) de Oliver Wight, que incorpora programación maestra , planificación de capacidad aproximada, planificación de requisitos de capacidad , S&OP en 1983 y otros conceptos al MRP clásico. Para 1989, aproximadamente un tercio de la industria del software era software MRP II vendido a la industria estadounidense (software por valor de 1200 millones de dólares). ^{[ 5 ]} El atractivo del MRP radica en una mejora financiera mayor que la de otros programas de gestión empresarial. Si bien la automatización de la nómina reduce la necesidad de empleados de nómina, pero requiere equipos informáticos y personal, Computerworld afirmó en 1986 que "en las empresas que obtienen todos los beneficios del MRP II, el retorno de la inversión promedia el 200 %". Mientras que el software de contabilidad automatiza las funciones manuales, el MRP permite análisis de requisitos de materiales actualizados, imposibles sin ordenadores. ^{[ 2 ]} Para entonces, existía una variedad de software MRP disponible para mainframes y minicomputadoras , como Manman de ASK y MAPICS de IBM . ^{[ 6 ]}