Master Planning and Scheduling, 4th Edition

IntroductionThe Master of All Detailed Supply Plans and Schedules (Below-the-Line)

I seek not to know all the answers, but to understand the questions.

The 1960s were times of radical change in America; the youth of the country challenged almost every traditional value, rebelling in ways unheard of in previous generations. In manufacturing, a much quieter, though no less dramatic, revolution also was taking place.

Traditional means of production and inventory control went by the wayside as companies like Twin Disc and J. I. Case made effective use of material requirements planning (MRP) a reality. Though crude by today's standards, these early attempts at MRP gave manufacturing professionals their first real weapons in the war on production inefficiencies.

When companies first began using MRP, they drove it with a sales forecast and/or customer orders (demand). In other words, to calculate material requirements, computers multiplied the latest demand numbers by the quantities required in the bills‐of‐material (BOM). The problem with this approach was that it blindly assumed that the resources would be available to manufacture products in sufficient quantities just as it was sold. In fact, in an effort to gain economies of scale and level‐load resources, manufacturing companies rarely produced each product in the quantities in which it was sold, though this would be rightfully and continuously challenged by the lean manufacturing school of thought in the coming decades.