Page 14 - Orlicky's Material Requirements Planning

Foreword

When I migrated from engineering to manufacturing around 1980, one of the first
things I heard about was a thing called MRP. I can clearly remember walking up the main
street of Annapolis, Maryland with my wife Debby, a systems engineer for Hewlett
Packard, and hearing her explain to me that MRP was a computer application that man-
ufacturers use to identify what they need and when they need it through a series of cal-
culations. “They do a forecast,” she said, “then check inventory to see what they need to
make and use the lead time to figure out when to start making it. Next, they use the bill
of materials to multiply out the quantities of each component they’ll need, check inven-
tory again, and use the lead times to see when to start making or buying whatever they
don’t have.”
As an engineer, I was impressed by the simple, straightforward logic and, yes, the
elegance of MRP. What could be simpler and more obvious? One could do this by hand,
but it was clear that this was a task ideally suited to a computer—easily defined and sim-
ply calculated but involving a lot of data and a lot of those simple multiplications, addi-
tions and subtractions. And in 1980, computing power was just becoming affordable for
mid-sized enterprises through the emergence of the mini-computer as an alternative to
expensive mainframes.
I wanted to learn more about MRP and, like many others, found what I needed in
Orlicky’s Material Requirements Planning. When I got involved with APICS a few years
later and pursued my certification in production and inventory management, Orlicky
again provided the definitive information on MRP and how it works. A whole generation
of manufacturing management learned MRP from Orlicky.
Can a technique and computer application first defined and developed in the 1960s,
which rose to common use in the 1980s, still be viable in the 2010s? Wasn’t MRP consid-
ered passé in the mid 1990s with the emergence of APS and ERP? Yes and yes. The MRP
of the 1970s became MRP II (Manufacturing Resource Planning) in the 1980s and

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