Manufacturing Resource Planning (MRP II
Earlier in thi chapter, our discussion of MRP focused only on the materials requirements rhar resulted from an explosion of the master schedule. We did not include the needs of all the other types of resources, such as staffing, facilities. and tools. In addition. while we discussed capacity requirements planning. we did this somewhat externally to the !vIRP system. In this section we discuss the logic of more advanced versions of MRP that include a wider range of resource and outputs.
An expansion of the materials requirements planning program to include other portions of the production system was natural and to be expected. One of the fir t to be included was the purchasing function. At the same time, there was a more detailed inclusion of the production Stern itself-e-on the shop floor, in dispatching, and in the detailed scheduling control. MRP already had included work center capacity limitations. so it was obvious the name materials requirements planning no longer adequately de cried the expanded system. Someone (probably MRP pioneer Ollie Wight) introduced the name manufacturing re source planning (MRP II) to reflect the idea that more and more of the firm was becoming involved in the program, To quote Wight.
The fundamental manufacturing equation is:
What are we going to make')
What does it take to make it?
What do we have?
What do we have to get?'
The initial intent for MRP II was to plan and monitor all the resources of a manufacturing firm- manufacturing, marketing, finance. and engineering-through a closed-loop system generating financial figures. The second important intent of the MRP II concept wa that it simulate the manufacturing system. It is generally conceived now as being a total. companywide system that allows everyone (buyers. marketing staff. production. accounting)to work with the same game plan and use the same numbers and i capable of simulation to plan and test alternative strategies. (See the OM in Practice on Furniture Manufacturer U es MRP II to Cut Delivery Time.)
Sales and Operations Planning2
Sales and operations planning (S&OP) is an extension of ARP II that goe out ide of the manufacturing function, aligning cut timer demand with both in-how e and supplier.