MRP Troubles, Enter Finite Scheduling

These articles are portions of a lecture presented to APICS by our friend Gene Caiola.

In our last segment  titled “The First Programs: Where it all began” we left off after MRP failed to account for the workers when planning out production…

Enter Finite Scheduling

As the 1980’s and 1990’s brought minicomputers and the personal computers, the cost of computer processing power went down dramatically and the complexity of scheduling models went up. One of the most common methodologies developed during the 1990’s was called “Finite Scheduling”. As the name implies, this methodology recognized that there was only a finite amount of capacity available. So if a large number of work orders needed to be completed and many of them specified the need for the same machine at an operation there would be the creation of a “constraint”. Constrained resources were referred to as bottlenecks on the shop floor.

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Dealing with constrained resources became a topic that was highlighted in the very popular book called “The Goal” by Eli Goldratt. Using the story of a manufacturing plant trying to keep its doors open, Goldratt described how the speed at which work can move through a shop floor is only as fast as the slowest resource. If a constrained resource is the source of this slowness then measures must be taken to either use the resource to its fullest or increase the capacity of the resource. We will not explore the full philosophy of constraint management here but suffice to say that is was a great leap forward and finally provided manufacturing systems with a way to manage a multitude of Work Orders all trying to get through the shop on time.

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But Finite Scheduling Was Not Easy

In theory Finite Scheduling would seem to be the answer to what was needed on the shop floor. The methodology also began to have accepted variations such as backward and forward scheduling. This is where the fun started…

What effect did backward, foward, and infinite scheduling have on the industry?  Stay tuned, in our next blog installment “Finite Scheduling – Turned Out Not So Easy To Be Successful” we will take a closer look.