Drum-Buffer-Rope

Drum-Buffer-Rope (DBR) is a method of synchronizing production to the constraint while minimizing inventory and work-in-process.

The Drum is the constraint. The speed at which the constraint runs sets the “beat” for the process and determines total throughput.

The Buffer is the level of inventory needed to maintain consistent production. It ensures that brief interruptions and fluctuations in non-constraints do not affect the constraint. Buffers represent time; the amount of time (usually measured in hours) that work-in-process should arrive in advance of being used to ensure steady operation of the protected resource. The more variation there is in the process the larger the buffers need to be. An alternative to large buffer inventories is sprint capacity (intentional overcapacity) at non-constraints. Typically, there are two buffers:

·         Constraint Buffer (immediately before the constraint; protects the constraint)

·         Customer Buffer (at the very end of the process; protects the shipping schedule)

The Rope