The time-based demand-pull system (“demand-pull system”) technology of the described demand-pull system provides an implementation of demand-pull scheduling for various production operations/systems/factories.  It works in conjunction with a Material Resource Planning (MRP) or Enterprise Resource Planning (ERP) system, which creates production WOs and houses associated data, such as workflows and operational standard hours, to pull work through a factory with results similar to that of POLCA.

The subject demand-pull system pulls work into a downstream WC by matching the Flow Time of the WO to the Need Time of the downstream WC.  Need Time is the time at which the downstream WC will be ready to process the WO, and Flow Time is the time it will take the WO to reach the downstream WC.  Further definitions of terminology used in this document may be found in the Table of Definitions.  Matching these two values results in seamless flow and reduced inventory.  While this may be simple in concept, the complexity of work flow in high-variety environments and the dynamic nature of their production activities, results in overwhelming execution difficulty without the aid of computing hardware and software.

Using data from MRP that is introduced into the demand-pull system with the WOs, as well as data that is created internally, the demand-pull system is able to "reach back" from a particular WC for work from upstream operations and identify exactly which WO should be processed and when.  It does this by analyzing the WOs in the queues at each upstream WC, identifying the highest priority WO, computing its arrival time at the subject WC, and then authorizing the WO to be processed, if its arrival time at the subject WC matches (or exceeds) the time at which the subject WC will be ready to begin work on it.  Matching the Flow Time of the next WO to be authorized with the Need Time of its downstream WC assures that work arrives just-in-time.  This demand-pull system describes this method.