Production Release Control: Paced, WIP-Based or Demand-Driven? Revisiting the Push/Pull and Make-to-Order/Make-to-Stock Distinctions George Liberopoulos Abstract We consider three elementary mechanisms for controlling the release of parts for production in manufacturing systems: 1) setting an external production pace by controlling the raw part arrival process, 2) authorizing releases based on the work-in-process (WIP) level in all or parts of the system, and 3) releasing new parts in response to actual demands. We present and compare different variants of these mechanisms on a simple serial flow line, using a queuing network representation, and we use these variants as a basis to revisit the push/pull and make-to-order/make- to-stock distinctions. We extend our descriptions and definitions to include advance demand information and forecasts. 1 Introduction The last two decades have seen a surge in the literature related to pull control, kanban-type control, WIP control, and more generally token-based production con- trol systems. Not only have many generalizations, extensions, and variants of the original kanban system been introduced, analyzed, and compared (e.g., generalized kanban control system (GKCS), CONstant WIP (CONWIP), production authoriza- tion card (PAC), paired-cell overlapping loops of cards with authorization (POLCA), extended kanban control system (EKCS), customized token-based system (CTBS), heijunka kanban, among others), but several reviews (e.g., [30], [16], [31], [13], [17]) and new approaches for representing and analyzing these systems (e.g., [7], [9], [12], [2], [1]) have appeared in the literature in the last five years only. New de- velopments have also taken place within the last five years in extending the analysis and performance of pull systems to include features such as advance demand in- formation (e.g., [47], [33], [38], [8], [22]), lot sizing (e.g., [45]), multiple products George Liberopoulos Department of Mechanical Engineering, University of Thessaly, Volos, Greece e-mail: glib@mie.uth.gr 1