Synchronous manufacturing : implementing "pull" production in a job shop environment

Abstract

In a recent contract, CVN 78, Northrop Grumman Corporation has been experiencing significant pressure from the Navy to reduce cost in the design and construction of the new nuclear aircraft carrier class. Furthermore, the joint venture project between General Dynamics Electric Boat and Northrop Grumman Newport News to build the next fleet of Virginia Class Submarines has budgetary incentives tied to the contract. In order to meet these expectations, Northrop Grumman Newport News shipyard has responded by focusing on ways to better synchronize manufacturing in order to meet schedule and reduce costs. Migrating from the traditional push production to the concept of pull production, it is projected that inventory and operating expense will reduce significantly as pull will help to synchronize production efforts. There are different ways to approach the implementation of pull. Goldratt's Theory of Constraints was chosen as the most appropriate method in the job shop environment of the shipyard's Fabrication Shop. This thesis focuses on the design of a Drum-Buffer-Rope implementation of the Theory of Constraints in a high variability, high volume steel fabrication shop. Additionally, it describes how this method was selected over alternative pull systems. Finally, a case study of implementation design will be described along with an evaluation of the system design.