Original Date: 10/10/2005
Revision Date: / /
Information : Pull System
By using a pull system, Raytheon’s Integrated Air Defense Center can place material onto the production floor at a rate that meets customer demand. The key to the Pull System is its concentration on bottlenecks – focusing on weak links, responding quickly to defects, and keeping parts moving throughout the production floor before new parts are issued for the next build quantity.
A shop floor Pull System is frequently and popularly defined as “a method of controlling the flow of resources by replacing only what has been consumed.” A pull system should provide what is needed, where it is needed, and when it is needed. This definition would suggest that having inventory on the shop floor or in storage is a waste of resources in a manufacturing environment. Raytheon Integrated Defense Systems (IDS) has recognized this waste and has implemented processes to mitigate the condition. In 2004, Raytheon’s Integrated Air Defense Center (IADC) facility implemented a pull system and was able to realize immediate results by reducing the waste associated with over-production (i.e., transportation, stocking, inventory, and cycle counting).
A Kanban system was implemented for work-in-process (WIP) so that only the amount of materials necessary to meet delivery schedules is allowed on the floor. With the Kanban system, problems are not masked by large quantities of WIP and the root cause of problems has to be addressed and corrected immediately. Point-of-use storage is implemented on the floor with a Kanban system. The Kanban system limits material being pulled from the feeder process to only the amount that will be used immediately to meet schedule Takt cycles and serves as a signal to the feeder process to begin manufacturing the next batch of required materials. Only the assets necessary to support the production schedule are allowed, and components are stored in cabinets on the production floor and at floor side for only the work that is actually in process.
Implementation of the Pull System for manufacture has allowed the Andover facility to use other lean manufacturing tools such as Work Place Organization (WPO) and cellular manufacturing to improve its delivery performance. On one product line alone, Andover was able to reduce inventory of a key component by 54% and realize a 41-day reduction in cycle time. The implementation of the Pull System has virtually eliminated batch processing, allowing the Andover IADC facility to implement manufacturing of near one-piece lots.
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