Original Date: 09/15/2003
Revision Date: 01/18/2007
Best Practice : System Lean Manufacturing
To improve performance on a U.S. Navy contract for missile Vertical Launching System components, United Defense, L.P. Ground Systems Division Aiken developed a System Lean Manufacturing process that significantly reduced production cost. As more process features are included in the lean implementation, the company anticipates additional savings.
System Lean Manufacturing implementation provides substantial benefits for the manufacture of major machined and welded components for defense systems. These benefits are derived from process changes in material management to minimize inventory and manufacturing operations, reducing the distance parts travel on the factory floor and relocating machinery to improve production performance. To improve performance on a U.S. Navy contract for missile Vertical Launching System components, United Defense, L.P. Ground Systems Division (UDLP GSD) Aiken developed a System Lean Manufacturing process and significantly reduced production costs.
UDLP GSD Aiken’s previous process focused on work orders to manufacture individual components in production lots that corresponded to two to three months of inventory. These components were produced at multiple work centers throughout the facility, and organized around the technical manufacturing disciplines. Inventory was stored at various locations around the plant, typically near the last manufacturing operation. Deliverable item assembly focused on assembly in the best order from component inventory. For example, one system included six weldments built up from 86 components, 82 of which were manufactured at UDLP GSD Aiken at 19 work centers in 311 manufacturing operations. Each weldment had its own work order, generated for one month’s production, and was delivered to final assembly where finished units including the other weldments were shipped weekly and not necessarily as a complete shipset. This process was accomplished after completing a 12-mile journey across the factory floor.
By contrast, the Lean Manufacturing implementation process treats the finished assembly as the principal focus of the manufacturing process, organizing manufacturing to minimize both direct and indirect costs. The review included evaluating individual machining operations, changing metal ordering to reduce the size and increase frequency of deliveries, generating kits to move the developing structure between work centers, reorganizing the process and eliminating work orders in favor of work instructions related to the kit components, consolidating the work centers, and minimizing component travel time on the shop floor by relocating machinery where necessary.
The System Lean Manufacturing process yielded impressive results. Process certification of all components contributes to variance elimination, thereby improving quality. Workstation involvement was reduced from 19 to 10, and manufacturing operations for the 82 manufactured components were reduced from 317 to 225. The average travel distance for all 86 components was reduced from 12 miles to 5.5 miles. Inventory was reduced from three months of production to one week of production, costs were reduced, and quality was increased, thereby increasing customer satisfaction.
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