Applying factory physics to manual assembly at an aerospace fabrication site

Abstract

The assembly of welded reservoirs at the Boeing Tube Duct, and Reservoir Center (TDRC) is a traditional batch and queue operation that relies heavily on manual craftsmanship. The production system experiences high variability in cycle times, high use of overtime, and poor ontime performance. The value provided by the system to Boeing and its customers is characterized by considering the associated costs of late delivery, inventory, labor, and opportunity cost. To understand the system's performance, the system's processes are mapped and modeled using discrete event simulation. The simulation is used to evaluate the benefits of changes to staffing, overtime implementation, and shop floor control. Based on the results of the simulation, lead times are increased to stabilize delivery and a CONWIP system is implemented to improve productivity and reduce overtime costs. Subsequent production data show that these changes are effective and that this framework provides successful strategies for value characterization, system stabilization, cost reduction, and increases in value creation.