Mitigating the impact of a time-dependent production process

Abstract

Value-added processes that bear associated wait times occur frequently during production manufacturing and increase cycle time. Since the wait time is integral to the value created by the process, it can be difficult to reduce the cycle time impact. The use of adhesives and the impact of their associated cure times is an example of such a time-dependent process and one that appears frequently on products made at Raytheon Space and Airborne Systems (SAS). Using a typical Raytheon pod system (RPS) as a case study, this thesis examines various ways to mitigate the impact of these value-added associated wait times (VAAWT) on cycle time. Adhesives with long cure and/or set times are used extensively throughout the design of this RPS in both structural and non-structural applications. Now that the RPS is well into full-rate production, the cycle time impact of these adhesives' VAAWT has become a burden, accounting for over 60% of the cycle time on the three assemblies studied on during the case study. Both short-term and long-term solutions were developed as a result of this project, which enabled a 23% reduction in cycle time exclusive of changes in design.

(cont.) Based upon the lessons learned during this case study, a set of guidelines is presented for application to other time-dependent processes and Raytheon products. This thesis also discusses some of the barriers encountered during the implementation of this project and suggestions for overcoming them. These guidelines and lessons have already been applied successfully to reducing the impact of adhesive cure times on a second SAS product line, resulting in a cycle time reduction of 80%.