This research presents an integrated simulation modelingDesign For Six Sigma (DFSS) framework to study the design and process issues in a server manufacturing environment. The server assembly process is characterized by long cycle times, high fall-out rates and extremely complex assembly operations. To ensure on-time customer delivery, these enterprises adopt a make-to-plan and build-to-order philosophy. However, this model is extremely complex, resulting in wastes and inefficiencies in the associated processes. Lean and six sigma approaches have been successful in improving performance by eliminating waste in the design and operational processes. In this study, an integrated simulation modeling - DFSS framework is proposed to (i) address effects of variation, (ii) assess interactions effects between various sub-systems, and (iii) study proposed process (or design) changes, while performing "what-if" analysis. This framework was then used to identify opportunities for improv...