ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE2009, San Diego, CA, 30 August-2 September 2009 ; In literature, there are a number of indexes suggested that serve as the indicator of commonality among product components, modules and variants. However, as these elements are increasingly interconnected with aspects other than the component view, the existing commonality metrics are unable to effectively model these aspects due to their limitation in capturing relevant information for analysis. Therefore, there exists a need to consider multiple design and manufacturing aspects in commonality metrics so that a comprehensive view of the commonality among product variants can be presented. In the current representation schemes proposed for product family modeling, ontology is one of the most promising ones to model the complex semantic relations among various elements in a product family. Nevertheless, the research and application of ontology in the analysis of a product family has so far received little attention. In this paper, we proposed a framework to generate a semantically annotated multi-facet product family ontology. Using a case study of a laptop computer family, we suggest and demonstrate a new commonality analysis approach based on the semantically annotated multi-facet laptop product family ontology. Together with a new method of deriving product variants based on the aforementioned ontology, our approach illustrates the merits of using semantic annotation in assisting ontology based product family analysis. ; Department of Industrial and Systems Engineering ; Refereed conference paper