Product Lifecycle Management (PLM) is one way to improve productivity in all manufacturing companies and this is truer in mechanical Small and Medium Enterprises (SMEs). Nevertheless the implementation of a PLM system is not an easy thing for such companies. SMEs have lots of difficulties to create the right information model in order to improve design efficiency. In this paper we propose a PLM model that could help SMEs of mechanical engineering field. Based on a literature review, on the analysis of the mechanical SMEs needs that would favour efficiency during design process, a new PLM model for mechanical SMEs is proposed.