CONCURRENT ENGINEERING: Research and Applications Concurrent Conceptual Evaluation of Tolerances’ Synthesis in Mechanical Design Roberto Pe´rez, 1, * Joaquim Ciurana, 2 Carles Riba, 3 Arturo Molina, 4 David Romero, 4 Luis W. Herna´ndez 1 and Ana M. Quesada 1 1 Mechanical Engineering Department, University of Holguı´n, P.O.Box 57, Holguı´n, 80100, Cuba 2 Department of Mechanical Engineering and Industrial Construction, Technical School, University of Girona, Spain 3 Industrial Equipments Design Centre. Polytechnic University of Catalonia. Barcelona, Spain 4 Research & Development, Tecnolo ´gico de Monterrey, Campus Ciudad de Me ´xico, Me ´xico Abstract: Taking into account the global competitive environment and the impact of collaborative engineering environments on Small and Medium-sized Enterprises, it has now become necessary to develop new models and tools that can keep helping the designers and engineers in the decision-making processes related to the product design lifecycle. The tolerance synthesis purpose is to provide a rational basis for assigning tolerances to dimensions, and it has become an important subject in the product design process. The aim of this research work is to present an approach to support a concurrent conceptual tolerance synthesis evaluation process in a mechanical design within a collaborative engineering environment context, for example, Virtual Enterprise. The reference model proposed was developed and refined through a set of mechanical design study cases. The analysis and reflections of the study case presented in this manuscript are described in detail to show an example of how the different study cases were used to develop an understanding of how the reference model proposed can stimulate the conceptual synthesis evaluation of tolerances in the product design process. Key Words: concurrent engineering, product design, tolerance synthesis, virtual enterprise. 1. Introduction Nowadays, the traditional linear engineering design and manufacturing processes are being replaced by a new paradigmatic concurrent approach that aims to facilitate an integrated product development process. To remain competitive in this continuously evolving design and manufacturing scenario, small and medium- sized enterprises (SMEs) are now focusing more and more on collaborative engineering tools in the design and manufacturing phases of the product lifecycle. In order to develop this collaborative-concurrent vision, there is a need for the formulation and application of collaborative engineering tools with the intention of supporting a virtual product design process in the new concurrent engineering approach. Advances in Information and Communication Technologies (ICTs), the increasing adoption of the Internet, unstable market, and economic conditions, are inciting the SMEs to examine their strategies and engage in new forms of collaboration. As a consequence, the engineering practices have started to migrate from traditional practices to concurrent engineering ones [1]. The engineering design could be regarded as a transformational process from a set of product func- tional specifications and requirements into a complete description of a physical product which meets those specifications and requirements stated by the customer and demanded by the market [2]. In fact, the engineering design is a heterogeneous procedure with different competences and actors, but with symbiotic interests to achieve a product design. These actors require adequate technologies and ICT platforms to assure the interoperability among them and their design activities. Authors in the field have worked in developing specialized systems to support a specific stage in the product development process as a first approach to support some collaborative engineering processes. An increasing number of SMEs are using virtual tools for their product development processes. These systems are characterized by 3D computer graphics systems with user-interactive control and viewer centered per- spectives [3,4]. *Author to whom correspondence should be addressed. E-mail: roberto.perez@itesm.mx Figures 1 and 3 appear in color online: http://cer.sagepub.com Volume 19 Number 2 June 2011 175 1063-293X/11/02 0175–12 $10.00/0 DOI: 10.1177/1063293X11406147 ß The Author(s), 2011. Reprints and permissions: http://www.sagepub.co.uk/journalsPermissions.nav