Reverse Engineering of Mechanical Parts: A Brief Overview of Existing Approaches and Possible New Strategies

Reverse Engineering (RE), also known as “CAD reconstruction”, aims at the reconstruction of 3D geometric models of objects/mechanical parts, starting from 3D measured data (points/mesh). In recent years, considerable developments in RE were achieved thanks to both academic and industrial research (e.g. RE software packages). The aim of this work is to provide an overview of state of the art techniques and approaches presented in recent years (considering at the same time tools and methods provided by commercial CAD software and RE systems). In particular, this article focuses on the “constrained fitting” approach, which considers geometrical constraints between the generated surfaces, improving the reconstruction result. On the basis of the overview, possible theoretical principles are drafted with the aim of suggest new strategies to make the CAD reconstruction process more effective in order to obtain more ready/usable CAD models. Finally, a new RE framework is briefly outlined: the proposed approach hypothesizes a tool built within the environment of an existing CAD system and considers the fitting of a custom-built archetypal model, defined with all the a-priori known dimensions and constraints, to the scanned data. INTRODUCTION The introduction of Computer Aided Design (CAD) tools dramatically changed the nature of modern engineering. CAD models, in particular, are currently essential in every engineering aspect and application. In mechanical engineering, specifically, CAD models are key-elements within the entire product development process, from the design phase (e.g. 3D modeling, FE simulations) to the final production (e.g. CAM tools). Given the relevance of CAD models, difficulties and limits come to light when dealing, for instance, with the reengineering of a part whenever its original digital representation is not available. Reverse Engineering (RE) aims at the reconstruction of 3D geometric models of objects and mechanical parts, starting from 3D measured data (points/mesh). This process, also known as “CAD reconstruction”, allows to recover a CAD model of an existing mechanical part/object in order to fulfill all possible designer’ needs. In recent years, considerable developments in RE were achieved thanks to both academic and industrial research (in this second case, mostly relate to RE software packages). Scientific literature is moving towards the development of techniques able to reconstruct CAD models more and more faithful to the original design intent; however, the obtained CAD models are usually not promptly usable by designers for their final needs. This is mainly due to 1) the format of the geometrical description (which usually cannot be directly interpreted by most CAD environments) and 2) imperfections in reconstruction that need to be amended. To better identify these limits and to outline the basis of a new RE strategy to improve the state of the art, a brief review of existing approaches to CAD reconstruction is presented in the following section. Proceedings of the ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference