ORIGINAL ARTICLE Enhancing moulds manufacturing by means of reverse engineering L. Iuliano & P. Minetola Received: 5 March 2008 / Accepted: 1 September 2008 / Published online: 23 September 2008 # Springer-Verlag London Limited 2008 Abstract Modern CAD/CAM techniques together with five-axis high-speed milling allow to reduce moulds manufacturing time and costs. Nevertheless, in order to put a mould into use, operations of manual finishing and fitting are still always required. Such operations, performed manually by mould makers, modify the milled surfaces of moulds. Reverse engineering techniques can be employed in quality control to evaluate dimensions and geometrical tolerances on moulds after machining and fitting. Changes in the product’ s shape are sometimes decided after a mould has already been machined. In such cases, if possible, the mould maker directly modifies the mould. Thus the final real geometry of the mould does not reflect the one of the original CAD model. The aim of this paper is to point out the benefits of non-contact quality control and to illustrate a procedure, based on reverse engineering techniques, to reconstruct and update the mathematical model of the mould after it has been polished and fit. The procedure was tested on a mould for the production of a plastic camera body that was previously inspected by means of a structured light scanner. Keywords CAD model . Reverse engineering . Mould . Surfaces reconstruction . Computer aided inspection 1 Introduction Production tools (better known as moulds) are an essential element in the manufacturing of wide consumption goods. The design and the fabrication of moulds are a very long and expensive step in the development of a new product. For such reason, any effort improving moulds’ manufac- turing helps to reduce times and costs. Nowadays, modern CAD/CAM technologies and five- axis high-speed milling [1] allow: & A fast design of moulds starting from the 3D CAD model of the piece; & The construction of electrodes for EDM, to overcome problems related with geometries that are not machin- able by milling tools; & The generation of the NC tool path, using strategies developed to reduce machining times [2]; & The achievement of high material removal rates in rough machining; & Better dimensional tolerances and low roughness in finishing [3, 4] No matter how far the boundaries of the cutting technology have been pushed, before putting a mould into use, the following operations are still always required: & Manual finishing, to obtain a smooth surface by removing marks of milling and EDM processes; & Fitting, to ensure the mould correct closure On one hand, polishing and fitting assure the moulding of the piece, but on the other one, they modify the cavity surface in a way that is mathematically non-definable. Therefore, the final real geometry of moulds does not reflect the one of the original CAD model (ideal geometry). Today CAD software resources do not allow to eliminate this incongruity. Int J Adv Manuf Technol (2009) 43:551–562 DOI 10.1007/s00170-008-1739-3 L. Iuliano : P. Minetola (*) Department of Manufacturing Systems and Economics, Politecnico di Torino, Corso Duca degli Abruzzi, 24-10129, Torino, Italy e-mail: paolo.minetola@polito.it L. Iuliano e-mail: luca.iuliano@polito.it