Rapid prototyping models and their quality evaluation using reverse engineering

This paper presents the results of a systematic research project carried out for evaluating the quality of a wide range of rapid prototyping (RP) models used in the manufacture of wax patterns for investment casting. The evaluation was based on geometrical accuracy, surface finish, visual inspection of RP patterns and the final casting process, compatibility with the standard casting process and casting quality based on X-ray analysis. A real high-integrity aerospace component was selected for these trials. Eight RP models of this component were constructed for each of the six different RP technologies. Based upon the requirements of the industrial applications, eight geometrical parameters for the example component have been chosen for the evaluation. These are four orientation angles, two diameters, one roundness and one surface flatness. Reverse engineering technology has been applied for the measurement of these eight parameters to overcome the difficulties faced by conventional inspection methods. In this paper it is hoped to present a comprehensive evaluation of the quality of the RP models for each RP method investigated. The findings provide meaningful information for industry to select RP technology best suited to their production requirements in order to reduce the leading time of product development.