Avaliação de metodologias de análise de imagem para medição de porosidade em peças de alumínio fabricadas por manufatura aditiva por deposição a arco

Abstract

A problem that limits the application of Aluminum parts built by Wire and Arc Additive Manufacturing – WAAM, process part of the Directed Energy Deposition field – is the formation of porosity. Techniques have been applied aiming to reduce the accumulation of voids, and methodologies to quantify the porosity in these components have been improved. In this paper, methodologies to analyze the porosity in cross sections of preforms of Aluminum, built with the aforementioned technology and different parameters, are evaluated from images captured with optical equipment and the software ImageJ. From images obtained with a scanner and a stereoscope, properly processed, procedures to capture and quantify the area of the pores in the cross sections were described and developed, verifying the validity against results that came from a manual selection of the pores, by visual inspection, as reference. The results were satisfying for most of the samples analyzed, compared to the reference, being also compared with a volumetric-based essay of percentage of voids by Gravimetry. Finally, it was concluded from the analysis that easily identified porosity, by visual inspection, is better selected by the automated methodology, and the building parameters used to deposit a sample also interfere in the application of the procedures described.