Porosity and density measurement of additively manufactured components: A comparative analysis of measurement methods across processes and materials

Part density and part porosity are important parameters for additively manufactured (AM) components, as they significantly influence mechanical properties and indicate printing process’s quality. Various measurement methods are available such as gas pycnometry, gravimetric density measurements (Archimedes’ principle), and micrograph analyses. This study compared these methods by analyzing test specimens made from different materials using diverse AM processes. AM components made of metal, ceramic, and plastic as well as composites were analyzed with regard to part density and porosity. The results provided new findings on part density and porosity in AM processes and materials. Furthermore, they demonstrated the suitability of the employed measurement methods for certain purposes. In this context, it is always important to distinguish between the determination of true and apparent density. Gas pycnometry is best suited for determining the true density and enables the most accurate density measurement. Gravimetric measurement according to Archimedes’ principle is generally best suited for determining the apparent density, which is more relevant for characterizing the technical properties of AM components. Micrograph analyses are the only investigated method that shows the position of the pores in the component. However, the method generally only allows statements to be made in the sectional plane under consideration. In addition, gas pycnometry is preferable for very dense AM components and the Archimedes method for porous parts. Finally, the results can be generalized and recommendations for measuring porosity and density can be concluded for other AM processes.