Density determination

But which method is the right one?

The Fraunhofer Institute analyses different methods of density determination in the field of additive manufacturing. Under various aspects such as the accuracy and reproducibility of results, the possibility of defect detection, as well as the economic efficiency in the manufacturing process, the methods are compared for practical use. For the first time, the automated density platform of Dimensionics Density GmbH will also be tested and the results will amaze...


1 Aim of the study

In additive manufacturing (AM), various methods exist to determine the density or porosity of a part or component. A new
method for automated density determination by Dimensionics Density — based on the Archimedes method — will be investigated
in this study. A comparison of the different methods in terms of technical suitability, accuracy, time required and cost
will be drawn. This comparison is considered from the perspective of three different use cases.

1.1 Importance density determination for additive manufacturing

In this study, different methods for determining the density of a specimen are investigated and compared. In particular, the special characteristics of AM are taken into account.

Compared to other manufacturing processes, AM is a comparatively young production method. Laser Powder Bed Fusion, the AM process used in this study, is based on a layer-by-layer exposure of powder to one or more lasers. These melt the powder locally, and the subsequent solidification bonds the individual layers together. In the next step, a new thin layer of powder is applied, which is again exposed locally. This is how components are built up layer by layer in the powder bed.

In material development for AM processes, a large number of samples are generated for the development of practicable parameter sets. An initial assessment of the quality of the parameters is possible by determining the density. Due to porosities within the material, the measured density deviates from the theoretically possible density. For new materials, the aim is to find a process window for the process parameters in which the density generated is as close as possible to the theoretically possible density.

In series production, density determination can be used ...