Determining density in additive manufacturing

The components produced are as varied as the options for production are versatile. The effort to determine the density of a workpiece increases with its complexity. Since printed components are often not full volume but have an internal support structure, theoretical control values are determined during the design and used as a reference for the post-study analysis. Defined cuboids are usually printed for this purpose, which subsequently provide information about the density of the complex workpiece through manual measurements or time-consuming micrographs. Using a relative method, the determined density of the cuboid is equated with that of the component and compared with the data determined using CAD models. As a result, possible deviations due to faults in the support structure can often not be detected. The alternative method of optical density determination, in which the volume of a body is measured by sensors and then weighed, quickly reaches its limits for complex components with minimal phases, core drillings and partially reflective surfaces. When determining density, a measurement according to the Archimedean principle is the best and most efficient solution. As a fully automated solution, the DIMENSIONICS DENSITY offers the right approach for a highly precise implementation of this measurement process. 

Here, the density of the test object is determined by weighing it in two different media. The first measurement is usually made in air, the second measurement in a defined liquid medium with a known density. The crucial factor for the accuracy of the result is the positioning on the scale. Deviations from the centre of mass and resulting off-centre measurements of the component will lead to strong deviations. To counteract this problem and ensure the repeatability of the measurements, Dimensionics Density GmbH offers specially developed inserts for the universal component carriers for each component type. These are adapted to the workpiece to be inspected and can be integrated manually without great effort. The determined density can be compared with the specifications of the CAD model. Possible construction faults or irregularities in the support structure. In this way, qualitatively more accurate assumptions can be made about the density of complex components. 

For many manufacturing processes, investigations using relative methods are still sufficient. For productions with a high number of pieces, a 100 per cent inspection is often not possible. Cuboids are still used here, which serve as a reference for the respective batch. In order to optimise the subsequent examination, the density scale DIMENSIONICS DENSITY offers the possibility to test cuboids of different materials in one measuring process. This reduces the effort of manual measurements and thus shortens times when the machine is down. With a cycle time of less than 3 minutes per component and the possibility of inspecting up to 15 components simultaneously in one inspection process as standard, the DIMENSIONICS DENSITY offers users the option of optimising manufacturing processes and making them more efficient. 

 The production process becomes more transparent through continuous process monitoring and analysis of the measurement data obtained. As a result, the existing process can be made more resource-efficient and the quality of the products can be increased at the same time.