Fabrisonic, a specialist in solid-state metal 3D printing, recently teamed up with EWI and Luna Innovations to develop a smart baseplate to better understand the powder bed fusion AM process and how baseplates can influence print quality. As Fabrisonic does not work with powder-based AM, it utilized its low-temperature Ultrasonic Additive Manufacturing (UAM) process to construct the build plate with embedded sensors.
As Fabrisonic CEO Mark Norfolk explained in a recent blog post, the company was inspired to 3D print a smart build plate for the PBF process after hearing certain concerns from its friends in the AM industry about how the build plate in a PBF machine can impact the success of a build.
The recurring problems included the debonding of parts from the build plate during the printing process, which is difficult to detect during the build; the distortion of build plates caused by residual stress; and the breaking of build plate bolts caused by excess residual stress during the print process. At the root of these issues is the fact that the industry still doesn’t fully understand how stress builds up for individual parts, which can lead to distortions.
To find a solution to this issue, the first step was to understand these stresses and find a way to measure the build plate’s loads throughout the print process. It was at this point that Fabrisonic realized its own AM technology could provide a way forward.
Together with EWI, a PBF expert, and Luna Innovations, a specialist in fiber optic sensors, Fabrisonic set about designing an instrumented PBF build plate for the Defense Logistics Agency (DLA). The project, part of a Phase I STTR, resulted in a 3D printed baseplate with a single embedded fiber optic sensor.
The sensor was embedded in a particular “undulating” pattern, which enabled it to detect strain across the whole build plate. When complete, the 3D printed baseplate was installed in EWI’s PBF machine, which was subsequently assigned a print job for a part with problematic features.
According to Norfolk, even this first build gave the team vital insight—including more than just bulk stress state. “Resolution and scan rate were high enough to actually discern the scan strategy of each layer,” he wrote. “Defects showed up as large compressive strains forming early in the build at localized points. Slow delamination of a specific feature could be seen in the data although the recoater blade never hit the build.”
Going forward, Fabrisonic and its partners believe the smart baseplate could enable better quality monitoring in the PBF process. In the context of series production, for instance, users could establish a good baseline for a part and compare it against subsequent serial numbers. Even for low volume production, flaws could be identified in a part sooner, enabling the print process to be stopped to save time and metal powder. For multi-part builds, the early detection in a single part could allow the printer operator to cease the problematic feature before affecting the rest of the components.
With the early success of the collaborative project, Fabrisonic, EWI and Luna Innovations have been awarded a PH II STTR from the DLA which will enable them to continue their smart baseplate research. In the next phase, they will explore the addition of more sensors as well as how to refine data mining techniques.