We recently reported on a project from the Sandia National Laboratories that relied on an innovative approach using precision tools to assemble imprecise 3D printed parts to build a functioning telescope. In a more recent project, however, precision AM seems to be the name of the game. A team from researchers from the Sandia National Labs has developed a robotic work cell for high-throughput testing of 3D printed components.
The six-sided work cell configuration, aptly named Alinstante (Spanish for “in an instant”), uses a commercial robot located at its center to conduct qualification tests on 3D printed parts. So far, the Sandia team, headed by materials scientist Brad Boyce, has installed two testing stations: an off-the-shelf structured light scanner which is used to scan and digitize parts for quantitative comparison and a load frame for testing physical properties including tensile and compression testing.
Currently, Alinstante is in its prototyping stage and there are a number of improvements and further developments that the Sandia team plans to add. Eventually, the team aims to integrate other testing stations including a laser-induced breakdown spectrometer, which could test the chemical composition of parts to ensure batch-to-batch consistency.
Tim Blada, the roboticist leading the design of the software interface, has also voiced plans to have a user interface in place in the next few months that will make it easier for non-experts to use the Alinstante configuration. The goal is to make it as simple as placing a part in a tray on the robot’s parts rack and selecting which tests are to be conducted. The software will also need to modular, Blada says, so that new tests and functions can be added easily.
Rewinding a bit, the Alinstante project was first conceived of by Boyce who had faced challenges in qualifying custom 3D printed parts in a time-efficient manner. “Once we committed ourselves to automation, we realized that the barriers could be overcome,” he said. “Yes, we invested some time and money, but the real challenge was getting ourselves out of the mindset of ‘business as usual’ to understanding that we need a faster solution.”
That is, though the Sandia labs already offer the facilities to conduct qualification tests for 3D printed parts, even just scheduling the tests can take weeks. With Alinstante, however, the scheduling process can be cut down, significantly reducing the turnaround time for qualification testing.
In realizing the project, Ross Burchard, a Sandia mechanical engineer, was brought on to the project in 2016 with the goal of designing an optimal structure for Alinstante, which needed to be modular and scalable. Eventually, the team settled on a hexagonal structure made up of up to six petal-shaped testing stations.
As a safety precaution, the Sandia team has also integrated safety light curtains which automatically stop the robot’s movement if a person reaches into the work cell or if the robotic arm reaches out of it. “Safety is always our No. 1 concern,” said Blada. “Every line of code we write, every piece of mechanical fixturing we do, is always safety first. ‘How is this safe? Can I do this without risking any injuries?’”
Longer term goals for Alinstante include the integration of a 3D printer, processing systems like a heat-treatment oven or a grinder, and other post-processing tests like X-ray tomography, corrosion testing and density measurements.
“Right now, Alinstante is really just scratching the surface of what it could be,” said Boyce of the work cell.
Even now, however, the robotic testing configuration offers a number of benefits. Boyce explained: “Friday afternoon you tell the 3D printer ‘I want you to print this part 10 different ways and then go test each one.’ You come to come back Monday morning and Alinstante tells you which process was the best. Let the robot do all the logistics work and get the human out of the loop except for making the important engineering decisions.”
Currently, the Sandia National Laboratory team developing Alinstante is seeking partners to support the creation of more testing modules for the robotic work cell.