ETH Zurich research achieves breakthrough in magnetic 3D printing

Kai von Petersdorff-Campen, a doctoral researcher at ETH Zurich, could perhaps go down in additive manufacturing history as a pioneer of magnetic 3D printing. The researcher, who is developing a process for 3D printing objects that contain embedded magnets, recently demonstrated the technology’s viability by 3D printing an artificial heart pump.

The process, called “embedded magnet printing” has already garnered a significant amount of attention from around the globe and notably from the American Society for Artificial Internal Organs (ASAIO), which invited Petersdorff-Campen to its conference in Washington this past June to give a podium speech. The researcher was also awarded the top prize for ASAIO’s prototype competition for the 3D printed artificial heart pump.

Ultimately, the 3D printed heart pump, which Petersdorff-Campen developed in just a few months, demonstrates the ability to 3D print objects with magnetic components built into them. The artificial heart pump, 3D printed in 15 hours, may not be the most sophisticated device, but its functionality makes it one of the first 3D printed prototypes that has magnetic elements in it, which is undeniably exciting.

As the researcher emphasized: “My goal was not to make a good heart pump, but to demonstrate the principle of how it can be produced in a single step.” Still, the decision to showcase the process with an artificial heart pump was not a random one. Artificial heart pumps are not only complexly structured devices, but they also incorporate magnets into their structure to function.

One of the key challenges in developing embedded magnetic printing was to make sure that the magnets could be 3D printed directly into the plastic. The ultimate solution was to mix a magnetic powder with plastic before being processed into a filament. This filament could then be run through a 3D printer and extruded into a pre-determined shape, and then magnetized.

The main difficulty in developing the magnetic filament was to find the right mixture. As Petersdorff-Campen discovered, the more magnetic powder that was added to the plastic granulate mix, the stronger the magnetic force but the more brittle the filament. Eventually, though, the researcher succeeded in finding a mixture that was both strong enough (magnetically, speaking) and flexible. 

“We tested various plastics and mixes, until the filaments were flexible enough for printing but still had enough magnetic force,” he explained. “Some people are already asking where they can order the material.”

While the response has been overwhelmingly positive, Petersdorff-Campen has encountered some push back, with some critiquing the process as unsuitable for producing medical devices because of stringent approval processes. “That was not my focus, however,” clarified Petersdorff-Campen. “I simply wanted to show the principle.”

In addition to the process’ potential for medical devices, the magnetic 3D printing technique could also have big implications for electric motors in such devices as microwaves, speakers and hard drives. Crucially, it could offer a faster and more effective alternative to existing processes for creating magnetic objects—which involve highly complex injection molding.

As one can imagine, there is still work to be done before the process is ready for the commercial market. But Petersdorff-Campen is up to the task. As he concluded: “There is still a lot to improve in terms of material and processing.”

Petersdorff-Campen is a doctoral researcher in the Product Development Group at the Institute for Design, Materials and Fabrication at ETH Zurich.