An old Prusa i3 with a damaged hot end turned out to be a useful starting point for an experiment in embedded 3D printing. Riley replaced the printer’s original hardware with a syringe-based system, using the machine to extrude materials inside a supportive medium rather than into open air.
In conventional FDM printing, material is deposited onto a build plate or an existing layer, where it solidifies. That approach works well for thermoplastics, but fluids and soft materials can sag or spread before they hold their shape. Embedded 3D printing addresses this by placing the extruded material within a supporting medium, which can hold it in position as it is printed.
The technique has potential applications in soft robotics, tissue engineering and microfluidics. Researchers are still exploring challenges such as print quality, extrusion control and whether supporting materials can be reused. Recent studies have also examined the difficulties of printing Newtonian fluids and living tissue.
For Riley’s setup, an open-source Allstruder syringe pump and a Caribou Duet 3 motherboard replaced the Prusa components. A test using cream cheese worked well. The next attempt used two-part epoxy in hair gel, but the materials did not work together. Epoxy also has a limited working time—about 40 minutes after mixing—so the syringe had to be emptied before it hardened.
Riley then switched to Sylgard 184 silicone, again using hair gel as the support. The silicone formed a trifold torus that appeared to take shape in midair, but the result was not fully successful: additives in the gel seemed to interfere with curing, and the print was still soft and sticky days later.
The experiment demonstrates the promise of printing materials inside a supportive medium, while highlighting a practical hurdle: finding a support material that holds a print in place without preventing it from curing.