Can You Make an FDM 3D Printer Work with UV Resin?
Proper Printing built this FDM resin 3D printer, which attempts to combine the principles of FDM/FFF 3D printing and UV resin 3D printing.
"Filament" printers, meaning FFF (Fused-Filament Fabrication) or FDM (Fused-Deposition Modeling) printers, work by melting and extruder thermoplastic. "Resin" printers, like MSLA (Masked Stereolithography) and DLP (Digital Light Processing) printers, work by curing UV-sensitive resin in layers within a vat. But what if you could combine those two processes? That is exactly what Proper Printing did when he built this FDM resin 3D printer.
The idea here is that the conventional FFF/FDM printer gets a completely new extruder. Instead of pushing out thermoplastic through a hot end, it will deposit liquid resin onto the bed or previous layer. At the same time, a powerful laser will cure and harden the resin. But that high-level overview simplifies the actual reality. To make this work in the real-world, Proper Printing had to design and build some new and innovative hardware.
The first challenge was "extruding" the resin with acceptable precision. For this, Proper Printing chose to build a custom peristaltic pump. That pushes the liquid resin through a sealed tube, which means that the resin never comes into contact with any of the mechanical components. The parts for the pump were custom 3D-printed designs. The pump ejects the resin through a blunt-tip syringe where the hot end would normally reside.
The second challenge was curing the resin. The obvious solution would be to add UV LEDs near the syringe tip. But there were space and power constraints that made that difficult. Instead, Proper Printing used a UV laser. It pipes the light to the deposited resin through fiber optic filament. Those keep the light strong and dense, while moving the laser module itself out of the way.
The results were ...mixed. It works, but not very well. Eventually, Proper Printing added a second UV laser module and ditched the fiber optics in favor of lenses to spread the light out. He also swapped the syringe for a more conventional nozzle. This improved things a little bit and Proper Printing was able to get a couple of simple prints finished.
Even though the results were lackluster, we think this idea has real potential. We're excited to see if other makers can refine the concept and create something practical.