There are dozens of factors that go into choosing which 3-D printer is right for you: How large can it print? Can I build it myself? How much does it cost ? How does it actually print?

With one notable, pricey exception, consumer-level 3-D printers have stuck with the additive (aka Fused Deposition Modeling) method, printing layer by plastic layer to keep costs down. But a new 3-D printer, the LumiFold is challenging that notion, using stereolithography, or the process of “curing” resin into solid shapes using UV light. What’s truly notable, though, is that it’s ultra-portable and only costs about $400.

The Formlabs Form 1 was the first widely available stereolithographic 3-D printer to compete with the MakerBot Replicators and Cubify Cubes of the world. But with a $3,100 price tag and $149 liters of resin, the Form 1 is less affordable than additive printers. It is, however, much more precise, printing each layer at 25 microns compared to the MakerBot Replicator 2’s 100 microns (the thinner the layer, the less choppy its edges). Using ideal equipment, the LumiFold claims to achieve minimum layers of 10 microns.

But that’s the major caveat of the device: Unlike every other 3-D printer, the LumiFold requires a mounted projector to project an image of the desired 3-D model down into the container of resin resting atop the LumiFold. A small circular baseplate rests just below the surface of the resin, and when that layer hardens, the circular baseplate lowers to let another infinitesimal layer of resin fill over the hardened layer. Thus, the LumiFold has only one axis of movement (vertical) with a UV sensor gauging the projector’s light intensity and directing the metal baseplate to descend appropriately. On the plus side, the downward-aiming projector obviates the need for a light-transparent container to hold the resin (you can even use a ceramic coffee cup).





The negative is, obviously, the need to acquire a DLP projector. Using a 1024×768 projector (which can be found for $400 online) and the tripod setup above, the LumiFold can print at 200 micron accuracy, but getting the projector closer to the resin or getting a higher-resolution projector can drive the layer depth down to 50 microns. Thus, tinkering is necessary (though the UV sensor should limit trial-and-error with the expensive resin) especially in build area; the LumiFold has a maximum build area of 3.5″/90mm, but the small circular metal baseplate is what the printing image rests on within the resin. Attach a larger baseplate to the descending arm, tinker with the software and projector, and you may be golden to expand the build area.

The positive? If projectors abound, you can haul this little guy anywhere, as it’s built to fold up into a 10″x4.8″x1.2″ carrying size. There’s even a little partner innovation to sweeten the deal–the “HoloDock,” a small pyramidal cube that uses the Pepper’s Ghost Haunted Mansion trick to show a HUD-style progress image. Of course, it needs underlit projection, either from a monitor, an iPhone (for the small HoloDock, via the app), or an iPad (for the large HoloDock, via the app). Not very necessary, but a cool addition, even if they cost extra ($79 for the small, $99 for the large).

Ultimately, the LumiFold isn’t a plug ‘n play printer–it’s the beginning of a new (and likely very hackable) direction for 3-D printing away from additive/FDM plastic modeling and toward using more detailed stereolithography. Factor in the LumiFold’s portability and ever-smaller projectors (even 4G smartphone-linked ones) and 3-D printing edges toward becoming a mobile beast.