Layer-Free, Ultra-Fast 3D Printing Is Now Available to You

There are many different 3D printing processes, but they all have one thing in common: layers. They may not all have flat layers, but they all work by building up material layer-by-layer. That limits 3D printing to the speed at which the machine can form a layer. Except I lied to you and it is possible to print without layers at all. And now that technology is available to you, thanks to OpenCAL.

CAL (computed axial lithography) isn’t intuitive at all, which is probably why it isn’t commonplace today. A CAL printer, like OpenCAL, consists of a laser projector and a rotating cylindrical vat of photosensitive resin gel. The part forms in the vat, suspended in the gel. That takes less than a minute and support structures aren’t necessary.

But how? How does the projector target a specific distance range to form the desired geometry?

The best analogy I can think of is string art made on a circular board. In this analogy, each string is a ray of projected light. Most of the board, when averaged out, has low string density. But the crossing strings make areas of high density that stand out to form an image. For CAL printing, those would be the cured areas.

Light shines through the entire vat, but not with much energy. Only the areas that get a lot of exposure — the dense areas — receive enough energy to cure and solidify. And some geometry is impossible. However, the benefits far outweigh the constraints in many use cases.

This is really remarkable technology. Precision and detail are low at this time, but this is cutting-edge stuff and there is room for a lot of improvement.

In the just-published documentation from UC Berkeley about the OpenCAL V2, the stated build cost is about $1,638. I think that’s very reasonable, considering what you’re getting.

$600 of that cost is just for the laser projector. The rest, however, is surprisingly mundane. We’re talking fasteners, aluminum extrusion, and a stepper motor — the kind of stuff you’d buy for any 3D printer build. So, savvy sourcing can bring the cost down quite a lot.

The resin gel, however, is anything but standard. It isn’t something you can buy off-the-shelf and though there are instructions for mixing it, that is hazardous and isn’t safe for hobbyists to do themselves at home. Thankfully, it appears that the OpenCAL team will be partnering with Formlabs to mix the resin and MatterHackers to sell the resin.

My recommendation would be to wait until that is available. But while you’re waiting, you can start building your own OpenCAL V2 printer.