OpenCAL's Open-Source Volumetric 3D Printer Prints Objects in Seconds

OpenCAL is turning volumetric 3D printing from a laboratory curiosity into a maker project. The fully open-source system uses computed axial lithography to harden entire resin objects in a single pass, producing a miniature space shuttle in about 20 seconds in one demonstration. That speed is unheard of on desktop machines that stack layers one at a time.

Traditional resin printers cure flat cross-sections and lift the build plate millimeter by millimeter. OpenCAL skips the Z-axis entirely. A compact projector shines 450-nanometer blue light through a spinning glass cylinder filled with viscous resin. As the cylinder rotates, light patterns intersect inside the liquid, accumulating a precise radiation dose that solidifies the part in predetermined coordinates.

The build is compact enough to fit inside standard checked luggage. Off-the-shelf electronics, custom software and standard photopolymer resins keep costs down. Researcher Taylor Waddell, who demonstrates the system in a YouTube video, says the contained design also avoids some of the health hazards that come with open resin vats on conventional printers.

Computed axial lithography has existed in university labs for years, but those rigs were room-sized and expensive. OpenCAL compresses the concept into a tabletop package with files anyone can download and modify. The software handles the complex projection math, rotating the image sequence in sync with the resin chamber.

The trade-off today is build size. Early prints are small, and the resin library is still limited compared to the hundreds of filaments and resins available for conventional printers. But the project is young, and the community is already experimenting with larger cylinders and faster projectors. For makers frustrated with overnight prints, OpenCAL offers a glimpse of a different future.