Most 3D printers need complex motion systems to draw out the pattern of the object being printed. FDM (Fused Deposition Modeling) printers need rigid x/y stages; SLA (Stereolithography) printers use galvanometers to move their laser around; but DLP (Digital Light Processing) printers don’t need any of these — they flash an entire layer at one time in one image. This simplification makes it easy to build a low-cost DLP 3D printer, and now Instructables user MasterMind (Matthew Krueger) has harnessed the power of Lego to do just that.
This isn’t the first low-cost, easy-to-build DLP printer to come out. The LittleRP and SeeMeCNC DropLit are both low cost and low volume options that come as complete kits (minus the projector). One of my personal favorites was the Bucket Printer that was unveiled last year at World Maker Faire. The bucket printer was made from a Home Depot bucket, some hand cut plywood, a few bike parts, and a few pieces of electronics to operate the z axis. This project may not have had the best print quality, but it showed how easily something like this could be constructed.
Krueger started out by building a base out of Lego and then a scaffold to hold the projector out of K’Nex. The Z axis was was built using a reclaimed CD-ROM drive that included a stepper motor. This gave him not only the motor, but also the linear rods to keep it all moving. To build the build platform, Krueger used a thin sheet of aluminum that he scavenged from more old computer parts. He cut the aluminum to fit his vat and then bent it into its final shape.
Krueger does a nice job in his writeup explaining how to modify his cheap projector to be able to focus on this short of a distance, along with how to remove the UV filter so it can better cure the resin. Even if you are not considering building a Lego printer, this guide will help you along with the process of building your own design.