Here is the project description:
The TETRIX 3D-Printer was designed as an educational tool for middle and high school technology students, robotics teams, and adults. The purpose of constructing the printer is to train people's building, tool usage, electronics, CAD, and programming skills with a single project. You also get a 3D-printer once you're done!
The printer design is based on TETRIX parts, which are designed by PITSCO and used in the FIRST Tech Challenge robotics competition. The printer also utilizes elements of various RepRap printer designs, such as the Printrboard control system. The design is completely open-source, so feel free to personalize and alter your printer.
The overall cost of the printer is about $640, and the educational value is priceless! The majority of the cost is attributed to the TETRIX parts, but the high accuracy of the pre-drilled, pre-sized aircraft-grade aluminum saves time and reduces error, which outweighs the price.
Very detailed build guide: