Tools @ MIT Media Lab | 2016 | In collaboration with >Clark Della Silva<
“bioPrint” is designed for cell printing. Cell liquid solution can be loaded into a cartridge and subsequently extruded through a inkjet based printing system.
The system consists of two parts: a printhead that can spray tiny droplets of spore solution and a desktop CNC milling machine that can move the printhead in three-axis. Printing is accomplished using a small CNC router (available from zentoolworks.com) modified to accept the print head. We designed a customized printhead to hold the inkjet cartridge carrier in place, and stabilize two pneumatic tubing, which accelerates the drying process of the spore solution by constantly blowing gentle air onto the substrate while printing. We used an Arduino InkShield (available from http://nicholasclewis.com) to control the deposition of the spore actuators. The InkShield uses HP C6602A cartridge, which has 12 nozzles that can be individually controlled. This attribute gives us the space to easily vary the density and the resolution of the spores for each print.
For converting the printing pattern to machine tool path, we used a free web-based software Makercam. The software converts an SVG file to G-code file for the milling machine to read. Since the generated CNC G-code contains spindle and Z-axis control, yet lacks of inkShield control, we have to customize the motor control board and the G-code to fit our system. The InkShield is controlled using the spindle head enable output of the motor control board. This output is connected to the Arduino controlling the print head, and the print head is enabled when the spindle enable line goes high. The G-code is then modified to bring the spindle enable line high after the print head has moved to the correct height. In contrary, for a normal CNC router, the spindle enable is brought high and then the head is moved down to start cutting. By starting to print after the head is moved down, excess spray of the ink is prevented.