Even judging by the name, an automatic tattoo machine is one of those devices that leaves anybody who has gone through a rough tattoo session wincing in unison. One 3D printing aficionado created the one device even the most tech-obsessed robot designer would question, designing a DIY automated tattoo machine to ink actual human flesh. There have been previous attempts at to make the automated tattoo machine mainstream. The Austin, Texas-based company Blackdot still promotes its automated tattoo machine. Then again, why should anybody think of spending hundreds or even thousands to get a tattoo from a machine that uses many of the same mechanics as a relatively cheap 3D printer? YouTuber Emily Yarid, AKA EmilytheEngineer (via Hackaday), retrofitted a printer to replace the plastic filament with ink, swap out the extruder and nozzle with a tattoo gun, andinstead of a build plateuse human skin. You can file this concept under the do not do this at home category. You shouldnt trust a non-professional tattoo artist for your health and safety for numerous reasons. Still, Yarid also made sure viewers know that her creation isnt for the faint of heart and isnt the type of thing you should try and replicate on your own. Yarid used an old Ender-7 printer from Creatily. That specific model includes a printer arm that can maneuver on a rail in both the X and Y axis, which would be necessary for drawing any 2D images. Is that just a normal CNC machine? Yes, but any automated tattoo device would need some ability to raise and lower unless you wanted to draw a canyon through a recipients thigh.The devices design involved modifying the printers hardware and software. The 3D printing software can generate an image that is a single layer thick instead of printing in multiple layers. That doesnt mean the engineer could ignore the Z axis completely. The remedy for this was a spring attached to the tattoo gun arm to deal with variations in skin height. The other hurdle was modifying the firmware to ignore values like temperature when printing. Of course, all of this still sounds like the worst possible way to get inked, so Yarid included an emergency lever to raise the gun arm in case the session started getting a little too painful. Finally, the 3D printer guru created a large bracket for the patients leg with a small window up top to expose the skin and make the printing surface as flat as possible.The end tattoo Yarid and her patient, fellow YouTuber and costume maker Dan from BuildDanielBuild, decided upon was a simple one-word tattoo in blue ink reading LEG. The device could potentially draw more elaborate designs, but without fine-tuning the hardware and software to add more variable depth and speed for the sake of finer lines and shading, theres not much point. Plus, the more elaborate and time-consuming the tattoo, the more likely something could go wrong. Emily the Engineer is mostly known for her 3D printing projects, such as one where she 3D printed a boat (though it did require non-3D printed tubes for stabilization and a non-3D printed motor and propeller). She has also made numerous cosplay pieces, including multiple recreations of the Marvel Iron Man suit and Buckys arm from Captain America and the Winter Soldier. Her latest design is probably the most brazen yet, though we hope the idea doesnt catch on any more than it already has.