Start Of A New Project: Hydra

It's been about a year since my first attempt at a homemade 3D printer. The first time around I used a belt drive composed of bike chain for the linear motion and hardware store threaded rod for the frame. While it worked and proved that the idea could be accomplished for ~$400, it left a lot to be desired. The frame was very top heavy and while moving at high speeds, the inertia of the moving printhead caused the frame to flex and hurt printing accuracy. The bike chain drive system was very unreliable and inaccurate. There was a lot of slop in the chain that caused a great deal of backlash when switching directions. Nonetheless, from looking at pictures of my prints, you can see that despite all of these problems, I was still able to achieve decent printing accuracy. I probably could have fixed a lot of the problems with the old machine by reinforcing the frame or adding a tensioner for the bike chain, but I decided that redesigning the whole machine from the ground up would be a better investment of my time and money. So enter the next phase in evolution... Hydra.

Hydra. The names comes from the Lernaean Hydra; a 9 headed creature in greek mythology. The machine will be designed to utilize MULTIPLE heads on the same cartesian positioning platform. Each of these "heads" will be mounted on their own independent Z-axis assembly. The table of the machine will be stationary with a moving gantry to accomplish the X and Y motion. Each of the Z-axis assemblies will have a universal mount that will allow any number of toolheads to be mounted. This could include an standard FDM extruder, a spindle for light milling, a pick-and-place machine for object manipulation (think automated part removal and assembly), or even a second extruder filled with a soluble support material. The linear motion will be accomplished using multi-start ACME leadscrews to achieve superior positional accuracy over a belt drive, but still maintain a relatively high maximum speed. The budget for the project is $500, but as before, the hope is that I can obtain a large portion of the parts for free either by salvaging them from old machines or through generous donations. While this is a pretty big undertaking, I will also be working with the help of 5 other Mechanical Engineers on my senior design team to accomplish the task. I learned a lot from my first attempt at a 3D printer so hopefully that will lead to a much better design the second time around.