Eggbot / Sphere-O-bot CNC with aluminium 2020 extrusions

thingiverse

**Eggbot made with single Aluminium 2020 (20x20 mm) extrusions.** **Story:** Every year around easter its time to dust off last years eggbot design and make improvements on it before the decorating begins. First year I built a simple "egg lathe" that seriously lacked mechanical integrity using cordless drill, a few sticks, two pieces of foam and small pieces of plywood. The second year I built V2 using BYJ-48 steppers. Unfortunately that one never really came to life due to steppers not moving at all no matter what I tried. For the V3 I went "the right way", going for NEMA17 steppers with corresponding drivers and an original arduino uno. I made the frame with laser cutter out of plywood. The electronics part of it worked great, but the frame lacked modularity and adjustability, had limited pen axis movement due to poor design, and was waaay too flexy. **Thus the Eggbot** *(If I may call it that if it's not copyrighted by EvilMadScientist?)* **V4 was born:** Designed around 2020 aluminium extrusions I solved issues of structural integrity, adjustability and modularity all at once. I liked the design of Sphere-o-bot pen arm (thing:1683764) so I used it for my plotter. I also found an already existing design of an eggbot using 2020 extrusions (thing:3991444) which served as an inspiration and base for this design. The self-tapping T-nuts and stepper mounts are both works of the latter projects author. I went with a T-frame with two extrusions in parallel held together only by t nuts on the mounts. Frame is connected with angle brackets. **Parts:** My project uses NEMA17 steppers, Arduino Nano V4 CNC shield, 9g servo, 608 skateboard bearings, M8 bolt, spring and 2 lego tyres. All the components are mounted and connected using M3 x 8mm hex bolts (around 30 of them from what I can remember). **Software:** I have GRBL (the servo plotter version) running on Arduino Nano. I am generating and sending Gcode from PC using "GRBL plotter" programme which has great functionality and features for Gcode modification (pen up/down commands, scaling, translating, rotating, tool change) and generation (import svg/png). **Note:** *This is not a complete build tutorial but rather an insight into my project. I hope that at least some resources and information given could help anyone building a similar project.*