Revised Fully Printable Eggbot
by Glasswalker, published
This is a fully printable eggbot, which was inspired by the original Eggbot as well as the other designs by Zaggo and Berserker.
I designed this one to be complete, and fully printable. And easily assembled. Also all parts are no larger than 100mm in any direction so should be printable on any 3D Printer out there. Lastly I wanted to keep the amount of plastic used to a minimum where possible.
It's intended to be printed in PLA on my Ultimaker.
It's unfinished in that I haven't printed it myself to test it. Normally I don't release things until they are "done" but since Easter is coming up fast, I thought I better get this one out there so hopefully some others can build one in time. I'm hoping to make mine this weekend, and will post pics once it's assembled.
It's intended to be used with the spherebot electronics and firmware. http://www.thingiverse.com/thing:7656
Hope you enjoy!
EDIT April 2 2012:
I've refined some of the parts. Updated STLs are uploaded. The Egg cup parts didn't work out as planned, replaced them with suction cup based ones. Also I strengthened and thickened up the Back Plate part as it was a little flimsy (still works in it's original form, as I left it on mine, but I figured it could use some strengthening for general use).
EDIT April 4 2012:
Ok another minor revision to a few parts. I've uploaded the new designs now. Also here are some pics of the finished build. I'm still just wrapping up the electronics. The changes I made were shortening the egg cup holders to allow for a larger egg to fit, and I had to adjust the arm pivot to allow the motor shaft to protrude through it. You will need washers on those screws now but it will allow a better depth adjustment for the pen to allow it to center up nicely on the egg (keeping the image from skewing when you print it).
EDIT April 4 2012:
Sketchup Sources uploaded.
These are rough instructions since I have yet to build it myself, these will be updated once I've verified the build:
You will need:
2x NEMA17 Stepper motors
1x 9g hobby servo (Turnigy TG9e or HXT900 is what it was designed for)
All electronics for Spherebot (see link above)
2x 608ZZ "Skate Bearings"
Some M8 Threaded Rod
Several M8 Nuts
Several M4 screws and nuts
A few M4 washers
Some childrens suction darts (see photo, like nerf darts)
A spring (8mm internal diameter, and as long as you need for your frame size)
A Sharpie (fine tip)
An egg or small ball to draw on
1x Back plate
2x End plates
1x Egg cup drive
1x Egg cup idle
1x Idler knob (optional to cover sharp ends of rod if kids will use)
2x Idler Bearing Plate
1x Pen Arm Shaft Coupler
1x Pen Arm Pivot
1x Pen Arm Top
- Put 2 threaded rods through the back plate and tighten it down with nuts so it's in the center.
- Assemble the two end plates using threaded rods through the 2 bottom, and the rear top hole (the motor mounts face the "front" side) So that the rear plate is between the 2 back plates. The completely flat side of the rear plate should face forward (with the "bumpy side" facing the rear of the machine)
- bolt the motors onto the NEMA17 mount on one end plate (doesn't matter which) and the rear plate.
- Press fit the egg drive cup onto the end motor
- Press fit the arm shaft coupler onto the rear motor
- Use an M4 nut and short screw to lock the shaft coupler onto the rear motor (the egg cup is just friction fit)
- Fit 2 M4 nuts into the trapped nut slots on the shaft coupler, and then use line up the arm pivot and put 2 M4 screws through the slots into the trapped nuts (just loose for now you can adjust later)
- Use an M4 screw, a couple washers in the middle, and a nut to create the hinge between the arm pivot and arm top parts. Tighten only minimally to allow free swinging with no resistance (use nylock nut or locktite to keep it from falling off)
- drop an M4 nut into the arm top trapped nut hole near the end, and thread an M4 screw into it via the setscrew hole, this is for tightening onto the pen
- Install the servo in the provided bracket on the arm pivot, so that the servo horn is inline with the arm top and can push it up and down with a little rotation.
- press fit 2 608 bearings into the bearing plates (these should be tight, so you may need a little tape depending on your printed parts)
- use 4x (or even 2x) M4 screws to screw the bearing plates in place of the second end plate's NEMA17 motor mount (make sure it's centered)
- Feed a length of M8 rod through the bearings. it just sits loose
- Thread (just twist the plastic part on the hole is just a little too small so it should thread onto the rod with some moderate force) the egg cup idler onto one end of the idler rod
- Fit the spring between the idler cup and the bearing block. It should provide minimal force against the drive cup when empty, and should have enough strength to hold the egg without breaking it.
- Screw the idler knob on the other end of the idler rod.
- Attach the rubber suction cup portion on the end of the egg cup parts
- Fit a sharpie, and wire up the electronics and you should be good to go!