ROBUST EASTER EGG PRINTER

thingiverse

Get the model here: https://cults3d.com/en/3d-model/naughties/robust-easter-egg-printer See it in action: https://www.youtube.com/watch?v=PWUuJ9wFqSc https://www.tiktok.com/@qsstudio_/video/7087679040873696518 I saw a YouTube video of a egg printer made by Lego, as well as another egg printer made by aluminum extrusion and 3d printed connection parts and pen holder. I also want to build one for Easter. However I don't have a set of Lego or any aluminum extrusion. So I decided to design my own. Will share a detailed documentation if there is high demand. You will need: - All 3D printed parts - 2x 8x22x7mm bearings - 1x M8 threaded rod - 1x M8 nut - a lot of M3 bolts and nuts - 2x NEMA 17 steppers - 1x Arduino Uno - 1x Arduino CNC Shield - 2x A4988 Stepper motor driver - 1x 2.1x5.5mm Female Power Plug - 1x 12V Power Adapter - 1x USB A to B cable (Arduino USB cable) - 1x Compression Spring (ID: 9mm, OD: 11mm, L: 32mm) Software: - Grbl https://github.com/grbl/grbl - Grbl pen servo https://github.com/bdring/Grbl_Pen_Servo - Inkscape https://inkscape.org/ - CNCjs https://github.com/cncjs/cncjs/releases There are several engineering challenges I discovered: It is hard to align the center line of the egg with the motor shaft which can cause the egg to wiggle while the y-axis motor is spinning and cause a failure print. I re-designed the "active egg holder", which is the egg holder mounted on the stepper motor, to have a 3-point contact with an egg. After an egg is mounted, simply rotate the motor shaft for a couple of turns to check if the center lines are aligned. The gripping force is too low in most of the time and cause the egg to slip while the y-axis motor is spinning. Thus the pattern printed on the egg will be distorted. Because of the new egg holders design, we can simply super-glue a couple pieces of rubber band to the jaws of the egg holder to increase the gripping force. If the pen clamped in the pen holder is long and light weight, the servo motor motion to lift the pen will most likely to overshoot and flip the whole pen holder link to flip completely to the other side. By adding a hook feature on the "pen holder link 1", which is the part mounted on the x-axis motor, we can hook a rubber band on this hook and hook the other side of the rubber band to the pen clamping screw on the end of the "pen holder link 2". A tension force then applied between link 1 and link 2 of the pen holder which will make the pen-lifting motion very smooth.