A pen plotter is often the first experience many ambitious makers have of the world of Computer Numerical Control, or CNC. While they typically operate on flat stock, with the right build, they can be designed to draw on curved surfaces, too – as [tuenhidiy] demonstrates with this rotary bottle plotter.
The plotter uses shafts salvaged from an old printer to act as the rollers for the bottle to be drawn upon, turned by a pair of stepper motors. X and Z axes are created out of two CD drive mechanisms – a popular way to build two linear axes on the cheap. The hardware is controlled by GRBL, running on an Arduino Uno kitted out with a CNC shield to handle the necessary I/O.
The build is somewhat limited to by the short range of its X axis, which prevents the plotter from easily drawing on a full-size bottle label or can. However, this could easily be fixed with some upgrades and extra steppers if so desired. As a home build, it’s a great way to learn about the CNC techniques required to work with curved surfaces effectively. Video after the break.
Eggbot .
https://shop.evilmadscientist.com/productsmenu/171
this one has distinctly different X stage
Specifically, eggbot rotates in X (b/c sphere), this one translates (b/c cylinder).
But the eggbot firmware doesn’t do anything tricky with the axes in terms of de-warping the surface or anything; both X and rotation are treated as a linear axes by the firmware. So you could run the exact same firmware, and just change up the X steps/mm calibration in eeprom to match your screw thread pitch — here the CD sled motors.
https://hackaday.com/2019/04/17/what-can-you-learn-from-an-eggbot/
I don’t get the point of this comment, is it an ad for the eggbot? The eggbot draws on eggs, and other round things roughly 1.25 to 4.25 inches in diameter, according to their website.
This draws on bottles.
That clears that up… Great project btw, thanks for sharing this. This is the type of project I’d be interested in trying to emulate, vs. buying an off the shelf kit – not that the eggbot isn’t cool, it’s just not as DIY.
Reminded me instantly of the Eggbot. That’s all. Not an advert…not a slam. I have been trying to find the link where a modified Eggbot or a clone of it draws on bottles or nearly any curved surface without distortion.
check thingiverse, there are eggbots on there which shouldn’t be to hard to DIY, even without a 3D printer: https://www.thingiverse.com/tag:eggbot
I made one of these 25 years ago at college as my final project using a BBC Micro Computer. The BBC had a User Port which enabled you to control external devices really easily.
Probably the BBC Micro was – although a “home compuer” much closer related to an Arduino (8 bit microcontroller) than to a modern PC. :-)
At least the C64 I had was this for sure.
So it’s a Blotter?
Why not just print the labels…? I JOKE, I joke :)