I've been getting into 3D printing lately. I have an older Ender 3 V2 at home I bought during COVID. And in the past year I've acquired an Ender 3 S1, Bambu Labs P1S, and Prusa MK4.
I also dove head-first into 3D CAD, and designed a number of small SBC cases or parts to help with things around the house.
But I'd never built my own 3D printer from a kit—all the printers I've had were pre-built and at most, required assembling the prebuilt gantry or toolhead. That finally changed with the Positron V3.2:
The Positron V3.2 has its origins in this design by K R A L Y N 3D, and the V3.2 version was turned into a kit by LDO Motors and Positron3D. There's also a reprap-style alternative that's slightly taller and a bit cheaper called Positron LT.
The Positron V3.2 is not cheap, with the kit (consisting of a hard carry case, the CNC machined parts, the PCBs, a touchscreen controller with Raspberry Pi CM4, belts, motors, screws, etc) priced at $699. If you don't have a 3D printer capable of printing the various 3D printed parts, you can buy a set of pre-printed parts for an additional $99.
Disclaimer: The Positron V3.2 kit I built was sent from Positron3D/LDO Motors. They don't have any input into this blog post or the video I published, but it's important to note I did not pay for this with my own money, and I would have a hard time justifying the price to my wife if I did, since I already am spoiled for choice with the 3D printers I have paid for :)
The first question most people ask is why upside-down? Many have already tested upside-down printing, and found it doesn't offer much improvement in terms of bridging and general print quality. Emily the Engineer even spun her Ender while printing, and found it was still quite happy to print out a decent benchy.
For the Positron, the advantage is keeping almost all the parts in the base. The X, Y, and Z motors are all contained within the base, and the toolhead is mounted directly above the base, keeping a low center of gravity, allowing the Z-axis to be the only vertical protrusion.
Seeing the image above, you may wonder about the bed—it's transparent glass, so I first wondered how they could advertise it as 'heated'?
They use borosilicate glass capable of handling higher temperatures than normal glass, and they coated the top with a 3-micron layer of ITO, or Indium Tin Oxide, the same stuff that's used for defrosting airplane cockpit windows.
Two leads on either edge of the glass heat up the bed very evenly, and it's great for PLA, and can reach beyond 100°C—but I was told it's not as useful for higher temperature materials like ASA, ABS, or Nylon. And the hot end isn't suited for those materials either, as the unique 90°-angled print head probably can't keep up at any reasonable flow rate past 250°C.
The biggest downside to upside-down printing is that the nozzle likes to turn into a little filament fountain—which requires a little vigilance picking errant filament goo off before starting a print:
Some updates to the Klipper macros may help with this, though—I'm told it's supposed to dock the nozzle on a silicon pad on the bed while heating, but right now it's a bit hard to get that to work correctly.
As a final test of this printer's portability, I set it up on my trunk in a local park, and printed a frisbee while plugged into my little 256 Watt-hour portable battery:
The Positron consumed between 50-150W while printing (spiking highest while the bed and toolhead heaters were going full blast), and idled around 20W with just Klipper and the fans running. I was going to test how long I could run a solar-powered print with a backpack-size foldable solar panel as well, but that didn't arrive in time for my testing.
I have a full video going through my build experience, some of the other quirks I encountered, and how it worked on my trunk in a local park. You can watch it below:
If you have the budget and would like to pick up a kit, Positron3D partnered with LDO Motoros and they have some kits linked from their website. All the designs and software are open source, you can find them on Positron3D's GitHub.
Comments
Can't wait for a tradesperson to pull up in their electric truck, call a supply and get told they don't have the part available for a month just to have the tradesperson print a one off. I've already used my printer for a bunch of one offs like printing aerator keys (darn male-female aerators) and other specifics.
Either that or having a lan party. Showing up at a maker space with friends is fun and all but remembering ppe and other stuff around can get tricky.'
I own a IT company and keep an A1 mini in my work truck. Print my own wall plates at various degrees for cable runs and installs. Plugs to seal the Starlink dish when running custom cables. Wall pass grommets. I didn't know how much I would end up using it but do quite often. People love it.
Thanks for everything, now that a new baby has been "printed" it's time to dedicate ourselves to something else. We'll wait, :)
Hi, great video and article, as always!
If I get things right, you now have a whopping five (!) 3D printers in your arsenal. :-)
I could very well be in the target market for the Positron 3D printer (and even own a Miata...) but am sill a bit hesitant given that there are, well waaay cheaper alternatives out there. Money is not a huge concern, but still.
Given that I...
* Value desktop and storage space
* Would only print stuff occasionally
* Have a past as a professional software developer
* Am starting to get up to speed with electronics
* Value open source as much as you do
* Don't mind tinkering to get going initially but once set up, expect things to run smoothly, preferably automated.
... is there *another* 3D printer that you would recommend over the Positron?
This would be my first 3D printer, but I'd rather get it right the first time and pay a little more than realising the thing I bought is too crappy and get another 3D printer later on.
What would I print? Small things like boxes for electronics, shims to stick things together etc. The first real usecase would be to put something together for my pico-based telecope aperture flaper for taking flat light and dark frames for astrophotography. Basically motorised cover for the telecscope using a servo to open/close an EL panel mounted on something flat using two angular "arms".
Any tips welcome!
Honestly, especially for your first printer in a tight space, I'd go with the Bambu A1 mini or Prusa mini. Both are reliable, have good support and a lot of great help if you run into problems, and will likely work out of the box!
For smaller and simpler prints, these printers are both plenty adequate.
I will take a closer look at booth. Thanks for the advise, much appreciated!