Small, light and plenty powerful -- this is Deltaprintr’s approach at making a hotend!
The tiny Deltaprintr Mini Hotend!
They say size doesn’t matter- so today we’ll have a look at this miniscule hotend, the very creatively named Deltaprintr Mini hotend. It was announced last year with promises of being able to reach up to 700°C and printing super reliably with a one-piece heat break, heater and nozzle element and all that for, quote, around 20 to 30$ once it’s available. Well, let’s see how many of those claims made it out of the prototyping stage.
And while this is a very compact hotend, especially when compared to the big boys like the E3D v6 or even the Printrbot Ubis 13, it is still a very real hotend for very real use. So basically, that means a mostly-metal construction with only one bit of insulation made from PTFE, but that one doesn’t get quite up to the full set temperature, so Deltaprintr rate the entire thing for 270°C, and I’d say it would be fit for a good bit more if you replace that sleeving with some glass fiber. Which is not even close to 700°C, and just barely enough to print the easiest of polycarbonate filaments. It’s got a 0.4mm brass nozzle, again, not the one-piece stainless steel construction that was promised, a new-generation Semitec thermistor, which is pretty much the exact same thing as the old ones, but with a new name, as well as a 25mm fan on its aluminum heatsink. So the next part is what makes this hotend special, and that’s the heater, it’s a custom-made cylindrical unit with an integrated heat break instead of the usual three-part assembly from a heat break, aluminum block and a cartridge heater. So what’s cool about this solution, first off, is that it’s incredibly compact and light, of course, but it also heats up incredibly quickly. For comparison, a v6 heats with about 2 to 3 degrees per second, the Deltaprintr mini hotend with a solid 10, so basically, it will go from completely cold to completely hot and stable in less than 30 seconds. It also means that, with such little mass it will cool down super fast, and that combination would make it extremely well suited for dual extruder setups, where you actually let the hotend you’re not currently using cool down to stop oozing and then need to heat it back up when you’re reengaging it -- so instead of that being a long waiting process, it’s just a few seconds added onto each extruder swap. Now, on the flipside, it also means that the filament itself will cool down the heater much more than on a more substantial hotend, and that makes printing at higher extrusion rates more difficult. Granted, it’s not an issue with any speeds you’d normally use, I believe because temperature drops are gradual enough there for the PID control loop to take care of it fast enough, but when experimenting with just pushing filament through by hand i was observing a full 10° drop from the nominal 215°C just after a few centimeters of filament, while an E3d v5 didn’t show any discernable drop. Granted, the thermistor placement is vastly different between these, so temperature fluctuations at the nozzle are smoothed out by the bigger aluminum block, but you could also feel that the Deltaprintr Mini hotend was basically solidly jammed until the temperature recovered while the E3D did get harder to push, but didn’t seize up completely. In my case, the usable limit for the Mini with PLA at 215°C was around 70mm/s with 0.3mm layers and the stock 0.4mm nozzle. Again, this isn’t an issue in day to day use where you’re printing with more reasonable layer heights, but I still think it’s worth mentioning since this is the first hotend I’m looking at with this sort of an ultra compact heater.
So about that thermistor placement, the Deltaprintr Mini has the thermistor mounted right in the hexagonal part of the nozzle. What’s interesting here is, while it does insulate the thermistor’s legs with glass fiber sleeving, the only thing actually holding it in place is the elastic sock around the heater. It does take the same fiddling as with the v6’s thermistor to get it and the sleeving seated well, but once it’s in there, it’s just a matter of holding it in place and sliding the sock over. Plus, it comes pre-assembled, so unless you end up swapping the nozzle, there’s a good chance you’ll never have to bother with it anyways.
Moving on, the brass nozzle itself is screwed directly into the heater unit, using a fine-pitch thread, which makes it incompatible with any existing nozzles, but Deltaprintr are planning on making finer or abrasion resistant nozzles available.
So for testing it, what better machine to use than, of course, my Delta printer, the CerbrisReborn, i’ll have a video on this one soon-ish, and i designed it with a modular effector that just takes three screws to replace the entire hotend and sensor part. So what would make the most sense for mounting the Deltaprintr Mini hotend would be just to use the M3 threads on top, which i did, but you can use the threads on the side that are used for the fan on the opposite side. The ones on top just barely clear the screws from the fan, but do end up fitting. So in either case, all you need is a planar surface to mount it to, and i actually like this sort of mount much better than the groovemount-style, which is a relic from the days the cold end of a hotend was still machined from a solid high-temperature polymer block instead of being a larger aluminum heatsink. So with that in there and the PID loop auto-tuned, it was time to look into print quality.
Well, actually there’s not much to talk about, the best things are those that just work. Geometry-wise is a very unexciting hotend, it’s got roughly the layout as most other all-metal hotends when it comes to the cold, transition and hot zones, the nozzle design is fairly standard, but because it doesn’t have that large aluminum block, it’s easier to get to your prints with a part cooling fan and you’re also reducing the heat that is radiated away from the block and potentially into your print, and that’s good for any sort of filament you might want to print. So in my case, ABS, PLA and and PET in the form of E3D’s Edge printed perfectly, there was nothing i could find to complain about other than slicing mistakes and machine inaccuracies, so in that regard the hotend is getting full points.
So one more thing to cover is price. Is it “around 20 to 30USD”? Nope. But still, at a regular 59USD + shipping and tax, where applicable, it fits in fairly well. Of course, now that the fine Englishmen have nuked the value of their British pound into oblivion, the DeltaPrintr Mini hotend doesn’t have that much of an edge over E3D, you know, but if you look at what you’re getting and want a solid, compact, light hotend, then the Mini is going to be right up your alley. Of course, it does break compatibility with anything i know of that came before it when it comes to mounting and nozzle choices, but the first one of those is pretty easy to figure out and the latter is, what it looks like, going to be solved by DeltaPrintr themselves.
Alright, so that’s my impressions of the DeltaPrintr Mini hotend. Not what we were promised, but still pretty solid. There’s one more thing i would like to point you at this week, and that’s a giveaway with 3Dprinterchat, The 3D printing Nerd Joel Telling, Daniel Noree and Anton Månsson, and you can win a Wanhao duplicator i3 at the link in the video description. I’d really appreciate your opinion in the comments on this sort of giveaway and of course, on the hotend we just had a look at.
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