Finding the best dirt-cheap, field-tough 3D printer for science and conservation work: six months later.

A fully upgraded Ender-3.

Four years ago, I had the chance to lead a research cruise on Lake Superior to explore the potential of low-cost, open-source tools for marine field work. This was the proving ground for the OpenCTD, the Niskin3D, the OpenROV 2.7, and the idea that, rather than packing cases and case of gear, we could put everything we needed on a flash drive and print it at sea. 

During that cruise, as my trusty Printrbot, was churning out Niskin bottles, we caught a wave and the 3D printer was thrown to the ground. I came down hours later to find it upside down on the floor of a retrofitted fish hold, happily chugging along. I picked it up, put it back on the counter, and went back to sleep. The print didn’t even fail.

That is the kind of beast we need. 

Over the years, whenever someone asked me what the best 3D Printer for field work was, the answer was always the same: The Printrbot Simple Metal. But Printrbot is gone (for now) and we needed a replacement.

Half a year ago, we completed an exhaustive review of the cheapest 3D-printers on the market, with an eye towards low-cost, robust tools that would endure the rigors of field work without blowing our grant budget. We wanted 3D printers that were workhorses. They didn’t have to be pretty, they didn’t have to produce perfect prints, they just had to spit out strong serviceable parts with minimal fuss. They had to be reasonably portable. And they had to be able to take a beating and keep on printing.

We never found a replacement for the absolute tank that is the Printrbot Simple Metal, but after months of testing, settled on a pair of good alternatives (notably for a fraction of the cost of the Printrbot when it was still in production): for those who need big build volumes, the Creality Ender-3. For those who need portability above all, the Monoprice Mini-Delta

But that was six months ago. I promised to put these two machines into heavy use. After several hundred hours of printing, we’re ready to update our review of both machines. 

Executive Summary. My recommendation still stands, both both printers need a few modifications before you can call them the ultimate field machine. 

Ender-3

The Ender-3 became the primary workhorse in my office/workshop. It’s tough, reliable, doesn’t take up a massive amount of space, and gets the job done. Because it’s in my office, I made a ton of modifications to make it near-silent, which may not be a priority for field work. 

Upgrades. The extruder on this is flimsier plastic than is really acceptable. The tension rod broke about 5 months into heavy use. But the good news is that an all-metal upgrade exists, is pretty cheap, and will dramatically improve the quality of your prints. The other major flaw was the heated bed, which is cheap aluminum and off-true. It’s good, but not perfectly level, and perfectly level is what you need for a good, big print. I replaced the stock bed with a piece of tempered glass, thus obtaining True Level.

To complement the newly leveled bed, I added stiffer springs, which help it hold level longer. I also lifted the whole printed up on big rubber feet to help damp vibration and increase airflow underneath. 

Parts (with Amazon Affiliate links):

Tuning. The gantry arm had a slight wobble to it, which can be solved by turning the eccentric nut on the inner v-roller until all three rollers sit snugly against the extruded aluminum. My mainboard came with thermal runaway enabled, but apparently some do not, so a quick firmware update to ensure that the printer shuts down rather than cranking up the heat in a cascade of terror is absolutely essential. 

Finally, the cooling fan inside the electronics case is tied to the parts cooling fan, which is a super weird design choice, since the parts cooling fan ramps with the print while the electronics cooling fan, like the hot end fan, should be on always. I patched the electronics cooling fan into the terminals for the hot end cooling fan to fix that. Another problem with that fan is that its intake is positioned directly under the heated bed, so it’s always pulling hot air. I 3D-printed a vent to redirect the intake away from the heated bed, which also prevents printer poop from falling into the intake. 

Silent Running. Now for the fun part. How quiet can we make a 3D printer.  There are four big noisy things on this printer: the stepper motors, the hot end cooling fan, the electronics cooling fan, and the PSU cooling fans. For the stepper motors, I upgraded the driver on the mainboard for more finely tuned operation that now renders the steppers almost silent. Creality sells an upgrade kit for this. 

The hot end fan is a bit more complicated. The Ender-3 is a 24 volt platform, but most good silent fans run at 12 volts. I added a Noctua silent fan and then wired it into a buck converter to bring the voltage down from 24 to 12 volts on the fan line. This also solved my problem with the electronics cooling fan. It’s not particularly loud inside the case, but the drivers don’t get particularly hot either, so by wiring the 24 volt fan into the new 12 volt line, I cut the fan speed and fan noise down enough that no other changes were needed. For completion’s sake, I might swap that fan out with a more efficient Noctua down the road. 

Finally, the PSU. Here’s where things get… dangerous. These cheap power supply units are not exactly the pinnacle of electrical engineering and they handle some pretty big loads coming off of the mains. You can really hurt yourself by messing with the PSU. But, they’re also over-built for most 3D printer and unless you’re really cranking the heated bed, they’re just not going to generate that much heat inside the power supply unit. 

The PSU fan is always on and it’s big, cheap, and loud. First, I 3D-printed a shroud to redirect the intake and quiet it down, but that didn’t do much. So I opened it up, ensured that the capacitors were discharged before getting close to it with a soldering iron, and soldered a 45C normally open thermal switch to the fan line. This keeps the fan off until the PSU actually gets hot, which means it stays off 95% of the time under normal loads but still kicks on if there’s a chance the unit could overheat. . 

So what are the results of all this tweaking? The printer now clocks in at a whispering 51 decibels while running, which is barely above the background noise of a very quiet office. You could run this in a library and no one would know it’s on. 

Parts (with Amazon Affiliate links):

The other big change. In addition to all this, I also added a permanent OctoPrint rig to the back of the machine. This allows me to print and control the printer wirelessly from a computer, monitor the progress from my phone, and rig up a camera for fun and safety. Because the Raspberry Pi 3 A+ I used requires 5 volts to power and I didn’t want two power cords coming off of the printer, I also installed a 5 volt buck converter to the PSU, which gives me both a micro-USB line to power the Pi and an auxiliary powered USB port that I could use for things like an LED light strip. 

Parts (with Amazon Affiliate links):

Cost with essential upgrades: $279.93

Cost with silent running + upgrades: $347.81

Cost with everything including OctoPrint and camera: $419.79


Mini-Delta

The Monoprice Mini Delta was my pick for the most portable option and it really has proved itself. I’ve shipped it, shoved it in my checked bags, tossed it in the back of a truck, and even plugged it into a power inverter and printed with it in the trunk of my SUV while driving. There’s not much that needs to be changed on this little monster. The frame is sturdy, the bowden extruder is solid, and the electronics are nicely contained. 

This printer does need a bit of tuning to get the best out of it, the spool is awkwardly positioned, and the heated bed is underwhelming, all of which are easy upgrades. 

Upgrades. The only major change to the printer was swapping the flimsy build-tac-like print bed for a piece of borosilicate glass. This makes the print surface nice and flat, is way more durable, and prints just stick to it a lot better. While there are a heap of different brackets you could print out to hold the glass, I instead went with a sheet of thermal padding. It holds the glass in place, makes the bed easy to remove, and conducts heat efficiently up through the wimpy heating element.

I also printed out a spool holder that mounts on top of the printer (and then remixed it to make it fit into the shipping crate) so that the printer takes up less counter space. Downside: the spool rack it too big to be printed on the Mini Delta. 

The power supply worries me, especially since there’s no switch for it, but instead of making any major changes, I’ve just opted to plug it into a surge bar and use that power switch to avoid sparks. I also threw some of those rubber feet that I got for the Ender-3 onto this printer as well to lift it up a bit and give it more airflow.

Tuning. The Mini Delta does not come particularly well calibrated out of the box, and bed leveling, end with the automatic bed leveler, is a bit of a nightmare. I spent a lot of time consulting Google before I came across this post that describes how to get everything nice and level. After that, no problems! 

And yes, I threw together a stand alone OctoPrint module to use on this or the old Printrbot when needed. 

Cost with essential mods: $182.05

So where do we stand now? With the mods, the Ender-3 is a truly superb printer. I wouldn’t put it up against a Prusa MK3, but for a low-cost, entry level printer, it’s really tough to beat. I’ve only had to go back to my Printrbot a few times in the last half year for some really specialized prints. But, the fact that a part actually broke makes me very wary of deploying the unmodified version in the field. So I’m dropping my original score for the Ender-3 without modifications, but with modifications it’s an even better value. 

The Mini Delta is still pretty much the same machine, just a little easier to work with. 

There is, of course, a new contender in this race. Prusa just released their own Mini printer, which isn’t really much smaller than the Ender-3, but it has a lot more going on. At $350, the Original Prusa MINI might finally be a real contender to challenge the Printrbot. Sadly, my budget for this project is long gone, so if you want to see us put the Original Prusa MINI through its paces, contribute to my Patreon campaign!


If you want to help support more projects like this, you can either use the Amazon Affiliate links in the post to buy printers, consumables, anything else or you can sign up for my Patreon and help keep Southern Fried Science running!

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