Is Prusa’s i3 MK3 The Tesla of Under-$1000 3D Printers?
[2023–03–29 Update: Prusa released the MK4, which is an improved version with a new extruder. Price is up a little, pushing the assembled version over the $1000 mark, but I’m leaving this here. See https://www.prusa3d.com/product/original-prusa-mk4-2/.]
There are lots of 3D printers on the market — so many that it’s probably ripe for a market contraction. And this article is just looking at desktop FDM printers, those that use a spool of plastic, basically a carefully-controlled hot-glue gun that can move in 3 axes. There are low-cost units in the $200–300 range. There are mid-scale printers around $1000. And there are high-end prosumer 3D printers around $2,000–3,000, with professional models going up from there. In both resin and metal-deposition printers, there’s basically no upper bound on the cost. And there are (much larger!) concrete-deposition printers used to build houses quickly — that’s a whole other article.
Josef Průša is a well-known contributor to the original RepRap 3D printer project, the original “self-replicating” printer project, founded by Adrian Bowyer and still active at https://reprap.org/. RepRap was the first open-source and open-hardware DIY project to build 3D printers. Josef has taken what he learned there and mixed it with a lot of skill and energy to drive Prusa Research into a very successful company making and selling their own 3D printers. The Original Prusa i3 MK3 is their latest and greatest (up until November 2021, when they pre-announced the XL), and great it is, not the least because of the optimizations built into it, the fact that the firmware and desktop software is both open source and constantly updated, the range of add-ons including multi-color printing, the great instructions that come with the device, and the fact that you can buy it in kit form to save $250 or if you just want to really know what’s inside it. Actually I lied about the “latest and greatest” part. The i3 Mk3 is no longer their latest — I’m happy to announce that they now have a resin printer too, the Original Prusa SL1 Open-source MSLA 3D printer. And there’s a Mini model as well. But these are new, and will have to wait for a later review.
Does it seem a bit audacious to call the Original Prusa i3 “the Tesla of 3D printers”? But that’s what it is. Tesla is the startup electric car company that both dragged the whole rest of the existing automotive industry from the dark, smoky age of combustion engines to the clean, quiet, efficient age of electric cars, and prompted dozens of startup companies to enter the same market with lower-cost products. Prusa has done the same: dragged a lot of companies into clean, quiet, efficient 3D printing, and prompted a lot of low-cost competition —that’s that $200–300 range I mentioned earlier. That price point, by the way, is a minefield — there is some real rubbish out there, but you can also find decent stuff if you shop carefully. Tesla and Prusa also share a culture of continuous improvement — Tesla firmware is frequently updated “over the air” just like your smartphone, whereas Prusa provides free updates which you can download and “flash” into your printer at any time. Prusa has even had their own version of “manufacturing hell” on a much smaller scale. As Josef wrote about the powdered-steel bed plates which make the printed object easier to remove: “Powder coated sheets manufacturing is a never-ending story. It’s incredibly difficult to manufacture them in high quantity, while keeping great quality.”
BTW, what’s with all the “Original Prusa” captioning? It turns out that Josef Prusa is so well-known and respected in the printing world that all the cheap knock-off printers feel obliged to appropriate his name. Just search on any other shopping site for “Prusa”, and you’ll find that most of the ones that say “Prusa” are not from Prusa Research, they’re just using his name. Too bad Josef never trademarked his own name. But then he probably wouldn’t; he prefers to get ahead by having a better product line instead of fighting it out in court. The Tesla analog of this, btw, is certain mainstream auto press writers stupidly calling every new EV concept car a “Tesla Killer” (concept cars are what you think: vaporware, possibly one working hand-made prototype, sometimes even a non-working prototype at a car show). Car journos have been saying that for a decade and Tesla’s still going strong.
Why Buy The Best? Why would you not?
So if you can buy a usable printer for $300, why should you buy the Prusa 3D at $750 (kit) or $999 (assembled)? Let me count the ways!
Constant innovation driven by the company and by the large community: new features get added. Some like the MMU are to buy, but others you can 3D print for yourself — The printer is open source so you can print replacement or improved parts — and software improvements are always free. Constant information provided by blogs from the company, such as this one on how to be sure your new i3 kit is assembled and set up correctly. Constant research into filaments:realizing they couldn’t depend on other manufacturers for top quality, they now blend, use, and sell their own filament, modestly named Prusament. Research into ongoing problems and solutions, and more.
Basic features that work: My first 3D printer — like many in the lower price range — lacked a heated bed and was designed in such a way that it was incredibly complicated to manually level the bed, so I had a lot of adhesion problems (getting the model to stick to the bed). The i3 includes a heated bed that is self-leveling. The i3 also has a removable bed plate (shown magically suspended mid-air in the above photo from prusa.com; it is of course flat on the table at the bottom of the machine when in service) that makes it easy to remove the finished model from the bed, just by flexing the plate. So many pain points salved over!
Custom firmware: instead of just using the original RepRap firmware, Prusa has extensively re-written it. Just one example: the i3 has a Belt Status indication that tells you if the belts that pull the print head are at the right tension. Too little or too much tension will cause printing problems. Of course the belt tension will be pre-set correctly on factory-assembled units, but on the kit you need to be sure it’s in range, and anyway, it can change over time if the belts stretch or if anything comes loose, so it’s great that they build in the self-test. I don’t know of any other under-$1,000 printer that does this.
A pair of additional save-your-butt features are “power panic” and “filament sensor.” Filament-based 3D printing is slow. Two of the worst things that can happen are running out of filament and running out of electricity. With many lesser printers, either of these results in the print being wasted — all that filament lost — and having to start over — all that time lost. Power Panic works by having the software remember where it was in the print and, after coming back from a power-off situation, asking if you want to resume from where you left off. Filament sensor, of course, notices when you run out of filament, pauses, and lets you continue after loading more filament. Both vital features!
But wait: there’s more! The Prusa i3 also detects “layer shift,” when one layer of the print is not in the correct position relative to the next, and automatically corrects it.
And, to top it all off, they provide a Prusa-customized version of Slic3r, the software that converts from generic “STL” (stereolithography) files — the output of CAD programs — into Gcode, the graphics language used by most 3D printers, and also sends them directly to your Prusa printer.
Sound: 3D printing can be noisy. The fans make noise, and the motors moving the nozzle around make noise. Fan noise makes some people drowsy. Premium components and good design reduce noise. The low-cost printers are loud — I measured the sound level while printing on one. In my house with hardly anything running, background level is about 18 dB. The cheap printer raises that to about 35dB (both measurements made with a smartphone app at a distance of 1 foot or 1/3 meter from the hot end fan). Sound is measured on a logarithmic scale, on which every 10 dB increase in the reading means you have 10x the noise. The Prusa i3 has two modes, normal and stealth. Even in normal mode it claims to be quieter than 90% of printers. In stealth mode it slows down a bit, but the noise level drops to an almost-unbelievable level.
Safety: While the cheaper imitations have a tendency to catch fire, the real Prusa has three fuses (standard automotive fuses, available at any auto supply store) on the main board, and software to notify you which one blew in the unlikely chance that one of them does. There’s even a thermal sensor on the main board that will tell you if the board is overheating, which almost always means that a wire to one of the two heating elements isn’t connected properly. That’s taking safety seriously!
Ongoing support: the company sells spare parts for its printers, and offers technical support. Starting with the New User Guide page, you will be given some guidance and lead to a detailed introductory book, blogs, community support, as well as online chat support and email support for owners, something you will usually not get for free from the cheap knock-off manufacturers.
Not only that, to avoid obsolescence, they sell upgrade kits! If you own an i3 MK2 or MK2.5, you can buy a kit of the new/changed parts and upgrade your machine to become an MK3. When they come out with the MK4, you’ll presumably be able to buy an upgrade the same way. If you have the two-color MMU, you can buy the parts to convert it to the five-color. It’s as though Ford or GM would sell you the parts to convert your 2015 Taurus or Cruze into a 2018 model — you know that’s never going to happen before the Sun goes nova and toasts all those little sedans into cosmic dust. But Prusa does it, now, at reasonable prices.
Here’s a fun fact for free: Prusa Research “eats its own dog food”, that is, it uses Prusa i3 printers to make all the plastic parts for Prusa i3 printers! And not just a few — they have 450 printers running non-stop making those parts to keep up with the demand! [Update: almost 600].
What I learned by kit-building
First, why build from a kit? Especially at the high end, there is a tension between taking the time to put the thing together like the factory does, and just getting on with using it. Part of the essence of being a “maker”-type person is understanding how things work, and putting all the pieces into place will definitely help you understand in more detail how your 3D printer works. On the other hand, if you’re really in a hurry to get started and don’t mind spending $250 to have the factory install and test your printer, or you need the greater warranty, or you’re buying a bunch of printers at the same time, you can order your Original Prusa i3 unit(s) fully assembled, and be printing while some of us are still adjusting belt tension and such like.
I’ve built two other 3D printers from a kit, the low-cost (almost embarrassed to say the name) “ElecFreaks” printer. I fell for it on Kickstarter because it is so small and portable. I learned from my multiple mistakes in building it — a belt routed over a pulley instead of under, another belt joined too loose, a bolt not tightened enough, and so on. To call the ElecFreaks instructions sparse would be like, well, true. So, figuring out how the parts actually go together was part of that education! And, because it does not have a heated bed (Prusa does) and is a bugger to level the printing bed (something the i3 does automatically), it took forever to get started making actual prints with the ElecFreaks, though I loved the form factor. Then I built the Creality Ender 3 Pro, the assembly of which you can read about here.
The process of building the Prusa i3 from a full kit is as different from the ElecFreaks as day is from night, because Prusa provides a very detailed guide on every step of assembling their printer. Unfortunately I didn’t build the Prusa kit, as I wasn’t able to obtain the kit in time for this review. Maybe later!
Conclusion
If you’re looking for the best mid-range printer in the sub-$1000 category, the Prusa i3 Mk3 is probably your best investment. And that’s not just my opinion: on their homepage, Prusa Research lists awards from Make Magazine, All3DPrinting, and others.
Where to buy: You can always buy direct from Prusa Research in Prague, Czech Republic, at https://shop.prusa3d.com/. However, you may wish to buy locally if there is a dealer in your area, for support: though it will cost marginally more, it’s nice to have someone to ask those basic questions of, especially if you are building it in kit form or just in case there’s a problem with your printer. One Toronto dealer bundles a coupon for their seminar on how to build your 3D printer — select the Prusa i3 kit to view this. There are also Facebook groups, both for general 3D printing and these two (one with 23,000 members, one with 11,000 members) for “Original Prusa i3” owners. And Meetup Groups, local user groups, etc.
All prices in USD, may not include shipping, and all specs are subject to improvement without notice.
Update — February 2019
In mid-February of 2019, Josef Průša himself took to the blogwaves to announce a series of updates to the i3 — now the MK3S — to improve reliability and serviceability. As is typical, these improvements did not affect the price of the current i3 (i.e., US$749 kit/$999 assembled now gets you the MK3S instead of the MK3) and are available quite inexpensively for owners of the existing MK3 (free for those who bought in the last two weeks, US$20 for the metal parts; you can print the plastic parts or buy them for an additional $20). There’s also an update to the “MMU” (multi-material or multi-color printing) which is free to all owners of the MMU, as there were many problems with the MMU’s serviceability. Numerous other upgrades too — read the blog post cited above to see them all.
Update —November 2021
Updates in the last while have been incorporated into the text.
About the Author
Ian Darwin has used, owned and built various electro-mechanical devices including 3D printers. Before 3D printing he did some woodwork and metal work using old-school tools such as hand planes, hand and power saws, lathes, milling machines, drill presses. In the early days of the PC era, he built several computers from bare circuit boards, and keeps his soldering iron handy. In addition he’s been successful as a software developer and instructor (on a wide range of computers culminating in modern mobile apps), computer book author, technology reviewer, the parent of three, and long ago, a SCUBA diving instructor.
