More than six years ago, on September 22nd, 2017, I could finally introduce the Original Prusa i3 MK3 to the world. We’ve been cooking it in our development kitchen for quite some time and we managed to stuff it full of awesome new features nobody could’ve expected. Removable print sheets, power panic, Trinamic 2130 drivers with 256 micro-stepping support, laser-based filament sensor, unbelievably quiet operation… Nobody had that back then.

The MK3 transformed the 3D printing world with its innovations and it became the key product that allowed our company to expand and bring you many other cool things – like PrusaSlicer, Prusament materials, the Original Prusa MINI, XL, Printables.com and eventually MK3’s successor, the MK4.

We released the MK4 a year ago, but the demand for the MK3S+ remained so strong that we kept manufacturing it for another year and released more firmware updates. It’s truly a 3D printing workhorse that keeps on going.

And now, it’s time to say our warmest goodbye to it. We will stop offering the MK3S+ assembly kit in our eshop on February 29th, 2024 and the assembled printers will be available only until the stocks last.

One of my favorite shots of the MK3, from the short movie by UMPRUM and AMU

“The most important 3D printer”

Just a few months before the production of the MK3 started, we had moved the entire company to a new location and our team started to grow like crazy. I kept seeing so many new faces every single day, everything was changing at the speed of light. It was an incredibly exciting time. New print farm, new manufacturing halls, new offices. To newcomers, it probably felt like visiting Hogwarts for the first time – everything constantly moving around. What was a meeting room in the afternoon became somebody’s office the next morning. The rest of the world would call it “a startup environment”, but here everybody called it “Prusa punk” and I think that’s a much better description. 🙂

And in the middle of this, we’ve been putting the finishing touches to the MK3. We practically lived in the office and worked day and night knowing we had something on our hands that would shake the whole desktop 3D printing market. Looking back, it’s almost unbelievable how far we’ve come in the last few years. We grew from a garage-based company into something much more organized and efficient. Below is a video we recorded five years ago and you can compare it with the recent 2024 tour linked further down in this article – what a change!

 

During the development, we were lucky enough to receive a ton of feedback thanks to the MK2, so when we started thinking about the MK3 (which was actually quite soon after the MK2’s release), we had a long list of everything we wanted to add. So the MK3 didn’t arrive just because we thought we should release a new machine but because we needed a new machine. Many feature requests came from inside the company.

For example, since the start, we had a print farm, only much smaller than today. I said it many times, and I’m gonna gladly repeat it: we’re designing our printers also for ourselves. Below is the 2024 factory tour video where we take you behind the scenes and show you that there aren’t many companies that would put our printers under such stress as we do. And it really shows the progress we made!

Back to the MK3 development: when our farm operators complained that removing hundreds of prints from the heatbed every day was pretty tedious, we started to develop our signature removable print sheets. Yes, maybe you don’t remember it, but the MK2 (just like all other printers back then) had a heatbed with a printable surface, not removable print sheets like the new printers have. Back then it was standard to print on a sheet of glass. We invented the powder-coated PEI sheets, which are now used by the whole industry. Needless to say, they became an instant hit, just like the entire MK3 line. I am happy to see removable print sheets and the use of PEI as the print surface becoming the de-facto standard on nearly all current 3D printers. It’s such a nice quality-of-life improvement, I really don’t miss my trusty metal spatula.

Thomas Sanladerer published his video review with the title “The most important 3D printer” and kicked it off by saying that “[the MK3 is] doing so many things that no 3D printer has done.” But before the reviews could even start rolling in, we had to show the printer to the world.

From Prague to New York

The MK3 had its public debut at Maker Faire 2017 in New York. The event was absolutely awesome but we were, of course, pretty nervous about it – we wanted to show the MK3 in the best possible light. We knew the hardware was solid, but there were still some kinks in the firmware to iron out.

In September 2017, when the Maker Faire took place, the MK3 was still two months from being shipped and we were still fixing several bugs. In fact, a couple of bugs were fixed by my brother Michal while he was on the plane from Prague to New York. 🙂 He spent the entire 11 hours of the flight working on the code, so when he landed, the MK3 was ready for the show – and we could show off its amazing features, such as the filament sensor or power panic.

I even recorded a very, VERY improvised video introduction of the MK3 with a phone camera and… oh boy, it’s a bit hard to watch. 🙂 But as you can see, everything worked as it should and visitors were swarming our tiny booth to see the new features, such as Power Panic, filament runout sensor and crash detection – those were pretty revolutionary things back then.

In the end, everything turned out so well! We received two Maker Faire Editor’s Choice ribbons and the entire team was in high spirits. The only thing left to do was to wrap up the development in the upcoming eight weeks, pack it and ship it.

Just in time for Xmas

We started shipping the first units at the end of November 2017. From the beginning, the MK3 was designed as a printer that would be available in two variants – as an assembled printer and as a printer kit you could assemble at home. And it was the assembly kit that quickly took the lead and became the users’ favorite option. No wonder. It’s like assembling one of the big Lego sets or rather like building your own computer – you know exactly how it works and where everything is, how to upgrade various components or replace them. It may sound like a cliché, but it’s true: the assembly kit is the best way how to get to know your 3D printer inside out, and that’s also why we continue this tradition even with the new MK4.

(You can watch the entire MK4 kit assembly video playlist on our YouTube channel)

We were able to ship out nearly 2.000 MK3 units before Xmas, but that covered only the first few hours after the orders started. We were at 180 team members at that point and it was clear that we would have to hire more. Many more. So just a quick night of celebrations and then back to work!

And while our manufacturing team was overwhelmed with the number of orders to fulfill, the dev team had more work ahead of them.

Getting better and better

One of the things I’m proud of the most is the fact that we continue to support and improve our machines even years after launch. Imagine a cordless drill receiving software and hardware updates. 🙂

To be completely honest, the MK3 could have spent a bit more time in the oven. Hardware-wise, it was great, but the software needed some extra work. Every 3D printer is a system of many moving parts, and often a perfect example of the butterfly effect. Even a tiny thing can affect the print in some unexpected way and unlocking the true potential of all the components such as Trinamic drivers or the stepper motors (and keeping everything balanced) was a huge task. Instead of simply pushing a different printer model the next year, we decided to keep improving the MK3 via software and hardware updates as far as we could. And, in fact, we kept doing that for six years.

One of the first things we focused on was the overall quality of prints. By the time the MK3 came out, the MK2 was an extremely well-tuned machine, it had superb print profiles, so in direct comparison right after release, the results were in favor of the MK2. But we kept releasing new print profiles and new firmware versions as fast as we could, and soon after, the MK3 took the lead.

There were dozens of smaller and bigger hardware changes over the years – one of the benefits of our 3D printing farm is that we can easily improve the plastic parts, and it’s exactly what we kept doing over the years. If you place the launch version of the MK3 next to the final MK3S+, you will quickly realize how different the machines are.

This is also one of the reasons why the MK3 kept receiving plenty of “printer of the year” awards, year after year. 🙂 Many of the “best of” recommendations came even more than four years after launch because we kept improving everything we could. We’ve been continuously battling with our suppliers to get the highest quality batches, and every time we received complaints about certain parts, we immediately started looking for better alternatives. I guess we could have released a dozen different MK3 versions to signify all the little changes, but I would much rather keep things simple and update the model to the latest version on the go. Only when there were fairly major hardware changes, we added the “S” and “+” to make the assembly and troubleshooting guides easier to navigate.

And speaking of the manual and troubleshooting guides: that was another area where we made extensive changes based on your feedback. As I wrote, the assembly kit was (and still is) the most popular option – over the years, we’ve been making constant adjustments to our guides based on your comments, to make the assembly as easy and straightforward as possible. If someone reported that a certain illustration was lacking, we went ahead and fixed it. The difference between the MK3 and MK3S+ assembly kits is pretty big.

What might surprise you: many people today still run their old MK2s and they have no intention to upgrade – the simplicity of the old machines is sometimes too good to abandon. Just like with old cars. Sometimes you just don’t want, or need, a car which feels more like a computer on wheels, but you’d rather have the good old analog feeling with a stick shift and hydraulic steering.

And I feel like the MK3 is heading in the same direction as the MK2. There are hundreds of thousands of MK3 3D printers around the world. If you don’t need higher speeds or a larger print volume, then you might not even have that many reasons to upgrade – you can put your MK3 into an enclosure and connect it to Prusa Connect which turns your machine into a fully-enclosed printer ready for advanced network functionality. You can, e.g., send G-codes wirelessly to your MK3 from your web browser, manage it remotely, watch a camera feed and much more. To make the process as simple as possible, we’re also offering Raspberry Pi boards in our e-shop, we prepared a number of guides and a handy article with a complete overview of Prusa Connect and its functions.

And for a massive speed boost, there’s the inexpensive MK3.5 upgrade, or you want more, you can opt for the MK3.9 or MK4 upgrades.

Community-driven development

The open-source philosophy behind the MK3 allowed all sorts of enthusiasts around the world to tinker with the printer in many different ways.

Soon after the release, people came up with awesome additions to the MK3, such as these really neat extruder visualizers, but also various functional parts for experimenting with different cooling configurations, the Bear upgrade by gregsaun, and so much more. We continue this tradition and you can find the printable parts for all of our printers at Printables.com, so you can print spare parts, but also modify the printer to your heart’s content. We had a ton of fun with the MK3, too!

Many others were drawn into the firmware source codes available on our GitHub. Programmers started adjusting the code, improving it, and adding new features… in several cases, it ended up with us hiring these independent programmers – that’s how guys like leptun and wavexx became part of our team and they are among the key people bringing you many of the exciting features in the recent firmware releases.

PrusaSlicer grew along with the MK3. Actually, the version that was released with the MK3 was still called Slic3r PE (Prusa Edition) forked from the original Slic3r by Alessandro Ranellucci. Back then, it was pretty much managed by a single developer. In the years that followed, the slicer team expanded to more than a dozen people who completely rewrote the entire codebase from Perl to C++ and brought many useful new features that are usually quickly adopted by teams working on PrusaSlicer forks. Did you know that Slic3r didn’t have something so seemingly basic like Undo/Redo? We added it into a major release in May 2019 along with many other tweaks and improvements. This was shortly after we made the decision to rename the application to PrusaSlicer.

The machine that made things possible

While the MK3 became a favorite tool for makers around the world, companies were a bit skeptical about it – after all, it was much cheaper than the machines they were used to. But the situation changed pretty quickly.

We interviewed Joshua Lee, who used our 3D printers when he was working on models for Star Wars. You can find the MK3 printers in CERN, Skoda Auto, SpaceX, NASA,  Volkswagen and many other important places, from universities to hospitals.

In the last several years, we brought you many inspirational stories from countries all around the world – if you haven’t seen them yet, do check them out on our YouTube channel.

It’s always incredible to see how many uses people found for this machine. When you use a special lightweight filament, you can even print an entire RC airplane which performs amazingly well. Those are things that will never cease to amaze me! And, of course, one of the best things is that 3D printers give you the option to repair and restore broken things instead of throwing them away.

Goodbye, MK3?

When I became interested in 3D printers back in 2009, it was just my brother and I who worked on our machines in a small workshop for quite some time. Just the two of us.

Eight years later, in 2017, the release of the MK3 was such a success thanks to the combined effort of dozens of talented people. As the MK3 development and manufacturing comes to an end, I would like to thank everyone who joined in and helped to bring this “little machine that could” to life. Over the years, we kept following all sorts of projects made possible thanks to the MK3 and it always was (and still is) something that motivated us to go further. Our development team expanded rapidly and many people who originally bought the printer either because of their curiosity or as a tool for their project became eventually part of our team. There are dozens of wonderful stories behind the development of the MK3, but I’ll save them for some other time.

We will end the production of the MK3S+ kit on February 29th, 2024 and we’ll keep offering the assembled printer until the stocks run out (we estimate around 2 months). However, we will keep offering support for the MK3S+ and we will hold spare parts in our warehouse. After all, there are still nearly 100.000 of these printers under warranty. So, while our production of the MK3S+ will stop, its story is far from over. Even more so with the MK3.5 and MK3.9 upgrades, which are still technically part of the MK3 line. There are still plenty of opportunities for them to shine.

Just a quick recap:

  • The Original Prusa MK3.5 is the most cost-effective way to double the speed of your MK3S+ and adds many of MK4’s features – such as native network connectivity and a large colorful LCD. It doesn’t contain the Nextruder with the Loadcell sensor for an always-perfect first layer. Read the details in the recent article.
  • The MK3.9 upgrade contains everything from the MK4 except for the motors (the Nextruder motor is included).
  • Finally, the MK4 Upgrade is the full package – you will replace nearly everything on your printer. Back when the MK3 was released, our users voiced strongly that they wanted a full MK2->MK3 upgrade. With the MK4, we made it available right from the start.

If you decide to share your favorite thing about the MK3 (or your favorite project) in the comments, the entire team will be really happy to read it! 🙂

Happy printing!