On Monday, February 5th, we started to ship the Original Prusa MK3.5 upgrade kit, so the first units are already on their way to their new owners! The MK3.5 is a major upgrade with many useful features taken directly from the MK4. One of the biggest changes is the hardware-based support for Input Shaper and Pressure Advance to give your MK3S+ a massive speed boost. It’s the most cost-effective way to get many of the MK4’s features on your MK3S/+.
Speaking of the MK3S+: please note that we’re ending the production of the MK3S+ assembly kits on February 15th February 29th (extended due to popular demand) and we’re planning to end the production of MK3S+ assembled printers – we will sell them only until the current stock lasts. But we will, of course, hold spare parts in our warehouse. So, if you’re looking to expand your MK3S+ print farm with the same models (instead of switching to MK4), now would be the time to do it.
Back to the MK3.5! Most of the new additions are possible thanks to the 32-bit embedded xBuddy platform, which also allows us to add a full-color LCD panel with useful things like print file preview, easier configuration and navigation, and more. Plus, you get built-in support for remote printer management via Prusa Connect.
The upgrade process is completely straightforward, so you don’t have to worry about taking half of the printer apart. We estimate it takes around 2 hours to install it – check out the assembly guide in case you want to see the entire process for yourself. 😉
Supercharge your MK3S+!
Thanks to the 32-bit xBuddy board and its support for Input Shaper and Pressure Advance, the MK3.5 is up to two times faster than the MK3S+.
The actual speed will always depend on the size and complexity of an object, but the good news is that the larger the object is, the more time you save. For the purpose of this article, we compared several objects, from statues to handy improvements (such as cases and storage boxes) and the results are pretty decisive across the board. An iFixit Mako Frame would take 7 hours and 7 minutes on the MK3 while it takes only 3 hours and 23 minutes on the MK3.5, that’s 2.1 times faster! We used the 0.20mm SPEED profile, PLA, and a 15% infill. Another popular model that takes full advantage of the higher speed is the wonderful Rugged Box (Parametric) by Whity which can be printed up to 2.2x faster in PLA or 1.8x faster in PETG.
Similarly, we sliced the popular Darth Vader bust and went for the 0.15mm Quality/Structural profiles. The MK3S+ required 1588 minutes (26 hours) to print it, while the MK3.5 did the same job 778 minutes (12h 58 minutes).
On the other hand, with small objects, the speed differences are less significant. A small-sized low-poly Pikachu model took the MK3S+ 36 minutes to finish while the MK3.5 did it in 33 minutes.
| Model | MK3S+ (minutes) | MK3.5 (minutes) | Speed increase |
| iFixit Mako Frame | 427 | 203 | 2.1x |
| Darth Vader (without base) | 827 | 455 | 1.8x |
| Rugged Box | 425 | 197 | 2.2x |
| Torture Toaster | 800 | 384 | 2.1x |
| Dragon Egg | 171 | 86 | 2.0x |
| Low-Poly Pikachu (20%) | 27 | 24 | 1.1x |
| Modern Spiral Planter (two pieces) | 940 | 487 | 1.9x |
All objects in the table above have been sliced with 0.20 SPEED profile, Prusament PLA, and with a 15% infill. Pre-release print profiles were used in combination with PrusaSlicer 2.7.1.
Easier and more convenient
With the new larger full-color LCD panel, operating the printer is easier and more convenient than ever before. Enjoy useful additions, such as print file preview – when you select a G-code from the USB drive (no more SD cards!), you will also see a thumbnail of the sliced object. Perfect for all of those who love to name their G-codes as askdfjhs.gcode. 😉
The larger screen makes all calibrations and configurations a breeze. And you can even customize the footer of the main screen with useful information about various parts of your printer. You can also flash firmware from a USB drive or remotely via Prusa Connect.
As always, the upgrade kit comes with detailed assembly instructions and a new 70-page 3D printing handbook to get you up to speed!
Built-in network features
The MK3.5 can easily connect to an existing network via ethernet cable or Wi-Fi. This step is completely optional and just like our other machines, the MK3.5 can be fully operated offline without any drawbacks.
With the built-in network features, you can connect your MK3.5 to our remote print management system, Prusa Connect. This gives you the ability to manage your printer remotely and send print files directly to your printer. We made extensive changes to the network code and Prusa Connect to boost the network speeds. With the introduction of “Instant Printing”, the MK3.5 starts printing only seconds after you upload your G-code to Prusa Connect. This is possible thanks to a new binary G-code format and data streaming features and using the MK3.5 this way is much more convenient. Plus, you don’t have to look for that pesky SD card reader every time you want to print something. Prusa Connect can do much more, though! Check out our recent article covering its features.
You can also enable “local Prusa Connect” called PrusaLink. This creates a simple local server on your MK3.5 in case you don’t want your data transferred via the internet.
Out now!
The Original Prusa MK3.5 is now available in our e-shop. The package includes everything you need to give your trusted workhorse a massive refresh.
With the addition of Input Shaper, the printer becomes crazy fast – even with the original extruder! In case you’re looking for a bigger upgrade, take a look at the MK3.9 Upgrade which also includes the entire Nextruder with its Loadcell technology for an always-perfect first layer. And since there was a huge demand for an MK2->MK3 upgrade, we also offer a full MK3 to MK4 upgrade.
Happy printing!
FAQ
Q: Are the plastic parts included?
A: There is a small PETG filament spool included for you to print the parts.
Q: Which MMU unit is compatible?
A: Our latest MMU3 unit is compatible with the MK3.5. To get MMU3 for your MK3.5 printer, you can choose from the following options:
- If this is your first multi-material, get the full MMU3 kit including MMU unit, buffer and spools.
- If you already have the MMU2S unit, get the MMU2S to MMU3 upgrade for MK3.5.
- If you currently own the MK3S+ with MMU3, get this MK3.5 upgrade and the MMU3 cable.
Q: Is the Wi-Fi ESP module included?
A: Yes, the Wi-Fi ESP module is included.
Q: Is the Revo compatible?
A: The Revo hotend is a third-party addon. As of firmware 5.2.0, there might be issues with running the REVO hotend on the MK3.5. During testing, we discovered that due to the strict checks built into the firmware, the initial self-test will fail. It is possible to start the print, although we recommend waiting for the upcoming releases, which will extend the support for 3rd party hotends. Please see the release notes for more details.
Q: Is OctoPrint compatible?
A: The MK3.5 has the same base level of support for OctoPrint as the MK4 and XL. We’re still looking into some features. More details can be found in the release notes.
If I upgrade to the 3.5, will there be a kit to go to a 4 later or would I need to purchase the 3->4 kit. I am thinking of going to the 3.5 and going to the 3.9 or 4 later.
Hello, an upgrade from MK3.5 (or MK3.9) to MK4 is currently not planned, but we are listening to feedback and if there is a demand, we might release it.
Jakub Kučera – Prusa Research
I hope so. I ordered the 3.5 kit. Mine gets delivered tomorrow and my plan was to upgrade it to the 3.9 kit later on.
Same, I ordered MK3.5 and I plan to Upgrade to MK3.9 later on.
Like many others that would be a nice upgrade. I would even get a MK2.5s to MK3.5 or even a MK4 if it was available.
I too would like to see a 2.5 to 3.5 upgrade. This is perfect upgrade path for us with the older printer.
I hope, my plan is to start with the board upgrade and then in the future do a full upgrade to mk4, and it seems like there's a few others who also have similar plans, so it would be nice.
Jakub, correct me if I'm wrong, but the product page for the 3.9 upgrade kit says that it's only missing the new X/Y/Z stepper motors and that you can complete the upgrade all the way to Mk4 by buying those separately. I assume that this is still correct (this is what I am aiming to do once I save up the money), and that only the 3.5-to-4 upgrade path is (currently) unsupported.
I'd also like a 3.5 to 3.9 upgrade being made available.
I'll chime in on this. I did the 3.5 upgrade this weekend and I love it however I definitely want to upgrade the extruder so I would be very interested in a 3.9 upgrade and eventually mk4. I bet you if you just ran a beta and slapped together 50 kits you'd sell them in the first day. Even as a convenience it wouldn't be bad to throw together a few of them to have sitting around for people that want to upgrade. I'm pretty sure you already have all the pictures and descriptions to piece together a manual and instructions 🙂
My kit should be here on Monday and I'm printing the necessary parts right now. Looking forward to putting it together!
Well, for some reason no one seems to ask the most obvious – and most important – question, so here goes: Does the upgrade come with some gummy bears like the original MK3S+ did ?
Yes, there's a bag of gummy bears. Pocket size bag.
Is there a timescale for the 3rd party hotend firmware release? I have a kit on the way, but I also have a revo hotend. I don't want to 'downgrade' to the V6, to upgrade to the revo a few days later!
I have an MK3S. Does the 3.9 Upgrade also enable the "perfect first layer" or is this an MK4 only function?
Yes it does
How long do you think it will be before the 3 5 will have support for the Revo 6? All 6 of my prusa's have the revo 6 and I want to upgrade to the 3.5 but I want to make sure the support is available.
Doh, printed all the parts and was about to start assembling, but it looks like the Revo won't work with the current firmware.
I fully assembled mine with a Revo V6 and had zero issues (with the hotend at least), but there is a chance it's thermal performance is different enough from the stock V6 to trip an alarm. I had run into that on one of the most recent MK3S firmware updates and had to switch to a modded version to keep printing.
Is this kit compatible with the Prusa enclosure?
I just put mine together over the weekend with an enclosure. It works fine. Just don't attach the PSU or the LCD panel. Attach them to the enclosure just like before. The attachments for the LCD is different on the enclosure so be sure to print the correct version before you start the upgrade.
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Fully assembled my MK3.5 kit with a Revo 6 and wow this thing is smoking fast now.
Two issues though, it won't pass a fan test with the original Noctua Hotend Fan, and I can't get a perfect first layer calibration. It's drifting too far away from the bed starting at about at about 40mm from the left edge of the bed when it never had an issue before. I tried multiple steel sheets and even changed the new heat bed spacers back to the original ones, but still nothing. I just have to stay away from the left edge until I find a solution.
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Do I understand correctly, that to upgrade my MMU3 to fit the MK3.5 I just need o get the MMU3 printer cable – xBuddy?
Just upgraded my MK3S (stock) to MK3.5. Took me more than the indicated 2 hours, guess that's because I double checked everything and am finiky about cable guidance. After that it started up and ran through the initial tests without a problem. After a few prints my impressions are very positive. Prints are much faster and look great and the noise it makes is more ore less the same although very different. One last thing, I tried Prusa linked but that became a hassle so I engaged Prusa connected and that works great. Not only for sending files to the printer but also to check the progress of a print.
Now that the last of the 8-bit printers is being retired, is firmware development for the old platform coming to an end? If it is, it could be a valid reason to upgrade to at least a MK3.5.
Mind you, I haven't had any firmware problems for quite some time now in my MK3S+, but perhaps a new feature here and there might be worth the upgrade for some (apart from the immediate benefits, of course). Just something to consider.
The full upgrade (MK3 to MK4) does not make financial sense. It ends up valuing a perfectly working MK3 at 250€/$ (if looking at kits, and not factoring time invested) that you now have to almost fully disassemble.
At this price point it is better to have the MK3 as a spare sitting somewhere, or donating it to a local school/makerspace/friend. If you sell it for anything more than that, the full upgrade makes even less sense.
I made a stock of all electric spare parts for my MK3S+ except motors, PSU and bed. Let's see how long can it last?
Upgrade to MK3.5 went smooth.
However, the clock on the display is 1 hour behind (eg 10:09 instead of 11:09).
Any idea how to fix this?
I have a MK3S. Do I have to purchase a seperate kit to upgrade to the MK3S+ before I can upgrade my printer to the 3.5?