Josef Prusa(Proo-sha) is one of the few celebrities in the 3d printing world. He helped pioneer the most successful open-source 3D printer designs out there today, which has led to 3D printers becoming so affordable and available. While a lot of other people have made their contributions to the field as well, I can’t name any others who started a successful 3D printer business and slapped their name on it. (Orville Creality? Melanie FlashForge? Don’t think so.) Prusa Research is considered one of the best manufacturers for consumer(non-commercial) 3D printers. Their printers are cutting edge wihle being rock-solid in pretty much every way. They are significantly more expensive than other printers in their class, but apart from cost, I have never heard anyone say they regret getting a Prusa. 

This past week, Prusa announced a new model, the Original Prusa XL. [author's sidenote: I don’t know why they put “Original” in front of the name since it’s not even out yet. My only theory is that they traveled into the future to a point where an upgraded version exists, and the new Prusa XL, which is their old Prusa XL, got branded as “the Original Prusa XL”, to differentiate it from their other Prusa XL (which would be current for them, but for us it is so new it does not yet exist.) And so they took an “Original Prusa XL”, but forgot to delete “Original” from the branding...perhaps due to mental fatigue brought on by time travel. In any case, I don’t want to write “Original” any more, so for this article, I’m just calling it the Prusa XL.] Prusa's I3 MK2 printer set the standard and popularized the style of FDM printers that are most used today so based on the name, I expected them to stick with their known winning formula and add a larger print area. I was really surprised to see that they made a ton of real, significant changes from their previous designs. There is almost no component on it that isn't a unique improvement over all the other printers out there (including their previous Prusa models). But progress has a price, and that price falls between $2,000 USD (basic and unassembled) and $4,000 USD (loaded and assembled). It's official release is scheduled for mid to late 2022 as well, so there's time to start saving your pennies, or put a swear jar by your current printer if you want to save up for when this new model comes out. But I'm a tinkerer (and I'm kinda cheap) so this level of luxury and convenience (yeah, and price) takes away a lot of the interaction that I enjoy in the first place. 

The legendary Prusa I3 MK2 - the inspiration for most current consumer printers

I don't see a Prusa XL in my future, but it has SO many innovative pieces that I thought it might be worth talking about. And since you can't talk about what's new unless you understand what's old, I thought I could take this opportunity to work in a compare/contrast introduction/discussion to some of the components on 3D printers, so even if you know nothing about how 3D printers work, you can still walk away saying “ah, that IS cool.” As I said earlier, in a comparison with pretty much any consumer printer, the Prusa XL’s features objectively win almost every category except speed and price so this is not a contest and I’m not writing to put other printers down. I'm just comparing what makes this printer unique with the things other printers are already doing.

Size : It's not surprising that the Prusa XL is bigger than the average printer. The most common printer models can build something that is 220mm x 220mm x 250mm (about an 8" cube, give or take). The largest consumer printers I have seen can basically double that. The Prusa XL can print 360mm x 360mm x 360mm, (about a 14" cube). Not the biggest out there, but big enough for almost every home-grown print project.

Extruder : Uuuuuuh, it's magic? To quote their own product description: "The XL comes with the brand new “Nextruder”, a completely redesigned extruder with a zero-backlash cycloidal gearbox, hot-swappable nozzles and a Load Cell-based system for fully automatic first layer calibration." Someone else can unpack that for you. In short, they did a lot of cool stuff here, but I suspect this is going to be made of mostly proprietary parts, so analyzing them one by one doesn't have a lot of value when I'm doing a general introduction. To give a high-level overview I may have to fly to the moon, but here goes. FDM printers(Fused Deposition Modeling...the printing technique that typically uses melted plastic) have a system of parts called the extruder. A string (filament) of plastic is fed into the system by a motor, there is a heater that melts the plastic in the hot end, and as filament is pushed in and melts, pressure builds and the melted plastic oozes out of the hot end through a nozzle on to the print surface where it will (hopefully) instantly start cooling and hardening into the final shape. In most printers, most of these parts are placed very close together, but they're actually separate pieces that work as a single "extruder" unit, and they are mostly attached directly to the printer frame. If you need to change something with the extruder, you can replace most of the assembled extruder as a unit, or you can replace individual pieces of it. From what I see, it looks like the XL is gathering most of these pieces together into a cartridge-like unit. Simply put, the cartridge takes filament in a tube on one side and extrudes plastic out the other. It's not a totally locked system, but it's not really something that looks tinker-able either. But the VERY cool part of this new extruder system is the fact that you can have up to 5 extruder tool heads set up on a single machine. Each tool head can be loaded with a different material. These other tool heads wait on the sidelines, ready to jump in and do part of the print in a totally different material. The main reasons to do this are either printing in multiple colors, or to print in a normal material like PLA, but use a water soluble filament to print supports that literally just wash away when the print is finished. Again, the multi-material concept is not new, and there are some very different approaches for printing with multiple materials, but this may be the best I've seen. Since every filament gets its own nozzle, you don't have to deal with iffy filament splicing and swapping, or enormous wasteful purge towers that are required to clean one filament out of the nozzle before printing with another. It looks like the carriage can swap tool heads without much difficulty, so if they are maintaining their accuracy and reliability with the head transfers, well then, that’s just super neat. The new tool head has a few other built-in goodies too, such as pressure sensing that might be able to anticipate when a clog is about to happen so that action can be taken before it destroys the print. There is also nozzle-pressure sensing bed leveling (which looks like another permutation of typical bed levelers...it touches spots on the print surface, and adjusts the print level to make up for unlevel places it found. They claim an “always perfect first layer,” no matter how gnarly the surface being printed on. People who print know that’s a bold claim, but Prusa could probably do it, and at that price, well...they better. 

General Design : One of the biggest differences between the Prusa XL and the most common printers is the basic design used. A few years back, Prusa's I3 became the standard design. At a glance, most of the printer's components stay low on the frame, and there is a upside down "U" rail that goes over it’s center. The print bed (the bottom printing surface) moves forward and backward(Y axis), and the extruder is mounted on a "gantry" across the upside down "U" and runs back and forth(X axis), and the entire gantry supporting the extruder raises and lowers(Z axis) to complete the print. This design is compact and simple and cheap, which is why it's popular. Instead of this common "I3" type design, the Prusa XL is using the "Core XY" design. This is not new or unique to Prusa, but it's still not very common. Core XY frames are built more like a cube. The extruder is always at the top of the printer. It is attached to a sliding rail and belts to position it anywhere in the XY plane. The entire bed moves up and down to control the Z axis. This design leads to more stability in the frame and less wobble as the extruder is flying around which improves potential printing speed and quality. And they admit, their Nextruder would be too much weight to put on an I3 gantry without gurting quality. Another nice feature about the Core XY design is that it's more "contained", relatively speaking. I3 printers need to be able to move the bed all the way forward and all the way back for the Y axis. That means the depth of space needed for the printer is almost double the printable depth, which is just a waste most of the time.
 
Heated Bed : This is another one of my favorite components that they added, at least in principle. Typical heated beds work by running current through a circuit around the bed to generate heat (like, literally, a printed circuit board that just carries current and transfers heat to the bed.) Covering the entire area with one heating pad can make it hard to heat evenly, leading to hot spots (or more importantly, cold spots). It’s also not efficient to heat the entire bed when you are printing something rather small. The Prusa XL separates the bed heater into 16 separate heaters (a 4x4 grid), and each can be controlled independently. This means you can save power and turn on just the areas you need, or crank up a spot that needs a little extra heat to help things hold. For heavy-duty users, you can also print smaller prints in different places around the bed to extend their life cycle by not overusing a single zone. Of course, your chances of a heater not working just multiplied by 16...so just hope it’s not the one you need. 

Software : Prusa has their own slicer with profiles tuned for their printers. If you want a low-effort, high quality experience (and if you bought a Prusa, that’s you) then using PrusaSlicer is probably the way to go, but I can’t speak from experience. For most other printers, general slicer software like Cura is most commonly used. Since it’s general use and can work for so many types of printers, it’s very helpful(read necessary) to find a profile for your printer. This will set up a lot of the default values that other experienced users have found work best for that printer.The main pro with general slicers are that they give you more freedom to make your print run the way you want it to. Their main con is that they give you more freedom to botch your settings and sabotage your own prints without realizing it. From what I hear, PrusaSlicer seems to lag behind the cutting edge on slicing features but unless you need something really new, advanced, or weird, PrusaSlicer probably does the best job of keeping you walled in where you're safe but giving you some room to customize settings if you want to. I guess it's worth mentioning that Prusa's printers are pretty well connected, and with some of the new sensors in the Prusa XL, they are hoping to observe diagnostic data from their deployed printers and be able to identify patterns that cause things like clogged nozzles, with the goal of being able to preemptively stop such disasters before they happen and tank your print. 

These are just some of the big points I found worthwhile to mention, but they really did some great stuff here and I'm glad Prusa has been busy moving forward and continuing to innovate in the printing industry. Even though all these features are more or less exclusive to the Prusa XL at the moment, It’s easy to see how elements of these features could be used to improve printers of every size, style, and budget. I look forward to seeing what else Prusa may come up with in the future, but I’m honestly more excited about the inspiration these features can give the community (because the 3D printing community can replicate and improve things at an incredible pace.) Prusa just took some interesting first steps, so what other steps can people in the printing community see now? Maybe an open source system that takes the multiple modular extruder idea and makes it an add-on for regular printers so people like me can easily run multi-material prints. Or if we can have a 4x4 heating grid, why not a 1024x1024 heated grid? (If you take that idea and run with it and it works, buy me lunch or something, ok?)

If you want to see the official product listing and/or pre-order an Original Prusa XL, click here. 

To view the announcement video (complete with dramatic overlays and extreme looking stuff) click here