I think Prusa has had a couple of missteps of late, but they’re not in the gutter yet.
On the XL: the 0.6mm makes sense with the build volume, to significantly improve print times, but seems to really not work well with the 5 toolhead models, and introduces massive amounts of zits, stringing, cross-contamination, etc.
On the Mk4: at the price point, it’s maybe missing a few features to really hold up against the X1C, maybe even the X1E. Spaghetti detection (camera support), klipper, real input shaping, etc.
On input shaping: Prusa bet on the wrong horse with input shaping. Adding a <2g sensor to the toolhead was the right solution, and generating default input shaping profiles based on models in the factory was not. Most Prusa customers would’ve been happy to add the part themselves. Now they’ve sunk so much development and money into this, they refuse to accept it was the wrong approach and switch gears.
Klipper: Marlin is old. Sure, it’s amazing what Prusa is able to squeeze out of it, but at some point, the tech debt is just going to hold you back too much to be competitive. That happened around mid 2022 for Prusa, and yet Prusa decided to push 3 new printers on the same ancient firmware.
>On the XL: the 0.6mm makes sense with the build volume, to significantly improve print times, but seems to really not work well with the 5 toolhead models, and introduces massive amounts of zits, stringing, cross-contamination, etc.
More fundamentally, the XL uses an open frame design specifically because Jo wanted to prioritize being able to easily see and remove prints.
The entire gantry sits on a cantilevered open frame -- that's a fundamental engineering failure that's going to mean the XL will always be slower and produce lower quality prints than closed frame designs.
Please explain to me why you think there is a fundamental engineering failure in the frame design - I'd like to see the data.
Just so you can get an idea of where I am coming from, I have a Prusa XL and a Voron 2.4 right next to each other.
The Prusa XL frame is very solid and it's also not a quad gantry. The lead screws take the weight of the bed. The Voron uses 20x20mm extrusions and the Prusa XL uses 30x30mm extrusions and it has stamped steel for additional rigidity and support. On the Voron, I've added titanium backers to reduce flex from thermal linear expansion. While the XL would technicall have thermal expansion, when enclosed, it will be much less from the much larger extrusions and additional support.
The toolheads on the XL on the other hand are heavy, they will likely be the larger issue with speed+quality. People also complain about the Stealthburner weight with TAP.
There are faster projects than the Voron just like there are faster printers than the XL. You have to weigh what you want. The toolchanger design, for me, works flawlessly and is so much better than the AMS, ERCF, MMS. More companies will clone it.
This is getting into first principles territory. The short version is that the gantry being on a cantilever and an open frame means it's going to act like a tuning fork under toolhead acceleration. Higher resonance limits toolhead acceleration before print quality nose dives.
I haven't seen any accelerometer graphs posted for an XL, but it doesn't take much more than opening up PrusaSlicer and finding maximum accels set to 3k to see the direct result of that. That's where the rest of the community was 4-5 years ago. There's a reason why Prusa has an entire blogpost making excuses for why their printers' performance numbers aren't up to snuff compared to modern designs (while also cherry picking comparative numbers)[1].
It's not my only complaint about the XL but it's the most obvious one. I haven't been impressed in general with the prints I've seen come off those machines.
You should also check out multi-color print times on the XL vs the ASM or any other solution.
I think what Bambu has done is incredible but these are different machines for different reasons. The XL has a massive print area compared to the Bambu printers and the toolhead design I prefer. I just gifted an x1-carbon to my mom for Christmas. I'm not a hater or Prusa shill but people are just spouting opinions without data or truly understanding the differences between the machines.
It's based on basic engineering principles. Prusa can't magic away physics and these are lessons the rest of the community learned years ago. E3D had to course correct on some of the same mistakes with their toolchanger. There are good reasons why nearly every other CoreXY design you're going to encounter uses a closed frame (and the best will use structural panels).
>I think what Bambu has done is incredible but these are different machines for different reasons.
Sure, it's got its niche. But the drawbacks will narrow that niche. Prusa's ever narrowing niche is kind of the focus of the OP.
> The XL has a massive print area
Which makes running slow compared to other designs more painful since print times are cubic with volume.
>just spouting opinions without data or truly understanding the differences between the machines.
If you showed me a square wheel, I can tell you it's not going to roll particularly smoothly without needing to perform extensive testing on that specific implementation of square wheel. I can do that because it's something that's been tried elsewhere and we already know the results.
This style of open frame has been tried before. We know Prusa didn't choose to use it because there's any sort of engineering advantage because Jo has explicitly told us why they're using it.
I didn’t know about this point. Which printer would be closed frame, so I can understand the difference?
From what I’ve been able to observe, the quality of the XL is quite good for single tool head prints, however the quality really nosedives when multiple tool heads are introduced, and a bunch of people have been finding tricks to improve things (more wiping, less lifting, insane retractions, etc).
There is nothing wrong with Marlin, especially not for the purposes Prusa uses it for.
Marlins biggest weakness is needing to recompile for some things because they are defined by compile-time. All other things like active input shaping calibration can be added relatively easy.
There is _a lot_ wrong with Marlin. It is a complex codebase, full with ancient artefacts, litterred with preprocessor ifdefs every 2-3 lines of code, dynamic includes in the middle of CPP files, etc[1]. It's about as unreadable as C++ code gets--well, I guess it's not template metaprogramming.
Klipper by contrast is a breeze to read through[2].
I am very grateful for Marlin, for all of reprap, and everyone who has contributed to it. But saying there is nothing wrong with it is straight up misguided.
I’ve converted all my Marlin printers to Klipper. The ease of tuning and macros made a substantial difference, and now I have a proper API (and MQTT integration) to get notified of printing progress and issues.
And just as far as _printing_ is concerned, the speed and quality I can get out of an 8-year-old Prusa clone with Klipper is pretty amazing.
On the XL: the 0.6mm makes sense with the build volume, to significantly improve print times, but seems to really not work well with the 5 toolhead models, and introduces massive amounts of zits, stringing, cross-contamination, etc.
On the Mk4: at the price point, it’s maybe missing a few features to really hold up against the X1C, maybe even the X1E. Spaghetti detection (camera support), klipper, real input shaping, etc.
On input shaping: Prusa bet on the wrong horse with input shaping. Adding a <2g sensor to the toolhead was the right solution, and generating default input shaping profiles based on models in the factory was not. Most Prusa customers would’ve been happy to add the part themselves. Now they’ve sunk so much development and money into this, they refuse to accept it was the wrong approach and switch gears.
Klipper: Marlin is old. Sure, it’s amazing what Prusa is able to squeeze out of it, but at some point, the tech debt is just going to hold you back too much to be competitive. That happened around mid 2022 for Prusa, and yet Prusa decided to push 3 new printers on the same ancient firmware.