A DIYer's Dream - Voron 2.4 Review
Following up on my build post, I've now spent some extended time with my Voron 2.4 and have my thoughts on the completed machine. With the assembly process being as much of a chore as everyone said it would be, the end product has to be worth all that effort, right? Let's find out.
I'm going to begin by saying that when I say I'm "reviewing" this printer, it's only very loosely. The Voron 2.4 is not a manufactured product you can just walk into a store and buy. What the folks behind Voron actually do is provide the blueprint for the printer so you can source the parts and build it yourself - how you want it. That puts a lot of the responsibility for how good or bad the printer is on your shoulders. You might self-source your parts, or buy a kit from a company like LDO or Formbot, but it's on you to put it all together, and put it together right.
The most accurate way of describing this would be "an assessment of a printer designed by Voron, with parts Formbot sourced, built and configured by me".
So, rather than try and juggle who takes responsibility for what on my specific printer, I'm just going to review it as it sits. This post won't cover the build process since I already did that in the previous post about the printer (and that's a more in-depth critique of Formbot's decisions with the kit), but it will hopefully give you a general idea of what the finished product is like and what things you might want to change or add on your own potential build. But again; it's only going to be as good as whoever builds it.
Alright? Here we go.
Hardware
The Voron 2.4 officially comes in three bed sizes: the 250mm, the 300mm, and the 350mm though technically, you can spec one out in any size you want (not even kidding, I saw someone on Facebook Marketplace selling an unfinished V2.4 sized for a one meter by one meter bed). I opted for the 250mm size since I don't have the room for a large-form-factor printer and it would fit in the exact same spot my Ender-3 S1 used to sit, though the 300mm version seems to be the most popular.
Even in it's smallest official size though, the Voron 2.4 is not a small machine. Or light. You find a home for it and you leave it there because moving this hog around is a little bit less than pleasant. It doesn't help that the printer doesn't have any handles to help you haul it around either.
But once you get it settled in - just pause a moment and take a good long look at the thing. This is one badass looking 3D printer. It weighs as much as a tank - well, it certainly has to look the part too. Black and red is done to death, but there's no denying that the Voron 2.4 wears it well. It looks properly sinister. The colors are yours to pick though, so as long as you have access to a 3D printer before you start building, feel free to let your imagination run wild.
The entire package is enclosed with foam sealed acrylic panels to help lock in chamber heat and keep nasty VOCs out of the surrounding space. The chamber is vented by a single 60mm fan in the top rear with an activated carbon sponge for air filtration while the air inside the chamber is circulated through another dual-fan activated carbon filter: the Nevermore V5 Duo - an optional add-on that often comes included with new kits, or you can print one yourself for an existing build.
The electronics are well ventilated and there are two 60mm fans to help move air over the heatsinks once the machine is under load. I do wish there was a better place for the power supply than right in front of one of the fans, but given the space constraints and the lengths of some of the wiring I was provided in this kit, this was the best solution I could come up with that didn't make the electronics bay too much of a rats nest.
Speaking of the toolhead, this thing is a marvel. Called the "Stealthburner", it's Voron's latest iteration of it's full sized direct drive toolhead. In it's standard form, this toolhead consists of a Voron designed dual-geared extruder called the Clockwork 2 feeding into a V6 style hotend which is cooled by a 40mm fan. This stock V6 hotend is possibly the most basic that you can fit to the Stealthburner and it's 24V heater cartridge heats it up to a stable 200 degrees C in about 1 minute 30 seconds. Part cooling is handled by a single 50mm blower fan that blasts air into two ducts covering each side of the nozzle.
But that's just the basics. The Stealthburner design is extremely modifiable, allowing for the use different aftermarket extruders, hotends, and cooling solutions such as dual blower arrangements or CPAP lines. It is also capable of equipping virtually any kind of bed leveling probe out there. Most printers opt for an inductive probe or microswitch probe like Klicky, though Tap - which uses the nozzle itself as the probe, and my printer is equipped with, has become a very popular option.
Formbot's kit makes use of the mainboard's CANbus capabilities, which moves all the control associated with the toolhead onto the Stealthburner itself. They accomplish this with an EBB board and it reduces the amount of wiring back to the mainboard to just one cable. The result is a fully modular package that makes smart use of available space and is very easy to service. One screw to open the electronics compartment, and four to pull the entire thing apart. Compared to the toolhead on my Ender-3 S1; the Sprite - the Stealthburner feels a lot better thought out from a component compatibility and usability standpoint, and less like things were just haphazardly bolted to it in order to make it work.
The main downside of all this unfortunately is size and and weight. The photos don't do it justice, but the Stealthburner is one big honkin' piece of kit. It's about the size of a can of soda and feels like it doesn't weigh that far off from one either. It's a double edged sword: you add things like better cooling, a better nozzle, electronics and sensors to the toolhead in order to improve usability, print quality and speed, and it has the potential of compromising the latter because you added more weight and slop to the printer's primary moving part. Though in practice I found this isn't that much of an issue, especially when running a barebones V6 hotend like I am.
The Voron 2.4 eschews the typical design favored by most CoreXY printers of a fixed XY gantry and a moving bed in Z, in favor of a moving gantry in XYZ and a fixed bed. There's a few advantages to this change; it lowers the printer's center of gravity and stabilizes the bed, which helps with vibration related print quality issues, and it eliminates the use of Z axis leadscrews in favor of belts, which should reduce Z artifacts commonly caused by warped leadscrews. It also gives you a fast moving Z axis - not a super important thing to have, but it makes moving the Z axis around during maintenance a lot easier than doing it manually.
The bed itself is a slab of 8mm thick machined aluminum with an AC bed heater that after PID tuning, heats up to 80 degrees C from room temperature with the chamber closed in about 2 minutes 30 seconds. It's topped with a two-sided magnetic PEI sheet with smooth and textured surfaces depending on your needs or preferences. The fixed bed is also great because I can effectively just yank prints off it and not worry about screwing up it's alignment, though it wouldn't matter anyways considering how effective the printer is at leveling itself.
Leveling the Voron 2.4, like most of the more well known CoreXY printers, is a piece of cake. Unlike the vast majority of bedslinger type printers, it is also a truly automated process. In the case of the Voron 2.4; since the four corners of the gantry can move themselves independently, the entire gantry can self-align itself parallel to the bed with the use of the bed probe. No more turning hand screws and dragging paper under the nozzle - except for setting the initial Z-offset. After that, it's completely hands free, and seeing the printer quad-gantry level for the first time and eliminate all that crookedness left over from the build is a pretty neat sight. It's unlike almost anything else out there.
Following a quad-gantry level usually is a bed mesh, which is where the Tap probe really comes into it's own. As I mentioned before, Tap uses the nozzle to probe the bed, which moves the entire toolhead on a short linear rail to trigger an optical sensor. This makes Tap a more sensitive probe, and it shows in readings that are usually more precise than those of inductive or microswitch based probes. For my 250mm bed, I run a 5x5 grid and it works perfectly, though larger printers should use a bigger grid.
Software, UX and Calibration
User interaction with the printer is accomplished primarily by the use of a web interface for Klipper called Mainsail. The web interface acts as a supplement for the onboard controls and is also similar in features to interfaces like Pronterface or Octoprint. You can send the printer G-code directly from your slicer, send terminal commands, monitor prints from your phone, and also update the machine's configuration without having to screw around with an SD card. Coming from the Marlin equipped Ender-3 S1, this is a huge step up in usability.
For those who enjoy a more hands on approach to printer control, the Formbot Voron 2.4 kit features a five inch capacitive touch screen that runs KlipperScreen. This screen packs nearly all of the web interface's features into an easily navigable UI, so if you have to monitor the printer without access to a phone, tablet, or computer, this is the best way to do it.
It's also worth noting that this is the full, official version of Klipper. It's not a feature stripped and locked version that some manufacturers such as Creality like to push. Everything under the hood is open to mess with to your heart's content.
For the slicer side, I opted to use OrcaSlicer, which is an open source fork of Bambu Studio that incorporates features from SuperSlicer and PrusaSlicer among other additions. OrcaSlicer has presets for the Voron 2.4 and it has built in compatibility with most net enabled printers, so I felt it was a good place to start getting the machine's performance dialed in.
My first print out of this machine post-build: a Voron test cube in orange Hatchbox PETG using the default profile with minimal tweaking was very surprising to say the least.
It looks decent! Like, what the hell?
No it's obviously not perfect. Ringing is rampant and the curling on some of the overhangs is terrible in typical PETG fashion, but look on the bright side. The edges and fine details are sharp, the top and bottom surfaces are basically flawless, it bridged through the middle perfectly, and there's practically no vertical banding or VFAs that I could see. This would have taken me months of troubleshooting on the Ender-3 S1 to get to this point, and the Voron 2.4 just spat it out on it's first try. With a little fine tuning, they would look damn near perfect - and they would. With my existing knowledge on print tuning, it wasn't long before I tweaked those default profiles to my liking.
But let's be real, you're not buying a CoreXY machine just to get quality prints. Hell, you can get quality prints off a sub $200 bowden machine if you put your mind to it. No, the real reason you want a CoreXY printer is for the speed, and getting prints to look good and print fast was a whole other can of worms. CoreXY motion systems are famous for reliable fast print speeds and the Voron 2.4 is no exception. But you also have to work at it, and the first step is taking into account everything that's bolted to your machine, and what it's sitting on.
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| Some fairly prominent ringing on the edges of this print. |
This is where we dive into input shaping: the key to squeezing every bit of speed you can out of a Klipper printer. Input shaping in essence is a form of vibration compensation that aims to iron out surface ringing while allowing you to raise the maximum acceleration, and in turn print speed of your machine. A lot of newer Klipper printers come with pre-baked input shaping values that will work fine for most use cases, but ideally you want to be able to calculate your own unique values because how effective input shaping can be is entirely dependent on how the machine is constructed, and where it's placed.
In my Voron's case, I've already established that the Stealthburner is pretty darn heavy for a toolhead, so I already know my potential input shaping value might take a hit because of that. I also have the printer set on top of one of my very heavy floor speakers, which isn't the worst place for it but considering that it's on carpet, it's elevated, and the footprint of the speaker is almost exactly the same as the printer itself, I expected my input shaping values to take a hit there too.
As for the actual calculation, the EBB board within the toolhead features a built in accelerometer, so all I have to do is send a terminal command in Mainsail and the printer automatically begins testing itself. After running the test on both the X and Y axis, it will return a recommended maximum acceleration and shaper values for each axis that I then plug into the printer's configuration file. I wound up with a maximum acceleration of 10900 mm2/s for X and 7300 mms2/s for Y, but I just run the lesser of the two in actual practice to play things safe. The more stable the printer is, the higher you can expect to push these numbers.
The second major factor to consider is maximum volumetric flow. Every hotend is different and it's important to find out just much filament it can reliably extrude before the motion system starts to "outrun" it at a certain speed. My V6 equipped Stealthburner was able to extrude reliably in Orcaslicer's volumetric flow test up until 19 mm3/s, which is higher than expected for a stock V6 hotend and nozzle, but when testing for VFAs, I found it was starting to produce noticeable artifacts after the 150 mm/s mark - which in itself, isn't a really dramatic improvement over the default Orcaslicer profile for the Voron 2.4 at 120 mm/s.
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| A hotend like the Phaetus Rapido 2 high-flow can extrude a volume up to 45 mm3/s, while it's ultra-high-flow version can push a whopping 75 mm3/s. |
So even though the motion system is capable of higher acceleration and speeds significantly higher than the 120 mm/s it's currently set at, I'm really limited by my hotend and nozzle. I would need to upgrade one or the other, but probably both to get a high enough volumetric flow that's actually usable for quality printing at substantially higher speeds. And even then, I'd ideally want to first relocate the printer to take full advantage of higher acceleration values.
But honestly, I'm not really disappointed by any of this. After doing input shaping and volumetric flow calibration for the printer and finding suitable pressure advance values for each filament, the Voron 2.4 is still printing roughly three times faster than my old Ender-3 S1 on otherwise lightly tweaked stock OrcaSlicer profiles - and the prints off it look freaking fantastic.
Print Quality
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| A MiniShooter in grey Anycubic PLA. |
PLA does perfectly fine in the Voron. Overhangs do suffer a bit in the hot ambient air so it's advised to keep the doors open when printing the stuff. That said, I don't print much standard PLA anymore so my tests with it are pretty limited, but my results with it have been close to perfect so far. Being one of the easier filaments to work with, I can't really say much more.
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| A few parts printed in red CC3D silk PLA. |
Silk PLA is another story entirely. This stuff behaves less like standard PLA and more like PETG from hell, in that it strings and curls like crazy, but it also has really poor layer adhesion for strength applications. It has historically been a nightmare for me to print on my Ender-3 S1 and at first, I was afraid it was going to suffer the exact same way with the Voron 2.4. Turns out, finding the sweet spot for speed and cooling was all it took to get my silk prints looking damn near flawless.
I cranked my outer wall speeds down to 40 mm/s and pulled the cooling fan back to 75 percent across the whole print. I also started the print at a 70 degree C bed temp and dialed it back to 55 C after the the first layer to ensure the chamber wouldn't stay too hot. All this made for longer layer times and a more gradual cooling that helped mitigate the rapid shrinking that is characteristic of silk filaments. The results are consistent and super shiny walls with very little curling. I feel like I've finally conquered my fear of this stuff.
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| A 3DBenchy in orange Hatchbox PETG. |
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| Some Pals printed in white TPOIMNS PETG. |
PETG generally works really well in the Voron 2.4 and the enclosure helps mitigate a bit of the warping that I found occurs when PETG cools too quickly in ambient air. Stringing is minimal, though I feel like that has more to do with me regularly drying my filament rolls than any alterations to my settings. I used 0.8mm of retraction, which was the default, and no Z-hop. Simpler models like the 3DBenchy turned out nearly flawless with my favorite Hatchbox PETG, while the more detailed models I printed with TPOIMNS PETG struggled with supported overhangs, even though most of the fine details were good. I wouldn't use PETG for finely detailed models anyways, but it didn't do half bad.
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| Two of my golf tee extenders mid-print with blue PRILINE 95A TPU. |
TPU also did well, but it took a little troubleshooting before it was printing right. Cutting my speeds in half across the board and dropping my bed temps to 35 C, but otherwise running the same print settings as PLA got this stuff printing just fine. I can't say the quality of TPU prints was any better than what I was getting with the Ender-3 S1. Just a little faster, which is always welcome.
Where the Voron 2.4 really shines though? ABS.
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| A Voron test cube in red Creality CR-series ABS. |
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| Some Voron parts in clear Kaaber ABS. |
That said, the enclosure doesn't seem to do as good of a job at keeping the nasty ABS fumes out as I would've thought. To be fair to the printer, I don't have anything else to compare it against, but printing clear Kaaber ABS reeked something fierce. I did end up trying Creality CR-series ABS which is supposedly low odor and it was indeed significantly better, so your choice of ABS is definitely a factor in how bad it smells. I still wouldn't want to be in the same room as it, but I'd print this stuff all the time if it wasn't for the fumes.
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| Get in the robot, Shinji. (Black Creality CR-series ABS) |
All that said, a common characteristic of all my prints across filament types is the remarkably smooth perimeters which is a product of input shaping - eliminating unwanted ringing artifacts in the print. The belt driven Z-axis, and I suspect the Clockwork 2 extruder also played a part in giving really consistent layering with minimal banding. This makes post-processing before filling and painting much easier and I'm actually happy to display some of these prints as is, they just generally look that nice.
Other Thoughts
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| On PEI, sometimes ABS and glue stick works a little "too well". |
The spring steel PEI sheet is a godsend after printing on glass for much of my time with the Ender-3 S1. Prints pop off with ease and it's far more durable, and offers better adhesion than the crappy PC surface the Ender came with. The bottom surfaces on these parts also have a nice texture to them with minimal elephants foot. Adhesion isn't so great with ABS however, even at nuclear hot bed temps. I still glue the bed in those cases, and even then I still might want to revisit glass. One of my larger ABS prints actually pulled the magnetic sticker off the aluminum bed when it curled, so unfortunately PEI isn't the end all, be all for larger warp prone parts. But for prints that don't take up the entire bed, it's great.
The machine also isn't very loud, at least in my opinion. The motion system is quiet under normal print speeds with virtually no bearing and belt noise, and very little stepper noise as well. Likewise, the toolhead fans and air filter are pretty well muffled when the doors are closed, and the 60mm exhaust and electronics cooling fans are whisper quiet. I measured around 53 decibels from the machine from about two feet away. You can certainly do things in it's vicinity and it won't be a glaring audible distraction.
I do have some other gripes though.
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| It might look like complete mumbo jumbo, but it's important... probably. |
The printer takes a painfully long time to run it's pre-print startup sequence. When I start a print, the printer homes, runs a quad gantry level, heats the bed to printing temperature and the nozzle to probing temperature at 150 C, homes again, probes a bed mesh, then fully heats the nozzle and finally begins printing. This whole process takes about 10 minutes for ABS and you can expect it to take even longer for bigger printers.
While I can shorten the sequences or remove them if I wish, it's not recommended to do so if you regularly print more than one material. The printer also has enough moving components within it's enclosure that it's not unheard of for the gantry to warp a bit as it heats up. I don't know if this less of a problem on the smaller printers like mine, but it's not a bad idea to use this time to let the printer heat soak a bit before it prints. It is still pitifully slow compared to my old Ender's startup time, so I may experiment with running a shorter QGL and a preloaded mesh to see if it screws up in any significant capacity between filament swaps.
The double front doors are... not good, and I think they contribute a great deal to the stronger than expected ABS odor. They don't seal very well against the frame and the fitment of the two acrylic panels against one another is fussy. It all depends on how well printed the hinges are - assuming the panels are correctly cut to size. A little too over-extruded and they bow inwards when the edges are pressed against one another. On the other hand, file them down too much and you're left with a gap. A single swing out panel with foam sealed edges would have been easier to implement and more effective.
The enclosed build height is also unfortunately limited. Although the Z-axis is capable of moving higher, the machine's configuration is set to 225 mm by default so the toolhead doesn't crash into the top panel. Even then, my CANbus equipped Stealthburner with it's upright cable gland, bows out the top panel as it nears the end of a print at those heights, so realistically my safe maximum build height is more like 200 mm. That's genuinely mediocre for a printer of this size.
But these kinds of problems are where having a fully DIY platform shows it's full benefits. If you hate something about the printer - you can fix it in any way you see fit. That's not unheard of with printers like the Ender-3 but on a Voron, it's practically by design. Call it a selling point, if you will.
Mod Potential
The BigTreeTech Knomi is probably the most silly and useless, but also one of the more fun mods you can throw onto the Voron. It adds a round 1.28" touchscreen to the front of the Stealthburner. Why the hell you would want a touchscreen on your toolhead? I have no idea, and all it's really good for is showing the exact same information you can find just by looking down at the screen that's already bolted to the front of the machine. But the neat graphics like the acceleration visualizer and the cute emotes add a layer of personality to the Voron that you really can't find anywhere else.
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| A TapChanger equipped Voron 2.4. (Source: viesturz/GitHub) |
Those few examples are just the tip of the iceberg too. You can get into mods as technically complex as a multi-material system akin to Bambu Labs' AMS called the Enraged Rabbit Carrot Feeder (ERCF), independent dual-extruders (IDEX), or what I'm personally very interested in building myself: a Prusa XL-like toolchanger system called TapChanger. The possibilities with this machine are virtually limitless.
Pricing and Competition
However, this all doesn't come cheap. My 250mm kit from Formbot including the printed parts ran me $874 before shipping from US. The 300mm and 350mm sizes would have ran me $934 and $994 respectively - and that's all considered on the low end of the pricing spectrum for a Voron 2.4 kit. An equivalent kit from LDO can get up to $1670, though many have reported you're paying for a higher quality sourcing and support service compared to brands like Formbot or FYSETC. That said, my experience with Formbot's kit leaves me wondering if LDO's kit is really all it's chalked up to be. I guess it's like an Epiphone versus a Gibson; you don't really know until you try them both.
At any of those prices, the Voron 2.4 is naturally going to get compared to some of the 3D printing world's upper echelon. For DIY kit printers, Voron's own Trident features a more traditional fixed gantry, moving bed design that offers similar print quality and speed, but with a simpler build and lower cost entry point. The RatRig V-Core 4 is probably the most similar non-Voron CoreXY kit on the market and like the Trident, it also offers a simpler build being fixed gantry, but it is on the pricier side. You could also throw in the more recent blazing fast cross-gantry oddity: the Annex K3 into the mix too, though it isn't anywhere as popular as the Voron or RatRig machines as of writing.
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As for OEM pre-built machines, Creality's K1 series comes to mind, as does Bambu Lab's P1S and X1 Carbon. The Bambu machines in particular offer probably the most accessible and refined 3D printing system on the market, but their closed source ecosystem and heavy reliance on sketchy cloud connectivity was the driving factor in me going with the Voron 2.4 instead. But after building one, I really can't fault anybody for going that route. They're just that good out of the box, and the P1S in particular is probably the best performance bargain on the market right now. The Creality K1 strives to be something similar at an even lower price, but the printer doesn't exactly have a great reputation for consistency either.
But really, there aren't many mass produced flying gantry-type CoreXY machines like the Voron 2.4 out there at the moment. There's Formbot's own Troodon 2.0 which heavily resembles the Voron 2.4, even undercutting Formbot's own kit in price. And then there's the Sovol SV08 which even fully optioned out, is actually cheaper than the Troodon 2.0 by several hundred dollars. They're both far easier to assemble and configure than a Voron 2.4: mere hours versus days at best, and they offer comparable performance straight out of the box.
Conclusion
So, why did I elect to go through all this effort opposed to buying something that's at least mostly pre-built in roughly the same price bracket? You wouldn't be wrong if you thought the Voron is a bit foolish from a value standpoint when compared to it's competition. For example, you can get a Bambu Labs P1S with the AMS multi-color system for roughly $150 more than Formbot's least expensive complete Voron 2.4 kit, and it will be a vastly better printer straight out of the box.
What the hell are you gaining from a Voron build, other than the potential of a massive headache and a printer that might not even perform as well as something you can start using straight out of the box - even after hours of tweaking?
The answer, in my opinion, is unrivaled versatility.
The Voron 2.4 is a machine that can almost endlessly adapt to your performance or feature requirements in ways most pre-built printers cannot. It's also very easy to obtain replacement parts for it in case shit hits the fan. Something like the closed-source P1S, with it's presently unknown longevity and no guarantee that Bambu Labs will continue to provide parts or service for the machine in the future, does not offer the same kind of long-term security that the Voron does. Machines like the Troodon 2.0 and SV08 are kind of outliers with their basic structure being mostly identical to the Voron 2.4, but there are many changes under the hood, especially on the electronics side that would need to be changed to gain functional and upgradable parity to an actual Voron build.
And considering that you built, configured, and calibrated the entire machine yourself, chances are you'll end up knowing the ins and outs of this machine far better than anything pre-built, and that knowledge will prove invaluable if you delve deeper into the hobby and potentially other printers in the future. It's an incredibly rewarding experience from start to finish, and at the end of it all - you get a fast, reliable, and just downright visual marvel of a 3D printer that is well and truly yours. From the first screw you turn, to the first print you pull off the bed - everything about it is of your own making.
But that heavily DIY geared aspect of Voron printers and really, most 3D printers in general has been the biggest turn off for a lot of potential users, especially newcomers to the hobby. The vast majority of people just want something that just works with no fuss and no confusion. That's something Bambu Labs excels at, and what many manufacturers such as Creality, Flashforge, and FLSun are pursuing: printers that are as easy to use as your microwave or washing machine. The Voron 2.4 definitely isn't that kind of printer - at least not without a large amount of time, money, and brainpower invested into it.
But then again, being easy isn't the point here - and maybe that's exactly what you want.
What's Good
- Outstanding print quality and speed across a wide variety of materials.
- Unrivaled upgrade potential and repairability, being fully open source.
- Eye-catching and extremely sturdy design.
- Quiet, low fume operation (with the right materials).
What's Crap
- Absolute chore to assemble and configure properly.
- Front doors feel like an afterthought.
- Bulky toolhead limits enclosed build height.
- Questionable value compared to pre-built machines.
Verdict
This is probably the ultimate 3D printer for DIY enthusiasts, but it demands absolute patience to get the best performance out of it.
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