The Prusa SL1 is Prusa’s first try at a budget small form factor resin 3D printer. While we were extremely impressed with its build quality, slick UI, ease of use, and class-leading slicer support, we were not so thrilled with its sky-high $1,399 price tag. After all, it shares the same internal components as the Elegoo Mars Pro, Anycubic Photon S, and EPAX X1—which are all much more affordable than the Prusa SL1. As a result, its community is tiny compared to its competitors. We cannot in good faith recommend the SL1 when its competitors can achieve the same print quality at a sixth of its price.
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Prusa Research is well known for their ecosystem of FDM 3D printers, branded filament, and customized slicer software. Prusa wanted to bring this same style of ecosystem to the resin 3D printer market with the SL1.
At first glance, the Prusa SL1 looks very similar to other popular 3D resin printers on the market, like the Anycubic Photon S, Elegoo Mars Pro, and EPAX X1. Available as a kit or a fully assembled machine at $1,399 and $1,699 respectively, it is nearly 6x more expensive than many of its competitors. However, what sets it apart are some key features that are only offered in the Prusa SL1. In this review, let’s take a closer look at its strengths and weaknesses and see whether it can command such a high price compared to the competition.
If you’re new to 3D printing, you might judge a 3D printer only based on print quality (which the Prusa SL1 scored a 9/10 for). However, there are many more things to watch out for.
For instance, the design of the Prusa SL1 is the one we like most. It has a gull-wing door that opens on both sides and in front—a translucent design that gives us a better view of the build plate The Prusa SL1 also has an aluminum construction that makes it rigid but not flimsy, among other things. This is why we scored the Prusa SL1 7/10 for hardware.
The benefits of a 3D printer’s design don’t stop at just the aesthetics but also continue on to the functional and safety side of things. The Prusa SL1 has a lower risk of electrical fires in comparison to other FDM 3D printers since it requires less power to function the LCD screen, UV light source, and motors. Less power also means less noise during printing, which the Prusa SL1 proves.
However, there are a few other safety and health concerns with the 405nm UV resin Prusa SL1 comes with. 405nm UV can be harmful if ingested and may cause allergic reactions when it comes into contact with bare skin. Always take the necessary precautions when handling this resin. Thankfully, the Prusa SL1 comes with a pair of nitrile gloves but purchase additional ones just in case.
The Prusa SL1 is also one of the easiest resin printers to use in its class. Even if you get stuck, the community support is just big enough to offer some help! Additionally, it is a well-supported printer by the manufacturer, so there are many available online resources. Hence, it, at the very least, deserves a 10/10 for ease of use.
Ranked #13 of 10
The Prusa SL1 sits at the very top of the budget small-form-factor MSLA resin 3D printer that specializes in highly detailed prints. These types of printers are well known for their small size, ease of setting up, and large community support. The Prusa SL1 is unique in this class because it is several times more expensive than many of its competitors.
We tested the Prusa SL1 with multiple printouts, visited all the major forums and spaces to ask questions to get a feel of the community, and stress tested this printer in some of the harshest environments it might encounter. In our quest to gauge its performance, we also compared the Prusa SL1 to its direct competitors (the Elegoo Mars Pro, EPAX X1, and the Anycubic Photon S). One notable claim from Prusa is its printer’s user friendliness compared to every other resin printer on the market, so we had individuals entirely new to 3D printing test it out.
All in all, this is research you don’t want to skip. If you select the wrong small-form-factor MSLA resin printer, you can be left with a difficult setup, poor quality prints, and very little support when running into technical difficulties. You can even easily run up your bill when parts break and overheat! With new 3D printers continually being released, we ensure that all the features justify whatever price machines retail at.
Calibrating the Vat and Leveling the Bed
The Prusa SL1 came nearly ready to print directly out of the box, so it’s this assembled version that we tested. The SL1 is well packaged with protective foam around the printer, build plate, and resin vat. Before setting up any 3D printer, users should first make sure the resin vat and build plate are free from any particles of foam.
Like almost all resin printers in its class, the SL1 needs to level its build plate before use. However, unlike the others, it also requires users to calibrate the tilting vat. Fortunately, the SL1 has a setup wizard that goes through the process with very clear and easy-to-read instructions. Even though the setup took more steps than the Elegoo Mars Pro or the Anycubic Photon S, it was a more user-friendly and polished experience overall.
Resin printers are capable of extremely detailed prints that FDM prints cannot hope to compete with. The limit of how much detail a resin printer can resolve is determined by the resolution of the LCD screen used. In the case of the Prusa SL1’s 2k screen, it can resolve details as small as 47um, allowing the machine to print just about any detail.
We tested this printer in three major areas: its ability to resolve detailed models, z height consistency, and consistent UV exposure across the whole build plate.
To test the Prusa SL1’s ability to print detailed models, we had it print several complicated figures both large and small. First, we printed a small figure and a medium-sized dragon figure. The printer had absolutely no issue printing the thin sword and did very well at reproducing the scales and texture found on the dragon model.
Next, we printed a much larger house model and robot figurine. The SL1, again, had no issues printing each of these models. Plus, the auto supports on the figures came off easier compared to models sliced in other resin slicers. The supports also left fewer scars on the models after removing them.
We then printed an Eiffel tower to test its ability to print tall objects, exaggerating any issues related to the z stepper motor. Fortunately, we could not find any issues concerning the SL1’s ability to reproduce the Eiffel Tower’s intricate details or problems with z layer alignment.
Finally, we printed a series of tiles across the Prusa SL1 to test how evenly the UV light is distributed across the build plate. If the light distribution is uneven, then details on the edge will look different compared to the details in the middle—which doesn’t seem to be the case for this printer. Overall, we were extremely pleased with the print quality of the Prusa SL1 and found it to be on par with all other resin printers in its class.
The Prusa SL1 creates excellent resin prints and is arguably the easiest resin printer to use in its class. Still, compared to its competitors, there are some minor differences in terms of speed and slicer compatibility.
Setting Up Prints
The Prusa SL1 comes equipped with a PrusaSlicer, their own customized fork of the open source Slic3r. Users familiar with PrusaSlicer for their FDM prints will feel at home since the workflow is nearly identical. Plus, among resin slicer programs, PrusaSlicer is one of our favorites to use. The system is user-friendly and easily lets you cut, modify, and fix models. It also comes with some of the best auto-supports on the market.
PrusaSlicer comes with built-in profiles for the Prusa SL1, making it incredibly easy to print files on the machine.
Files are then loaded into a USB flash drive and inserted into the front of the 3D printer. By the way, the SL1 arguably has the cleanest and best-looking user interface among any other resin printers we’ve tested. The menu is easy to navigate, and the text and icons are sharp and easy to read and scroll through. There is a level of polish to the Prusa SL1 that its competitors do not have.
Like many resin printers, the Prusa SL1 is a very quiet machine since it doesn’t have a lot of moving parts. The “loudest” components are probably the cooling fans, which recorded about 38db of noise during printing. For comparison, this is about as “loud” as a quiet office.
Since the Prusa SL1 utilizes a tilting resin vat, it does not need to go through the process of moving the build plate up and down before moving to the next layer. This makes it slightly faster than the EPAX X1, Anycubic Photon S, and Elegoo Mars Pro by about 3% to 5%.
While we would recommend using PrusaSlicer to create print files for the SL1, the resin printer also offers Lychee slicer support. On the other hand, Chitubox, at the time of this writing, does not offer support for the Prusa SL1.
With a build volume of 120mm (l) x 68mm (w) x 150mm (h), overall dimensions of 240mm (l) x 220mm (w) x 400mm (h), and weight of 9kg, the Prusa SL1 is noticeably heavier and larger than the Elegoo Mars Pro and the Anycubic Photon S even though they all have the same build volume. The EPAX X1 is slightly more compact but heavier at 10kg due to its full metal construction.
The Prusa SL1 sports a full aluminum build—except for its acrylic gull wing door—making it incredibly rigid. In comparison, the Anycubic Photon S features a flimsy plastic shell. And while the Elegoo Mars Pro is sturdily constructed, it does not have the same premium feel to it. When looking at rigidity and polish, only the EPAX X1 is a match for the SL1.
Out of all the consumer resin printers we’ve tested, the Prusa SL1’s design is one we admire the most. It features a gull-wing door, similar to Anycubic’s Photon S, except it opens up on both sides and in the front, giving us more room to access the build plate. Another feature that sets it apart is the use of translucent orange acrylic for the door, which offers a superior view of the build plate compared to the Anycubic Photon S and EPAX X1. Only the Elegoo Mars Pro supersedes its visibility with its fully acrylic lid.
MSLA resin printers are more electrically sound than filament-based FDM 3D printers. Resin printers require significantly less power to operate because they drive an LCD screen, a UV light source, and only two stepper motors. As a result, MSLA resin printers, like the Prusa SL1, do not have the risks associated with electrical fires that FDM 3D printers do.
Resin Health Concerns
There are many known health hazard risks associated with 405nm UV resin that consumers should be aware of. 405nm UV resin is extremely toxic if ingested and can cause allergic reactions when it comes into contact with bare skin. Several precautions should be taken when handling 405nm UV resin, and luckily the Prusa SL1 does a few things to address safety concerns.
For example, nitrile gloves should always be worn when handling resin, so it’s always a good idea to have several extra pairs at home. Prusa ships their resin printers with a pair of orange disposable gloves, which is common practice with most 3D resin printers.
Additionally, the SL1’s UV light source can be harmful to your eyes and should never be looked at directly without safety glasses on. The acrylic windows on the gull-wing door are tinted orange to prevent UV light exposure. Interestingly, this also prevents UV light from reaching the UV-sensitive resin within.
Built-in Air Filter
405nm UV resin is known for its intense smell and potentially toxic fumes. In fact, it gives off fumes even when the printer isn’t running. Thus, it’s extremely important to properly ventilate the printer to avoid toxic fume buildup.
The Prusa SL1 is equipped with an air filter that removes fumes coming from 405nm UV resin. And while we found that the SL1’s filter does a good job of removing the resin smell, there was no HEPA certification attached to it. For this reason, we cannot guarantee that this filter will remove harmful particulates from the resin fumes. Instead, we highly recommend users operate in highly ventilated areas or attach a HEPA-certified filtration system to their resin 3D printers.
Finding Replacement Parts
The LCD screen and the FEP film in the resin vat are considered consumables in resin printers like the Prusa SL1, though Prusa claims that the machine’s LCD screen does have a lifespan of around 500 hours.
When you do need to replace the LCD, the process is relatively straightforward. It involves unscrewing the old LCD module and replacing it with a new one. However, there’s a catch: The LCD module for the Prusa SL1 is a proprietary part, meaning you can only get replacements from Prusa, and they come at a cost of $75 each. This is notably more expensive and harder to source compared to replacements for competitor machines, which typically range from $20 to $40. Other components such as the control board are also proprietary to Prusa, making the SL1 more difficult and expensive to repair.
Accessing the Control Board
Since there are very few moving parts on the SL1, opening up the resin printer should be a rare occurrence. However, if the user needs to access the control board or any other internal components, it can be done by removing eight screws from the sides of the machine. This removes the entire bottom cover, allowing you to access the mounted control board and other components very easily. Prusa also does not hot glue its connectors, so it’s easy to replace cables if needed.
Tilting Resin Vat
Resin printing involves curing a layer of resin to the build plate, lifting the build plate to the next position, and repeating the process. The action of lifting the build plate introduces a lot of suction force between the resin vat and the build plate, which can result in prints falling off. This is usually one of the biggest causes of print failures (the other being incorrect leveling of the build plate). Prusa aims to solve this with a motorized tilting resin vat.
By tilting the resin vat, the print plate is slowly peeled away from the resin vat, dramatically reducing the amount of suction force. This feature makes the Prusa SL1 more reliable with prints. Tilting or moving resin vats are typically found on professional resin printers like the Formlabs Form 3 and the Peopoly Moai—both of which are considerably more expensive. That’s why it’s great to see a feature like this appearing on a consumer machine. The tilting resin vat also gives the Prusa SL1 a slight speed advantage by not requiring the build plate to move up and down before traveling to the next layer.
Resin Level Sensor
The Prusa SL1 features a capacity sensor that detects the presence of resin before printing, alerting the user if there is not enough resin detected. However, while it can detect the amount of resin in the vat, it will not pause the print if your machine runs out of resin. Always make sure that your vat has enough resin to complete the print.
The Prusa SL1 comes equipped with WiFi connectivity. Currently, it can only monitor prints by displaying a very basic webpage with the progress, time remaining, and current layer view of the print.
The Prusa SL1 is an incredibly refined 3D printer with a polished user experience and an unmatched workflow. It excels in producing excellent prints, whether you use its branded resin or third-party options. Moreover, its autosupports feature is top-notch.
However, the Prusa SL1 retails at $1,699, which is significantly more expensive than competitors like the Elegoo Mars Pro, which can be found for $299 or even less. Considering the cost, we cannot recommend the Prusa SL1 in good faith when you can achieve similar print quality with the Elegoo Mars Pro. Plus, all competitive resin printers can take advantage of Prusa’s best-in-class autosupports by loading their models into PrusaSlicer, exporting with autosupports into the slicer, and printing on their machines.
With the newer generation of resin 3D printers, the value proposition of the Prusa SL1 gets worse. The Phrozen Sonic Mini ($400) has a 4K monochromatic screen that resolves in greater detail and prints 50% faster. The Anycubic Photon Mono SE and Elegoo Mars 2 Pro both feature faster monochromatic screens and are priced at $400. We highly recommend users look to these 3D printers instead if they’re looking for a machine that provides the exact value of their monetary worth.
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1. Prusa3D.com, “Prusa Research a.s.” Accessed July 26, 2022.