Prusa Research is obviously well known for the incredible Original Prusa i3 3D printers, the amazing new filaments they produce in their own manufacturing facility in Prague (Czech Republic) called Prusament. The service and help you’ll receive with Prusa products are great and the community around the brand is one of the largest in the 3D printing world. Prusa Research was founded in 2012 by maker and inventor Josef Prusa and together with a small team, he managed to grow a small start-up to one of the largest 3D printing all-rounders in the world. Currently Prusa research employs over 300 people and ships thousands of new printers all around the world.

The Original Prusa SL1 & CW1 before shipping to external beta testers.
Source: Josef Prusa Twitter

About a year ago Josef Prusa bought the Czech company Futur3D that was already specialized in SLA 3D printing and their experienced team joined Prusa Research to start a new adventure. So after the Prusa i3’s, the Multi-Material Upgrades and Prusament the next logical step was an Original Prusa SLA 3D printer and that my friends, is now a reality! The Original Prusa SL1 and CW1 (Curing and Washing station) are currently being tested by 20 beta testers. Prusa Research worked really hard to finish the machine and polish out all problems but they managed to bring us an incredible new SLA 3D printer that is available for pre-order and starts shipping late April. I was one of the lucky ones that got selected for the SL1 and CW1 beta units and I have both machines running non-stop for the last two weeks. The cool thing is that this is my first resin based printer so I really could act like a first time customer. I have the Original Prusa i3 MK3 and MMU2S and love the Prusa brand but this clearly is a dream come true for me. I always had so much interest for SLA/DLP printers but because most quality machines are just a bit too expansive I never started. So I was really happy to find out Prusa joined the SLA world with a completely Open Source machine. I was excited like a child when I heard that the printer was on it’s way to me and couldn’t sleep that weekend. The machine arrived exactly two weeks ago so it’s time to tell you guys what I think of the SL1 and CW1.

A package from Prusa Research! Look at my face… Hahaha.

So first things first. What are these machines? The Prusa SL1 is the new SLA printer and the CW1 is the curing and washing machine. The SL1 creates highly detailed 3d prints with resolutions between 0,1 mm and 25 microns by curing liquid photosensitive resin with an LCD screen and a light source. The CW1 washing and curing station does exactly that. You can use this machine to wash the model in IPA and after drying the model it can be cured during the last stage in UV light. Both machines are made in exceptional quality and can compete with SLA printers that are much more expansive than these machines. Both are available build and calibrated but you can also get them as kit versions and build them yourself. In this way, you can save some money and learn everything about the machines. The Prusa Handbooks are incredibly well written and guide you step by step through the build process. I got the build version and I’m happy to tell you this machine does work out of the box after a super simple calibration process. The best part is that you can find guidance including photo’s on the color display of the SL1 to help you during setup. It takes 3 minutes and after it’s done you can pour some resin in the tank and start printing.

Unboxing the Original Prusa SL1 beta unit.

The printer and curing/washing station are both packed in the same sized box and on the inside, you can find the accessories box on top and the well-protected machine under it. In the accessories box are all the things to get you started printing. First thing i found was a personal letter from Jo Prusa with instructions for the Beta Testers. There are a few gloves, a protective tray, some pliers, a funnel with a filter, a metal, and a plastic spatula, Allen keys, the power cord, Prusa Solid Orange resin, an SD-Card, and an FEP film replacement. The handbook for the SL1 is included in the box but this is a beta machine so we had to download it from the special Prusa SL1 beta website. Under the accessories box, you will find the machine. Well packed in foam plastic and enough space on all sides to prevent damage during shipping. There was also a bottle of Prusa Red resin included in the accessories box of the CW1 for us Beta Testers. It’s time to take the machine out of the box.

Introducing the Original Prusa SL1 – Open Source SLA printer by Josef Prusa.
Source: Prusa Research YouTube Channel.

The Original Prusa SL1 is actually an MSLA (Masked SLA) printer. It’s a bit hard to explain all the technical stuff but there are three different SLA technologies. SLA – Laser-based stereolithography, DLP-SLA –
digital light processing stereolithography and MSLA. All these processes are using light to cure the liquid resin in a tank above the light source and produce a 3d model by curing the resin layer by layer. DLP printers are using a lens and the quality of the prints it produces depends on how much the lens can zoom and scale. The SL1 uses an LCD and the X and Y accuracy is fixed so this technology is more precise!

The SL1 has a build volume of 120 × 68 × 150 mm (or 4.7 × 2.6 × 5.9 in.) and
5.5’’ high-resolution LCD display with 2560×1440p resolution and that is good for 0.047mm per pixel fixed XY resolution. It has a rigid dural frame and separate body and feels nice and heavy and that’s great for stability. And yes! It uses Trinamic drivers so the machine is silent and very accurate.

The Original SL1 & CW1 beta test versions first print.

I ade some room for the machines of my workbench and they look beautiful. I really like the orange and black Prusa uses for its products so I like to create some more room on the bench and just reserve it for my Prusa printers. On the left side of the little white YAN 3d printer is my enclosed Prusa i3 MK3 so that small guy has to go. I have a few more 3D printers so I have to make some more room anyway. The SL1 and CW1 are good looking and high-quality machines but working with resin can be a bit messy so I might want to buy a plastic table cloth to protect the wooden workbench from the chemicals. I am really careful myself but believe me you will spill a few drips now and then. Time to boot up the machines and print some cool stuff after calibration.

Automatic Calibration of the Original Prusa SL1.
Source: Prusa Research YouTube channel.

On the Prusa SL1 Beta Testers website, we could find some pre-sliced models that we could use for the first four prints. I started with a little Josef Prusa SL1 calibration file. Before you start pouring the resin in the tank you need to put on the protective gloves and shake the bottle for at least 20 seconds and let it sit for a few minutes so the air bubbles can escape. After a short while, you can pour the resin in the tank and there’s a guideline inside for the level of the liquid. For smaller prints starting with 35% is sufficient. The next step is pressing the power button and wait for the Prusa Research logo to appear. I almost forgot to tell that the SL1 can be connected to the internet by wired or WiFi connection and can receive over-the-air updates and controlled via remote connection. The machine will prompt whenever an update is available. I put the sliced model I’m going to print and selected it from the menu of the printer. The machine homes, the platform goes down into the tank and the SL1 does it’s preprint calibration. When everything was ok it started making the model.

The first print on the Original Prusa SL1 beta version 3D Printer.

The calibration file took about 4 hours to complete and finished without any problems. It is a bit strange to use a printer like this for the first time when you are used to FDM printers like the Original Prusa i3 MK3. When the printer is curing the first couple of layers it sounds like you rip a piece of tape from an object. This sound comes from the cured resin that gets pulled of the FEP film so nothing to worry. Luckily there are some amazing Prusa employees that are helping us figure things out and they listen really carefully to our feedback as well to give you the best possible experience when the printer gets released into the wild. After the print was finished it was time to set-up and try the CW1. Using the washing and curing station is really easy and in my opinion, a must have when you order the SL1. Yes, it is possible to cure the model in sunlight but you also need to wash it in IPA 70% or above and dry the model after washing. The CW1 saves you a lot of hassle and time. It can do all three stages and is easier to operate than starting a print on your MK3. The CW1 is a simple but strong unit with a rotating platform on the bottom. You will get a large steel container with a cover that you need to fill with around two liters of IPA. Inside the container, you’ll place a round disk with a small magnet attached to make the disk spin and stir the IPA during the washing phase. The container also comes with a steel basket to contain the model during washing. After washing you can take the basket out of the IPA and dry the model with a piece of paper towel.

Original Prusa CW1 washing stage during beta test.

When removed as much as IPA residue from the model as possible you can remove the IPA container and basket from the CW1 and place the model on the rotating disk on the machine and start the drying and curing stages. The standard time setting for each stage is 3 minutes but you can change that from the menu of the machine and set it higher if needed. Some highly detailed and smaller models are really hard to dry with a paper towel because you can’t possibly reach every surface and in that case, it’s better to up the dry time a bit. For larger models, you might want to increase the curing time.

Finished Eiffel Tower beta test object in the CW1.
Printed in Prusa Red Resin.

After the final stages are finished the CW1 will beep to let you know it’s finished and you can open the hood to remove the model from the platform. The model is now washed, dried and cured and can be handled without protective gloves. When you printed the model with supports you can now easily remove them by cutting them carefully with the provided pliers. In some cases, you can just break them off without problems. It’s a wonderful experience to see the detail on the finished products that come from the Prusa SL1 and CW1 beta versions. It’s almost impossible to see any layer lines even at 1mm layers and the models feel really strong even when it’s size is really small and delicate. Here are some of the prints I’ve made these first two weeks.

This is just a small collection of the prints I’ve made during the first two weeks of the external beta test of the Original Prusa SL1 and CW1 by Prusa Research. I enjoyed myself a lot so far and fell completely in love with both machines. I can think of so many things I would love to try to print and I can’t wait to see where Prusa is going to take this next. I’m guessing that like Prusament there will steadily be more resins available and I’m pretty sure these will be just as cool as the Solid Orange and Transparent Red we are using today. The SL1 and CW1 are already available for pre-order and new orders start shipping in June so you better order fast. ;-). I will you updated in the next few weeks and after the beta testing is done I will give my final opinion about the machine. At the moment all works great and I just can’t stop printing.


Original Prusa SL1 & CW1 links:

The Original Prusa SL1 and CW1 are available for pre-order at the Prusa3D online shop. And just like the Original Prusa i3 series 3D printer you can also choose the kit version.

Original Prusa SL1 3D Printer

Original Prusa SL1 & CW1 Bundle

For more information about the Original Prusa SL1 & CW1 and the Prusa i3 MK3S and MMU2S visit the Prusa Research website by clicking HERE.

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