May 5, 2026
Description
This project upgrades your Core One with an internal recirculating HEPA and activated carbon filter. This is achieved without major modifications to your machine, as the filter fits into the left rear corner and mount directly onto the nylon rivets.
You can use either 4028 axial fans or 4020 blower fans, or even one of each if that is what you have available. The HEPA filter should be the one linked below or something equivalent in size. Make sure you use activated carbon suitable for 3D printers. To be safe, I recommend getting some made by the Nevermore team, such as the one below.
Filters chamber air without an exhaust. Good for maintaining high chamber temperatures.
Mounts with the original nylon rivets without modifications to the stock enclosure. No invasive or permanent modifications are necessary.
Both the HEPA filters and carbon pellets are housed in magnetically attached filter pods, which are easy to change anytime. It is necessary to remove the side panel only for the base unit installation, and then refills can be done without hassle.
Prints without supports.
There is no interference with the stock chamber fans / filter, so the cooling performance of the chamber is not compromised. The EdgeCase can be used either in addition to or instead of the advanced filtration system.
Use a reasonably heat-resistant filament, at least for the base. I used ABS-CF (dirt cheap and heat-resistant) for the base and Prusament PETG for the filter pods. Possibly, PETG could be okay for everything, but I didn't test. Unfortunately, I ran out of Prusa Orange for the very final version :(
The models are already oriented in the intended print direction, in which they will print without supports.
Everything is dimensioned for a 0.4mm nozzle, and many walls are dimensioned exactly to yield the correct number of perimeters. A larger nozzle might result in weak spots, seam lines in unexpected places, or even holes. Don't underestimate how tightly the space was budgeted to make this happen!
HEPA filters, which must be 8 cm x 4 cm x 1.5 cm, such as these: (Aliexpress link)
Fans, which can be either 4020 radial blowers or axial fans of size 4028 or 4020. I tested the 4020 turbo 24V radial fan from here: (Aliexpress link) and the 24V 4028 axial fan from here: (Aliexpress link). I think the performance is very close, but perhaps the 4028 axial is a bit more powerful, although the 4020 radial is definitely quieter, so go with what you prioritize.
Activated carbon, which must be acid-free to avoid damage to your printer. A reliable source is the activated carbon formulated by the folks at Nevermore. Find a reseller here: (Nevermore resellers)
Mangets for attachment of the filter pods, which should be of size 6x2mm. You will need 28 magnets. I recommend these: (Aliexpress link)
M3 screws to attach your fans to the base units:
Two 4028 axial fans will require a total of eight M3x35 screws
Two 4020 blower fans will require three M3x20mm screws and three M3x15mm screws.
One M3 screw of any head type of 15mm or longer for joining the two base halves.
Two countersunk M3x6 screw, such as these: (Amazon.it link)
Wires to connect the fans to power.
Optional: The Prusa GPIO hackerboard (see below)
Depending on your ambition, you can wire and connect the filter to your printer in different ways:
The simplest option is to go for 2-wire 24V DC fans, which you can power by simply running a wire to your printer's main PSU. In this way, the filter will run whenever your printer is powered on.
To gain more control, you can connect the filter through the Prusa GPIO hackerboard. The Hackerboard can act as a relay for the 24V DC power of the main PSU and you can thus control the filter fans from gcode. This way, the filter runs only when you have an active print.
You can house the hackerboard next to the wifi module, for which purpose I made this remix: (link to GPIO mount).
To control the fans with the hacker board, go to the Printers tab in PrusaSlicer, go to Custom G-code and add the following to your start gcode:
Philip Sørensen; ------------------------------------------
; Enable EdgeCase fans
M262 P0 B0 ; Set pin 0 as an output pin
M262 P1 B0 ; Set pin 1 as an output pin
M264 P0 B1 ; Set pin 0 to on, enabling the bottom fan
M264 P1 B1 ; Set pin 1 to on, enabling the top fan
; ------------------------------------------And the following to your end gcode:
; ------------------------------------------
; turn off EdgeCase fans
M264 P0 B0 ; Set pin 0 to off, disabling the bottom fan
M264 P1 B0 ; Set pin 1 to off, disabling the top fan
; ------------------------------------------
If you get 24VDC 4-wire PWM fans, then you can also control the fans using the xBuddy board directly. I have not done this myself, but I see two scenarios in which this can work:
If you do not also have the Advanced Filtration System installed, then you can use the Fan3 port intended for the filter fan. I know other similar projects (for example, this one) do this, so this is known to work.
If you also have the Advanced Filtration System installed, and you are willing to give up the chamber fans, which are then disabled by default, then you might be able to recycle those connectors. However, I'm not sure if the firmware play along with this, so do you own research if you want to pursue this. And make sure to give feedback here if you try!
I would like to keep both my Advanced Filtration System (to provide slight negative pressure) and the chamber fans (to boost PLA/PETG/TPU chamber cooling), so I went with option 2, 2-wire 24VDC fans and the Hackerboard. But, you do you!
Remove the side panel by pulling out the nylon rivets. You can push out the rivets from the inside, or you can use something like a pair of pincers. Save the rivets for later. They are reusable, and they will be needed. Remove exactly these rivets, and the panel will come off: (link to the Prusa assembly manual)
Remove the rear wire cover to gain access to the good wiring pathway. Essentially, undo this as the next few steps of the assembly manual: (link to the Prusa assembly manual)
The stock M3 screws holding the xBuddy case, unfortunately, take up too much space, so I recommend exchanging them for something with a smaller profile. I used countersunk M3x6 screws such as the ones linked above. Exchange the screws one at a time so that the xBuddy case does not become loose, and make sure to not use any screws longer than the original 6mm M3 scews. The two screws to be exchanged are the ones highlighted here:
Press 6x2 magnets into all slots on both base units and filter units. Each piece has seven magnet mounts, which use crush ribs so that no glue is be required. Some force might be necessary, and it can be difficult with just your fingers. I recommend finding some kind of tool with a tip no larger than 6mm that you can use to press with - I used a chopstick, which worked great.
Screw your preferred fan type to the base units. The model uses a tap-less hole that the screw can grip without too much effort.
Join the two base units with an M3 screw
Being mindful not to pinch any wires, align the base units with the rivet holes in the rear profile of the printer. With the fans I used, I found it convenient to run the lower fan wires along the rear left corner of the base. You may want to align your wires behind the base now also.
Reinsert the rivets to fix the base units to the printer.
Run the wires out hole along with the other electronics.
Finish your wiring of the fans to your choosen control/power supply. I recommend using the Hackerboard as described above.
Replace the rear wire cover.
Replace the side panel.
Enjoy!
Note: I have no way of quantitatively verifying the efficiency of the filter. If used as a stand-alone filtration solution, then I encourage you to ensure that your chamber is as sealed as possible. Pay attention to e.g. how well the door closes against the seals and close all corner gaps. I have also made a press-fit corner plug you might want to use: (link to corner plug)
This is a brand new model, and there might still be some kinks that need working out. Here are a few known potential issues you may face:
PrusaSlicer may sometimes have an issue in loading some of the included .step files. The root cause of this problem is unknown at this point, but the problem can be resolved by reloading the file in the slicer by using this option:
It has come to my attention that many of the 40 x 80 x 15 mm filters on the market actually have quite a bit larger tolerance than the filters I use. At this point, there is little you can do to mitigate this issue except for forcing the filter into place. I will try to see if I can gain a little more space to allow more manufacturer tolerance, but that will take a little time to implement.
There are reports that the magnets may be difficult to insert into the crush rib holes. This is true, and it might be difficult to do with bare fingers. I recommend using some kind of flat-pointed tool to apply force better. I used a wooden chopstick, which allowed me to push the magnets into place quite easily. I recommend that you look for something similar before you try to place the magnets.
Will this fit on the Core One L?
I have looked into this, and unfortunately, the left corner in the Core One L is actually 3mm narrower than in the original Core One. Because of this surprising fact, it is not easy to port this model to the Core One L. It would require a major redesign, which I am not sure I will find the time to do anytime soon.
License:
Creative Commons — Attribution — Noncommercial
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