Crude unofficial XL+ nozzle replacement tool

At the time I made this, there was no nozzle replacement tool for the Prusa XL+, which has a different arrangement for its fan and fan shroud that makes it incompatible with the official XL Nozzle Replacement Tool. So, I decided to do something about it. I make no claim that this solution is ideal, and honestly, I hope Prusa Research comes out with its own nozzle replacement tool that makes this one obsolete.

When I tested this in PLA, I just used the default number of perimeters for the "0.2 mm Balanced" profile for a 0.4 high-flow nozzle (that is, 2) and the default infill type (grid) and density (15%, I think). When I printed a more final version in PETG, I used 3 perimeters and 20% adaptive cubic infill. Realistically, the exact print parameters probably don't matter much, though you might want to avoid a layer height greater than 0.2 mm.

No supports are needed.

Instructions for removing a sacrificial layer in the print of this tool

(Scroll down to the section "Instructions for use" if you just want to know how to use this nozzle replacement tool.)

This tool has a screw hole that is above a larger hole to accommodate the screw head. To make it easier to print this without supports, there's a thin layer of sacrificial material at the bottom of the screw hole. To get rid of that layer, just poke through it, as can be seen in the picture below:

I used an Allen wrench to poke it out, but an awl or really any decently sturdy thin thing 3 mm in diameter or below should do it.

Instructions for use

Since I have a multi-tool XL+, the instructions below show the toolhead laying on its side on the printbed, which is personally convenient for me. For the single-tool XL, that's not a realistic option, obviously, and I'm pretty sure that it's unnecessary. The only other difference between using this nozzle replacement tool for a single-tool XL+ versus the multi-tool version should be that the hole that you'll need to stick a Torx wrench into (to loosen the grub screw holding the nozzle) will be different.

If one of the nozzle in the photos below looks odd to you, it's probably because I start with a 0.8 mm high-flow nozzle from E3D, which sticks out a lot more from the heater block than the 0.4 mm typical Prusa-branded Nextruder nozzle, that I screw in at the end.

Unfortunately, to install this simplistic tool, the fan shroud needs to be removed, which requires unscrewing a M3x8 Torx screw from it, as shown below:

Here's how things look once the shroud is removed:

If the little screw doesn't stay in the shroud, it doesn't really matter, since you'll probably want to pull it out anyway.

Here's the nozzle replacement tool put in place, complete with the screw that I had pulled from the fan shroud:

The screw goes through the hole in the nozzle replacement tool and into the threaded hole in the toolhead that it was just screwed out of in the previous step. Since the nozzle I'm using is one of those high-flow ones from E3D, the heater block does not sit flush at the bottom of the tool the way it would if a "regular" Prusa Nextruder nozzle were used.

Loosen the grub screw holding the nozzle, using a T8 Torx key as shown below. Do NOT unscrew it all the way, just make a two or three turns with the key:

At this point, one can pull on the nozzle, moving the bottom of the heater block towards the bottom of the nozzle replacement tool, and then loosen the nozzle by starting to unscrew it with a 7 mm wrench. Prusa's universal wrench has a 7 mm cutout just for this, and Slice Engineering also sells a 1.5 N-m torque wrench that can be used for this as well. The result should look about like this:

It is possible for the heater block to come out a bit crooked, looking like this instead:

If it does, try adjusting it with your fingers until it looks more like the picture just above this one.

After this, insert your desired nozzle and screw it in WITH YOUR FINGERS. Do NOT touch a wrench at this point, because that can lead to cross-threading because the screw threads of the brass nozzle are harder than the screw threads in the aluminum heater block, and the brass threads can cut into the aluminum ones if too much force is used. (I learned about that the hard way!) If you feel a lot of resistance using just your hands, the nozzle is probably in a little bit crooked, and you should back off and try again. Be gentle.

Only after the nozzle is almost entirely within the heater block should you use a wrench. I prefer using a 1.5 N-m torque wrench for this rather than Prusa's universal wrench, because the former wrench will make it much easier to avoid using too much torque. When the replacement nozzle is finally back in place, it should look something like this:

Again, if the nozzle has a more "standard" geometry, then the bottom of the heater block should be about flush with the bottom of the nozzle replacement tool. You may want to push the nozzle up a bit with your fingers to make sure that the top of the nozzle is seated where it should be inside the Nextruder.

Once the nozzle is in place, tighten up the grub screw that holds the nozzle:

Just tighten it until you feel it stop, and then turn the key a "smidge" more to lock the nozzle in place. Don't overdo it, or else you may pinch the nozzle tube. Alternatively, you might try to use this to help keep you from applying too much torque, though I haven't tried it myself: https://www.printables.com/model/1259282-prusa-xl-03-nm-nextruder-torque-wrench-for-the-def

After the nozzle is in place, you of course need to put the fan shroud back on. Note that there's a tab on the toolhead that fits into a slot in the fan shroud:

If you have a multi-tool version of the Prusa XL+, then after changing nozzles and putting the toolheads with changed nozzles back in their docks, then you should rerun the Tool Offset Calibration to account for any subtle shifts in the z-positions of the nozzle tips.