changing nozzle size

I removed the nozzle off my Taz Hexagon V2 for the first time on Saturday. It was not too difficult. I used a crescent wrench on the heater block, and a 7mm open end on the nozzle. I heated the nozzle to 240, then cooled to 160. I did a cold pull and then removed the nozzle, using the crescent wrench to make sure the rest of the hotend did not move.
I found that my cold pull still left abs in the nozzle. I carefully drilled most of it out and soaked the nozzle in acetone. I used a scotch pad to remove most the baked on abs, then a series of fine mesh pads (from 1800 down to 8000) to finish cleaning and polishing the tip. I also had a .0125" and a .35mm drill that I used to clear the tip. After completely cleaning the threads of the nozzle, it went back in without having to heat the nozzle. I was very careful installing the nozzle, turning about 1/2 turn, then back out 1/4, then forward 1/2 until it was fully on. I do not have a torque wrench, so I used the “that feels about right” method. It worked for me. After replacing the nozzle, the extrusion was very smooth and there was no ooze out the threads at all. (I did hit the seat of the threads with a 3600 mesh pad.)

As for smaller size nozzles, the only one I’ve found so far is a .25mm nozzle from http://www.printspace3d.com. They also carry the .35mm, .4mm, and .5mm sizes.

I have their .25 nozzle, and verified it is the proper thread, but I have not installed and used it yet.

Scott

I tried to remove a nozzle from the original buda while trying to fix a bad leak, and I will never do it again. I’d rather build a few more hot ends with dedicated nozzle sizes than experience the frustration and destruction that resulted.

Replacing the nozzle on the Hex hotend isn’t anything like the Buda. I have changed the nozzle size on three Hex units without issue.

With that said, if I would not want to regularly change nozzles to move between nozzle sizes . That would be a hassle and I would just build up separate extruder assemblies in that case.

I have had my Hex Hot end apart several times for cleaning. As previously stated, Its not difficult at all, however it most likely voids warranty. I even sand blasted the heater block to remove nasty burnt on filament a few times. I will add that I now have a bit of filament that squeezes out onto the top of the heater block on very long builds. Doesn’t cause any issues, but it does occur.

Having said that, It is a hassle to do, and probably voids your warranty. The Hexagon Hot ends are cheap though…

Changing nozzle size is not a big deal IF you have some mechanical ability. Its got threads and its designed to be replaced, common sense would say if you have plastic inside it needs to be heated to remove. Brass against stainless steel should not need anything to keep from leaking.

As a mechanical engineer I like to imagine I have some level of mechanical ability. :slight_smile: In my case, with the original buda, the problem was aluminum binding up on aluminum. I’m sure brass on stainless is much nicer to work with. That said, I still have no interest in taking apart my hot end and potentially introducing new problems. I would rather stock multiple extruders.

curious if anyone actually was able to torque the nozzle to the torque spec of 30 lbf. It won’t accept a metric 7 mm socket (nor 8 or 9 mm). I have a torque wrench and tried to find Crow’s foot wrench attachments (a wrench end that can attach to a socket wrench but I could not find any in 7 mm. Seems that most sets start at 10 mm and up. am I missing something in terms of another simple way to ensure I get the right torque setting?? thanks

At what temperature do you tighten the nozzle to 30in lbs? Cold (room temperature), 270 C? Other? Temperature was never mentioned, only “technique”. And the “tighten to 30in lbs” was mentioned as a reply from somebody in support. I have the right size torque wrench, I want to replace the nozzle correctly by specificaitons.

Note: 30 INCH POUNDS!!! Not 30 FOOT POUNDS!! This is not the cylinder head on your car engine!

Pete

I’ve never tried to torque to the 30ft/lb. Just snug the nozzle at extrusion temp (250C). The brass is soft, so be careful not to overtighten.

LOL :unamused: . did not even notice the units. just finished replacing the control arms in my car and had foot pounds in my head. will need to get a torque wrench for inch/lbs. think Harbor Freight has a $20 one.

BTW, I posted earlier and had no response so maybe you know Pete, what attachment to the torque wrench do you use for the nozzle. The nozzle wont take a 7 mm socket. And I could not find a 7 mm crow’s wrench with drive attachment to the torque wrench. All crow wrench online start at 10 mm. So what are you attaching to the torque wrench to grab onto the nozzle. thanks

Sorry, I can’t help with that. Remember, a crow’s foot changes the effective length of the wrench, thus changing the torque you get for a given reading/setting.

pete

If you want to avoid all the hassle with replacing the Hexagon nozzle, buy an E3D nozzle instead. The threads are the same and the nozzle is a little longer so it tightens against the heat brake instead of the heater block. No crows feet, no torque wrenches… nothing.

Heat the hotend to 160 C, hold the heater block with a wrench or pliers and remove the old nozzle. Install the new nozzle until it contacts the heat brake. Lightly tighten it. Heat the hotend to your highest print temperature. Lightly tighten the nozzle again. Adjust you Z end stop or offset to accommodate the slightly longer nozzle. Print happily!

I couldn’t agree more. And while you’re at it, spend a few buck more on the hardened steel ones and you’re done for the rest of your printer’s life! Read up on this topic for gcode and z_offset details https://forum.lulzbot.com/t/replacement-nozzles-for-the-mini/3920/1

What about the micro-Swiss nozzles. Anyone has good success with them? They make hardened 3 mm for the Lulzbots

I have had great luck with Micro Swiss Nozzles, they are pretty much a swap out replacement from what I have found.

In Cura, aside from changing the nozzle size, are there any other configurations you need to make? Like do you need to reduce the flow rate for the filament? Or is Cura smart enough to figure that out for me?

Thanks,

That’s exactly what the nozzle size setting is for.

I put in a new hotend assembly, which comes with a .35mm nozzle. A developer edition Cura threw up some red flags about a new printer head — and it won’t say when you’ve successfully updated firmware.

There are some things that you might need to dig through in Cura/Octoprint, beyond just changing your nozzle size. I think your Wall Thickness will need to change to a multiple of your new nozzle size.

My experience is mixed so far. I printed some numbers on a dial, and the numbers looked nice and thick with .5mm…but with a .35mm nozzle, there were gaps within the numbers and the numbers were very thin. Might have to go back and tell Blender to pretend I have a .7mm nozzle, so the numbers will come out better. I didn’t see much of a speed hit going to a smaller nozzle.