I am having issues with ABS sometimes sticking to the nozzle and figured I should replace it since I bough it used and have no idea how much it has been used. I went to Lulzbot site and tried to look for a replacement on their site and filtered to only show Mini compatible parts and didn’t find any nozzles. Do the nozzles that are sold for the Taz 6 work on the Mini?
Here you go, Minis and TAZ 6s use the same nozzles: https://itworks3d.com/product/nozzle-hexagon-hotend/
Please note that changing the nozzle voids the warranty on the toolhead
Not applicable in your case, just adding that for anyone with a LulzBot under warranty.
Okay that is good to know, I was looking into possibly selling my Mini and upgrading to a new Taz 6 in the future and though changing out the nozzle was just part of regular maintenance and that they just wore out over time, is that not the case?
Nozzles do wear out over time, and get clogged and need to be cleaned. This is normal wear and tear.
Changing the nozzle does NOT automatically void the warranty on the whole tool head. but any damage you do, or cause to be done by changing the nozzle will not be covered by the warranty. It is very easy to cross-thread the nozzle into the hot end, and this of course would not be covered under warranty.
I did it once, and had to completely remove the heat block and then run a tap thru the whole thing and then it all went back together fine luckily.
I’ve had some issues with the nozzles getting clogged when using PLA and then trying to go back to ABS on occasion. But that is a practice not recommended anyway. I don’t really like the Lulzbot version of the brass nozzles, so i have since switched to these hex style which are easier to remove with metric ratchets as opposed to some sort of wrench (which i dont think i have).
I havn’t had a problem with cross threading, but maybe that’s because i know what i’m doing. Brass threads in aluminum can get cross threaded easily if your not careful. And the nozzle needs to be heated up when replacing the nozzles, but it can be done.
We’ve considered stocking similar nozzles, and do have the .6 hardened Micro Swiss.
There’s some concern about how the longer nozzles don’t sit flat against the heater block. Of course this is ok, as a tight joint between the nozzle’s threaded tube and the heatsink’s threaded is the important thing.
Maybe we should add them, along with a picture of one installed with a “this is normal” caption?
Yeah, I could see that as a concern. You could probably do what you suggest and have an installation guide and “this is normal” caption or you probably could change the design dimensions of the E3D brass nozzles slightly so they would fit flush and have them custom machined somewhere (http://wiki.e3d-online.com/images/3/3a/V6-NOZZLE-ALL.pdf).
I do notice that the Lulzbot R&D guys are experimenting with a new brass nozzle design in the Gladiola dev folder, but i don’t know if i like the idea of a nozzle that long or not.
In a slightly related note, i noticed on the new E3D V6 design files that they are moving away from thermistors that poke into a tiny hole and screw down, and instead are adapting to cartridge-style “plug-n-play” temperature sensors. That seems like a great idea in theory. If that works well i wonder if lulzbot will adapt that idea into future hexagon hotend assemblies. (http://wiki.e3d-online.com/images/a/ab/V6-BLOCK-CARTRIDGE.pdf)
This is true
I’m contemplating replacing the standard Mini nozzle with a e3d hardened steel one. I read up on all the topics about this and I think I can manage. But one thing I wondered wasn’t covered: It seems the thread of the e3d nozzle is a tad longer than the stock one, making it stick out of the heater block a bit, which can be compensated for in the cleaning start g-code.
My question: if I wanted to fully align the nozzle with the heater block, would unscrewing the heat-break from the heaterblock and screwing it a tad deeper in the heat sink be an option? Or is there no spare room on the top of the heat sink?
The longer E3D style nozzle has worked better than the stock nozzle on my Mini. It seals against the heat brake instead of the heater block. That eliminates the fractured nozzle problem that can happen with the stock setup.
On my mini, I did not need to adjust the wipe gcode. It was install and print for me.
I wouldn’t think you need to adjust the g-code for the new nozzle. The bottom of the nozzle will still tap the washer, and the z-offset will adjust it down from there, the same as always. If your nozzle is longer, the end result is that your print-head rides a little higher, not that the nozzle distance above the bed changes.
if the nozzle length were dramatically different, I could maybe see it changing the cooling a bit, since the fan would be higher off the bed, but I imagine the difference would be miniscule or un-measurable for the kinds of changes we are talking about here.
Someone on here used to have an alternate nozzle replacement method that did not require a torque wrench, and was reportedly a very save way of getting it installed properly. I should have copied it down. (I have an appropriate torque wrench, and know how to use it, but would need a custom socket to fit the standard Mini nozzles.)
Does anyone have that description? I think it had something to do with hand-threading the nozzle on while at temperature, but I don;t remember it clearly.
Operations before G29 are affected; i.e., if the nozzle is 2mm longer then the clean/wipe Z coordinates would need to be raised by 2mm or it would dig into the pad too far. Also, the MaxZ is reduced because the head is 2mm higher when the nozzle is at the bed surface – so the slicer should be told about the smaller build envelope, otherwise it would be possible to create gcode that exceeds the MaxZ. Of course neither of those are big issues if it’s only 0.25mm longer.
This might be it:
Suppose the new nozzle sticks out so far (let’s say 5mm) that it plunges too deep into the wiper. The default wiping gcode looks like this:
G1 X45 Y174 F11520 ; move behind scraper G1 Z0 F1200 ; CRITICAL: set Z to height of top of scraper
I could change that to:
G1 X45 Y174 F11520 ; move behind scraper G1 Z5 F1200 ; CRITICAL: set Z to height of top of scraper
… to lift the extruder 5mm on wiping.
But would changing the following line in Marling Configuration.h do the same?
- #define Z_MAX_POS 159 + #define Z_MAX_POS 154
This way, I would only need to reflash the firmware once and could rely on stock Lulzbot profiles in Cura accross updates?
Understood on the g-code adjustments. I’ve got to think further than just the actual leveling and printing.
ScottW, that was the nozzle change description I was thinking about. Sebastian has a link to it in his signatures. I just couldn;t remember the username to look for the signature link. Thanks. (BTW, still want to catch up to you about setting up for g-code editing, once I figure out how to get the appropriate software set up on my Mac)
I agree. Changes to the hardware (and particularly travel limits) are best reflected by changing configuration.h to match. Not only does that compensate the shorter distance from Z-max-endstop down to the wiper, it also maintains the standard starting distance above the washers for the start of G29 probing.
Changing scripts to compensate would work fine, but – as you recognize – you will need to integrate those changes into all future profiles. Further, any previously-sliced gcode files still have the “old” scripts embedded, so you have to be careful to only use gcode files sliced with your “new” scripts.
Perhaps even more important… The latest mini firmware (18.104.22.168 and later) includes a “rewipe/reprobe” feature with its own configuration.h parameters. The Z position of the wiper is significant there, and that cannot be accommodated by the starting gcode! It currently sets Z=-1 for the rewipe (#define Z_REWIPE_PT (Z_MIN_POS + 1)). If you add a nozzle that is 5mm longer and don’t compensate by changing Z_MAX_POS or redefining the Z_REWIPE_PT, then a rewipe sequence is going to drive the nozzle 6mm into the wiper pad.
But is my assumption correct (changing Z_MAX_POS to 154)? I wouldn’t want my nozzle dive one centimeter into the wiper because I had the direction of Z_MAX_POS the wrong way round?
Yes. You want Z_MAX_POS to be the distance between the nozzle and wiper pad when the head is at the upper Z endstop position. A longer nozzle decreases that distance.
Example… If you hit the upper Z endstop with Z_MAX_POS=159, then commanded a move to Z=0, it would move downward 159mm. If you hit the upper endstop with Z_MAX_POS=154, then commanded a move to Z=0, it would move downward 154mm. That’s what you would want if your nozzle was 5mm longer than stock.
Am I correct in assuming that I could achieve the same without rebuilding the firmware using:
M206 Z-5 M500
Took me a while to get the sign of Z offset correct. I experimented a little observing the extruder height and this seems correct for a nozzle that sticks out 5mm compared to an original.
Setting home_offset via M206 Z-5 should work fine. It will be added to Z when homed, so after homing to Z_Max_pos=159, the Z coordinate would effectively be offset to Z=154. All subsequent Z positioning should honor that offset.
I say should, because I have never used M206 so I don’t know if there are any potential issues.